10.3. re — Regular expressions

Source code: src/text/re.h, src/text/re.c

Test code: tst/text/re/main.c

Test coverage: src/text/re.c

Version
7.0.0

Defines

RE_IGNORECASE

Perform case-insensitive matching; expressions like [A-Z] will match lowercase letters, too.

RE_DOTALL

Make the '.' special character match any character at all, including a newline; without this flag, '.' will match anything except a newline.

RE_MULTILINE

When specified, the pattern character '^' matches at the beginning of the string and at the beginning of each line (immediately following each newline); and the pattern character '$' matches at the end of the string and at the end of each line (immediately preceding each newline). By default, ‘^’ matches only at the beginning of the string, and '$' only at the end of the string and immediately before the newline (if any) at the end of the string.

Functions

char *re_compile(char *compiled_p, const char *pattern_p, char flags, size_t size)

Compile given pattern.

Pattern syntax:

  • '.' - Any character.
  • '^' - Beginning of the string (not yet supported).
  • '$' - End of the string (not yet supported).
  • '?' - Zero or one repetitions (greedy).
  • '*' - Zero or more repetitions (greedy).
  • '+' - One or more repetitions (greedy).
  • '??' - Zero or one repetitions (non-greedy).
  • *? - Zero or more repetitions (non-greedy).
  • +? - One or more repetitions (non-greedy).
  • {m} - Exactly m repetitions.
  • \\ - Escape character.
  • [] - Set of characters.
  • '|' - Alternatives (not yet supported).
  • (...) - Groups (not yet supported).
  • \\d - Decimal digits [0-9].
  • \\w - Alphanumerical characters [a-ZA-Z0-9_].
  • \\s - Whitespace characters [ \t\r\n\f\v].

Return
Compiled patten, or NULL if the compilation failed.
Parameters
  • compiled_p -

    Compiled regular expression pattern.

  • pattern_p -

    Regular expression pattern.

  • flags -

    A combination of the flags RE_IGNORECASE, RE_DOTALL and RE_MULTILINE (RE_MULTILINE is not yet supported).

  • size -

    Size of the compiled buffer.

ssize_t re_match(const char *compiled_p, const char *buf_p, size_t size, struct re_group_t *groups_p, size_t *number_of_groups_p)

Apply given regular expression to the beginning of given string.

Return
Number of matched bytes or negative error code.
Parameters
  • compiled_p -

    Compiled regular expression pattern. Compile a pattern with re_compile().

  • buf_p -

    Buffer to apply the compiled pattern to.

  • size -

    Number of bytes in the buffer.

  • groups_p -

    Read groups or NULL.

  • number_of_groups_p -

    Number of read groups or NULL.

struct re_group_t

Public Members

const char *buf_p
ssize_t size