cosmopolitan/third_party/duktape/duk_api_string.c

379 lines
11 KiB
C

/*
* String manipulation
*/
#include "third_party/duktape/duk_internal.h"
DUK_LOCAL void duk__concat_and_join_helper(duk_hthread *thr, duk_idx_t count_in, duk_bool_t is_join) {
duk_uint_t count;
duk_uint_t i;
duk_size_t idx;
duk_size_t len;
duk_hstring *h;
duk_uint8_t *buf;
DUK_CTX_ASSERT_VALID(thr);
if (DUK_UNLIKELY(count_in <= 0)) {
if (count_in < 0) {
DUK_ERROR_RANGE_INVALID_COUNT(thr);
DUK_WO_NORETURN(return;);
}
DUK_ASSERT(count_in == 0);
duk_push_hstring_empty(thr);
return;
}
count = (duk_uint_t) count_in;
if (is_join) {
duk_size_t t1, t2, limit;
h = duk_to_hstring(thr, -((duk_idx_t) count) - 1);
DUK_ASSERT(h != NULL);
/* A bit tricky overflow test, see doc/code-issues.rst. */
t1 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h);
t2 = (duk_size_t) (count - 1);
limit = (duk_size_t) DUK_HSTRING_MAX_BYTELEN;
if (DUK_UNLIKELY(t2 != 0 && t1 > limit / t2)) {
/* Combined size of separators already overflows. */
goto error_overflow;
}
len = (duk_size_t) (t1 * t2);
} else {
len = (duk_size_t) 0;
}
for (i = count; i >= 1; i--) {
duk_size_t new_len;
h = duk_to_hstring(thr, -((duk_idx_t) i));
new_len = len + (duk_size_t) DUK_HSTRING_GET_BYTELEN(h);
/* Impose a string maximum length, need to handle overflow
* correctly.
*/
if (new_len < len || /* wrapped */
new_len > (duk_size_t) DUK_HSTRING_MAX_BYTELEN) {
goto error_overflow;
}
len = new_len;
}
DUK_DDD(DUK_DDDPRINT("join/concat %lu strings, total length %lu bytes",
(unsigned long) count, (unsigned long) len));
/* Use stack allocated buffer to ensure reachability in errors
* (e.g. intern error).
*/
buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len);
DUK_ASSERT(buf != NULL);
/* [ ... (sep) str1 str2 ... strN buf ] */
idx = 0;
for (i = count; i >= 1; i--) {
if (is_join && i != count) {
h = duk_require_hstring(thr, -((duk_idx_t) count) - 2); /* extra -1 for buffer */
duk_memcpy(buf + idx, DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
idx += DUK_HSTRING_GET_BYTELEN(h);
}
h = duk_require_hstring(thr, -((duk_idx_t) i) - 1); /* extra -1 for buffer */
duk_memcpy(buf + idx, DUK_HSTRING_GET_DATA(h), DUK_HSTRING_GET_BYTELEN(h));
idx += DUK_HSTRING_GET_BYTELEN(h);
}
DUK_ASSERT(idx == len);
/* [ ... (sep) str1 str2 ... strN buf ] */
/* Get rid of the strings early to minimize memory use before intern. */
if (is_join) {
duk_replace(thr, -((duk_idx_t) count) - 2); /* overwrite sep */
duk_pop_n(thr, (duk_idx_t) count);
} else {
duk_replace(thr, -((duk_idx_t) count) - 1); /* overwrite str1 */
duk_pop_n(thr, (duk_idx_t) (count - 1));
}
/* [ ... buf ] */
(void) duk_buffer_to_string(thr, -1); /* Safe if inputs are safe. */
/* [ ... res ] */
return;
error_overflow:
DUK_ERROR_RANGE(thr, DUK_STR_RESULT_TOO_LONG);
DUK_WO_NORETURN(return;);
}
DUK_EXTERNAL void duk_concat(duk_hthread *thr, duk_idx_t count) {
DUK_ASSERT_API_ENTRY(thr);
duk__concat_and_join_helper(thr, count, 0 /*is_join*/);
}
#if defined(DUK_USE_PREFER_SIZE)
DUK_INTERNAL void duk_concat_2(duk_hthread *thr) {
DUK_ASSERT_API_ENTRY(thr);
duk_concat(thr, 2);
}
#else /* DUK_USE_PREFER_SIZE */
DUK_INTERNAL void duk_concat_2(duk_hthread *thr) {
duk_hstring *h1;
duk_hstring *h2;
duk_uint8_t *buf;
duk_size_t len1;
duk_size_t len2;
duk_size_t len;
DUK_ASSERT_API_ENTRY(thr);
DUK_ASSERT(duk_get_top(thr) >= 2); /* Trusted caller. */
h1 = duk_to_hstring(thr, -2);
h2 = duk_to_hstring(thr, -1);
len1 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h1);
len2 = (duk_size_t) DUK_HSTRING_GET_BYTELEN(h2);
len = len1 + len2;
if (DUK_UNLIKELY(len < len1 || /* wrapped */
len > (duk_size_t) DUK_HSTRING_MAX_BYTELEN)) {
goto error_overflow;
}
buf = (duk_uint8_t *) duk_push_fixed_buffer_nozero(thr, len);
DUK_ASSERT(buf != NULL);
duk_memcpy((void *) buf, (const void *) DUK_HSTRING_GET_DATA(h1), (size_t) len1);
duk_memcpy((void *) (buf + len1), (const void *) DUK_HSTRING_GET_DATA(h2), (size_t) len2);
(void) duk_buffer_to_string(thr, -1); /* Safe if inputs are safe. */
/* [ ... str1 str2 buf ] */
duk_replace(thr, -3);
duk_pop_unsafe(thr);
return;
error_overflow:
DUK_ERROR_RANGE(thr, DUK_STR_RESULT_TOO_LONG);
DUK_WO_NORETURN(return;);
}
#endif /* DUK_USE_PREFER_SIZE */
DUK_EXTERNAL void duk_join(duk_hthread *thr, duk_idx_t count) {
DUK_ASSERT_API_ENTRY(thr);
duk__concat_and_join_helper(thr, count, 1 /*is_join*/);
}
/* XXX: could map/decode be unified with duk_unicode_support.c code?
* Case conversion needs also the character surroundings though.
*/
DUK_EXTERNAL void duk_decode_string(duk_hthread *thr, duk_idx_t idx, duk_decode_char_function callback, void *udata) {
duk_hstring *h_input;
const duk_uint8_t *p, *p_start, *p_end;
duk_codepoint_t cp;
DUK_ASSERT_API_ENTRY(thr);
h_input = duk_require_hstring(thr, idx); /* Accept symbols. */
DUK_ASSERT(h_input != NULL);
p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
p = p_start;
for (;;) {
if (p >= p_end) {
break;
}
cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p, p_start, p_end);
callback(udata, cp);
}
}
DUK_EXTERNAL void duk_map_string(duk_hthread *thr, duk_idx_t idx, duk_map_char_function callback, void *udata) {
duk_hstring *h_input;
duk_bufwriter_ctx bw_alloc;
duk_bufwriter_ctx *bw;
const duk_uint8_t *p, *p_start, *p_end;
duk_codepoint_t cp;
DUK_ASSERT_API_ENTRY(thr);
idx = duk_normalize_index(thr, idx);
h_input = duk_require_hstring(thr, idx); /* Accept symbols. */
DUK_ASSERT(h_input != NULL);
bw = &bw_alloc;
DUK_BW_INIT_PUSHBUF(thr, bw, DUK_HSTRING_GET_BYTELEN(h_input)); /* Reasonable output estimate. */
p_start = (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_input);
p_end = p_start + DUK_HSTRING_GET_BYTELEN(h_input);
p = p_start;
for (;;) {
/* XXX: could write output in chunks with fewer ensure calls,
* but relative benefit would be small here.
*/
if (p >= p_end) {
break;
}
cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p, p_start, p_end);
cp = callback(udata, cp);
DUK_BW_WRITE_ENSURE_XUTF8(thr, bw, cp);
}
DUK_BW_COMPACT(thr, bw);
(void) duk_buffer_to_string(thr, -1); /* Safe, extended UTF-8 encoded. */
duk_replace(thr, idx);
}
DUK_EXTERNAL void duk_substring(duk_hthread *thr, duk_idx_t idx, duk_size_t start_offset, duk_size_t end_offset) {
duk_hstring *h;
duk_hstring *res;
duk_size_t start_byte_offset;
duk_size_t end_byte_offset;
duk_size_t charlen;
DUK_ASSERT_API_ENTRY(thr);
idx = duk_require_normalize_index(thr, idx); /* Accept symbols. */
h = duk_require_hstring(thr, idx);
DUK_ASSERT(h != NULL);
charlen = DUK_HSTRING_GET_CHARLEN(h);
if (end_offset >= charlen) {
end_offset = charlen;
}
if (start_offset > end_offset) {
start_offset = end_offset;
}
DUK_ASSERT_DISABLE(start_offset >= 0);
DUK_ASSERT(start_offset <= end_offset && start_offset <= DUK_HSTRING_GET_CHARLEN(h));
DUK_ASSERT_DISABLE(end_offset >= 0);
DUK_ASSERT(end_offset >= start_offset && end_offset <= DUK_HSTRING_GET_CHARLEN(h));
/* Guaranteed by string limits. */
DUK_ASSERT(start_offset <= DUK_UINT32_MAX);
DUK_ASSERT(end_offset <= DUK_UINT32_MAX);
start_byte_offset = (duk_size_t) duk_heap_strcache_offset_char2byte(thr, h, (duk_uint_fast32_t) start_offset);
end_byte_offset = (duk_size_t) duk_heap_strcache_offset_char2byte(thr, h, (duk_uint_fast32_t) end_offset);
DUK_ASSERT(end_byte_offset >= start_byte_offset);
DUK_ASSERT(end_byte_offset - start_byte_offset <= DUK_UINT32_MAX); /* Guaranteed by string limits. */
/* No size check is necessary. */
res = duk_heap_strtable_intern_checked(thr,
DUK_HSTRING_GET_DATA(h) + start_byte_offset,
(duk_uint32_t) (end_byte_offset - start_byte_offset));
duk_push_hstring(thr, res);
duk_replace(thr, idx);
}
/* XXX: this is quite clunky. Add Unicode helpers to scan backwards and
* forwards with a callback to process codepoints?
*/
DUK_EXTERNAL void duk_trim(duk_hthread *thr, duk_idx_t idx) {
duk_hstring *h;
const duk_uint8_t *p, *p_start, *p_end, *p_tmp1, *p_tmp2; /* pointers for scanning */
const duk_uint8_t *q_start, *q_end; /* start (incl) and end (excl) of trimmed part */
duk_codepoint_t cp;
DUK_ASSERT_API_ENTRY(thr);
idx = duk_require_normalize_index(thr, idx); /* Accept symbols. */
h = duk_require_hstring(thr, idx);
DUK_ASSERT(h != NULL);
p_start = DUK_HSTRING_GET_DATA(h);
p_end = p_start + DUK_HSTRING_GET_BYTELEN(h);
p = p_start;
while (p < p_end) {
p_tmp1 = p;
cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p_tmp1, p_start, p_end);
if (!(duk_unicode_is_whitespace(cp) || duk_unicode_is_line_terminator(cp))) {
break;
}
p = p_tmp1;
}
q_start = p;
if (p == p_end) {
/* Entire string is whitespace. */
q_end = p;
goto scan_done;
}
p = p_end;
while (p > p_start) {
p_tmp1 = p;
while (p > p_start) {
p--;
if (((*p) & 0xc0) != 0x80) {
break;
}
}
p_tmp2 = p;
cp = (duk_codepoint_t) duk_unicode_decode_xutf8_checked(thr, &p_tmp2, p_start, p_end);
if (!(duk_unicode_is_whitespace(cp) || duk_unicode_is_line_terminator(cp))) {
p = p_tmp1;
break;
}
}
q_end = p;
scan_done:
/* This may happen when forward and backward scanning disagree
* (possible for non-extended-UTF-8 strings).
*/
if (q_end < q_start) {
q_end = q_start;
}
DUK_ASSERT(q_start >= p_start && q_start <= p_end);
DUK_ASSERT(q_end >= p_start && q_end <= p_end);
DUK_ASSERT(q_end >= q_start);
DUK_DDD(DUK_DDDPRINT("trim: p_start=%p, p_end=%p, q_start=%p, q_end=%p",
(const void *) p_start, (const void *) p_end,
(const void *) q_start, (const void *) q_end));
if (q_start == p_start && q_end == p_end) {
DUK_DDD(DUK_DDDPRINT("nothing was trimmed: avoid interning (hashing etc)"));
return;
}
duk_push_lstring(thr, (const char *) q_start, (duk_size_t) (q_end - q_start));
duk_replace(thr, idx);
}
DUK_EXTERNAL duk_codepoint_t duk_char_code_at(duk_hthread *thr, duk_idx_t idx, duk_size_t char_offset) {
duk_hstring *h;
duk_ucodepoint_t cp;
DUK_ASSERT_API_ENTRY(thr);
/* XXX: Share code with String.prototype.charCodeAt? Main difference
* is handling of clamped offsets.
*/
h = duk_require_hstring(thr, idx); /* Accept symbols. */
DUK_ASSERT(h != NULL);
DUK_ASSERT_DISABLE(char_offset >= 0); /* Always true, arg is unsigned. */
if (char_offset >= DUK_HSTRING_GET_CHARLEN(h)) {
return 0;
}
DUK_ASSERT(char_offset <= DUK_UINT_MAX); /* Guaranteed by string limits. */
cp = duk_hstring_char_code_at_raw(thr, h, (duk_uint_t) char_offset, 0 /*surrogate_aware*/);
return (duk_codepoint_t) cp;
}