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