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cosmopolitan/third_party/zlib/infback.c

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/*-*- 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 1995-2016 Jean-loup Gailly and Mark Adler │
│ Use of this source code is governed by the BSD-style licenses that can │
│ be found in the third_party/zlib/LICENSE file. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/str/str.h"
#include "third_party/zlib/inffast.h"
#include "third_party/zlib/inflate.h"
#include "third_party/zlib/inftrees.h"
#include "third_party/zlib/internal.h"
#include "third_party/zlib/zutil.h"
asm(".ident\t\"\\n\\n\
zlib (zlib License)\\n\
Copyright 1995-2017 Jean-loup Gailly and Mark Adler\"");
asm(".include \"libc/disclaimer.inc\"");
/*
This code is largely copied from inflate.c. Normally either infback.o or
inflate.o would be linked into an application--not both. The interface
with inffast.c is retained so that optimized assembler-coded versions of
inflate_fast() can be used with either inflate.c or infback.c.
*/
/**
* strm provides memory allocation functions in zalloc and zfree, or
* Z_NULL to use the library memory allocation functions.
*
* windowBits is in the range 8..15, and window is a user-supplied
* window and output buffer that is 2**windowBits bytes.
*/
int inflateBackInit(z_streamp strm, int windowBits, unsigned char *window) {
struct InflateState *state;
if (strm == Z_NULL || window == Z_NULL || windowBits < 8 || windowBits > 15) {
return Z_STREAM_ERROR;
}
strm->msg = Z_NULL; /* in case we return an error */
if (strm->zalloc == (alloc_func)0) {
strm->zalloc = zcalloc;
strm->opaque = (voidpf)0;
}
if (strm->zfree == (free_func)0) {
strm->zfree = zcfree;
}
state = (struct InflateState *)ZALLOC(strm, 1, sizeof(struct InflateState));
if (state == Z_NULL) return Z_MEM_ERROR;
Tracev((stderr, "inflate: allocated\n"));
strm->state = (struct DeflateState *)state;
state->dmax = 32768U;
state->wbits = (uInt)windowBits;
state->wsize = 1U << windowBits;
state->window = window;
state->wnext = 0;
state->whave = 0;
return Z_OK;
}
/**
* Returns state with length and distance decoding tables and index
* sizes set to fixed code decoding. Normally this returns fixed tables
* from inffixed.h. If BUILDFIXED is defined, then instead this routine
* builds the tables the first time it's called, and returns those
* tables the first time and thereafter. This reduces the size of the
* code by about 2K bytes, in exchange for a little execution time.
* However, BUILDFIXED should not be used for threaded applications,
* since the rewriting of the tables and virgin may not be thread-safe.
*/
static void fixedtables(struct InflateState *state) {
#ifdef BUILDFIXED
static int virgin = 1;
static code *lenfix, *distfix;
static code fixed[544];
/* build fixed huffman tables if first call (may not be thread safe) */
if (virgin) {
unsigned sym, bits;
static code *next;
/* literal/length table */
sym = 0;
while (sym < 144) state->lens[sym++] = 8;
while (sym < 256) state->lens[sym++] = 9;
while (sym < 280) state->lens[sym++] = 7;
while (sym < 288) state->lens[sym++] = 8;
next = fixed;
lenfix = next;
bits = 9;
inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
/* distance table */
sym = 0;
while (sym < 32) state->lens[sym++] = 5;
distfix = next;
bits = 5;
inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
/* do this just once */
virgin = 0;
}
state->lencode = lenfix;
state->distcode = distfix;
#else /* !BUILDFIXED */
state->lencode = kZlibLenfix;
state->distcode = kZlibDistfix;
#endif /* BUILDFIXED */
state->lenbits = 9;
state->distbits = 5;
}
/* Macros for inflateBack(): */
/* Load returned state from inflate_fast() */
#define LOAD() \
do { \
put = strm->next_out; \
left = strm->avail_out; \
next = strm->next_in; \
have = strm->avail_in; \
hold = state->hold; \
bits = state->bits; \
} while (0)
/* Set state from registers for inflate_fast() */
#define RESTORE() \
do { \
strm->next_out = put; \
strm->avail_out = left; \
strm->next_in = next; \
strm->avail_in = have; \
state->hold = hold; \
state->bits = bits; \
} while (0)
/* Clear the input bit accumulator */
#define INITBITS() \
do { \
hold = 0; \
bits = 0; \
} while (0)
/* Assure that some input is available. If input is requested, but denied,
then return a Z_BUF_ERROR from inflateBack(). */
#define PULL() \
do { \
if (have == 0) { \
have = in(in_desc, &next); \
if (have == 0) { \
next = Z_NULL; \
ret = Z_BUF_ERROR; \
goto inf_leave; \
} \
} \
} while (0)
/* Get a byte of input into the bit accumulator, or return from inflateBack()
with an error if there is no input available. */
#define PULLBYTE() \
do { \
PULL(); \
have--; \
hold += (unsigned long)(*next++) << bits; \
bits += 8; \
} while (0)
/* Assure that there are at least n bits in the bit accumulator. If there is
not enough available input to do that, then return from inflateBack() with
an error. */
#define NEEDBITS(n) \
do { \
while (bits < (unsigned)(n)) PULLBYTE(); \
} while (0)
/* Return the low n bits of the bit accumulator (n < 16) */
#define BITS(n) ((unsigned)hold & ((1U << (n)) - 1))
/* Remove n bits from the bit accumulator */
#define DROPBITS(n) \
do { \
hold >>= (n); \
bits -= (unsigned)(n); \
} while (0)
/* Remove zero to seven bits as needed to go to a byte boundary */
#define BYTEBITS() \
do { \
hold >>= bits & 7; \
bits -= bits & 7; \
} while (0)
/* Assure that some output space is available, by writing out the window
if it's full. If the write fails, return from inflateBack() with a
Z_BUF_ERROR. */
#define ROOM() \
do { \
if (left == 0) { \
put = state->window; \
left = state->wsize; \
state->whave = left; \
if (out(out_desc, put, left)) { \
ret = Z_BUF_ERROR; \
goto inf_leave; \
} \
} \
} while (0)
/**
* strm provides the memory allocation functions and window buffer on
* input, and provides information on the unused input on return. For
* Z_DATA_ERROR returns, strm will also provide an error message.
*
* in() and out() are the call-back input and output functions. When
* inflateBack() needs more input, it calls in(). When inflateBack() has
* filled the window with output, or when it completes with data in the
* window, it calls out() to write out the data. The application must
* not change the provided input until in() is called again or
* inflateBack() returns. The application must not change the
* window/output buffer until inflateBack() returns.
*
* in() and out() are called with a descriptor parameter provided in the
* inflateBack() call. This parameter can be a structure that provides
* the information required to do the read or write, as well as
* accumulated information on the input and output such as totals and
* check values.
*
* in() should return zero on failure. out() should return non-zero on
* failure. If either in() or out() fails, than inflateBack() returns a
* Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether
* it was in() or out() that caused in the error. Otherwise,
* inflateBack() returns Z_STREAM_END on success, Z_DATA_ERROR for an
* deflate format error, or Z_MEM_ERROR if it could not allocate memory
* for the state. inflateBack() can also return Z_STREAM_ERROR if the
* input parameters are not correct, i.e. strm is Z_NULL or the state
* was not initialized.
*/
int inflateBack(z_streamp strm, in_func in, void *in_desc, out_func out,
void *out_desc) {
struct InflateState *state;
const unsigned char *next; /* next input */
unsigned char *put; /* next output */
unsigned have, left; /* available input and output */
unsigned long hold; /* bit buffer */
unsigned bits; /* bits in bit buffer */
unsigned copy; /* number of stored or match bytes to copy */
unsigned char *from; /* where to copy match bytes from */
struct zcode here; /* current decoding table entry */
struct zcode last; /* parent table entry */
unsigned len; /* length to copy for repeats, bits to drop */
int ret; /* return code */
static const unsigned short order[19] = /* permutation of code lengths */
{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
/* Check that the strm exists and that the state was initialized */
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
state = (struct InflateState *)strm->state;
/* Reset the state */
strm->msg = Z_NULL;
state->mode = TYPE;
state->last = 0;
state->whave = 0;
next = strm->next_in;
have = next != Z_NULL ? strm->avail_in : 0;
hold = 0;
bits = 0;
put = state->window;
left = state->wsize;
/* Inflate until end of block marked as last */
for (;;) switch (state->mode) {
case TYPE:
/* determine and dispatch block type */
if (state->last) {
BYTEBITS();
state->mode = DONE;
break;
}
NEEDBITS(3);
state->last = BITS(1);
DROPBITS(1);
switch (BITS(2)) {
case 0: /* stored block */
Tracev((stderr, "inflate: stored block%s\n",
state->last ? " (last)" : ""));
state->mode = STORED;
break;
case 1: /* fixed block */
fixedtables(state);
Tracev((stderr, "inflate: fixed codes block%s\n",
state->last ? " (last)" : ""));
state->mode = LEN; /* decode codes */
break;
case 2: /* dynamic block */
Tracev((stderr, "inflate: dynamic codes block%s\n",
state->last ? " (last)" : ""));
state->mode = TABLE;
break;
case 3:
strm->msg = (char *)"invalid block type";
state->mode = BAD;
}
DROPBITS(2);
break;
case STORED:
/* get and verify stored block length */
BYTEBITS(); /* go to byte boundary */
NEEDBITS(32);
if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
strm->msg = (char *)"invalid stored block lengths";
state->mode = BAD;
break;
}
state->length = (unsigned)hold & 0xffff;
Tracev((stderr, "inflate: stored length %u\n", state->length));
INITBITS();
/* copy stored block from input to output */
while (state->length != 0) {
copy = state->length;
PULL();
ROOM();
if (copy > have) copy = have;
if (copy > left) copy = left;
memcpy(put, next, copy);
have -= copy;
next += copy;
left -= copy;
put += copy;
state->length -= copy;
}
Tracev((stderr, "inflate: stored end\n"));
state->mode = TYPE;
break;
case TABLE:
/* get dynamic table entries descriptor */
NEEDBITS(14);
state->nlen = BITS(5) + 257;
DROPBITS(5);
state->ndist = BITS(5) + 1;
DROPBITS(5);
state->ncode = BITS(4) + 4;
DROPBITS(4);
#ifndef PKZIP_BUG_WORKAROUND
if (state->nlen > 286 || state->ndist > 30) {
strm->msg = (char *)"too many length or distance symbols";
state->mode = BAD;
break;
}
#endif
Tracev((stderr, "inflate: table sizes ok\n"));
/* get code length code lengths (not a typo) */
state->have = 0;
while (state->have < state->ncode) {
NEEDBITS(3);
state->lens[order[state->have++]] = (unsigned short)BITS(3);
DROPBITS(3);
}
while (state->have < 19) state->lens[order[state->have++]] = 0;
state->next = state->codes;
state->lencode = (const struct zcode *)(state->next);
state->lenbits = 7;
ret = inflate_table(CODES, state->lens, 19, &(state->next),
&(state->lenbits), state->work);
if (ret) {
strm->msg = (char *)"invalid code lengths set";
state->mode = BAD;
break;
}
Tracev((stderr, "inflate: code lengths ok\n"));
/* get length and distance code code lengths */
state->have = 0;
while (state->have < state->nlen + state->ndist) {
for (;;) {
here = state->lencode[BITS(state->lenbits)];
if ((unsigned)(here.bits) <= bits) break;
PULLBYTE();
}
if (here.val < 16) {
DROPBITS(here.bits);
state->lens[state->have++] = here.val;
} else {
if (here.val == 16) {
NEEDBITS(here.bits + 2);
DROPBITS(here.bits);
if (state->have == 0) {
strm->msg = (char *)"invalid bit length repeat";
state->mode = BAD;
break;
}
len = (unsigned)(state->lens[state->have - 1]);
copy = 3 + BITS(2);
DROPBITS(2);
} else if (here.val == 17) {
NEEDBITS(here.bits + 3);
DROPBITS(here.bits);
len = 0;
copy = 3 + BITS(3);
DROPBITS(3);
} else {
NEEDBITS(here.bits + 7);
DROPBITS(here.bits);
len = 0;
copy = 11 + BITS(7);
DROPBITS(7);
}
if (state->have + copy > state->nlen + state->ndist) {
strm->msg = (char *)"invalid bit length repeat";
state->mode = BAD;
break;
}
while (copy--) state->lens[state->have++] = (unsigned short)len;
}
}
/* handle error breaks in while */
if (state->mode == BAD) break;
/* check for end-of-block code (better have one) */
if (state->lens[256] == 0) {
strm->msg = (char *)"invalid code -- missing end-of-block";
state->mode = BAD;
break;
}
/* build code tables -- note: do not change the lenbits or distbits
values here (9 and 6) without reading the comments in inftrees.h
concerning the ENOUGH constants, which depend on those values */
state->next = state->codes;
state->lencode = (const struct zcode *)(state->next);
state->lenbits = 9;
ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
&(state->lenbits), state->work);
if (ret) {
strm->msg = (char *)"invalid literal/lengths set";
state->mode = BAD;
break;
}
state->distcode = (const struct zcode *)(state->next);
state->distbits = 6;
ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
&(state->next), &(state->distbits), state->work);
if (ret) {
strm->msg = (char *)"invalid distances set";
state->mode = BAD;
break;
}
Tracev((stderr, "inflate: codes ok\n"));
state->mode = LEN;
case LEN:
/* use inflate_fast() if we have enough input and output */
if (have >= INFLATE_FAST_MIN_INPUT && left >= INFLATE_FAST_MIN_OUTPUT) {
RESTORE();
if (state->whave < state->wsize) state->whave = state->wsize - left;
inflate_fast(strm, state->wsize);
LOAD();
break;
}
/* get a literal, length, or end-of-block code */
for (;;) {
here = state->lencode[BITS(state->lenbits)];
if ((unsigned)(here.bits) <= bits) break;
PULLBYTE();
}
if (here.op && (here.op & 0xf0) == 0) {
last = here;
for (;;) {
here = state->lencode[last.val +
(BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)(last.bits + here.bits) <= bits) break;
PULLBYTE();
}
DROPBITS(last.bits);
}
DROPBITS(here.bits);
state->length = (unsigned)here.val;
/* process literal */
if (here.op == 0) {
Tracevv((stderr,
here.val >= 0x20 && here.val < 0x7f
? "inflate: literal '%c'\n"
: "inflate: literal 0x%02x\n",
here.val));
ROOM();
*put++ = (unsigned char)(state->length);
left--;
state->mode = LEN;
break;
}
/* process end of block */
if (here.op & 32) {
Tracevv((stderr, "inflate: end of block\n"));
state->mode = TYPE;
break;
}
/* invalid code */
if (here.op & 64) {
strm->msg = (char *)"invalid literal/length code";
state->mode = BAD;
break;
}
/* length code -- get extra bits, if any */
state->extra = (unsigned)(here.op) & 15;
if (state->extra != 0) {
NEEDBITS(state->extra);
state->length += BITS(state->extra);
DROPBITS(state->extra);
}
Tracevv((stderr, "inflate: length %u\n", state->length));
/* get distance code */
for (;;) {
here = state->distcode[BITS(state->distbits)];
if ((unsigned)(here.bits) <= bits) break;
PULLBYTE();
}
if ((here.op & 0xf0) == 0) {
last = here;
for (;;) {
here = state->distcode[last.val +
(BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)(last.bits + here.bits) <= bits) break;
PULLBYTE();
}
DROPBITS(last.bits);
}
DROPBITS(here.bits);
if (here.op & 64) {
strm->msg = (char *)"invalid distance code";
state->mode = BAD;
break;
}
state->offset = (unsigned)here.val;
/* get distance extra bits, if any */
state->extra = (unsigned)(here.op) & 15;
if (state->extra != 0) {
NEEDBITS(state->extra);
state->offset += BITS(state->extra);
DROPBITS(state->extra);
}
if (state->offset >
state->wsize - (state->whave < state->wsize ? left : 0)) {
strm->msg = (char *)"invalid distance too far back";
state->mode = BAD;
break;
}
Tracevv((stderr, "inflate: distance %u\n", state->offset));
/* copy match from window to output */
do {
ROOM();
copy = state->wsize - state->offset;
if (copy < left) {
from = put + copy;
copy = left - copy;
} else {
from = put - state->offset;
copy = left;
}
if (copy > state->length) copy = state->length;
state->length -= copy;
left -= copy;
do {
*put++ = *from++;
} while (--copy);
} while (state->length != 0);
break;
case DONE:
/* inflate stream terminated properly -- write leftover output */
ret = Z_STREAM_END;
if (left < state->wsize) {
if (out(out_desc, state->window, state->wsize - left))
ret = Z_BUF_ERROR;
}
goto inf_leave;
case BAD:
ret = Z_DATA_ERROR;
goto inf_leave;
default: /* can't happen, but makes compilers happy */
ret = Z_STREAM_ERROR;
goto inf_leave;
}
/* Return unused input */
inf_leave:
strm->next_in = next;
strm->avail_in = have;
return ret;
}
int inflateBackEnd(z_streamp strm) {
if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
return Z_STREAM_ERROR;
ZFREE(strm, strm->state);
strm->state = Z_NULL;
Tracev((stderr, "inflate: end\n"));
return Z_OK;
}
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