зеркало из https://github.com/github/ruby.git
73 строки
2.4 KiB
C
73 строки
2.4 KiB
C
#include "prism/util/pm_strpbrk.h"
|
|
|
|
/**
|
|
* This is the slow path that does care about the encoding.
|
|
*/
|
|
static inline const uint8_t *
|
|
pm_strpbrk_multi_byte(const pm_parser_t *parser, const uint8_t *source, const uint8_t *charset, size_t maximum) {
|
|
size_t index = 0;
|
|
|
|
while (index < maximum) {
|
|
if (strchr((const char *) charset, source[index]) != NULL) {
|
|
return source + index;
|
|
}
|
|
|
|
size_t width = parser->encoding->char_width(source + index, (ptrdiff_t) (maximum - index));
|
|
if (width == 0) {
|
|
return NULL;
|
|
}
|
|
|
|
index += width;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* This is the fast path that does not care about the encoding.
|
|
*/
|
|
static inline const uint8_t *
|
|
pm_strpbrk_single_byte(const uint8_t *source, const uint8_t *charset, size_t maximum) {
|
|
size_t index = 0;
|
|
|
|
while (index < maximum) {
|
|
if (strchr((const char *) charset, source[index]) != NULL) {
|
|
return source + index;
|
|
}
|
|
|
|
index++;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* Here we have rolled our own version of strpbrk. The standard library strpbrk
|
|
* has undefined behavior when the source string is not null-terminated. We want
|
|
* to support strings that are not null-terminated because pm_parse does not
|
|
* have the contract that the string is null-terminated. (This is desirable
|
|
* because it means the extension can call pm_parse with the result of a call to
|
|
* mmap).
|
|
*
|
|
* The standard library strpbrk also does not support passing a maximum length
|
|
* to search. We want to support this for the reason mentioned above, but we
|
|
* also don't want it to stop on null bytes. Ruby actually allows null bytes
|
|
* within strings, comments, regular expressions, etc. So we need to be able to
|
|
* skip past them.
|
|
*
|
|
* Finally, we want to support encodings wherein the charset could contain
|
|
* characters that are trailing bytes of multi-byte characters. For example, in
|
|
* Shift-JIS, the backslash character can be a trailing byte. In that case we
|
|
* need to take a slower path and iterate one multi-byte character at a time.
|
|
*/
|
|
const uint8_t *
|
|
pm_strpbrk(const pm_parser_t *parser, const uint8_t *source, const uint8_t *charset, ptrdiff_t length) {
|
|
if (length <= 0) {
|
|
return NULL;
|
|
} else if (parser->encoding_changed && parser->encoding->multibyte) {
|
|
return pm_strpbrk_multi_byte(parser, source, charset, (size_t) length);
|
|
} else {
|
|
return pm_strpbrk_single_byte(source, charset, (size_t) length);
|
|
}
|
|
}
|