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Use the cursor cache to speed up string-cursor->index as well

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Daphne Preston-Kendal 2021-12-11 10:08:17 +01:00
parent c09897c449
commit 4e0f10ad21
1 changed files with 17 additions and 0 deletions
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17
sexp.c
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@ -1300,7 +1300,24 @@ sexp sexp_string_cursor_to_index (sexp ctx, sexp self, sexp_sint_t n, sexp str,
sexp_assert_type(ctx, sexp_string_cursorp, SEXP_STRING_CURSOR, offset);
if (off < 0 || off > (sexp_sint_t)sexp_string_size(str))
return sexp_user_exception(ctx, self, "string-cursor->index: offset out of range", offset);
#if SEXP_USE_STRING_REF_CACHE
sexp_uint_t cached_idx = sexp_cached_char_idx(str);
sexp_sint_t cached_off = sexp_unbox_string_cursor(sexp_cached_cursor(str));
unsigned char* string_data = (unsigned char*)sexp_string_data(str);
sexp_sint_t idx_delta;
if (off >= cached_off) {
idx_delta = sexp_string_utf8_length(string_data+cached_off, off-cached_off);
} else {
idx_delta = 0 - sexp_string_utf8_length(string_data+off, cached_off-off);
}
sexp_uint_t new_idx = cached_idx + idx_delta;
sexp_cached_char_idx(str) = new_idx;
sexp_cached_cursor(str) = offset;
return sexp_make_fixnum(new_idx);
#else
return sexp_make_fixnum(sexp_string_utf8_length((unsigned char*)sexp_string_data(str), off));
#endif
}
sexp sexp_string_cursor_offset (sexp ctx, sexp self, sexp_sint_t n, sexp cur) {