prism/util/pm_strpbrk.h

   1 /**
   2  * @file pm_strpbrk.h
   3  *
   4  * A custom strpbrk implementation.
   5  */
   6 #ifndef PRISM_STRPBRK_H
   7 #define PRISM_STRPBRK_H
   8
   9 #include "prism/defines.h"
  10 #include "prism/diagnostic.h"
  11 #include "prism/parser.h"
  12
  13 #include <stddef.h>
  14 #include <string.h>
  15
  16 /**
  17  * Here we have rolled our own version of strpbrk. The standard library strpbrk
  18  * has undefined behavior when the source string is not null-terminated. We want
  19  * to support strings that are not null-terminated because pm_parse does not
  20  * have the contract that the string is null-terminated. (This is desirable
  21  * because it means the extension can call pm_parse with the result of a call to
  22  * mmap).
  23  *
  24  * The standard library strpbrk also does not support passing a maximum length
  25  * to search. We want to support this for the reason mentioned above, but we
  26  * also don't want it to stop on null bytes. Ruby actually allows null bytes
  27  * within strings, comments, regular expressions, etc. So we need to be able to
  28  * skip past them.
  29  *
  30  * Finally, we want to support encodings wherein the charset could contain
  31  * characters that are trailing bytes of multi-byte characters. For example, in
  32  * Shift-JIS, the backslash character can be a trailing byte. In that case we
  33  * need to take a slower path and iterate one multi-byte character at a time.
  34  *
  35  * @param parser The parser.
  36  * @param source The source to search.
  37  * @param charset The charset to search for.
  38  * @param length The maximum number of bytes to search.
  39  * @param validate Whether to validate that the source string is valid in the
  40  *     current encoding of the parser.
  41  * @return A pointer to the first character in the source string that is in the
  42  *     charset, or NULL if no such character exists.
  43  */
  44 const uint8_t * pm_strpbrk(pm_parser_t *parser, const uint8_t *source, const uint8_t *charset, ptrdiff_t length, bool validate);
  45
  46 #endif