cosmopolitan/third_party/lex/regex.c

182 lines
5.3 KiB
C

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│vi: set et ft=c ts=8 sw=8 fenc=utf-8 :vi│
└─────────────────────────────────────────────────────────────────────────────*/
/* clang-format off */
/* $OpenBSD: regex.c,v 1.3 2015/11/19 23:20:34 tedu Exp $ */
/** regex - regular expression functions related to POSIX regex lib. */
/* This file is part of flex. */
/* Redistribution and use in source and binary forms, with or without */
/* modification, are permitted provided that the following conditions */
/* are met: */
/* 1. Redistributions of source code must retain the above copyright */
/* notice, this list of conditions and the following disclaimer. */
/* 2. Redistributions in binary form must reproduce the above copyright */
/* notice, this list of conditions and the following disclaimer in the */
/* documentation and/or other materials provided with the distribution. */
/* Neither the name of the University nor the names of its contributors */
/* may be used to endorse or promote products derived from this software */
/* without specific prior written permission. */
/* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
/* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
/* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
/* PURPOSE. */
#include "libc/str/str.h"
#include "libc/mem/mem.h"
#include "libc/fmt/fmt.h"
#include "libc/conv/conv.h"
#include "flexdef.h"
static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";
regex_t regex_linedir; /**< matches line directives */
regex_t regex_blank_line; /**< matches blank lines */
/** Initialize the regular expressions.
* @return true upon success.
*/
bool flex_init_regex(void)
{
flex_regcomp(&regex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
flex_regcomp(&regex_blank_line, REGEXP_BLANK_LINE, REG_EXTENDED);
return true;
}
/** Compiles a regular expression or dies trying.
* @param preg Same as for regcomp().
* @param regex Same as for regcomp().
* @param cflags Same as for regcomp().
*/
void flex_regcomp(regex_t *preg, const char *regex, int cflags)
{
int err;
memset (preg, 0, sizeof (regex_t));
if ((err = regcomp (preg, regex, cflags)) != 0) {
const int errbuf_sz = 200;
char *errbuf, *rxerr;
errbuf = (char*)malloc(errbuf_sz *sizeof(char));
if (!errbuf)
flexfatal(_("Unable to allocate buffer to report regcomp"));
rxerr = (char*)malloc(errbuf_sz *sizeof(char));
if (!rxerr)
flexfatal(_("Unable to allocate buffer for regerror"));
regerror (err, preg, rxerr, errbuf_sz);
snprintf (errbuf, errbuf_sz, "regcomp for \"%s\" failed: %s", regex, rxerr);
flexfatal (errbuf);
free(errbuf);
free(rxerr);
}
}
/** Extract a copy of the match, or NULL if no match.
* @param m A match as returned by regexec().
* @param src The source string that was passed to regexec().
* @return The allocated string.
*/
char *regmatch_dup (regmatch_t * m, const char *src)
{
char *str;
int len;
if (m == NULL || m->rm_so < 0)
return NULL;
len = m->rm_eo - m->rm_so;
str = (char *) malloc ((len + 1) * sizeof (char));
if (!str)
flexfatal(_("Unable to allocate a copy of the match"));
strncpy (str, src + m->rm_so, len);
str[len] = 0;
return str;
}
/** Copy the match.
* @param m A match as returned by regexec().
* @param dest The destination buffer.
* @param src The source string that was passed to regexec().
* @return dest
*/
char *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
{
if (m == NULL || m->rm_so < 0) {
if (dest)
dest[0] = '\0';
return dest;
}
snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
return dest;
}
/** Get the length in characters of the match.
* @param m A match as returned by regexec().
* @param src The source string that was passed to regexec().
* @return The length of the match.
*/
int regmatch_len (regmatch_t * m)
{
if (m == NULL || m->rm_so < 0) {
return 0;
}
return m->rm_eo - m->rm_so;
}
/** Convert a regmatch_t object to an integer using the strtol() function.
* @param m A match as returned by regexec().
* @param src The source string that was passed to regexec().
* @param endptr Same as the second argument to strtol().
* @param base Same as the third argument to strtol().
* @return The converted integer or error (Return value is the same as for strtol()).
*/
int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
int base2)
{
int n = 0;
#define bufsz 20
char buf[bufsz];
char *s;
if (m == NULL || m->rm_so < 0)
return 0;
if (regmatch_len (m) < bufsz)
s = regmatch_cpy (m, buf, src);
else
s = regmatch_dup (m, src);
n = strtol (s, endptr, base2);
if (s != buf)
free (s);
return n;
}
/** Check for empty or non-existent match.
* @param m A match as returned by regexec().
* @return false if match length is non-zero.
* Note that reg_empty returns true even if match did not occur at all.
*/
bool regmatch_empty (regmatch_t * m)
{
return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
}