/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/*
This is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language. See
the file Tech.Notes for some information on the internals.

This module is a wrapper that provides a POSIX API to the underlying PCRE
functions.

Written by: Philip Hazel <ph10@cam.ac.uk>

           Copyright (c) 1997-2004 University of Cambridge

-----------------------------------------------------------------------------
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.

    * 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 of Cambridge 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 BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
-----------------------------------------------------------------------------
*/

#include "internal.h"
#include "pcreposix.h"
#include "stdlib.h"


/* Corresponding tables of PCRE error messages and POSIX error codes. */

static const char *const estring[] = {
  ERR1,  ERR2,  ERR3,  ERR4,  ERR5,  ERR6,  ERR7,  ERR8,  ERR9,  ERR10,
  ERR11, ERR12, ERR13, ERR14, ERR15, ERR16, ERR17, ERR18, ERR19, ERR20,
  ERR21, ERR22, ERR23, ERR24, ERR25, ERR26, ERR27, ERR29, ERR29, ERR30,
  ERR31, ERR32, ERR33, ERR34, ERR35, ERR36, ERR37, ERR38, ERR39, ERR40,
  ERR41, ERR42, ERR43, ERR44, ERR45, ERR46, ERR47 };

static const int eint[] = {
  REG_EESCAPE, /* "\\ at end of pattern" */
  REG_EESCAPE, /* "\\c at end of pattern" */
  REG_EESCAPE, /* "unrecognized character follows \\" */
  REG_BADBR,   /* "numbers out of order in {} quantifier" */
  REG_BADBR,   /* "number too big in {} quantifier" */
  REG_EBRACK,  /* "missing terminating ] for character class" */
  REG_ECTYPE,  /* "invalid escape sequence in character class" */
  REG_ERANGE,  /* "range out of order in character class" */
  REG_BADRPT,  /* "nothing to repeat" */
  REG_BADRPT,  /* "operand of unlimited repeat could match the empty string" */
  REG_ASSERT,  /* "internal error: unexpected repeat" */
  REG_BADPAT,  /* "unrecognized character after (?" */
  REG_BADPAT,  /* "POSIX named classes are supported only within a class" */
  REG_EPAREN,  /* "missing )" */
  REG_ESUBREG, /* "reference to non-existent subpattern" */
  REG_INVARG,  /* "erroffset passed as NULL" */
  REG_INVARG,  /* "unknown option bit(s) set" */
  REG_EPAREN,  /* "missing ) after comment" */
  REG_ESIZE,   /* "parentheses nested too deeply" */
  REG_ESIZE,   /* "regular expression too large" */
  REG_ESPACE,  /* "failed to get memory" */
  REG_EPAREN,  /* "unmatched brackets" */
  REG_ASSERT,  /* "internal error: code overflow" */
  REG_BADPAT,  /* "unrecognized character after (?<" */
  REG_BADPAT,  /* "lookbehind assertion is not fixed length" */
  REG_BADPAT,  /* "malformed number after (?(" */
  REG_BADPAT,  /* "conditional group containe more than two branches" */
  REG_BADPAT,  /* "assertion expected after (?(" */
  REG_BADPAT,  /* "(?R or (?digits must be followed by )" */
  REG_ECTYPE,  /* "unknown POSIX class name" */
  REG_BADPAT,  /* "POSIX collating elements are not supported" */
  REG_INVARG,  /* "this version of PCRE is not compiled with PCRE_UTF8 support" */
  REG_BADPAT,  /* "spare error" */
  REG_BADPAT,  /* "character value in \x{...} sequence is too large" */
  REG_BADPAT,  /* "invalid condition (?(0)" */
  REG_BADPAT,  /* "\\C not allowed in lookbehind assertion" */
  REG_EESCAPE, /* "PCRE does not support \\L, \\l, \\N, \\U, or \\u" */
  REG_BADPAT,  /* "number after (?C is > 255" */
  REG_BADPAT,  /* "closing ) for (?C expected" */
  REG_BADPAT,  /* "recursive call could loop indefinitely" */
  REG_BADPAT,  /* "unrecognized character after (?P" */
  REG_BADPAT,  /* "syntax error after (?P" */
  REG_BADPAT,  /* "two named groups have the same name" */
  REG_BADPAT,  /* "invalid UTF-8 string" */
  REG_BADPAT,  /* "support for \\P, \\p, and \\X has not been compiled" */
  REG_BADPAT,  /* "malformed \\P or \\p sequence" */
  REG_BADPAT   /* "unknown property name after \\P or \\p" */
};

/* Table of texts corresponding to POSIX error codes */

static const char *const pstring[] = {
  "",                                /* Dummy for value 0 */
  "internal error",                  /* REG_ASSERT */
  "invalid repeat counts in {}",     /* BADBR      */
  "pattern error",                   /* BADPAT     */
  "? * + invalid",                   /* BADRPT     */
  "unbalanced {}",                   /* EBRACE     */
  "unbalanced []",                   /* EBRACK     */
  "collation error - not relevant",  /* ECOLLATE   */
  "bad class",                       /* ECTYPE     */
  "bad escape sequence",             /* EESCAPE    */
  "empty expression",                /* EMPTY      */
  "unbalanced ()",                   /* EPAREN     */
  "bad range inside []",             /* ERANGE     */
  "expression too big",              /* ESIZE      */
  "failed to get memory",            /* ESPACE     */
  "bad back reference",              /* ESUBREG    */
  "bad argument",                    /* INVARG     */
  "match failed"                     /* NOMATCH    */
};


/*************************************************
*          Translate PCRE text code to int       *
*************************************************/

/* PCRE compile-time errors are given as strings defined as macros. We can just
look them up in a table to turn them into POSIX-style error codes. */

static int
pcre_posix_error_code(const char *s)
{
size_t i;
for (i = 0; i < sizeof(estring)/sizeof(char *); i++)
  if (strcmp(s, estring[i]) == 0) return eint[i];
return REG_ASSERT;
}


/*************************************************
*          Translate error code to string        *
*************************************************/

EXPORT size_t
regerror(int errcode, const regex_t *preg, char *errbuf, size_t errbuf_size)
{
const char *message, *addmessage;
size_t length, addlength;

message = (errcode >= (int)(sizeof(pstring)/sizeof(char *)))?
  "unknown error code" : pstring[errcode];
length = strlen(message) + 1;

addmessage = " at offset ";
addlength = (preg != NULL && (int)preg->re_erroffset != -1)?
  strlen(addmessage) + 6 : 0;

if (errbuf_size > 0)
  {
  if (addlength > 0 && errbuf_size >= length + addlength)
    sprintf(errbuf, "%s%s%-6d", message, addmessage, (int)preg->re_erroffset);
  else
    {
    strncpy(errbuf, message, errbuf_size - 1);
    errbuf[errbuf_size-1] = 0;
    }
  }

return length + addlength;
}


/*************************************************
*           Free store held by a regex           *
*************************************************/

EXPORT void
regfree(regex_t *preg)
{
(pcre_free)(preg->re_pcre);
}


/*************************************************
*            Compile a regular expression        *
*************************************************/

/*
Arguments:
  preg        points to a structure for recording the compiled expression
  pattern     the pattern to compile
  cflags      compilation flags

Returns:      0 on success
              various non-zero codes on failure
*/

EXPORT int
regcomp(regex_t *preg, const char *pattern, int cflags)
{
const char *errorptr;
int erroffset;
int options = 0;

if ((cflags & REG_ICASE) != 0) options |= PCRE_CASELESS;
if ((cflags & REG_NEWLINE) != 0) options |= PCRE_MULTILINE;

preg->re_pcre = pcre_compile(pattern, options, &errorptr, &erroffset, NULL);
preg->re_erroffset = erroffset;

if (preg->re_pcre == NULL) return pcre_posix_error_code(errorptr);

preg->re_nsub = pcre_info((const pcre *)preg->re_pcre, NULL, NULL);
return 0;
}


/*************************************************
*              Match a regular expression        *
*************************************************/

/* Unfortunately, PCRE requires 3 ints of working space for each captured
substring, so we have to get and release working store instead of just using
the POSIX structures as was done in earlier releases when PCRE needed only 2
ints. However, if the number of possible capturing brackets is small, use a
block of store on the stack, to reduce the use of malloc/free. The threshold is
in a macro that can be changed at configure time. */

EXPORT int
regexec(const regex_t *preg, const char *string, size_t nmatch,
  regmatch_t pmatch[], int eflags)
{
int rc;
int options = 0;
int *ovector = NULL;
int small_ovector[POSIX_MALLOC_THRESHOLD * 3];
BOOL allocated_ovector = FALSE;

if ((eflags & REG_NOTBOL) != 0) options |= PCRE_NOTBOL;
if ((eflags & REG_NOTEOL) != 0) options |= PCRE_NOTEOL;

((regex_t *)preg)->re_erroffset = (size_t)(-1);  /* Only has meaning after compile */

if (nmatch > 0)
  {
  if (nmatch <= POSIX_MALLOC_THRESHOLD)
    {
    ovector = &(small_ovector[0]);
    }
  else
    {
    ovector = (int *)malloc(sizeof(int) * nmatch * 3);
    if (ovector == NULL) return REG_ESPACE;
    allocated_ovector = TRUE;
    }
  }

rc = pcre_exec((const pcre *)preg->re_pcre, NULL, string, (int)strlen(string),
  0, options, ovector, nmatch * 3);

if (rc == 0) rc = nmatch;    /* All captured slots were filled in */

if (rc >= 0)
  {
  size_t i;
  for (i = 0; i < (size_t)rc; i++)
    {
    pmatch[i].rm_so = ovector[i*2];
    pmatch[i].rm_eo = ovector[i*2+1];
    }
  if (allocated_ovector) free(ovector);
  for (; i < nmatch; i++) pmatch[i].rm_so = pmatch[i].rm_eo = -1;
  return 0;
  }

else
  {
  if (allocated_ovector) free(ovector);
  switch(rc)
    {
    case PCRE_ERROR_NOMATCH: return REG_NOMATCH;
    case PCRE_ERROR_NULL: return REG_INVARG;
    case PCRE_ERROR_BADOPTION: return REG_INVARG;
    case PCRE_ERROR_BADMAGIC: return REG_INVARG;
    case PCRE_ERROR_UNKNOWN_NODE: return REG_ASSERT;
    case PCRE_ERROR_NOMEMORY: return REG_ESPACE;
    case PCRE_ERROR_MATCHLIMIT: return REG_ESPACE;
    case PCRE_ERROR_BADUTF8: return REG_INVARG;
    case PCRE_ERROR_BADUTF8_OFFSET: return REG_INVARG;
    default: return REG_ASSERT;
    }
  }
}

/* End of pcreposix.c */