/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ │vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│ ╞══════════════════════════════════════════════════════════════════════════════╡ │ Copyright 2020 Justine Alexandra Roberts Tunney │ │ │ │ This program is free software; you can redistribute it and/or modify │ │ it under the terms of the GNU General Public License as published by │ │ the Free Software Foundation; version 2 of the License. │ │ │ │ This program is distributed in the hope that it will be useful, but │ │ WITHOUT ANY WARRANTY; without even the implied warranty of │ │ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │ │ General Public License for more details. │ │ │ │ You should have received a copy of the GNU General Public License │ │ along with this program; if not, write to the Free Software │ │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │ │ 02110-1301 USA │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/assert.h" #include "libc/bits/bits.h" #include "libc/calls/calls.h" #include "libc/conv/conv.h" #include "libc/limits.h" #include "libc/log/gdb.h" #include "libc/log/log.h" #include "libc/macros.h" #include "libc/math.h" #include "libc/mem/mem.h" #include "libc/nexgen32e/x86feature.h" #include "libc/runtime/runtime.h" #include "libc/stdio/stdio.h" #include "libc/str/str.h" #include "libc/x/x.h" #include "third_party/stb/internal.h" #include "third_party/stb/stb_image.h" asm(".ident\t\"\\n\\n\ stb_image (Public Domain)\\n\ Credit: Sean Barrett, et al.\\n\ http://nothings.org/stb\""); #ifndef STBI_REALLOC_SIZED #define STBI_REALLOC_SIZED(p, oldsz, newsz) realloc(p, newsz) #endif // stbi__context structure is our basic context used by all images, so it // contains all the IO context, plus some basic image information typedef struct { uint32_t img_x, img_y; int img_n, img_out_n; stbi_io_callbacks io; void *io_user_data; int read_from_callbacks; int buflen; unsigned char buffer_start[128]; unsigned char *img_buffer, *img_buffer_end; unsigned char *img_buffer_original, *img_buffer_original_end; } stbi__context; static const unsigned char kPngSig[8] = {137, 80, 78, 71, 13, 10, 26, 10}; static void stbi__refill_buffer(stbi__context *s); // initialize a memory-decode context static void stbi__start_mem(stbi__context *s, unsigned char const *buffer, int len) { s->io.read = NULL; s->read_from_callbacks = 0; s->img_buffer = s->img_buffer_original = (unsigned char *)buffer; s->img_buffer_end = s->img_buffer_original_end = (unsigned char *)buffer + len; } // initialize a callback-based context static void stbi__start_callbacks(stbi__context *s, stbi_io_callbacks *c, void *user) { s->io = *c; s->io_user_data = user; s->buflen = sizeof(s->buffer_start); s->read_from_callbacks = 1; s->img_buffer_original = s->buffer_start; stbi__refill_buffer(s); s->img_buffer_original_end = s->img_buffer_end; } static int stbi__stdio_read(void *user, char *data, int size) { return fread(data, 1, size, user); } static void stbi__stdio_skip(void *user, int n) { fseek(user, n, SEEK_CUR); } static int stbi__stdio_eof(void *user) { return feof(user); } static stbi_io_callbacks stbi__stdio_callbacks = { stbi__stdio_read, stbi__stdio_skip, stbi__stdio_eof, }; static void stbi__start_file(stbi__context *s, FILE *f) { stbi__start_callbacks(s, &stbi__stdio_callbacks, (void *)f); } static void stbi__rewind(stbi__context *s) { // conceptually rewind SHOULD rewind to the beginning of the stream, // but we just rewind to the beginning of the initial buffer, because // we only use it after doing 'test', which only ever looks at at most 92 // bytes s->img_buffer = s->img_buffer_original; s->img_buffer_end = s->img_buffer_original_end; } enum { STBI_ORDER_RGB, STBI_ORDER_BGR }; typedef struct { int bits_per_channel; int num_channels; } stbi__result_info; static int stbi__jpeg_test(stbi__context *); static void *stbi__jpeg_load(stbi__context *, int *, int *, int *, int, stbi__result_info *); static int stbi__jpeg_info(stbi__context *, int *, int *, int *); static int stbi__png_test(stbi__context *); static void *stbi__png_load(stbi__context *, int *, int *, int *, int, stbi__result_info *); static int stbi__png_info(stbi__context *, int *, int *, int *); static int stbi__png_is16(stbi__context *); static int stbi__gif_test(stbi__context *); static void *stbi__gif_load(stbi__context *, int *, int *, int *, int, stbi__result_info *); static void *stbi__load_gif_main(stbi__context *, int **, int *, int *, int *, int *, int); static int stbi__gif_info(stbi__context *, int *, int *, int *); static int stbi__pnm_test(stbi__context *); static void *stbi__pnm_load(stbi__context *, int *, int *, int *, int, stbi__result_info *); static int stbi__pnm_info(stbi__context *, int *, int *, int *); static const char *stbi__g_failure_reason; static int stbi__vertically_flip_on_load = 0; const char *stbi_failure_reason(void) { return stbi__g_failure_reason; } static int stbi__err(const char *specific_details, const char *general_details) { /* DebugBreak(); */ /* WARNF("%s: %s", general_details, specific_details); */ stbi__g_failure_reason = general_details; return 0; } // stb_image uses ints pervasively, including for offset calculations. // therefore the largest decoded image size we can support with the // current code, even on 64-bit targets, is INT_MAX. this is not a // significant limitation for the intended use case. // // we do, however, need to make sure our size calculations don't // overflow. hence a few helper functions for size calculations that // multiply integers together, making sure that they're non-negative // and no overflow occurs. // return 1 if the sum is valid, 0 on overflow. // negative terms are considered invalid. static int stbi__addsizes_valid(int a, int b) { if (b < 0) return 0; // now 0 <= b <= INT_MAX, hence also // 0 <= INT_MAX - b <= INTMAX. // And "a + b <= INT_MAX" (which might overflow) is the // same as a <= INT_MAX - b (no overflow) return a <= INT_MAX - b; } // returns 1 if the product is valid, 0 on overflow. // negative factors are considered invalid. static int stbi__mul2sizes_valid(int a, int b) { if (a < 0 || b < 0) return 0; if (b == 0) return 1; // mul-by-0 is always safe // portable way to check for no overflows in a*b return a <= INT_MAX / b; } // returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow static int stbi__mad2sizes_valid(int a, int b, int add) { return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a * b, add); } // returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow static int stbi__mad3sizes_valid(int a, int b, int c, int add) { return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a * b, c) && stbi__addsizes_valid(a * b * c, add); } // mallocs with size overflow checking static void *stbi__malloc_mad2(int a, int b, int add) { if (!stbi__mad2sizes_valid(a, b, add)) return NULL; return xmalloc(a * b + add); } static void *stbi__malloc_mad3(int a, int b, int c, int add) { if (!stbi__mad3sizes_valid(a, b, c, add)) return NULL; return xmalloc(a * b * c + add); } #define stbi__errpf(x, y) \ ({ \ stbi__err(x, y); \ NULL; \ }) #define stbi__errpuc(x, y) \ ({ \ stbi__err(x, y); \ NULL; \ }) void stbi_image_free(void *retval_from_stbi_load) { free(retval_from_stbi_load); } void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip) { stbi__vertically_flip_on_load = flag_true_if_should_flip; } static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc) { memset(ri, 0, sizeof(*ri)); ri->bits_per_channel = 8; ri->num_channels = 0; #ifndef STBI_NO_JPEG if (stbi__jpeg_test(s)) return stbi__jpeg_load(s, x, y, comp, req_comp, ri); #endif #ifndef STBI_NO_PNG if (stbi__png_test(s)) return stbi__png_load(s, x, y, comp, req_comp, ri); #endif #ifndef STBI_NO_GIF if (stbi__gif_test(s)) return stbi__gif_load(s, x, y, comp, req_comp, ri); #endif #ifndef STBI_NO_PNM if (stbi__pnm_test(s)) return stbi__pnm_load(s, x, y, comp, req_comp, ri); #endif return stbi__errpuc("unknown image type", "Image not of any known type, or corrupt"); } unsigned char *stbi__convert_16_to_8(uint16_t *orig, int w, int h, int channels) { int i; int img_len = w * h * channels; unsigned char *reduced = xmalloc(img_len); for (i = 0; i < img_len; ++i) { // top half of each byte is sufficient // approx of 16->8 bit scaling reduced[i] = (orig[i] >> 8) & 0xff; } free(orig); return reduced; } uint16_t *stbi__convert_8_to_16(unsigned char *orig, int w, int h, int channels) { int i; int img_len = w * h * channels; uint16_t *enlarged = xmalloc(img_len * 2); for (i = 0; i < img_len; ++i) { // replicate to high and low byte, maps 0->0, 255->0xffff enlarged[i] = (uint16_t)((orig[i] << 8) + orig[i]); } free(orig); return enlarged; } static void stbi__vertical_flip(void *image, int w, int h, int bytes_per_pixel) { int row; size_t bytes_per_row, bytes_left, bytes_copy; unsigned char *row0, *row1, *bytes, temp[2048]; bytes = image; bytes_per_row = bytes_per_pixel * w; for (row = 0; row < (h >> 1); row++) { row0 = bytes + row * bytes_per_row; row1 = bytes + (h - row - 1) * bytes_per_row; // swap row0 with row1 bytes_left = bytes_per_row; while (bytes_left) { bytes_copy = bytes_left < sizeof(temp) ? bytes_left : sizeof(temp); memcpy(temp, row0, bytes_copy); memcpy(row0, row1, bytes_copy); memcpy(row1, temp, bytes_copy); row0 += bytes_copy; row1 += bytes_copy; bytes_left -= bytes_copy; } } } static void stbi__vertical_flip_slices(void *image, int w, int h, int z, int bytes_per_pixel) { unsigned char *bytes; int slice, slice_size; bytes = image; slice_size = w * h * bytes_per_pixel; for (slice = 0; slice < z; ++slice) { stbi__vertical_flip(bytes, w, h, bytes_per_pixel); bytes += slice_size; } } static unsigned char *stbi__load_and_postprocess_8bit(stbi__context *s, int *x, int *y, int *comp, int req_comp) { void *result; stbi__result_info ri; result = stbi__load_main(s, x, y, comp, req_comp, &ri, 8); if (result == NULL) return NULL; if (ri.bits_per_channel != 8) { assert(ri.bits_per_channel == 16); result = stbi__convert_16_to_8(result, *x, *y, req_comp == 0 ? *comp : req_comp); ri.bits_per_channel = 8; } // @TODO: move stbi__convert_format to here if (stbi__vertically_flip_on_load) { int channels = req_comp ? req_comp : *comp; stbi__vertical_flip(result, *x, *y, channels * sizeof(unsigned char)); } return (unsigned char *)result; } static uint16_t *stbi__load_and_postprocess_16bit(stbi__context *s, int *x, int *y, int *comp, int req_comp) { stbi__result_info ri; void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 16); if (result == NULL) return NULL; if (ri.bits_per_channel != 16) { assert(ri.bits_per_channel == 8); result = stbi__convert_8_to_16((unsigned char *)result, *x, *y, req_comp == 0 ? *comp : req_comp); ri.bits_per_channel = 16; } // @TODO: move stbi__convert_format16 to here // @TODO: special case RGB-to-Y (and RGBA-to-YA) for 8-bit-to-16-bit case to // keep more precision if (stbi__vertically_flip_on_load) { int channels = req_comp ? req_comp : *comp; stbi__vertical_flip(result, *x, *y, channels * sizeof(uint16_t)); } return (uint16_t *)result; } static FILE *stbi__fopen(char const *filename, char const *mode) { return fopen(filename, mode); } unsigned char *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp) { FILE *f = stbi__fopen(filename, "rb"); unsigned char *result; if (!f) return stbi__errpuc("can't fopen", "Unable to open file"); result = stbi_load_from_file(f, x, y, comp, req_comp); fclose(f); return result; } unsigned char *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp) { unsigned char *result; stbi__context s; stbi__start_file(&s, f); result = stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp); if (result) { // need to 'unget' all the characters in the IO buffer fseek(f, -(int)(s.img_buffer_end - s.img_buffer), SEEK_CUR); } return result; } uint16_t *stbi_load_from_file_16(FILE *f, int *x, int *y, int *comp, int req_comp) { uint16_t *result; stbi__context s; stbi__start_file(&s, f); result = stbi__load_and_postprocess_16bit(&s, x, y, comp, req_comp); if (result) { // need to 'unget' all the characters in the IO buffer fseek(f, -(int)(s.img_buffer_end - s.img_buffer), SEEK_CUR); } return result; } unsigned short *stbi_load_16(char const *filename, int *x, int *y, int *comp, int req_comp) { FILE *f = stbi__fopen(filename, "rb"); uint16_t *result; if (!f) return stbi__errpuc("can't fopen", "Unable to open file"); result = stbi_load_from_file_16(f, x, y, comp, req_comp); fclose(f); return result; } unsigned short *stbi_load_16_from_memory(unsigned char const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels) { stbi__context s; stbi__start_mem(&s, buffer, len); return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels); } unsigned short *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels) { stbi__context s; stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user); return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels); } unsigned char *stbi_load_from_memory(unsigned char const *buffer, int len, int *x, int *y, int *comp, int req_comp) { stbi__context s; stbi__start_mem(&s, buffer, len); return stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp); } unsigned char *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp) { stbi__context s; stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user); return stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp); } unsigned char *stbi_load_gif_from_memory(unsigned char const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp) { unsigned char *result; stbi__context s; stbi__start_mem(&s, buffer, len); result = (unsigned char *)stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp); if (stbi__vertically_flip_on_load) { stbi__vertical_flip_slices(result, *x, *y, *z, *comp); } return result; } enum { STBI__SCAN_load = 0, STBI__SCAN_type, STBI__SCAN_header }; static void stbi__refill_buffer(stbi__context *s) { int n = (s->io.read)(s->io_user_data, (char *)s->buffer_start, s->buflen); if (n == 0) { // at end of file, treat same as if from memory, but need to handle case // where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file s->read_from_callbacks = 0; s->img_buffer = s->buffer_start; s->img_buffer_end = s->buffer_start + 1; *s->img_buffer = 0; } else { s->img_buffer = s->buffer_start; s->img_buffer_end = s->buffer_start + n; } } forceinline unsigned char stbi__get8(stbi__context *s) { if (s->img_buffer < s->img_buffer_end) return *s->img_buffer++; if (s->read_from_callbacks) { stbi__refill_buffer(s); return *s->img_buffer++; } return 0; } forceinline int stbi__at_eof(stbi__context *s) { if (s->io.read) { if (!(s->io.eof)(s->io_user_data)) return 0; // if feof() is true, check if buffer = end // special case: we've only got the special 0 character at the end if (s->read_from_callbacks == 0) return 1; } return s->img_buffer >= s->img_buffer_end; } static void stbi__skip(stbi__context *s, int n) { if (n < 0) { s->img_buffer = s->img_buffer_end; return; } if (s->io.read) { int blen = (int)(s->img_buffer_end - s->img_buffer); if (blen < n) { s->img_buffer = s->img_buffer_end; (s->io.skip)(s->io_user_data, n - blen); return; } } s->img_buffer += n; } static int stbi__getn(stbi__context *s, unsigned char *buffer, int n) { if (s->io.read) { int blen = (int)(s->img_buffer_end - s->img_buffer); if (blen < n) { int res, count; memcpy(buffer, s->img_buffer, blen); count = (s->io.read)(s->io_user_data, (char *)buffer + blen, n - blen); res = (count == (n - blen)); s->img_buffer = s->img_buffer_end; return res; } } if (s->img_buffer + n <= s->img_buffer_end) { memcpy(buffer, s->img_buffer, n); s->img_buffer += n; return 1; } else { return 0; } } static int stbi__get16le(stbi__context *s) { int z = stbi__get8(s); return z + (stbi__get8(s) << 8); } static int stbi__get16be(stbi__context *s) { int z = stbi__get8(s); return (z << 8) + stbi__get8(s); } static uint32_t stbi__get32be(stbi__context *s) { uint32_t z = stbi__get16be(s); return (z << 16) + stbi__get16be(s); } #define STBI__BYTECAST(x) \ ((unsigned char)((x)&255)) // truncate int to byte without warnings ////////////////////////////////////////////////////////////////////////////// // // generic converter from built-in img_n to req_comp // individual types do this automatically as much as possible (e.g. jpeg // does all cases internally since it needs to colorspace convert anyway, // and it never has alpha, so very few cases ). png can automatically // interleave an alpha=255 channel, but falls back to this for other cases // // assume data buffer is malloced, so malloc a new one and free that one // only failure mode is malloc failing static unsigned char stbi__compute_y(int r, int g, int b) { return (unsigned char)(((r * 77) + (g * 150) + (29 * b)) >> 8); } static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y) { int i, j; unsigned char *good, *src, *dest; if (req_comp == img_n) return data; assert(req_comp >= 1 && req_comp <= 4); good = stbi__malloc_mad3(req_comp, x, y, 0); for (j = 0; j < (int)y; ++j) { src = data + j * x * img_n; dest = good + j * x * req_comp; #define STBI__COMBO(a, b) ((a)*8 + (b)) #define STBI__CASE(a, b) \ case STBI__COMBO(a, b): \ for (i = x - 1; i >= 0; --i, src += a, dest += b) // convert source image with img_n components to one with req_comp // components; avoid switch per pixel, so use switch per scanline and // massive macros switch (STBI__COMBO(img_n, req_comp)) { STBI__CASE(1, 2) { dest[0] = src[0]; dest[1] = 255; } break; STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; } break; STBI__CASE(1, 4) { dest[0] = dest[1] = dest[2] = src[0]; dest[3] = 255; } break; STBI__CASE(2, 1) { dest[0] = src[0]; } break; STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; } break; STBI__CASE(2, 4) { dest[0] = dest[1] = dest[2] = src[0]; dest[3] = src[1]; } break; STBI__CASE(3, 4) { dest[0] = src[0]; dest[1] = src[1]; dest[2] = src[2]; dest[3] = 255; } break; STBI__CASE(3, 1) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); } break; STBI__CASE(3, 2) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); dest[1] = 255; } break; STBI__CASE(4, 1) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); } break; STBI__CASE(4, 2) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); dest[1] = src[3]; } break; STBI__CASE(4, 3) { dest[0] = src[0]; dest[1] = src[1]; dest[2] = src[2]; } break; default: assert(0); } #undef STBI__CASE } free(data); return good; } static uint16_t stbi__compute_y_16(int r, int g, int b) { return (uint16_t)(((r * 77) + (g * 150) + (29 * b)) >> 8); } static uint16_t *stbi__convert_format16(uint16_t *data, int img_n, int req_comp, unsigned int x, unsigned int y) { int i, j; uint16_t *good; if (req_comp == img_n) return data; assert(req_comp >= 1 && req_comp <= 4); good = xmalloc(req_comp * x * y * 2); for (j = 0; j < (int)y; ++j) { uint16_t *src = data + j * x * img_n; uint16_t *dest = good + j * x * req_comp; #define STBI__COMBO(a, b) ((a)*8 + (b)) #define STBI__CASE(a, b) \ case STBI__COMBO(a, b): \ for (i = x - 1; i >= 0; --i, src += a, dest += b) // convert source image with img_n components to one with req_comp // components; avoid switch per pixel, so use switch per scanline and // massive macros switch (STBI__COMBO(img_n, req_comp)) { STBI__CASE(1, 2) { dest[0] = src[0]; dest[1] = 0xffff; } break; STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; } break; STBI__CASE(1, 4) { dest[0] = dest[1] = dest[2] = src[0]; dest[3] = 0xffff; } break; STBI__CASE(2, 1) { dest[0] = src[0]; } break; STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; } break; STBI__CASE(2, 4) { dest[0] = dest[1] = dest[2] = src[0]; dest[3] = src[1]; } break; STBI__CASE(3, 4) { dest[0] = src[0]; dest[1] = src[1]; dest[2] = src[2]; dest[3] = 0xffff; } break; STBI__CASE(3, 1) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); } break; STBI__CASE(3, 2) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); dest[1] = 0xffff; } break; STBI__CASE(4, 1) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); } break; STBI__CASE(4, 2) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); dest[1] = src[3]; } break; STBI__CASE(4, 3) { dest[0] = src[0]; dest[1] = src[1]; dest[2] = src[2]; } break; default: assert(0); } #undef STBI__CASE } free(data); return good; } ////////////////////////////////////////////////////////////////////////////// // // "baseline" JPEG/JFIF decoder // // simple implementation // - doesn't support delayed output of y-dimension // - simple interface (only one output format: 8-bit interleaved RGB) // - doesn't try to recover corrupt jpegs // - doesn't allow partial loading, loading multiple at once // - still fast on x86 (copying globals into locals doesn't help x86) // - allocates lots of intermediate memory (full size of all components) // - non-interleaved case requires this anyway // - allows good upsampling (see next) // high-quality // - upsampled channels are bilinearly interpolated, even across blocks // - quality integer IDCT derived from IJG's 'slow' // performance // - fast huffman; reasonable integer IDCT // - some SIMD kernels for common paths on targets with SSE2/NEON // - uses a lot of intermediate memory, could cache poorly // huffman decoding acceleration #define FAST_BITS 9 // larger handles more cases; smaller stomps less cache typedef struct { unsigned char fast[1 << FAST_BITS]; // weirdly, repacking this into AoS is a 10% speed loss, instead of a win uint16_t code[256]; unsigned char values[256]; unsigned char size[257]; unsigned int maxcode[18]; int delta[17]; // old 'firstsymbol' - old 'firstcode' } stbi__huffman; typedef struct { stbi__context *s; stbi__huffman huff_dc[4]; stbi__huffman huff_ac[4]; uint16_t dequant[4][64]; int16_t fast_ac[4][1 << FAST_BITS]; // sizes for components, interleaved MCUs int img_h_max, img_v_max; int img_mcu_x, img_mcu_y; int img_mcu_w, img_mcu_h; // definition of jpeg image component struct { int id; int h, v; int tq; int hd, ha; int dc_pred; int x, y, w2, h2; unsigned char *data; unsigned char *linebuf; short *coeff; // progressive only int coeff_w, coeff_h; // number of 8x8 coefficient blocks } img_comp[4]; uint32_t code_buffer; // jpeg entropy-coded buffer int code_bits; // number of valid bits unsigned char marker; // marker seen while filling entropy buffer int nomore; // flag if we saw a marker so must stop int progressive; int spec_start; int spec_end; int succ_high; int succ_low; int eob_run; int jfif; int app14_color_transform; // Adobe APP14 tag int rgb; int scan_n, order[4]; int restart_interval, todo; // kernels unsigned char *(*resample_row_hv_2_kernel)(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs); } stbi__jpeg; static int stbi__build_huffman(stbi__huffman *h, int *count) { int i, j, k = 0; unsigned int code; // build size list for each symbol (from JPEG spec) for (i = 0; i < 16; ++i) for (j = 0; j < count[i]; ++j) h->size[k++] = (unsigned char)(i + 1); h->size[k] = 0; // compute actual symbols (from jpeg spec) code = 0; k = 0; for (j = 1; j <= 16; ++j) { // compute delta to add to code to compute symbol id h->delta[j] = k - code; if (h->size[k] == j) { while (h->size[k] == j) h->code[k++] = (uint16_t)(code++); if (code - 1 >= (1u << j)) { return stbi__err("bad code lengths", "Corrupt JPEG"); } } // compute largest code + 1 for this size, preshifted as needed later h->maxcode[j] = code << (16 - j); code <<= 1; } h->maxcode[j] = 0xffffffff; // build non-spec acceleration table; 255 is flag for not-accelerated memset(h->fast, 255, 1 << FAST_BITS); for (i = 0; i < k; ++i) { int s = h->size[i]; if (s <= FAST_BITS) { int c = h->code[i] << (FAST_BITS - s); int m = 1 << (FAST_BITS - s); for (j = 0; j < m; ++j) { h->fast[c + j] = (unsigned char)i; } } } return 1; } // build a table that decodes both magnitude and value of small ACs in // one go. static void stbi__build_fast_ac(int16_t *fast_ac, stbi__huffman *h) { int i; for (i = 0; i < (1 << FAST_BITS); ++i) { unsigned char fast = h->fast[i]; fast_ac[i] = 0; if (fast < 255) { int rs = h->values[fast]; int run = (rs >> 4) & 15; int magbits = rs & 15; int len = h->size[fast]; if (magbits && len + magbits <= FAST_BITS) { // magnitude code followed by receive_extend code int k = ((i << len) & ((1 << FAST_BITS) - 1)) >> (FAST_BITS - magbits); int m = 1 << (magbits - 1); if (k < m) k += (~0U << magbits) + 1; // if the result is small enough, we can fit it in fast_ac table if (k >= -128 && k <= 127) fast_ac[i] = (int16_t)((k * 256) + (run * 16) + (len + magbits)); } } } } static void stbi__grow_buffer_unsafe(stbi__jpeg *j) { do { unsigned b = j->nomore ? 0 : stbi__get8(j->s); if (b == 0xff) { int c = stbi__get8(j->s); while (c == 0xff) c = stbi__get8(j->s); // consume fill bytes if (c != 0) { j->marker = (unsigned char)c; j->nomore = 1; return; } } j->code_buffer |= b << (24 - j->code_bits); j->code_bits += 8; } while (j->code_bits <= 24); } // (1 << n) - 1 static const uint32_t stbi__bmask[17] = {0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535}; // decode a jpeg huffman value from the bitstream forceinline int stbi__jpeg_huff_decode(stbi__jpeg *j, stbi__huffman *h) { unsigned int temp; int c, k; if (j->code_bits < 16) stbi__grow_buffer_unsafe(j); // look at the top FAST_BITS and determine what symbol ID it is, // if the code is <= FAST_BITS c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1); k = h->fast[c]; if (k < 255) { int s = h->size[k]; if (s > j->code_bits) return -1; j->code_buffer <<= s; j->code_bits -= s; return h->values[k]; } // naive test is to shift the code_buffer down so k bits are // valid, then test against maxcode. To speed this up, we've // preshifted maxcode left so that it has (16-k) 0s at the // end; in other words, regardless of the number of bits, it // wants to be compared against something shifted to have 16; // that way we don't need to shift inside the loop. temp = j->code_buffer >> 16; for (k = FAST_BITS + 1;; ++k) if (temp < h->maxcode[k]) break; if (k == 17) { // error! code not found j->code_bits -= 16; return -1; } if (k > j->code_bits) return -1; // convert the huffman code to the symbol id c = ((j->code_buffer >> (32 - k)) & stbi__bmask[k]) + h->delta[k]; assert((((j->code_buffer) >> (32 - h->size[c])) & stbi__bmask[h->size[c]]) == h->code[c]); // convert the id to a symbol j->code_bits -= k; j->code_buffer <<= k; return h->values[c]; } // bias[n] = (-1<code_bits < n) stbi__grow_buffer_unsafe(j); sgn = (int32_t)j->code_buffer >> 31; // sign bit is always in MSB k = ROL(j->code_buffer, n); assert(n >= 0 && n < (int)(sizeof(stbi__bmask) / sizeof(*stbi__bmask))); j->code_buffer = k & ~stbi__bmask[n]; k &= stbi__bmask[n]; j->code_bits -= n; return k + (stbi__jbias[n] & ~sgn); } // get some unsigned bits forceinline int stbi__jpeg_get_bits(stbi__jpeg *j, int n) { unsigned int k; if (j->code_bits < n) stbi__grow_buffer_unsafe(j); k = ROL(j->code_buffer, n); j->code_buffer = k & ~stbi__bmask[n]; k &= stbi__bmask[n]; j->code_bits -= n; return k; } forceinline int stbi__jpeg_get_bit(stbi__jpeg *j) { unsigned int k; if (j->code_bits < 1) stbi__grow_buffer_unsafe(j); k = j->code_buffer; j->code_buffer <<= 1; --j->code_bits; return k & 0x80000000; } // given a value that's at position X in the zigzag stream, // where does it appear in the 8x8 matrix coded as row-major? static const unsigned char stbi__jpeg_dezigzag[64 + 15] = { 0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63, // let corrupt input sample past end 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63}; // decode one 64-entry block static optimizespeed int stbi__jpeg_decode_block(stbi__jpeg *j, short data[64], stbi__huffman *hdc, stbi__huffman *hac, int16_t *fac, int b, uint16_t *dequant) { unsigned int zig; int diff, dc, k, t, c, r, s, rs; if (j->code_bits < 16) stbi__grow_buffer_unsafe(j); t = stbi__jpeg_huff_decode(j, hdc); if (t < 0) return stbi__err("bad huffman code", "Corrupt JPEG"); // 0 all the ac values now so we can do it 32-bits at a time memset(data, 0, 64 * sizeof(data[0])); diff = t ? stbi__extend_receive(j, t) : 0; dc = j->img_comp[b].dc_pred + diff; j->img_comp[b].dc_pred = dc; data[0] = (short)(dc * dequant[0]); // decode AC components, see JPEG spec k = 1; do { if (j->code_bits < 16) stbi__grow_buffer_unsafe(j); c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1); r = fac[c]; if (r) { // fast-AC path k += (r >> 4) & 15; // run s = r & 15; // combined length j->code_buffer <<= s; j->code_bits -= s; // decode into unzigzag'd location zig = stbi__jpeg_dezigzag[k++]; data[zig] = (short)((r >> 8) * dequant[zig]); } else { rs = stbi__jpeg_huff_decode(j, hac); if (rs < 0) return stbi__err("bad huffman code", "Corrupt JPEG"); s = rs & 15; r = rs >> 4; if (s == 0) { if (rs != 0xf0) break; // end block k += 16; } else { k += r; // decode into unzigzag'd location zig = stbi__jpeg_dezigzag[k++]; data[zig] = (short)(stbi__extend_receive(j, s) * dequant[zig]); } } } while (k < 64); return 1; } static int stbi__jpeg_decode_block_prog_dc(stbi__jpeg *j, short data[64], stbi__huffman *hdc, int b) { int t; short s; int diff, dc; if (j->spec_end != 0) { return stbi__err("can't merge dc and ac", "Corrupt JPEG"); } if (j->code_bits < 16) stbi__grow_buffer_unsafe(j); if (j->succ_high == 0) { // first scan for DC coefficient, must be first memset(data, 0, 64 * sizeof(data[0])); // 0 all the ac values now t = stbi__jpeg_huff_decode(j, hdc); diff = t ? stbi__extend_receive(j, t) : 0; dc = j->img_comp[b].dc_pred + diff; j->img_comp[b].dc_pred = dc; s = dc; s *= 1u << j->succ_low; data[0] = s; /* (short)(dc << j->succ_low); */ } else { // refinement scan for DC coefficient if (stbi__jpeg_get_bit(j)) data[0] += (short)(1 << j->succ_low); } return 1; } // @OPTIMIZE: store non-zigzagged during the decode passes, // and only de-zigzag when dequantizing static int stbi__jpeg_decode_block_prog_ac(stbi__jpeg *j, short data[64], stbi__huffman *hac, int16_t *fac) { short bit; unsigned zig; int k, c, r, s, rs, shift; if (j->spec_start == 0) { return stbi__err("can't merge dc and ac", "Corrupt JPEG"); } if (j->succ_high == 0) { shift = j->succ_low; if (j->eob_run) { --j->eob_run; return 1; } k = j->spec_start; do { if (j->code_bits < 16) stbi__grow_buffer_unsafe(j); c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1); r = fac[c]; if (r) { // fast-AC path k += (r >> 4) & 15; // run s = r & 15; // combined length j->code_buffer <<= s; j->code_bits -= s; zig = stbi__jpeg_dezigzag[k++]; data[zig] = (r / 256) * (1u << shift); } else { rs = stbi__jpeg_huff_decode(j, hac); if (rs < 0) return stbi__err("bad huffman code", "Corrupt JPEG"); s = rs & 15; r = rs >> 4; if (s == 0) { if (r < 15) { j->eob_run = (1 << r); if (r) j->eob_run += stbi__jpeg_get_bits(j, r); --j->eob_run; break; } k += 16; } else { k += r; zig = stbi__jpeg_dezigzag[k++]; data[zig] = stbi__extend_receive(j, s) * (1u << shift); } } } while (k <= j->spec_end); } else { // refinement scan for these AC coefficients bit = (short)(1 << j->succ_low); if (j->eob_run) { --j->eob_run; for (k = j->spec_start; k <= j->spec_end; ++k) { short *p = &data[stbi__jpeg_dezigzag[k]]; if (*p != 0) if (stbi__jpeg_get_bit(j)) if ((*p & bit) == 0) { if (*p > 0) *p += bit; else *p -= bit; } } } else { k = j->spec_start; do { rs = stbi__jpeg_huff_decode(j, hac); if (rs < 0) return stbi__err("bad huffman code", "Corrupt JPEG"); s = rs & 15; r = rs >> 4; if (s == 0) { if (r < 15) { j->eob_run = (1 << r) - 1; if (r) j->eob_run += stbi__jpeg_get_bits(j, r); r = 64; // force end of block } else { // r=15 s=0 should write 16 0s, so we just do // a run of 15 0s and then write s (which is 0), // so we don't have to do anything special here } } else { if (s != 1) return stbi__err("bad huffman code", "Corrupt JPEG"); // sign bit if (stbi__jpeg_get_bit(j)) { s = bit; } else { s = -bit; } } // advance by r while (k <= j->spec_end) { short *p = &data[stbi__jpeg_dezigzag[k++]]; if (*p != 0) { if (stbi__jpeg_get_bit(j)) if ((*p & bit) == 0) { if (*p > 0) *p += bit; else *p -= bit; } } else { if (r == 0) { *p = (short)s; break; } --r; } } } while (k <= j->spec_end); } } return 1; } // take a -128..127 value and stbi__clamp it and convert to 0..255 forceinline unsigned char stbi__clamp(int x) { // trick to use a single test to catch both cases if ((unsigned int)x > 255) { if (x < 0) return 0; if (x > 255) return 255; } return (unsigned char)x; } #define STBI__MARKER_none 0xff // if there's a pending marker from the entropy stream, return that // otherwise, fetch from the stream and get a marker. if there's no // marker, return 0xff, which is never a valid marker value static unsigned char stbi__get_marker(stbi__jpeg *j) { unsigned char x; if (j->marker != STBI__MARKER_none) { x = j->marker; j->marker = STBI__MARKER_none; return x; } x = stbi__get8(j->s); if (x != 0xff) return STBI__MARKER_none; while (x == 0xff) x = stbi__get8(j->s); // consume repeated 0xff fill bytes return x; } // in each scan, we'll have scan_n components, and the order // of the components is specified by order[] #define STBI__RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7) // after a restart interval, stbi__jpeg_reset the entropy decoder and // the dc prediction static void stbi__jpeg_reset(stbi__jpeg *j) { j->code_bits = 0; j->code_buffer = 0; j->nomore = 0; j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = j->img_comp[3].dc_pred = 0; j->marker = STBI__MARKER_none; j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff; j->eob_run = 0; // no more than 1<<31 MCUs if no restart_interal? that's plenty safe, // since we don't even allow 1<<30 pixels } static int stbi__parse_entropy_coded_data(stbi__jpeg *z) { stbi__jpeg_reset(z); if (!z->progressive) { if (z->scan_n == 1) { int i, j; short data[64] aligned(16); int n = z->order[0]; // non-interleaved data, we just need to process one block at a time, // in trivial scanline order // number of blocks to do just depends on how many actual "pixels" this // component has, independent of interleaved MCU blocking and such int w = (z->img_comp[n].x + 7) >> 3; int h = (z->img_comp[n].y + 7) >> 3; for (j = 0; j < h; ++j) { for (i = 0; i < w; ++i) { int ha = z->img_comp[n].ha; if (!stbi__jpeg_decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0; stbi__idct_simd$sse( z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data); // every data block is an MCU, so countdown the restart interval if (--z->todo <= 0) { if (z->code_bits < 24) stbi__grow_buffer_unsafe(z); // if it's NOT a restart, then just bail, so we get corrupt data // rather than no data if (!STBI__RESTART(z->marker)) return 1; stbi__jpeg_reset(z); } } } return 1; } else { // interleaved int i, j, k, x, y; short data[64] aligned(16); for (j = 0; j < z->img_mcu_y; ++j) { for (i = 0; i < z->img_mcu_x; ++i) { // scan an interleaved mcu... process scan_n components in order for (k = 0; k < z->scan_n; ++k) { int n = z->order[k]; // scan out an mcu's worth of this component; that's just determined // by the basic H and V specified for the component for (y = 0; y < z->img_comp[n].v; ++y) { for (x = 0; x < z->img_comp[n].h; ++x) { int x2 = (i * z->img_comp[n].h + x) * 8; int y2 = (j * z->img_comp[n].v + y) * 8; int ha = z->img_comp[n].ha; if (!stbi__jpeg_decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0; stbi__idct_simd$sse( z->img_comp[n].data + z->img_comp[n].w2 * y2 + x2, z->img_comp[n].w2, data); } } } // after all interleaved components, that's an interleaved MCU, // so now count down the restart interval if (--z->todo <= 0) { if (z->code_bits < 24) stbi__grow_buffer_unsafe(z); if (!STBI__RESTART(z->marker)) return 1; stbi__jpeg_reset(z); } } } return 1; } } else { if (z->scan_n == 1) { int i, j; int n = z->order[0]; // non-interleaved data, we just need to process one block at a time, // in trivial scanline order // number of blocks to do just depends on how many actual "pixels" this // component has, independent of interleaved MCU blocking and such int w = (z->img_comp[n].x + 7) >> 3; int h = (z->img_comp[n].y + 7) >> 3; for (j = 0; j < h; ++j) { for (i = 0; i < w; ++i) { short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w); if (z->spec_start == 0) { if (!stbi__jpeg_decode_block_prog_dc( z, data, &z->huff_dc[z->img_comp[n].hd], n)) return 0; } else { int ha = z->img_comp[n].ha; if (!stbi__jpeg_decode_block_prog_ac(z, data, &z->huff_ac[ha], z->fast_ac[ha])) return 0; } // every data block is an MCU, so countdown the restart interval if (--z->todo <= 0) { if (z->code_bits < 24) stbi__grow_buffer_unsafe(z); if (!STBI__RESTART(z->marker)) return 1; stbi__jpeg_reset(z); } } } return 1; } else { // interleaved int i, j, k, x, y; for (j = 0; j < z->img_mcu_y; ++j) { for (i = 0; i < z->img_mcu_x; ++i) { // scan an interleaved mcu... process scan_n components in order for (k = 0; k < z->scan_n; ++k) { int n = z->order[k]; // scan out an mcu's worth of this component; that's just determined // by the basic H and V specified for the component for (y = 0; y < z->img_comp[n].v; ++y) { for (x = 0; x < z->img_comp[n].h; ++x) { int x2 = (i * z->img_comp[n].h + x); int y2 = (j * z->img_comp[n].v + y); short *data = z->img_comp[n].coeff + 64 * (x2 + y2 * z->img_comp[n].coeff_w); if (!stbi__jpeg_decode_block_prog_dc( z, data, &z->huff_dc[z->img_comp[n].hd], n)) return 0; } } } // after all interleaved components, that's an interleaved MCU, // so now count down the restart interval if (--z->todo <= 0) { if (z->code_bits < 24) stbi__grow_buffer_unsafe(z); if (!STBI__RESTART(z->marker)) return 1; stbi__jpeg_reset(z); } } } return 1; } } } static void stbi__jpeg_dequantize(short *data, uint16_t *dequant) { int i; for (i = 0; i < 64; ++i) data[i] *= dequant[i]; } static void stbi__jpeg_finish(stbi__jpeg *z) { if (z->progressive) { // dequantize and idct the data int i, j, n; for (n = 0; n < z->s->img_n; ++n) { int w = (z->img_comp[n].x + 7) >> 3; int h = (z->img_comp[n].y + 7) >> 3; for (j = 0; j < h; ++j) { for (i = 0; i < w; ++i) { short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w); stbi__jpeg_dequantize(data, z->dequant[z->img_comp[n].tq]); stbi__idct_simd$sse( z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data); } } } } } static int stbi__process_marker(stbi__jpeg *z, int m) { int L; switch (m) { case STBI__MARKER_none: // no marker found return stbi__err("expected marker", "Corrupt JPEG"); case 0xDD: // DRI - specify restart interval if (stbi__get16be(z->s) != 4) return stbi__err("bad DRI len", "Corrupt JPEG"); z->restart_interval = stbi__get16be(z->s); return 1; case 0xDB: // DQT - define quantization table L = stbi__get16be(z->s) - 2; while (L > 0) { int q = stbi__get8(z->s); int p = q >> 4, sixteen = (p != 0); int t = q & 15, i; if (p != 0 && p != 1) return stbi__err("bad DQT type", "Corrupt JPEG"); if (t > 3) return stbi__err("bad DQT table", "Corrupt JPEG"); for (i = 0; i < 64; ++i) z->dequant[t][stbi__jpeg_dezigzag[i]] = (uint16_t)(sixteen ? stbi__get16be(z->s) : stbi__get8(z->s)); L -= (sixteen ? 129 : 65); } return L == 0; case 0xC4: // DHT - define huffman table L = stbi__get16be(z->s) - 2; while (L > 0) { unsigned char *v; int sizes[16], i, n = 0; int q = stbi__get8(z->s); int tc = q >> 4; int th = q & 15; if (tc > 1 || th > 3) return stbi__err("bad DHT header", "Corrupt JPEG"); for (i = 0; i < 16; ++i) { sizes[i] = stbi__get8(z->s); n += sizes[i]; } L -= 17; if (tc == 0) { if (!stbi__build_huffman(z->huff_dc + th, sizes)) return 0; v = z->huff_dc[th].values; } else { if (!stbi__build_huffman(z->huff_ac + th, sizes)) return 0; v = z->huff_ac[th].values; } for (i = 0; i < n; ++i) v[i] = stbi__get8(z->s); if (tc != 0) stbi__build_fast_ac(z->fast_ac[th], z->huff_ac + th); L -= n; } return L == 0; } // check for comment block or APP blocks if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) { L = stbi__get16be(z->s); if (L < 2) { if (m == 0xFE) return stbi__err("bad COM len", "Corrupt JPEG"); else return stbi__err("bad APP len", "Corrupt JPEG"); } L -= 2; if (m == 0xE0 && L >= 5) { // JFIF APP0 segment static const unsigned char tag[5] = {'J', 'F', 'I', 'F', '\0'}; int ok = 1; int i; for (i = 0; i < 5; ++i) if (stbi__get8(z->s) != tag[i]) ok = 0; L -= 5; if (ok) z->jfif = 1; } else if (m == 0xEE && L >= 12) { // Adobe APP14 segment static const unsigned char tag[6] = {'A', 'd', 'o', 'b', 'e', '\0'}; int ok = 1; int i; for (i = 0; i < 6; ++i) if (stbi__get8(z->s) != tag[i]) ok = 0; L -= 6; if (ok) { stbi__get8(z->s); // version stbi__get16be(z->s); // flags0 stbi__get16be(z->s); // flags1 z->app14_color_transform = stbi__get8(z->s); // color transform L -= 6; } } stbi__skip(z->s, L); return 1; } return stbi__err("unknown marker", "Corrupt JPEG"); } // after we see SOS static int stbi__process_scan_header(stbi__jpeg *z) { int i; int Ls = stbi__get16be(z->s); z->scan_n = stbi__get8(z->s); if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int)z->s->img_n) return stbi__err("bad SOS component count", "Corrupt JPEG"); if (Ls != 6 + 2 * z->scan_n) return stbi__err("bad SOS len", "Corrupt JPEG"); for (i = 0; i < z->scan_n; ++i) { int id = stbi__get8(z->s), which; int q = stbi__get8(z->s); for (which = 0; which < z->s->img_n; ++which) if (z->img_comp[which].id == id) break; if (which == z->s->img_n) return 0; // no match z->img_comp[which].hd = q >> 4; if (z->img_comp[which].hd > 3) return stbi__err("bad DC huff", "Corrupt JPEG"); z->img_comp[which].ha = q & 15; if (z->img_comp[which].ha > 3) return stbi__err("bad AC huff", "Corrupt JPEG"); z->order[i] = which; } { int aa; z->spec_start = stbi__get8(z->s); z->spec_end = stbi__get8(z->s); // should be 63, but might be 0 aa = stbi__get8(z->s); z->succ_high = (aa >> 4); z->succ_low = (aa & 15); if (z->progressive) { if (z->spec_start > 63 || z->spec_end > 63 || z->spec_start > z->spec_end || z->succ_high > 13 || z->succ_low > 13) return stbi__err("bad SOS", "Corrupt JPEG"); } else { if (z->spec_start != 0) return stbi__err("bad SOS", "Corrupt JPEG"); if (z->succ_high != 0 || z->succ_low != 0) return stbi__err("bad SOS", "Corrupt JPEG"); z->spec_end = 63; } } return 1; } static int stbi__free_jpeg_components(stbi__jpeg *z, int ncomp, int why) { int i; for (i = 0; i < ncomp; ++i) { if (z->img_comp[i].data) { free(z->img_comp[i].data); z->img_comp[i].data = NULL; } if (z->img_comp[i].coeff) { free(z->img_comp[i].coeff); z->img_comp[i].coeff = NULL; } if (z->img_comp[i].linebuf) { free(z->img_comp[i].linebuf); z->img_comp[i].linebuf = NULL; } } return why; } static int stbi__process_frame_header(stbi__jpeg *z, int scan) { stbi__context *s = z->s; int Lf, p, i, q, h_max = 1, v_max = 1, c; Lf = stbi__get16be(s); if (Lf < 11) return stbi__err("bad SOF len", "Corrupt JPEG"); // JPEG p = stbi__get8(s); if (p != 8) return stbi__err("only 8-bit", "JPEG format not supported: 8-bit only"); // JPEG baseline s->img_y = stbi__get16be(s); if (s->img_y == 0) return stbi__err( "no header height", "JPEG format not supported: delayed height"); // Legal, but we don't // handle it--but neither // does IJG s->img_x = stbi__get16be(s); if (s->img_x == 0) return stbi__err("0 width", "Corrupt JPEG"); // JPEG requires c = stbi__get8(s); if (c != 3 && c != 1 && c != 4) return stbi__err("bad component count", "Corrupt JPEG"); s->img_n = c; for (i = 0; i < c; ++i) { z->img_comp[i].data = NULL; z->img_comp[i].linebuf = NULL; } if (Lf != 8 + 3 * s->img_n) return stbi__err("bad SOF len", "Corrupt JPEG"); z->rgb = 0; for (i = 0; i < s->img_n; ++i) { static const unsigned char rgb[3] = {'R', 'G', 'B'}; z->img_comp[i].id = stbi__get8(s); if (s->img_n == 3 && z->img_comp[i].id == rgb[i]) ++z->rgb; q = stbi__get8(s); z->img_comp[i].h = (q >> 4); if (!z->img_comp[i].h || z->img_comp[i].h > 4) return stbi__err("bad H", "Corrupt JPEG"); z->img_comp[i].v = q & 15; if (!z->img_comp[i].v || z->img_comp[i].v > 4) return stbi__err("bad V", "Corrupt JPEG"); z->img_comp[i].tq = stbi__get8(s); if (z->img_comp[i].tq > 3) return stbi__err("bad TQ", "Corrupt JPEG"); } if (scan != STBI__SCAN_load) return 1; if (!stbi__mad3sizes_valid(s->img_x, s->img_y, s->img_n, 0)) return stbi__err("too large", "Image too large to decode"); for (i = 0; i < s->img_n; ++i) { if (z->img_comp[i].h > h_max) h_max = z->img_comp[i].h; if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v; } // compute interleaved mcu info z->img_h_max = h_max; z->img_v_max = v_max; z->img_mcu_w = h_max * 8; z->img_mcu_h = v_max * 8; // these sizes can't be more than 17 bits z->img_mcu_x = (s->img_x + z->img_mcu_w - 1) / z->img_mcu_w; z->img_mcu_y = (s->img_y + z->img_mcu_h - 1) / z->img_mcu_h; for (i = 0; i < s->img_n; ++i) { // number of effective pixels (e.g. for non-interleaved MCU) z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max - 1) / h_max; z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max - 1) / v_max; // to simplify generation, we'll allocate enough memory to decode // the bogus oversized data from using interleaved MCUs and their // big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't // discard the extra data until colorspace conversion // // img_mcu_x, img_mcu_y: <=17 bits; comp[i].h and .v are <=4 (checked // earlier) so these muls can't overflow with 32-bit ints (which we require) z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8; z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8; z->img_comp[i].coeff = NULL; z->img_comp[i].linebuf = NULL; z->img_comp[i].data = stbi__malloc_mad2(z->img_comp[i].w2, z->img_comp[i].h2, 15); if (z->progressive) { // w2, h2 are multiples of 8 (see above) z->img_comp[i].coeff_w = z->img_comp[i].w2 / 8; z->img_comp[i].coeff_h = z->img_comp[i].h2 / 8; z->img_comp[i].coeff = stbi__malloc_mad3( z->img_comp[i].w2, z->img_comp[i].h2, sizeof(short), 15); } } return 1; } // use comparisons since in some cases we handle more than one case (e.g. SOF) #define stbi__DNL(x) ((x) == 0xdc) #define stbi__SOI(x) ((x) == 0xd8) #define stbi__EOI(x) ((x) == 0xd9) #define stbi__SOF(x) ((x) == 0xc0 || (x) == 0xc1 || (x) == 0xc2) #define stbi__SOS(x) ((x) == 0xda) #define stbi__SOF_progressive(x) ((x) == 0xc2) static int stbi__decode_jpeg_header(stbi__jpeg *z, int scan) { int m; z->jfif = 0; z->app14_color_transform = -1; // valid values are 0,1,2 z->marker = STBI__MARKER_none; // initialize cached marker to empty m = stbi__get_marker(z); if (!stbi__SOI(m)) return 0; if (scan == STBI__SCAN_type) return 1; m = stbi__get_marker(z); while (!stbi__SOF(m)) { if (!stbi__process_marker(z, m)) return 0; m = stbi__get_marker(z); while (m == STBI__MARKER_none) { // some files have extra padding after their blocks, so ok, we'll scan if (stbi__at_eof(z->s)) return stbi__err("no SOF", "Corrupt JPEG"); m = stbi__get_marker(z); } } z->progressive = stbi__SOF_progressive(m); if (!stbi__process_frame_header(z, scan)) return 0; return 1; } // decode image to YCbCr format static int stbi__decode_jpeg_image(stbi__jpeg *j) { int m; for (m = 0; m < 4; m++) { j->img_comp[m].data = NULL; j->img_comp[m].coeff = NULL; } j->restart_interval = 0; if (!stbi__decode_jpeg_header(j, STBI__SCAN_load)) return 0; m = stbi__get_marker(j); while (!stbi__EOI(m)) { if (stbi__SOS(m)) { if (!stbi__process_scan_header(j)) return 0; if (!stbi__parse_entropy_coded_data(j)) return 0; if (j->marker == STBI__MARKER_none) { // handle 0s at the end of image data from IP Kamera 9060 while (!stbi__at_eof(j->s)) { int x = stbi__get8(j->s); if (x == 255) { j->marker = stbi__get8(j->s); break; } } // if we reach eof without hitting a marker, stbi__get_marker() below // will fail and we'll eventually return 0 } } else if (stbi__DNL(m)) { int Ld = stbi__get16be(j->s); uint32_t NL = stbi__get16be(j->s); if (Ld != 4) return stbi__err("bad DNL len", "Corrupt JPEG"); if (NL != j->s->img_y) return stbi__err("bad DNL height", "Corrupt JPEG"); } else { if (!stbi__process_marker(j, m)) return 0; } m = stbi__get_marker(j); } if (j->progressive) stbi__jpeg_finish(j); return 1; } // static jfif-centered resampling (across block boundaries) typedef unsigned char *(*resample_row_func)(unsigned char *out, unsigned char *in0, unsigned char *in1, int w, int hs); #define stbi__div4(x) ((unsigned char)((x) >> 2)) static unsigned char *resample_row_1(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { return in_near; } static unsigned char *stbi__resample_row_v_2(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { // need to generate two samples vertically for every one in input int i; for (i = 0; i < w; ++i) out[i] = stbi__div4(3 * in_near[i] + in_far[i] + 2); return out; } static unsigned char *stbi__resample_row_h_2(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { // need to generate two samples horizontally for every one in input int i; unsigned char *input = in_near; if (w == 1) { // if only one sample, can't do any interpolation out[0] = out[1] = input[0]; return out; } out[0] = input[0]; out[1] = stbi__div4(input[0] * 3 + input[1] + 2); for (i = 1; i < w - 1; ++i) { int n = 3 * input[i] + 2; out[i * 2 + 0] = stbi__div4(n + input[i - 1]); out[i * 2 + 1] = stbi__div4(n + input[i + 1]); } out[i * 2 + 0] = stbi__div4(input[w - 2] * 3 + input[w - 1] + 2); out[i * 2 + 1] = input[w - 1]; return out; } #define stbi__div16(x) ((unsigned char)((x) >> 4)) static unsigned char *stbi__resample_row_hv_2(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { // need to generate 2x2 samples for every one in input int i, t0, t1; if (w == 1) { out[0] = out[1] = stbi__div4(3 * in_near[0] + in_far[0] + 2); return out; } t1 = 3 * in_near[0] + in_far[0]; out[0] = stbi__div4(t1 + 2); for (i = 1; i < w; ++i) { t0 = t1; t1 = 3 * in_near[i] + in_far[i]; out[i * 2 - 1] = stbi__div16(3 * t0 + t1 + 8); out[i * 2] = stbi__div16(3 * t1 + t0 + 8); } out[w * 2 - 1] = stbi__div4(t1 + 2); return out; } #if defined(STBI_SSE2) static unsigned char *stbi__resample_row_hv_2_simd(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { // need to generate 2x2 samples for every one in input int i = 0, t0, t1; if (w == 1) { out[0] = out[1] = stbi__div4(3 * in_near[0] + in_far[0] + 2); return out; } t1 = 3 * in_near[0] + in_far[0]; // process groups of 8 pixels for as long as we can. // note we can't handle the last pixel in a row in this loop // because we need to handle the filter boundary conditions. for (; i < ((w - 1) & ~7); i += 8) { // load and perform the vertical filtering pass // this uses 3*x + y = 4*x + (y - x) __m128i zero = _mm_setzero_si128(); __m128i farb = _mm_loadl_epi64((__m128i *)(in_far + i)); __m128i nearb = _mm_loadl_epi64((__m128i *)(in_near + i)); __m128i farw = _mm_unpacklo_epi8(farb, zero); __m128i nearw = _mm_unpacklo_epi8(nearb, zero); __m128i diff = _mm_sub_epi16(farw, nearw); __m128i nears = _mm_slli_epi16(nearw, 2); __m128i curr = _mm_add_epi16(nears, diff); // current row // horizontal filter works the same based on shifted vers of current // row. "prev" is current row shifted right by 1 pixel; we need to // insert the previous pixel value (from t1). // "next" is current row shifted left by 1 pixel, with first pixel // of next block of 8 pixels added in. __m128i prv0 = _mm_slli_si128(curr, 2); __m128i nxt0 = _mm_srli_si128(curr, 2); __m128i prev = _mm_insert_epi16(prv0, t1, 0); __m128i next = _mm_insert_epi16(nxt0, 3 * in_near[i + 8] + in_far[i + 8], 7); // horizontal filter, polyphase implementation since it's convenient: // even pixels = 3*cur + prev = cur*4 + (prev - cur) // odd pixels = 3*cur + next = cur*4 + (next - cur) // note the shared term. __m128i bias = _mm_set1_epi16(8); __m128i curs = _mm_slli_epi16(curr, 2); __m128i prvd = _mm_sub_epi16(prev, curr); __m128i nxtd = _mm_sub_epi16(next, curr); __m128i curb = _mm_add_epi16(curs, bias); __m128i even = _mm_add_epi16(prvd, curb); __m128i odd = _mm_add_epi16(nxtd, curb); // interleave even and odd pixels, then undo scaling. __m128i int0 = _mm_unpacklo_epi16(even, odd); __m128i int1 = _mm_unpackhi_epi16(even, odd); __m128i de0 = _mm_srli_epi16(int0, 4); __m128i de1 = _mm_srli_epi16(int1, 4); // pack and write output __m128i outv = _mm_packus_epi16(de0, de1); _mm_storeu_si128((__m128i *)(out + i * 2), outv); // "previous" value for next iter t1 = 3 * in_near[i + 7] + in_far[i + 7]; } t0 = t1; t1 = 3 * in_near[i] + in_far[i]; out[i * 2] = stbi__div16(3 * t1 + t0 + 8); for (++i; i < w; ++i) { t0 = t1; t1 = 3 * in_near[i] + in_far[i]; out[i * 2 - 1] = stbi__div16(3 * t0 + t1 + 8); out[i * 2] = stbi__div16(3 * t1 + t0 + 8); } out[w * 2 - 1] = stbi__div4(t1 + 2); return out; } #endif static unsigned char *stbi__resample_row_nearest(unsigned char *out, unsigned char *in_near, unsigned char *in_far, int w, int hs) { int i, j; for (i = 0; i < w; ++i) { for (j = 0; j < hs; ++j) { out[i * hs + j] = in_near[i]; } } return out; } // set up the kernels static void stbi__setup_jpeg(stbi__jpeg *j) { j->resample_row_hv_2_kernel = stbi__resample_row_hv_2; #if 0 if (stbi__sse2_available()) { j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd; } #endif } // clean up the temporary component buffers static void stbi__cleanup_jpeg(stbi__jpeg *j) { stbi__free_jpeg_components(j, j->s->img_n, 0); } typedef struct { resample_row_func resample; unsigned char *line0, *line1; int hs, vs; // expansion factor in each axis int w_lores; // horizontal pixels pre-expansion int ystep; // how far through vertical expansion we are int ypos; // which pre-expansion row we're on } stbi__resample; // fast 0..255 * 0..255 => 0..255 rounded multiplication static unsigned char stbi__blinn_8x8(unsigned char x, unsigned char y) { unsigned t; t = x * y + 128; return (t + (t >> 8)) >> 8; } static unsigned char *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp, int req_comp) { int n, decode_n, is_rgb; z->s->img_n = 0; // make stbi__cleanup_jpeg safe // validate req_comp if (req_comp < 0 || req_comp > 4) { return stbi__errpuc("bad req_comp", "Internal error"); } // load a jpeg image from whichever source, but leave in YCbCr format if (!stbi__decode_jpeg_image(z)) { stbi__cleanup_jpeg(z); return NULL; } // determine actual number of components to generate n = req_comp ? req_comp : z->s->img_n >= 3 ? 3 : 1; is_rgb = z->s->img_n == 3 && (z->rgb == 3 || (z->app14_color_transform == 0 && !z->jfif)); if (z->s->img_n == 3 && n < 3 && !is_rgb) { decode_n = 1; } else { decode_n = z->s->img_n; } // resample and color-convert { int k; unsigned int i, j; unsigned char *output; unsigned char *coutput[4]; stbi__resample res_comp[4]; memset(coutput, 0, sizeof(coutput)); for (k = 0; k < decode_n; ++k) { stbi__resample *r = &res_comp[k]; // allocate line buffer big enough for upsampling off the edges // with upsample factor of 4 z->img_comp[k].linebuf = xmalloc(z->s->img_x + 3); r->hs = z->img_h_max / z->img_comp[k].h; r->vs = z->img_v_max / z->img_comp[k].v; r->ystep = r->vs >> 1; r->w_lores = (z->s->img_x + r->hs - 1) / r->hs; r->ypos = 0; r->line0 = r->line1 = z->img_comp[k].data; if (r->hs == 1 && r->vs == 1) { r->resample = resample_row_1; } else if (r->hs == 1 && r->vs == 2) { r->resample = stbi__resample_row_v_2; } else if (r->hs == 2 && r->vs == 1) { r->resample = stbi__resample_row_h_2; } else if (r->hs == 2 && r->vs == 2) { r->resample = z->resample_row_hv_2_kernel; } else { r->resample = stbi__resample_row_nearest; } } // can't error after this so, this is safe output = stbi__malloc_mad3(n, z->s->img_x, z->s->img_y, 1); // now go ahead and resample for (j = 0; j < z->s->img_y; ++j) { unsigned char *out = output + n * z->s->img_x * j; for (k = 0; k < decode_n; ++k) { stbi__resample *r = &res_comp[k]; int y_bot = r->ystep >= (r->vs >> 1); coutput[k] = r->resample(z->img_comp[k].linebuf, y_bot ? r->line1 : r->line0, y_bot ? r->line0 : r->line1, r->w_lores, r->hs); if (++r->ystep >= r->vs) { r->ystep = 0; r->line0 = r->line1; if (++r->ypos < z->img_comp[k].y) r->line1 += z->img_comp[k].w2; } } if (n >= 3) { unsigned char *y = coutput[0]; if (z->s->img_n == 3) { if (is_rgb) { for (i = 0; i < z->s->img_x; ++i) { out[0] = y[i]; out[1] = coutput[1][i]; out[2] = coutput[2][i]; out[3] = 255; out += n; } } else { stbi__YCbCr_to_RGB_row(out, y, coutput[1], coutput[2], z->s->img_x, n); } } else if (z->s->img_n == 4) { if (z->app14_color_transform == 0) { // CMYK for (i = 0; i < z->s->img_x; ++i) { unsigned char m = coutput[3][i]; out[0] = stbi__blinn_8x8(coutput[0][i], m); out[1] = stbi__blinn_8x8(coutput[1][i], m); out[2] = stbi__blinn_8x8(coutput[2][i], m); out[3] = 255; out += n; } } else if (z->app14_color_transform == 2) { // YCCK stbi__YCbCr_to_RGB_row(out, y, coutput[1], coutput[2], z->s->img_x, n); for (i = 0; i < z->s->img_x; ++i) { unsigned char m = coutput[3][i]; out[0] = stbi__blinn_8x8(255 - out[0], m); out[1] = stbi__blinn_8x8(255 - out[1], m); out[2] = stbi__blinn_8x8(255 - out[2], m); out += n; } } else { // YCbCr + alpha? Ignore the fourth channel for now stbi__YCbCr_to_RGB_row(out, y, coutput[1], coutput[2], z->s->img_x, n); } } else for (i = 0; i < z->s->img_x; ++i) { out[0] = out[1] = out[2] = y[i]; out[3] = 255; // not used if n==3 out += n; } } else { if (is_rgb) { if (n == 1) for (i = 0; i < z->s->img_x; ++i) *out++ = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]); else { for (i = 0; i < z->s->img_x; ++i, out += 2) { out[0] = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]); out[1] = 255; } } } else if (z->s->img_n == 4 && z->app14_color_transform == 0) { for (i = 0; i < z->s->img_x; ++i) { unsigned char m = coutput[3][i]; unsigned char r = stbi__blinn_8x8(coutput[0][i], m); unsigned char g = stbi__blinn_8x8(coutput[1][i], m); unsigned char b = stbi__blinn_8x8(coutput[2][i], m); out[0] = stbi__compute_y(r, g, b); out[1] = 255; out += n; } } else if (z->s->img_n == 4 && z->app14_color_transform == 2) { for (i = 0; i < z->s->img_x; ++i) { out[0] = stbi__blinn_8x8(255 - coutput[0][i], coutput[3][i]); out[1] = 255; out += n; } } else { unsigned char *y = coutput[0]; if (n == 1) for (i = 0; i < z->s->img_x; ++i) out[i] = y[i]; else for (i = 0; i < z->s->img_x; ++i) { *out++ = y[i]; *out++ = 255; } } } } stbi__cleanup_jpeg(z); *out_x = z->s->img_x; *out_y = z->s->img_y; if (comp) *comp = z->s->img_n >= 3 ? 3 : 1; // report original components, not output return output; } } static noinline void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri) { unsigned char *result; stbi__jpeg *j = (stbi__jpeg *)malloc(sizeof(stbi__jpeg)); j->s = s; stbi__setup_jpeg(j); result = load_jpeg_image(j, x, y, comp, req_comp); free(j); return result; } static int stbi__jpeg_test(stbi__context *s) { int r; stbi__jpeg *j; j = malloc(sizeof(stbi__jpeg)); j->s = s; stbi__setup_jpeg(j); r = stbi__decode_jpeg_header(j, STBI__SCAN_type); stbi__rewind(s); free(j); return r; } static int stbi__jpeg_info_raw(stbi__jpeg *j, int *x, int *y, int *comp) { if (!stbi__decode_jpeg_header(j, STBI__SCAN_header)) { stbi__rewind(j->s); return 0; } if (x) *x = j->s->img_x; if (y) *y = j->s->img_y; if (comp) *comp = j->s->img_n >= 3 ? 3 : 1; return 1; } static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp) { int result; stbi__jpeg *j = (stbi__jpeg *)(malloc(sizeof(stbi__jpeg))); j->s = s; result = stbi__jpeg_info_raw(j, x, y, comp); free(j); return result; } // public domain zlib decode v0.2 Sean Barrett 2006-11-18 // simple implementation // - all input must be provided in an upfront buffer // - all output is written to a single output buffer (can malloc/realloc) // performance // - fast huffman // fast-way is faster to check than jpeg huffman, but slow way is slower #define STBI__ZFAST_BITS 9 // accelerate all cases in default tables #define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1) // zlib-style huffman encoding // (jpegs packs from left, zlib from right, so can't share code) typedef struct { uint16_t fast[1 << STBI__ZFAST_BITS]; uint16_t firstcode[16]; int maxcode[17]; uint16_t firstsymbol[16]; unsigned char size[288]; uint16_t value[288]; } stbi__zhuffman; forceinline int stbi__bitreverse16(int n) { n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1); n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2); n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4); n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8); return n; } forceinline int stbi__bit_reverse(int v, int bits) { assert(bits <= 16); // to bit reverse n bits, reverse 16 and shift // e.g. 11 bits, bit reverse and shift away 5 return stbi__bitreverse16(v) >> (16 - bits); } static int stbi__zbuild_huffman(stbi__zhuffman *z, const unsigned char *sizelist, int num) { int i, k = 0; int code, next_code[16], sizes[17]; // DEFLATE spec for generating codes memset(sizes, 0, sizeof(sizes)); memset(z->fast, 0, sizeof(z->fast)); for (i = 0; i < num; ++i) ++sizes[sizelist[i]]; sizes[0] = 0; for (i = 1; i < 16; ++i) if (sizes[i] > (1 << i)) return stbi__err("bad sizes", "Corrupt PNG"); code = 0; for (i = 1; i < 16; ++i) { next_code[i] = code; z->firstcode[i] = (uint16_t)code; z->firstsymbol[i] = (uint16_t)k; code = (code + sizes[i]); if (sizes[i]) if (code - 1 >= (1 << i)) return stbi__err("bad codelengths", "Corrupt PNG"); z->maxcode[i] = code << (16 - i); // preshift for inner loop code <<= 1; k += sizes[i]; } z->maxcode[16] = 0x10000; // sentinel for (i = 0; i < num; ++i) { int s = sizelist[i]; if (s) { int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s]; uint16_t fastv = (uint16_t)((s << 9) | i); z->size[c] = (unsigned char)s; z->value[c] = (uint16_t)i; if (s <= STBI__ZFAST_BITS) { int j = stbi__bit_reverse(next_code[s], s); while (j < (1 << STBI__ZFAST_BITS)) { z->fast[j] = fastv; j += (1 << s); } } ++next_code[s]; } } return 1; } // zlib-from-memory implementation for PNG reading // because PNG allows splitting the zlib stream arbitrarily, // and it's annoying structurally to have PNG call ZLIB call PNG, // we require PNG read all the IDATs and combine them into a single // memory buffer typedef struct { unsigned char *zbuffer, *zbuffer_end; int num_bits; uint32_t code_buffer; char *zout; char *zout_start; char *zout_end; int z_expandable; stbi__zhuffman z_length, z_distance; } stbi__zbuf; forceinline unsigned char stbi__zget8(stbi__zbuf *z) { if (z->zbuffer >= z->zbuffer_end) return 0; return *z->zbuffer++; } static void stbi__fill_bits(stbi__zbuf *z) { do { assert(z->code_buffer < (1u << z->num_bits)); z->code_buffer |= (unsigned int)stbi__zget8(z) << z->num_bits; z->num_bits += 8; } while (z->num_bits <= 24); } forceinline unsigned int stbi__zreceive(stbi__zbuf *z, int n) { unsigned int k; if (z->num_bits < n) stbi__fill_bits(z); k = z->code_buffer & ((1 << n) - 1); z->code_buffer >>= n; z->num_bits -= n; return k; } static int stbi__zhuffman_decode_slowpath(stbi__zbuf *a, stbi__zhuffman *z) { int b, s, k; // not resolved by fast table, so compute it the slow way // use jpeg approach, which requires MSbits at top k = stbi__bit_reverse(a->code_buffer, 16); for (s = STBI__ZFAST_BITS + 1;; ++s) if (k < z->maxcode[s]) break; if (s == 16) return -1; // invalid code! // code size is s, so: b = (k >> (16 - s)) - z->firstcode[s] + z->firstsymbol[s]; assert(z->size[b] == s); a->code_buffer >>= s; a->num_bits -= s; return z->value[b]; } forceinline int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z) { int b, s; if (a->num_bits < 16) stbi__fill_bits(a); b = z->fast[a->code_buffer & STBI__ZFAST_MASK]; if (b) { s = b >> 9; a->code_buffer >>= s; a->num_bits -= s; return b & 511; } return stbi__zhuffman_decode_slowpath(a, z); } static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) { char *q; int cur, limit, old_limit; z->zout = zout; if (!z->z_expandable) return stbi__err("output buffer limit", "Corrupt PNG"); cur = (int)(z->zout - z->zout_start); limit = old_limit = (int)(z->zout_end - z->zout_start); while (cur + n > limit) limit *= 2; q = (char *)STBI_REALLOC_SIZED(z->zout_start, old_limit, limit); if (q == NULL) return stbi__err("outofmem", "Out of memory"); z->zout_start = q; z->zout = q + cur; z->zout_end = q + limit; return 1; } static const int stbi__zlength_base[31] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0, }; static const int stbi__zlength_extra[31] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0, }; static const int stbi__zdist_base[32] = { 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0, }; static const int stbi__zdist_extra[32] = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, }; static int stbi__parse_huffman_block(stbi__zbuf *a) { char *zout = a->zout; for (;;) { int z = stbi__zhuffman_decode(a, &a->z_length); if (z < 256) { if (z < 0) return stbi__err("bad huffman code", "Corrupt PNG"); if (zout >= a->zout_end) { if (!stbi__zexpand(a, zout, 1)) return 0; zout = a->zout; } *zout++ = (char)z; } else { unsigned char *p; int len, dist; if (z == 256) { a->zout = zout; return 1; } z -= 257; len = stbi__zlength_base[z]; if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]); z = stbi__zhuffman_decode(a, &a->z_distance); if (z < 0) return stbi__err("bad huffman code", "Corrupt PNG"); dist = stbi__zdist_base[z]; if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]); if (zout - a->zout_start < dist) return stbi__err("bad dist", "Corrupt PNG"); if (zout + len > a->zout_end) { if (!stbi__zexpand(a, zout, len)) return 0; zout = a->zout; } p = (unsigned char *)(zout - dist); if (dist == 1) { // run of one byte; common in images. unsigned char v = *p; if (len) { do *zout++ = v; while (--len); } } else { if (len) { do *zout++ = *p++; while (--len); } } } } } static int stbi__compute_huffman_codes(stbi__zbuf *a) { static const unsigned char length_dezigzag[19] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; stbi__zhuffman z_codelength; unsigned char lencodes[286 + 32 + 137]; // padding for maximum single op unsigned char codelength_sizes[19]; int i, n; int hlit = stbi__zreceive(a, 5) + 257; int hdist = stbi__zreceive(a, 5) + 1; int hclen = stbi__zreceive(a, 4) + 4; int ntot = hlit + hdist; memset(codelength_sizes, 0, sizeof(codelength_sizes)); for (i = 0; i < hclen; ++i) { int s = stbi__zreceive(a, 3); codelength_sizes[length_dezigzag[i]] = (unsigned char)s; } if (!stbi__zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0; n = 0; while (n < ntot) { int c = stbi__zhuffman_decode(a, &z_codelength); if (c < 0 || c >= 19) return stbi__err("bad codelengths", "Corrupt PNG"); if (c < 16) lencodes[n++] = (unsigned char)c; else { unsigned char fill = 0; if (c == 16) { c = stbi__zreceive(a, 2) + 3; if (n == 0) return stbi__err("bad codelengths", "Corrupt PNG"); fill = lencodes[n - 1]; } else if (c == 17) c = stbi__zreceive(a, 3) + 3; else { assert(c == 18); c = stbi__zreceive(a, 7) + 11; } if (ntot - n < c) return stbi__err("bad codelengths", "Corrupt PNG"); memset(lencodes + n, fill, c); n += c; } } if (n != ntot) return stbi__err("bad codelengths", "Corrupt PNG"); if (!stbi__zbuild_huffman(&a->z_length, lencodes, hlit)) return 0; if (!stbi__zbuild_huffman(&a->z_distance, lencodes + hlit, hdist)) return 0; return 1; } static int stbi__parse_uncompressed_block(stbi__zbuf *a) { unsigned char header[4]; int len, nlen, k; if (a->num_bits & 7) stbi__zreceive(a, a->num_bits & 7); // discard // drain the bit-packed data into header k = 0; while (a->num_bits > 0) { header[k++] = (unsigned char)(a->code_buffer & 255); // suppress MSVC run-time check a->code_buffer >>= 8; a->num_bits -= 8; } assert(a->num_bits == 0); // now fill header the normal way while (k < 4) header[k++] = stbi__zget8(a); len = header[1] * 256 + header[0]; nlen = header[3] * 256 + header[2]; if (nlen != (len ^ 0xffff)) return stbi__err("zlib corrupt", "Corrupt PNG"); if (a->zbuffer + len > a->zbuffer_end) return stbi__err("read past buffer", "Corrupt PNG"); if (a->zout + len > a->zout_end) if (!stbi__zexpand(a, a->zout, len)) return 0; memcpy(a->zout, a->zbuffer, len); a->zbuffer += len; a->zout += len; return 1; } static int stbi__parse_zlib_header(stbi__zbuf *a) { int cmf = stbi__zget8(a); int cm = cmf & 15; /* int cinfo = cmf >> 4; */ int flg = stbi__zget8(a); if ((cmf * 256 + flg) % 31 != 0) return stbi__err("bad zlib header", "Corrupt PNG"); // zlib spec if (flg & 32) return stbi__err("no preset dict", "Corrupt PNG"); // preset dictionary not allowed in png if (cm != 8) return stbi__err("bad compression", "Corrupt PNG"); // DEFLATE required for png // window = 1 << (8 + cinfo)... but who cares, we fully buffer output return 1; } static const unsigned char stbi__zdefault_length[288] = { 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8}; static const unsigned char stbi__zdefault_distance[32] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, }; /* Init algorithm:{ int i; // use <= to match clearly with spec for (i=0; i <= 143; ++i) stbi__zdefault_length[i] = 8; for ( ; i <= 255; ++i) stbi__zdefault_length[i] = 9; for ( ; i <= 279; ++i) stbi__zdefault_length[i] = 7; for ( ; i <= 287; ++i) stbi__zdefault_length[i] = 8; for (i=0; i <= 31; ++i) stbi__zdefault_distance[i] = 5; } */ static int stbi__parse_zlib(stbi__zbuf *a, int parse_header) { int final, type; if (parse_header) if (!stbi__parse_zlib_header(a)) return 0; a->num_bits = 0; a->code_buffer = 0; do { final = stbi__zreceive(a, 1); type = stbi__zreceive(a, 2); if (type == 0) { if (!stbi__parse_uncompressed_block(a)) return 0; } else if (type == 3) { return 0; } else { if (type == 1) { // use fixed code lengths if (!stbi__zbuild_huffman(&a->z_length, stbi__zdefault_length, 288)) return 0; if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance, 32)) return 0; } else { if (!stbi__compute_huffman_codes(a)) return 0; } if (!stbi__parse_huffman_block(a)) return 0; } } while (!final); return 1; } static int stbi__do_zlib(stbi__zbuf *a, char *obuf, int olen, int exp, int parse_header) { a->zout_start = obuf; a->zout = obuf; a->zout_end = obuf + olen; a->z_expandable = exp; return stbi__parse_zlib(a, parse_header); } char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen) { char *res, *p; stbi__zbuf *a; a = NULL; res = NULL; if ((p = (char *)malloc(initial_size)) && (a = (stbi__zbuf *)malloc(sizeof(stbi__zbuf)))) { a->zbuffer = (unsigned char *)buffer; a->zbuffer_end = (unsigned char *)buffer + len; if (stbi__do_zlib(a, p, initial_size, 1, 1)) { if (outlen) *outlen = (int)(a->zout - a->zout_start); res = a->zout_start; a->zout_start = NULL; } } free(a->zout_start); free(a); return res; } char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen) { return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen); } char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header) { char *res; stbi__zbuf *a = malloc(sizeof(stbi__zbuf)); char *p = (char *)malloc(initial_size); if (!p) return NULL; a->zbuffer = (unsigned char *)buffer; a->zbuffer_end = (unsigned char *)buffer + len; if (stbi__do_zlib(a, p, initial_size, 1, parse_header)) { if (outlen) *outlen = (int)(a->zout - a->zout_start); res = a->zout_start; } else { free(a->zout_start); res = NULL; } free(a); return res; } int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen) { stbi__zbuf a; a.zbuffer = (unsigned char *)ibuffer; a.zbuffer_end = (unsigned char *)ibuffer + ilen; if (stbi__do_zlib(&a, obuffer, olen, 0, 1)) return (int)(a.zout - a.zout_start); else return -1; } char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen) { stbi__zbuf a; char *p = (char *)malloc(16384); if (p == NULL) return NULL; a.zbuffer = (unsigned char *)buffer; a.zbuffer_end = (unsigned char *)buffer + len; if (stbi__do_zlib(&a, p, 16384, 1, 0)) { if (outlen) *outlen = (int)(a.zout - a.zout_start); return a.zout_start; } else { free(a.zout_start); return NULL; } } int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen) { stbi__zbuf a; a.zbuffer = (unsigned char *)ibuffer; a.zbuffer_end = (unsigned char *)ibuffer + ilen; if (stbi__do_zlib(&a, obuffer, olen, 0, 0)) return (int)(a.zout - a.zout_start); else return -1; } // public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18 // simple implementation // - only 8-bit samples // - no CRC checking // - allocates lots of intermediate memory // - avoids problem of streaming data between subsystems // - avoids explicit window management // performance // - uses stb_zlib, a PD zlib implementation with fast huffman decoding typedef struct { uint32_t length; uint32_t type; } stbi__pngchunk; static stbi__pngchunk stbi__get_chunk_header(stbi__context *s) { stbi__pngchunk c; c.length = stbi__get32be(s); c.type = stbi__get32be(s); return c; } static int stbi__check_png_header(stbi__context *s) { int i; for (i = 0; i < 8; ++i) { if (stbi__get8(s) != kPngSig[i]) { return stbi__err("bad png sig", "Not a PNG"); } } return 1; } typedef struct { stbi__context *s; unsigned char *idata, *expanded, *out; int depth; } stbi__png; enum { STBI__F_none = 0, STBI__F_sub = 1, STBI__F_up = 2, STBI__F_avg = 3, STBI__F_paeth = 4, // synthetic filters used for first scanline to avoid needing a dummy row of // 0s STBI__F_avg_first, STBI__F_paeth_first }; static int stbi__de_iphone_flag = 0; static int stbi__unpremultiply_on_load = 0; static unsigned char first_row_filter[5] = {STBI__F_none, STBI__F_sub, STBI__F_none, STBI__F_avg_first, STBI__F_paeth_first}; static int stbi__paeth(int a, int b, int c) { int p = a + b - c; int pa = abs(p - a); int pb = abs(p - b); int pc = abs(p - c); if (pa <= pb && pa <= pc) return a; if (pb <= pc) return b; return c; } static const unsigned char stbi__depth_scale_table[9] = { 0, 0xff, 0x55, 0, 0x11, 0, 0, 0, 0x01}; // create the png data from post-deflated data static int stbi__create_png_image_raw(stbi__png *a, unsigned char *raw, uint32_t raw_len, int out_n, uint32_t x, uint32_t y, int depth, int color) { int bytes = (depth == 16 ? 2 : 1); stbi__context *s = a->s; uint32_t i, j, stride = x * out_n * bytes; uint32_t img_len, img_width_bytes; int k; int img_n = s->img_n; // copy it into a local for later int output_bytes = out_n * bytes; int filter_bytes = img_n * bytes; int width = x; assert(out_n == s->img_n || out_n == s->img_n + 1); a->out = stbi__malloc_mad3(x, y, output_bytes, 0); // extra bytes to write off the end into if (!stbi__mad3sizes_valid(img_n, x, depth, 7)) return stbi__err("too large", "Corrupt PNG"); img_width_bytes = (((img_n * x * depth) + 7) >> 3); img_len = (img_width_bytes + 1) * y; // we used to check for exact match between raw_len and img_len on // non-interlaced PNGs, but issue #276 reported a PNG in the wild that had // extra data at the end (all zeros), so just check for raw_len < img_len // always. if (raw_len < img_len) return stbi__err("not enough pixels", "Corrupt PNG"); for (j = 0; j < y; ++j) { unsigned char *cur = a->out + stride * j; unsigned char *prior; int filter = *raw++; if (filter > 4) return stbi__err("invalid filter", "Corrupt PNG"); if (depth < 8) { assert(img_width_bytes <= x); cur += x * out_n - img_width_bytes; // store output to the rightmost img_len // bytes, so we can decode in place filter_bytes = 1; width = img_width_bytes; } prior = cur - stride; // bugfix: need to compute this after 'cur +=' // computation above // if first row, use special filter that doesn't sample previous row if (j == 0) filter = first_row_filter[filter]; // handle first byte explicitly for (k = 0; k < filter_bytes; ++k) { switch (filter) { case STBI__F_none: cur[k] = raw[k]; break; case STBI__F_sub: cur[k] = raw[k]; break; case STBI__F_up: cur[k] = STBI__BYTECAST(raw[k] + prior[k]); break; case STBI__F_avg: cur[k] = STBI__BYTECAST(raw[k] + (prior[k] >> 1)); break; case STBI__F_paeth: cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(0, prior[k], 0)); break; case STBI__F_avg_first: cur[k] = raw[k]; break; case STBI__F_paeth_first: cur[k] = raw[k]; break; } } if (depth == 8) { if (img_n != out_n) cur[img_n] = 255; // first pixel raw += img_n; cur += out_n; prior += out_n; } else if (depth == 16) { if (img_n != out_n) { cur[filter_bytes] = 255; // first pixel top byte cur[filter_bytes + 1] = 255; // first pixel bottom byte } raw += filter_bytes; cur += output_bytes; prior += output_bytes; } else { raw += 1; cur += 1; prior += 1; } // this is a little gross, so that we don't switch per-pixel or // per-component if (depth < 8 || img_n == out_n) { int nk = (width - 1) * filter_bytes; #define STBI__CASE(f) \ case f: \ for (k = 0; k < nk; ++k) switch (filter) { // "none" filter turns into a memcpy here; make that explicit. case STBI__F_none: memcpy(cur, raw, nk); break; STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - filter_bytes]); } break; STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break; STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - filter_bytes]) >> 1)); } break; STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - filter_bytes], prior[k], prior[k - filter_bytes])); } break; STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - filter_bytes] >> 1)); } break; STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - filter_bytes], 0, 0)); } break; } #undef STBI__CASE raw += nk; } else { assert(img_n + 1 == out_n); #define STBI__CASE(f) \ case f: \ for (i = x - 1; i >= 1; --i, cur[filter_bytes] = 255, raw += filter_bytes, \ cur += output_bytes, prior += output_bytes) \ for (k = 0; k < filter_bytes; ++k) switch (filter) { STBI__CASE(STBI__F_none) { cur[k] = raw[k]; } break; STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - output_bytes]); } break; STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break; STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - output_bytes]) >> 1)); } break; STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - output_bytes], prior[k], prior[k - output_bytes])); } break; STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - output_bytes] >> 1)); } break; STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - output_bytes], 0, 0)); } break; } #undef STBI__CASE // the loop above sets the high byte of the pixels' alpha, but for // 16 bit png files we also need the low byte set. we'll do that here. if (depth == 16) { cur = a->out + stride * j; // start at the beginning of the row again for (i = 0; i < x; ++i, cur += output_bytes) { cur[filter_bytes + 1] = 255; } } } } // we make a separate pass to expand bits to pixels; for performance, // this could run two scanlines behind the above code, so it won't // intefere with filtering but will still be in the cache. if (depth < 8) { for (j = 0; j < y; ++j) { unsigned char *cur = a->out + stride * j; unsigned char *in = a->out + stride * j + x * out_n - img_width_bytes; // unpack 1/2/4-bit into a 8-bit buffer. allows us to keep the common // 8-bit path optimal at minimal cost for 1/2/4-bit png guarante byte // alignment, if width is not multiple of 8/4/2 we'll decode dummy // trailing data that will be skipped in the later loop unsigned char scale = (color == 0) ? stbi__depth_scale_table[depth] : 1; // scale grayscale values to 0..255 range // note that the final byte might overshoot and write more data than // desired. we can allocate enough data that this never writes out of // memory, but it could also overwrite the next scanline. can it // overwrite non-empty data on the next scanline? yes, consider // 1-pixel-wide scanlines with 1-bit-per-pixel. so we need to explicitly // clamp the final ones if (depth == 4) { for (k = x * img_n; k >= 2; k -= 2, ++in) { *cur++ = scale * ((*in >> 4)); *cur++ = scale * ((*in) & 0x0f); } if (k > 0) *cur++ = scale * ((*in >> 4)); } else if (depth == 2) { for (k = x * img_n; k >= 4; k -= 4, ++in) { *cur++ = scale * ((*in >> 6)); *cur++ = scale * ((*in >> 4) & 0x03); *cur++ = scale * ((*in >> 2) & 0x03); *cur++ = scale * ((*in) & 0x03); } if (k > 0) *cur++ = scale * ((*in >> 6)); if (k > 1) *cur++ = scale * ((*in >> 4) & 0x03); if (k > 2) *cur++ = scale * ((*in >> 2) & 0x03); } else if (depth == 1) { for (k = x * img_n; k >= 8; k -= 8, ++in) { *cur++ = scale * ((*in >> 7)); *cur++ = scale * ((*in >> 6) & 0x01); *cur++ = scale * ((*in >> 5) & 0x01); *cur++ = scale * ((*in >> 4) & 0x01); *cur++ = scale * ((*in >> 3) & 0x01); *cur++ = scale * ((*in >> 2) & 0x01); *cur++ = scale * ((*in >> 1) & 0x01); *cur++ = scale * ((*in) & 0x01); } if (k > 0) *cur++ = scale * ((*in >> 7)); if (k > 1) *cur++ = scale * ((*in >> 6) & 0x01); if (k > 2) *cur++ = scale * ((*in >> 5) & 0x01); if (k > 3) *cur++ = scale * ((*in >> 4) & 0x01); if (k > 4) *cur++ = scale * ((*in >> 3) & 0x01); if (k > 5) *cur++ = scale * ((*in >> 2) & 0x01); if (k > 6) *cur++ = scale * ((*in >> 1) & 0x01); } if (img_n != out_n) { int q; // insert alpha = 255 cur = a->out + stride * j; if (img_n == 1) { for (q = x - 1; q >= 0; --q) { cur[q * 2 + 1] = 255; cur[q * 2 + 0] = cur[q]; } } else { assert(img_n == 3); for (q = x - 1; q >= 0; --q) { cur[q * 4 + 3] = 255; cur[q * 4 + 2] = cur[q * 3 + 2]; cur[q * 4 + 1] = cur[q * 3 + 1]; cur[q * 4 + 0] = cur[q * 3 + 0]; } } } } } else if (depth == 16) { // force the image data from big-endian to platform-native. // this is done in a separate pass due to the decoding relying // on the data being untouched, but could probably be done // per-line during decode if care is taken. unsigned char *cur = a->out; uint16_t *cur16 = (uint16_t *)cur; for (i = 0; i < x * y * out_n; ++i, cur16++, cur += 2) { *cur16 = (cur[0] << 8) | cur[1]; } } return 1; } static int stbi__create_png_image(stbi__png *a, unsigned char *image_data, uint32_t image_data_len, int out_n, int depth, int color, int interlaced) { int bytes = (depth == 16 ? 2 : 1); int out_bytes = out_n * bytes; unsigned char *final; int p; if (!interlaced) return stbi__create_png_image_raw(a, image_data, image_data_len, out_n, a->s->img_x, a->s->img_y, depth, color); // de-interlacing final = stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0); for (p = 0; p < 7; ++p) { int xorig[] = {0, 4, 0, 2, 0, 1, 0}; int yorig[] = {0, 0, 4, 0, 2, 0, 1}; int xspc[] = {8, 8, 4, 4, 2, 2, 1}; int yspc[] = {8, 8, 8, 4, 4, 2, 2}; int i, j, x, y; // pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1 x = (a->s->img_x - xorig[p] + xspc[p] - 1) / xspc[p]; y = (a->s->img_y - yorig[p] + yspc[p] - 1) / yspc[p]; if (x && y) { uint32_t img_len = ((((a->s->img_n * x * depth) + 7) >> 3) + 1) * y; if (!stbi__create_png_image_raw(a, image_data, image_data_len, out_n, x, y, depth, color)) { free(final); return 0; } for (j = 0; j < y; ++j) { for (i = 0; i < x; ++i) { int out_y = j * yspc[p] + yorig[p]; int out_x = i * xspc[p] + xorig[p]; memcpy(final + out_y * a->s->img_x * out_bytes + out_x * out_bytes, a->out + (j * x + i) * out_bytes, out_bytes); } } free(a->out); image_data += img_len; image_data_len -= img_len; } } a->out = final; return 1; } static int stbi__compute_transparency(stbi__png *z, unsigned char tc[3], int out_n) { stbi__context *s = z->s; uint32_t i, pixel_count = s->img_x * s->img_y; unsigned char *p = z->out; // compute color-based transparency, assuming we've // already got 255 as the alpha value in the output assert(out_n == 2 || out_n == 4); if (out_n == 2) { for (i = 0; i < pixel_count; ++i) { p[1] = (p[0] == tc[0] ? 0 : 255); p += 2; } } else { for (i = 0; i < pixel_count; ++i) { if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2]) p[3] = 0; p += 4; } } return 1; } static int stbi__compute_transparency16(stbi__png *z, uint16_t tc[3], int out_n) { stbi__context *s = z->s; uint32_t i, pixel_count = s->img_x * s->img_y; uint16_t *p = (uint16_t *)z->out; // compute color-based transparency, assuming we've // already got 65535 as the alpha value in the output assert(out_n == 2 || out_n == 4); if (out_n == 2) { for (i = 0; i < pixel_count; ++i) { p[1] = (p[0] == tc[0] ? 0 : 65535); p += 2; } } else { for (i = 0; i < pixel_count; ++i) { if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2]) p[3] = 0; p += 4; } } return 1; } static int stbi__expand_png_palette(stbi__png *a, unsigned char *palette, int len, int pal_img_n) { uint32_t i, pixel_count = a->s->img_x * a->s->img_y; unsigned char *p, *temp_out, *orig = a->out; p = stbi__malloc_mad2(pixel_count, pal_img_n, 0); // between here and free(out) below, exitting would leak temp_out = p; if (pal_img_n == 3) { for (i = 0; i < pixel_count; ++i) { int n = orig[i] * 4; p[0] = palette[n]; p[1] = palette[n + 1]; p[2] = palette[n + 2]; p += 3; } } else { for (i = 0; i < pixel_count; ++i) { int n = orig[i] * 4; p[0] = palette[n]; p[1] = palette[n + 1]; p[2] = palette[n + 2]; p[3] = palette[n + 3]; p += 4; } } free(a->out); a->out = temp_out; return 1; } void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply) { stbi__unpremultiply_on_load = flag_true_if_should_unpremultiply; } void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert) { stbi__de_iphone_flag = flag_true_if_should_convert; } static void stbi__de_iphone(stbi__png *z) { stbi__context *s = z->s; uint32_t i, pixel_count = s->img_x * s->img_y; unsigned char *p = z->out; if (s->img_out_n == 3) { // convert bgr to rgb for (i = 0; i < pixel_count; ++i) { unsigned char t = p[0]; p[0] = p[2]; p[2] = t; p += 3; } } else { assert(s->img_out_n == 4); if (stbi__unpremultiply_on_load) { // convert bgr to rgb and unpremultiply for (i = 0; i < pixel_count; ++i) { unsigned char a = p[3]; unsigned char t = p[0]; if (a) { unsigned char half = a / 2; p[0] = (p[2] * 255 + half) / a; p[1] = (p[1] * 255 + half) / a; p[2] = (t * 255 + half) / a; } else { p[0] = p[2]; p[2] = t; } p += 4; } } else { // convert bgr to rgb for (i = 0; i < pixel_count; ++i) { unsigned char t = p[0]; p[0] = p[2]; p[2] = t; p += 4; } } } } #define STBI__PNG_TYPE(a, b, c, d) \ (((unsigned)(a) << 24) + ((unsigned)(b) << 16) + ((unsigned)(c) << 8) + \ (unsigned)(d)) static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp) { unsigned char palette[1024], pal_img_n = 0; unsigned char has_trans = 0, tc[3] = {0}; uint16_t tc16[3]; uint32_t ioff = 0, idata_limit = 0, i, pal_len = 0; int first = 1, k, interlace = 0, color = 0, is_iphone = 0; stbi__context *s = z->s; z->expanded = NULL; z->idata = NULL; z->out = NULL; if (!stbi__check_png_header(s)) return 0; if (scan == STBI__SCAN_type) return 1; for (;;) { stbi__pngchunk c = stbi__get_chunk_header(s); switch (c.type) { case STBI__PNG_TYPE('C', 'g', 'B', 'I'): is_iphone = 1; stbi__skip(s, c.length); break; case STBI__PNG_TYPE('I', 'H', 'D', 'R'): { int comp, filter; if (!first) return stbi__err("multiple IHDR", "Corrupt PNG"); first = 0; if (c.length != 13) return stbi__err("bad IHDR len", "Corrupt PNG"); s->img_x = stbi__get32be(s); if (s->img_x > (1 << 24)) return stbi__err("too large", "Very large image (corrupt?)"); s->img_y = stbi__get32be(s); if (s->img_y > (1 << 24)) return stbi__err("too large", "Very large image (corrupt?)"); z->depth = stbi__get8(s); if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16) return stbi__err("1/2/4/8/16-bit only", "PNG not supported: 1/2/4/8/16-bit only"); color = stbi__get8(s); if (color > 6) return stbi__err("bad ctype", "Corrupt PNG"); if (color == 3 && z->depth == 16) return stbi__err("bad ctype", "Corrupt PNG"); if (color == 3) pal_img_n = 3; else if (color & 1) return stbi__err("bad ctype", "Corrupt PNG"); comp = stbi__get8(s); if (comp) return stbi__err("bad comp method", "Corrupt PNG"); filter = stbi__get8(s); if (filter) return stbi__err("bad filter method", "Corrupt PNG"); interlace = stbi__get8(s); if (interlace > 1) return stbi__err("bad interlace method", "Corrupt PNG"); if (!s->img_x || !s->img_y) return stbi__err("0-pixel image", "Corrupt PNG"); if (!pal_img_n) { s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0); if ((1 << 30) / s->img_x / s->img_n < s->img_y) return stbi__err("too large", "Image too large to decode"); if (scan == STBI__SCAN_header) return 1; } else { // if paletted, then pal_n is our final components, and // img_n is # components to decompress/filter. s->img_n = 1; if ((1 << 30) / s->img_x / 4 < s->img_y) return stbi__err("too large", "Corrupt PNG"); // if SCAN_header, have to scan to see if we have a tRNS } break; } case STBI__PNG_TYPE('P', 'L', 'T', 'E'): { if (first) return stbi__err("first not IHDR", "Corrupt PNG"); if (c.length > 256 * 3) return stbi__err("invalid PLTE", "Corrupt PNG"); pal_len = c.length / 3; if (pal_len * 3 != c.length) return stbi__err("invalid PLTE", "Corrupt PNG"); for (i = 0; i < pal_len; ++i) { palette[i * 4 + 0] = stbi__get8(s); palette[i * 4 + 1] = stbi__get8(s); palette[i * 4 + 2] = stbi__get8(s); palette[i * 4 + 3] = 255; } break; } case STBI__PNG_TYPE('t', 'R', 'N', 'S'): { if (first) return stbi__err("first not IHDR", "Corrupt PNG"); if (z->idata) return stbi__err("tRNS after IDAT", "Corrupt PNG"); if (pal_img_n) { if (scan == STBI__SCAN_header) { s->img_n = 4; return 1; } if (pal_len == 0) return stbi__err("tRNS before PLTE", "Corrupt PNG"); if (c.length > pal_len) return stbi__err("bad tRNS len", "Corrupt PNG"); pal_img_n = 4; for (i = 0; i < c.length; ++i) palette[i * 4 + 3] = stbi__get8(s); } else { if (!(s->img_n & 1)) return stbi__err("tRNS with alpha", "Corrupt PNG"); if (c.length != (uint32_t)s->img_n * 2) return stbi__err("bad tRNS len", "Corrupt PNG"); has_trans = 1; if (z->depth == 16) { for (k = 0; k < s->img_n; ++k) tc16[k] = (uint16_t)stbi__get16be(s); // copy the values as-is } else { for (k = 0; k < s->img_n; ++k) tc[k] = (unsigned char)(stbi__get16be(s) & 255) * stbi__depth_scale_table[z->depth]; // non 8-bit images // will be larger } } break; } case STBI__PNG_TYPE('I', 'D', 'A', 'T'): { if (first) return stbi__err("first not IHDR", "Corrupt PNG"); if (pal_img_n && !pal_len) return stbi__err("no PLTE", "Corrupt PNG"); if (scan == STBI__SCAN_header) { s->img_n = pal_img_n; return 1; } if ((int)(ioff + c.length) < (int)ioff) return 0; if (ioff + c.length > idata_limit) { uint32_t idata_limit_old = idata_limit; unsigned char *p; if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096; while (ioff + c.length > idata_limit) idata_limit *= 2; (void)idata_limit_old; p = STBI_REALLOC_SIZED(z->idata, idata_limit_old, idata_limit); if (p == NULL) return stbi__err("outofmem", "Out of memory"); z->idata = p; } if (!stbi__getn(s, z->idata + ioff, c.length)) return stbi__err("outofdata", "Corrupt PNG"); ioff += c.length; break; } case STBI__PNG_TYPE('I', 'E', 'N', 'D'): { uint32_t raw_len, bpl; if (first) return stbi__err("first not IHDR", "Corrupt PNG"); if (scan != STBI__SCAN_load) return 1; if (z->idata == NULL) return stbi__err("no IDAT", "Corrupt PNG"); // initial guess for decoded data size to avoid unnecessary reallocs bpl = (s->img_x * z->depth + 7) / 8; // bytes per line, per component raw_len = bpl * s->img_y * s->img_n /* pixels */ + s->img_y /* filter mode per row */; z->expanded = (unsigned char *)stbi_zlib_decode_malloc_guesssize_headerflag( (char *)z->idata, ioff, raw_len, (int *)&raw_len, !is_iphone); if (z->expanded == NULL) return 0; // zlib should set error free(z->idata); z->idata = NULL; if ((req_comp == s->img_n + 1 && req_comp != 3 && !pal_img_n) || has_trans) { s->img_out_n = s->img_n + 1; } else { s->img_out_n = s->img_n; } if (!stbi__create_png_image(z, z->expanded, raw_len, s->img_out_n, z->depth, color, interlace)) return 0; if (has_trans) { if (z->depth == 16) { if (!stbi__compute_transparency16(z, tc16, s->img_out_n)) return 0; } else { if (!stbi__compute_transparency(z, tc, s->img_out_n)) return 0; } } if (is_iphone && stbi__de_iphone_flag && s->img_out_n > 2) stbi__de_iphone(z); if (pal_img_n) { // pal_img_n == 3 or 4 s->img_n = pal_img_n; // record the actual colors we had s->img_out_n = pal_img_n; if (req_comp >= 3) s->img_out_n = req_comp; if (!stbi__expand_png_palette(z, palette, pal_len, s->img_out_n)) return 0; } else if (has_trans) { // non-paletted image with tRNS -> source image has (constant) alpha ++s->img_n; } free(z->expanded); z->expanded = NULL; stbi__get32be(s); /* nothings/stb#835 */ return 1; } default: // if critical, fail if (first) return stbi__err("first not IHDR", "Corrupt PNG"); if ((c.type & (1 << 29)) == 0) { #ifndef STBI_NO_FAILURE_STRINGS // not threadsafe static char invalid_chunk[] = "XXXX PNG chunk not known"; invalid_chunk[0] = STBI__BYTECAST(c.type >> 24); invalid_chunk[1] = STBI__BYTECAST(c.type >> 16); invalid_chunk[2] = STBI__BYTECAST(c.type >> 8); invalid_chunk[3] = STBI__BYTECAST(c.type >> 0); #endif return stbi__err(invalid_chunk, "PNG not supported: unknown PNG chunk type"); } stbi__skip(s, c.length); break; } // end of PNG chunk, read and skip CRC stbi__get32be(s); } } static void *stbi__do_png(stbi__png *p, int *x, int *y, int *n, int req_comp, stbi__result_info *ri) { void *result = NULL; if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error"); if (stbi__parse_png_file(p, STBI__SCAN_load, req_comp)) { if (p->depth < 8) ri->bits_per_channel = 8; else ri->bits_per_channel = p->depth; result = p->out; p->out = NULL; if (req_comp && req_comp != p->s->img_out_n) { if (ri->bits_per_channel == 8) result = stbi__convert_format((unsigned char *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y); else result = stbi__convert_format16((uint16_t *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y); p->s->img_out_n = req_comp; if (result == NULL) return result; } *x = p->s->img_x; *y = p->s->img_y; if (n) *n = p->s->img_n; } free(p->out); p->out = NULL; free(p->expanded); p->expanded = NULL; free(p->idata); p->idata = NULL; return result; } static noinline void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri) { stbi__png p; p.s = s; return stbi__do_png(&p, x, y, comp, req_comp, ri); } static int stbi__png_test(stbi__context *s) { int r; r = stbi__check_png_header(s); stbi__rewind(s); return r; } static int stbi__png_info_raw(stbi__png *p, int *x, int *y, int *comp) { if (!stbi__parse_png_file(p, STBI__SCAN_header, 0)) { stbi__rewind(p->s); return 0; } if (x) *x = p->s->img_x; if (y) *y = p->s->img_y; if (comp) *comp = p->s->img_n; return 1; } static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp) { stbi__png p; p.s = s; return stbi__png_info_raw(&p, x, y, comp); } static int stbi__png_is16(stbi__context *s) { stbi__png p; p.s = s; if (!stbi__png_info_raw(&p, NULL, NULL, NULL)) return 0; if (p.depth != 16) { stbi__rewind(p.s); return 0; } return 1; } // ***************************************************************************** // GIF loader -- public domain by Jean-Marc Lienher -- simplified/shrunk by // stb typedef struct { int16_t prefix; unsigned char first; unsigned char suffix; } stbi__gif_lzw; typedef struct { int w, h; unsigned char *out; // output buffer (always 4 components) unsigned char *background; // The current "background" as far as a gif is concerned unsigned char *history; int flags, bgindex, ratio, transparent, eflags; unsigned char pal[256][4]; unsigned char lpal[256][4]; stbi__gif_lzw codes[8192]; unsigned char *color_table; int parse, step; int lflags; int start_x, start_y; int max_x, max_y; int cur_x, cur_y; int line_size; int delay; } stbi__gif; static int stbi__gif_test_raw(stbi__context *s) { int sz; if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8') return 0; sz = stbi__get8(s); if (sz != '9' && sz != '7') return 0; if (stbi__get8(s) != 'a') return 0; return 1; } static int stbi__gif_test(stbi__context *s) { int r = stbi__gif_test_raw(s); stbi__rewind(s); return r; } static void stbi__gif_parse_colortable(stbi__context *s, unsigned char pal[256][4], int num_entries, int transp) { int i; for (i = 0; i < num_entries; ++i) { pal[i][2] = stbi__get8(s); pal[i][1] = stbi__get8(s); pal[i][0] = stbi__get8(s); pal[i][3] = transp == i ? 0 : 255; } } static int stbi__gif_header(stbi__context *s, stbi__gif *g, int *comp, int is_info) { unsigned char version; if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8') return stbi__err("not GIF", "Corrupt GIF"); version = stbi__get8(s); if (version != '7' && version != '9') { return stbi__err("not GIF", "Corrupt GIF"); } if (stbi__get8(s) != 'a') return stbi__err("not GIF", "Corrupt GIF"); stbi__g_failure_reason = ""; g->w = stbi__get16le(s); g->h = stbi__get16le(s); g->flags = stbi__get8(s); g->bgindex = stbi__get8(s); g->ratio = stbi__get8(s); g->transparent = -1; if (comp != 0) { *comp = 4; // can't actually tell whether it's 3 or 4 until we parse the // comments } if (is_info) return 1; if (g->flags & 0x80) { stbi__gif_parse_colortable(s, g->pal, 2 << (g->flags & 7), -1); } return 1; } static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp) { stbi__gif *g = (stbi__gif *)malloc(sizeof(stbi__gif)); if (!stbi__gif_header(s, g, comp, 1)) { free(g); stbi__rewind(s); return 0; } if (x) *x = g->w; if (y) *y = g->h; free(g); return 1; } static void stbi__out_gif_code(stbi__gif *g, uint16_t code) { unsigned char *p, *c; int idx; // recurse to decode the prefixes, since the linked-list is backwards, // and working backwards through an interleaved image would be nasty if (g->codes[code].prefix >= 0) stbi__out_gif_code(g, g->codes[code].prefix); if (g->cur_y >= g->max_y) return; idx = g->cur_x + g->cur_y; p = &g->out[idx]; g->history[idx / 4] = 1; c = &g->color_table[g->codes[code].suffix * 4]; if (c[3] > 128) { // don't render transparent pixels; p[0] = c[2]; p[1] = c[1]; p[2] = c[0]; p[3] = c[3]; } g->cur_x += 4; if (g->cur_x >= g->max_x) { g->cur_x = g->start_x; g->cur_y += g->step; while (g->cur_y >= g->max_y && g->parse > 0) { g->step = (1 << g->parse) * g->line_size; g->cur_y = g->start_y + (g->step >> 1); --g->parse; } } } static unsigned char *stbi__process_gif_raster(stbi__context *s, stbi__gif *g) { unsigned char lzw_cs; int32_t len, init_code; uint32_t first; int32_t codesize, codemask, avail, oldcode, bits, valid_bits, clear; stbi__gif_lzw *p; lzw_cs = stbi__get8(s); if (lzw_cs > 12) return NULL; clear = 1 << lzw_cs; first = 1; codesize = lzw_cs + 1; codemask = (1 << codesize) - 1; bits = 0; valid_bits = 0; for (init_code = 0; init_code < clear; init_code++) { g->codes[init_code].prefix = -1; g->codes[init_code].first = (unsigned char)init_code; g->codes[init_code].suffix = (unsigned char)init_code; } // support no starting clear code avail = clear + 2; oldcode = -1; len = 0; for (;;) { if (valid_bits < codesize) { if (len == 0) { len = stbi__get8(s); // start new block if (len == 0) return g->out; } --len; bits |= (int32_t)stbi__get8(s) << valid_bits; valid_bits += 8; } else { int32_t code = bits & codemask; bits >>= codesize; valid_bits -= codesize; // @OPTIMIZE: is there some way we can accelerate the non-clear path? if (code == clear) { // clear code codesize = lzw_cs + 1; codemask = (1 << codesize) - 1; avail = clear + 2; oldcode = -1; first = 0; } else if (code == clear + 1) { // end of stream code stbi__skip(s, len); while ((len = stbi__get8(s)) > 0) stbi__skip(s, len); return g->out; } else if (code <= avail) { if (first) { return stbi__errpuc("no clear code", "Corrupt GIF"); } if (oldcode >= 0) { p = &g->codes[avail++]; if (avail > 8192) { return stbi__errpuc("too many codes", "Corrupt GIF"); } p->prefix = (int16_t)oldcode; p->first = g->codes[oldcode].first; p->suffix = (code == avail) ? p->first : g->codes[code].first; } else if (code == avail) return stbi__errpuc("illegal code in raster", "Corrupt GIF"); stbi__out_gif_code(g, (uint16_t)code); if ((avail & codemask) == 0 && avail <= 0x0FFF) { codesize++; codemask = (1 << codesize) - 1; } oldcode = code; } else { return stbi__errpuc("illegal code in raster", "Corrupt GIF"); } } } } // this function is designed to support animated gifs, although stb_image // doesn't support it two back is the image from two frames ago, used for a // very specific disposal format static unsigned char *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, unsigned char *two_back) { int dispose; int first_frame; int pi; int pcount; // on first frame, any non-written pixels get the background colour // (non-transparent) first_frame = 0; if (g->out == 0) { if (!stbi__gif_header(s, g, comp, 0)) return 0; // stbi__g_failure_reason set by stbi__gif_header if (!stbi__mad3sizes_valid(4, g->w, g->h, 0)) return stbi__errpuc("too large", "GIF image is too large"); pcount = g->w * g->h; g->out = malloc(4 * pcount); g->background = malloc(4 * pcount); g->history = malloc(pcount); if (!g->out || !g->background || !g->history) return stbi__errpuc("outofmem", "Out of memory"); // image is treated as "transparent" at the start - ie, nothing overwrites // the current background; background colour is only used for pixels that // are not rendered first frame, after that "background" color refers to // the color that was there the previous frame. memset(g->out, 0x00, 4 * pcount); memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent) memset(g->history, 0x00, pcount); // pixels that were affected previous frame first_frame = 1; } else { // second frame - how do we dispoase of the previous one? dispose = (g->eflags & 0x1C) >> 2; pcount = g->w * g->h; if ((dispose == 3) && (two_back == 0)) { dispose = 2; // if I don't have an image to revert back to, default to // the old background } if (dispose == 3) { // use previous graphic for (pi = 0; pi < pcount; ++pi) { if (g->history[pi]) { memcpy(&g->out[pi * 4], &two_back[pi * 4], 4); } } } else if (dispose == 2) { // restore what was changed last frame to background before that frame; for (pi = 0; pi < pcount; ++pi) { if (g->history[pi]) { memcpy(&g->out[pi * 4], &g->background[pi * 4], 4); } } } else { // This is a non-disposal case eithe way, so just // leave the pixels as is, and they will become the new background // 1: do not dispose // 0: not specified. } // background is what out is after the undoing of the previou frame; memcpy(g->background, g->out, 4 * g->w * g->h); } // clear my history; memset(g->history, 0x00, g->w * g->h); // pixels that were affected previous frame for (;;) { int tag = stbi__get8(s); switch (tag) { case 0x2C: /* Image Descriptor */ { int32_t x, y, w, h; unsigned char *o; x = stbi__get16le(s); y = stbi__get16le(s); w = stbi__get16le(s); h = stbi__get16le(s); if (((x + w) > (g->w)) || ((y + h) > (g->h))) return stbi__errpuc("bad Image Descriptor", "Corrupt GIF"); g->line_size = g->w * 4; g->start_x = x * 4; g->start_y = y * g->line_size; g->max_x = g->start_x + w * 4; g->max_y = g->start_y + h * g->line_size; g->cur_x = g->start_x; g->cur_y = g->start_y; // if the width of the specified rectangle is 0, that means // we may not see *any* pixels or the image is malformed; // to make sure this is caught, move the current y down to // max_y (which is what out_gif_code checks). if (w == 0) g->cur_y = g->max_y; g->lflags = stbi__get8(s); if (g->lflags & 0x40) { g->step = 8 * g->line_size; // first interlaced spacing g->parse = 3; } else { g->step = g->line_size; g->parse = 0; } if (g->lflags & 0x80) { stbi__gif_parse_colortable(s, g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1); g->color_table = (unsigned char *)g->lpal; } else if (g->flags & 0x80) { g->color_table = (unsigned char *)g->pal; } else return stbi__errpuc("missing color table", "Corrupt GIF"); o = stbi__process_gif_raster(s, g); if (!o) return NULL; // if this was the first frame, pcount = g->w * g->h; if (first_frame && (g->bgindex > 0)) { // if first frame, any pixel not drawn to gets the background color for (pi = 0; pi < pcount; ++pi) { if (g->history[pi] == 0) { g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It // will be reset next frame if need be; memcpy(&g->out[pi * 4], &g->pal[g->bgindex], 4); } } } return o; } case 0x21: // Comment Extension. { int len; int ext = stbi__get8(s); if (ext == 0xF9) { // Graphic Control Extension. len = stbi__get8(s); if (len == 4) { g->eflags = stbi__get8(s); g->delay = 10 * stbi__get16le( s); // delay - 1/100th of a second, saving as 1/1000ths. // unset old transparent if (g->transparent >= 0) { g->pal[g->transparent][3] = 255; } if (g->eflags & 0x01) { g->transparent = stbi__get8(s); if (g->transparent >= 0) { g->pal[g->transparent][3] = 0; } } else { // don't need transparent stbi__skip(s, 1); g->transparent = -1; } } else { stbi__skip(s, len); break; } } while ((len = stbi__get8(s)) != 0) { stbi__skip(s, len); } break; } case 0x3B: // gif stream termination code return ( unsigned char *)s; // using '1' causes warning on some compilers default: return stbi__errpuc("unknown code", "Corrupt GIF"); } } } static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp) { if (stbi__gif_test(s)) { int layers = 0; unsigned char *u = 0; unsigned char *out = 0; unsigned char *two_back = 0; stbi__gif *g; int stride; g = calloc(1, sizeof(stbi__gif)); if (delays) { *delays = 0; } do { u = stbi__gif_load_next(s, g, comp, req_comp, two_back); if (u == (unsigned char *)s) u = 0; // end of animated gif marker if (u) { *x = g->w; *y = g->h; ++layers; stride = g->w * g->h * 4; if (out) { out = (unsigned char *)realloc(out, layers * stride); if (!out) abort(); if (delays) { *delays = (int *)realloc(*delays, sizeof(int) * layers); if (!*delays) abort(); } } else { out = malloc(layers * stride); if (delays) { *delays = malloc(layers * sizeof(int)); } } memcpy(out + ((layers - 1) * stride), u, stride); if (layers >= 2) { two_back = out - 2 * stride; } if (delays) { (*delays)[layers - 1U] = g->delay; } } } while (u != 0); free(g->out); free(g->history); free(g->background); // do the final conversion after loading everything; if (req_comp && req_comp != 4) out = stbi__convert_format(out, 4, req_comp, layers * g->w, g->h); free(g); *z = layers; return out; } else { return stbi__errpuc("not GIF", "Image was not as a gif type."); } } static noinline void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri) { unsigned char *u = 0; stbi__gif *g; g = calloc(1, sizeof(stbi__gif)); u = stbi__gif_load_next(s, g, comp, req_comp, 0); if (u == (unsigned char *)s) u = 0; // end of animated gif marker if (u) { *x = g->w; *y = g->h; // moved conversion to after successful load so that the same // can be done for multiple frames. if (req_comp && req_comp != 4) u = stbi__convert_format(u, 4, req_comp, g->w, g->h); } else if (g->out) { // if there was an error and we allocated an image buffer, free it! free(g->out); } // free buffers needed for multiple frame loading; free(g->history); free(g->background); free(g); return u; } static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp) { return stbi__gif_info_raw(s, x, y, comp); } // ******************************************************************** // Portable Gray Map and Portable Pixel Map loader // by Ken Miller // // PGM: http://netpbm.sourceforge.net/doc/pgm.html // PPM: http://netpbm.sourceforge.net/doc/ppm.html // // Known limitations: // Does not support comments in the header section // Does not support ASCII image data (formats P2 and P3) // Does not support 16-bit-per-channel static int stbi__pnm_test(stbi__context *s) { char p, t; p = (char)stbi__get8(s); t = (char)stbi__get8(s); if (p != 'P' || (t != '5' && t != '6')) { stbi__rewind(s); return 0; } return 1; } static noinline void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri) { unsigned char *out; if (!stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n)) { return 0; } *x = s->img_x; *y = s->img_y; if (comp) *comp = s->img_n; if (!stbi__mad3sizes_valid(s->img_n, s->img_x, s->img_y, 0)) { return stbi__errpuc("too large", "PNM too large"); } out = stbi__malloc_mad3(s->img_n, s->img_x, s->img_y, 0); stbi__getn(s, out, s->img_n * s->img_x * s->img_y); if (req_comp && req_comp != s->img_n) { out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y); if (out == NULL) return out; // stbi__convert_format frees input on failure } return out; } static int stbi__pnm_isspace(char c) { return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r'; } static void stbi__pnm_skip_whitespace(stbi__context *s, char *c) { for (;;) { while (!stbi__at_eof(s) && stbi__pnm_isspace(*c)) *c = (char)stbi__get8(s); if (stbi__at_eof(s) || *c != '#') break; while (!stbi__at_eof(s) && *c != '\n' && *c != '\r') *c = (char)stbi__get8(s); } } static int stbi__pnm_isdigit(char c) { return c >= '0' && c <= '9'; } static int stbi__pnm_getinteger(stbi__context *s, char *c) { int value = 0; while (!stbi__at_eof(s) && stbi__pnm_isdigit(*c)) { value = value * 10 + (*c - '0'); *c = (char)stbi__get8(s); } return value; } static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp) { int maxv, dummy; char c, p, t; if (!x) x = &dummy; if (!y) y = &dummy; if (!comp) comp = &dummy; stbi__rewind(s); // Get identifier p = (char)stbi__get8(s); t = (char)stbi__get8(s); if (p != 'P' || (t != '5' && t != '6')) { stbi__rewind(s); return 0; } *comp = (t == '6') ? 3 : 1; // '5' is 1-component .pgm; '6' is 3-component .ppm c = (char)stbi__get8(s); stbi__pnm_skip_whitespace(s, &c); *x = stbi__pnm_getinteger(s, &c); // read width stbi__pnm_skip_whitespace(s, &c); *y = stbi__pnm_getinteger(s, &c); // read height stbi__pnm_skip_whitespace(s, &c); maxv = stbi__pnm_getinteger(s, &c); // read max value if (maxv > 255) return stbi__err("max value > 255", "PPM image not 8-bit"); else { return 1; } } static int stbi__info_main(stbi__context *s, int *x, int *y, int *comp) { #ifndef STBI_NO_JPEG if (stbi__jpeg_info(s, x, y, comp)) return 1; #endif #ifndef STBI_NO_PNG if (stbi__png_info(s, x, y, comp)) return 1; #endif #ifndef STBI_NO_GIF if (stbi__gif_info(s, x, y, comp)) return 1; #endif #ifndef STBI_NO_PNM if (stbi__pnm_info(s, x, y, comp)) return 1; #endif return stbi__err("unknown image type", "Image not of any known type, or corrupt"); } static int stbi__is_16_main(stbi__context *s) { if (stbi__png_is16(s)) return 1; return 0; } int stbi_info(char const *filename, int *x, int *y, int *comp) { FILE *f = stbi__fopen(filename, "rb"); int result; if (!f) return stbi__err("can't fopen", "Unable to open file"); result = stbi_info_from_file(f, x, y, comp); fclose(f); return result; } int stbi_info_from_file(FILE *f, int *x, int *y, int *comp) { int r; stbi__context s; long pos = ftell(f); stbi__start_file(&s, f); r = stbi__info_main(&s, x, y, comp); fseek(f, pos, SEEK_SET); return r; } int stbi_is_16_bit(char const *filename) { FILE *f = stbi__fopen(filename, "rb"); int result; if (!f) return stbi__err("can't fopen", "Unable to open file"); result = stbi_is_16_bit_from_file(f); fclose(f); return result; } int stbi_is_16_bit_from_file(FILE *f) { int r; stbi__context s; long pos = ftell(f); stbi__start_file(&s, f); r = stbi__is_16_main(&s); fseek(f, pos, SEEK_SET); return r; } int stbi_info_from_memory(unsigned char const *buffer, int len, int *x, int *y, int *comp) { stbi__context s; stbi__start_mem(&s, buffer, len); return stbi__info_main(&s, x, y, comp); } int stbi_info_from_callbacks(stbi_io_callbacks const *c, void *user, int *x, int *y, int *comp) { stbi__context s; stbi__start_callbacks(&s, (stbi_io_callbacks *)c, user); return stbi__info_main(&s, x, y, comp); } int stbi_is_16_bit_from_memory(unsigned char const *buffer, int len) { stbi__context s; stbi__start_mem(&s, buffer, len); return stbi__is_16_main(&s); } int stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *c, void *user) { stbi__context s; stbi__start_callbacks(&s, (stbi_io_callbacks *)c, user); return stbi__is_16_main(&s); }