path: root/contrib/libs/re2/util/pcre.cc

// Copyright 2003-2009 Google Inc.  All rights reserved. 
// Use of this source code is governed by a BSD-style 
// license that can be found in the LICENSE file. 
 
// This is a variant of PCRE's pcrecpp.cc, originally written at Google. 
// The main changes are the addition of the HitLimit method and 
// compilation as PCRE in namespace re2. 
 
#include <assert.h> 
#include <ctype.h> 
#include <errno.h> 
#include <stdlib.h> 
#include <string.h> 
#include <limits> 
#include <string> 
#include <utility> 
 
#include "util/util.h" 
#include "util/flags.h" 
#include "util/logging.h" 
#include "util/pcre.h" 
#include "util/strutil.h" 
 
// Silence warnings about the wacky formatting in the operator() functions. 
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 6 
#pragma GCC diagnostic ignored "-Wmisleading-indentation" 
#endif 
 
#define PCREPORT(level) LOG(level) 
 
// Default PCRE limits. 
// Defaults chosen to allow a plausible amount of CPU and 
// not exceed main thread stacks.  Note that other threads 
// often have smaller stacks, and therefore tightening 
// regexp_stack_limit may frequently be necessary. 
DEFINE_FLAG(int, regexp_stack_limit, 256 << 10, 
            "default PCRE stack limit (bytes)"); 
DEFINE_FLAG(int, regexp_match_limit, 1000000, 
            "default PCRE match limit (function calls)"); 
 
#ifndef USEPCRE 
 
// Fake just enough of the PCRE API to allow this file to build. :) 
 
struct pcre_extra { 
  int flags; 
  int match_limit; 
  int match_limit_recursion; 
}; 
 
#define PCRE_EXTRA_MATCH_LIMIT 0 
#define PCRE_EXTRA_MATCH_LIMIT_RECURSION 0 
#define PCRE_ANCHORED 0 
#define PCRE_NOTEMPTY 0 
#define PCRE_ERROR_NOMATCH 1 
#define PCRE_ERROR_MATCHLIMIT 2 
#define PCRE_ERROR_RECURSIONLIMIT 3 
#define PCRE_INFO_CAPTURECOUNT 0 
 
void pcre_free(void*) { 
} 
 
pcre* pcre_compile(const char*, int, const char**, int*, const unsigned char*) { 
  return NULL; 
} 
 
int pcre_exec(const pcre*, const pcre_extra*, const char*, int, int, int, int*, int) { 
  return 0; 
} 
 
int pcre_fullinfo(const pcre*, const pcre_extra*, int, void*) { 
  return 0; 
} 
 
#endif 
 
namespace re2 { 
 
// Maximum number of args we can set 
static const int kMaxArgs = 16; 
static const int kVecSize = (1 + kMaxArgs) * 3;  // results + PCRE workspace 
 
// Approximate size of a recursive invocation of PCRE's 
// internal "match()" frame.  This varies depending on the 
// compiler and architecture, of course, so the constant is 
// just a conservative estimate.  To find the exact number, 
// run regexp_unittest with --regexp_stack_limit=0 under 
// a debugger and look at the frames when it crashes. 
// The exact frame size was 656 in production on 2008/02/03. 
static const int kPCREFrameSize = 700; 
 
// Special name for missing C++ arguments. 
PCRE::Arg PCRE::no_more_args((void*)NULL); 
 
const PCRE::PartialMatchFunctor PCRE::PartialMatch = { }; 
const PCRE::FullMatchFunctor PCRE::FullMatch = { } ; 
const PCRE::ConsumeFunctor PCRE::Consume = { }; 
const PCRE::FindAndConsumeFunctor PCRE::FindAndConsume = { }; 
 
// If a regular expression has no error, its error_ field points here 
static const std::string empty_string; 
 
void PCRE::Init(const char* pattern, Option options, int match_limit, 
              int stack_limit, bool report_errors) { 
  pattern_ = pattern; 
  options_ = options; 
  match_limit_ = match_limit; 
  stack_limit_ = stack_limit; 
  hit_limit_ = false; 
  error_ = &empty_string; 
  report_errors_ = report_errors; 
  re_full_ = NULL; 
  re_partial_ = NULL; 
 
  if (options & ~(EnabledCompileOptions | EnabledExecOptions)) { 
    error_ = new std::string("illegal regexp option"); 
    PCREPORT(ERROR) 
        << "Error compiling '" << pattern << "': illegal regexp option"; 
  } else { 
    re_partial_ = Compile(UNANCHORED); 
    if (re_partial_ != NULL) { 
      re_full_ = Compile(ANCHOR_BOTH); 
    } 
  } 
} 
 
PCRE::PCRE(const char* pattern) { 
  Init(pattern, None, 0, 0, true); 
} 
PCRE::PCRE(const char* pattern, Option option) { 
  Init(pattern, option, 0, 0, true); 
} 
PCRE::PCRE(const std::string& pattern) { 
  Init(pattern.c_str(), None, 0, 0, true); 
} 
PCRE::PCRE(const std::string& pattern, Option option) { 
  Init(pattern.c_str(), option, 0, 0, true); 
} 
PCRE::PCRE(const std::string& pattern, const PCRE_Options& re_option) { 
  Init(pattern.c_str(), re_option.option(), re_option.match_limit(), 
       re_option.stack_limit(), re_option.report_errors()); 
} 
 
PCRE::PCRE(const char *pattern, const PCRE_Options& re_option) { 
  Init(pattern, re_option.option(), re_option.match_limit(), 
       re_option.stack_limit(), re_option.report_errors()); 
} 
 
PCRE::~PCRE() { 
  if (re_full_ != NULL)         pcre_free(re_full_); 
  if (re_partial_ != NULL)      pcre_free(re_partial_); 
  if (error_ != &empty_string)  delete error_; 
} 
 
pcre* PCRE::Compile(Anchor anchor) { 
  // Special treatment for anchoring.  This is needed because at 
  // runtime pcre only provides an option for anchoring at the 
  // beginning of a string. 
  // 
  // There are three types of anchoring we want: 
  //    UNANCHORED      Compile the original pattern, and use 
  //                    a pcre unanchored match. 
  //    ANCHOR_START    Compile the original pattern, and use 
  //                    a pcre anchored match. 
  //    ANCHOR_BOTH     Tack a "\z" to the end of the original pattern 
  //                    and use a pcre anchored match. 
 
  const char* error = ""; 
  int eoffset; 
  pcre* re; 
  if (anchor != ANCHOR_BOTH) { 
    re = pcre_compile(pattern_.c_str(), 
                      (options_ & EnabledCompileOptions), 
                      &error, &eoffset, NULL); 
  } else { 
    // Tack a '\z' at the end of PCRE.  Parenthesize it first so that 
    // the '\z' applies to all top-level alternatives in the regexp. 
    std::string wrapped = "(?:";  // A non-counting grouping operator 
    wrapped += pattern_; 
    wrapped += ")\\z"; 
    re = pcre_compile(wrapped.c_str(), 
                      (options_ & EnabledCompileOptions), 
                      &error, &eoffset, NULL); 
  } 
  if (re == NULL) { 
    if (error_ == &empty_string) error_ = new std::string(error); 
    PCREPORT(ERROR) << "Error compiling '" << pattern_ << "': " << error; 
  } 
  return re; 
} 
 
/***** Convenience interfaces *****/ 
 
bool PCRE::FullMatchFunctor::operator ()(const StringPiece& text, 
                                       const PCRE& re, 
                                       const Arg& a0, 
                                       const Arg& a1, 
                                       const Arg& a2, 
                                       const Arg& a3, 
                                       const Arg& a4, 
                                       const Arg& a5, 
                                       const Arg& a6, 
                                       const Arg& a7, 
                                       const Arg& a8, 
                                       const Arg& a9, 
                                       const Arg& a10, 
                                       const Arg& a11, 
                                       const Arg& a12, 
                                       const Arg& a13, 
                                       const Arg& a14, 
                                       const Arg& a15) const { 
  const Arg* args[kMaxArgs]; 
  int n = 0; 
  if (&a0 == &no_more_args)  goto done; args[n++] = &a0; 
  if (&a1 == &no_more_args)  goto done; args[n++] = &a1; 
  if (&a2 == &no_more_args)  goto done; args[n++] = &a2; 
  if (&a3 == &no_more_args)  goto done; args[n++] = &a3; 
  if (&a4 == &no_more_args)  goto done; args[n++] = &a4; 
  if (&a5 == &no_more_args)  goto done; args[n++] = &a5; 
  if (&a6 == &no_more_args)  goto done; args[n++] = &a6; 
  if (&a7 == &no_more_args)  goto done; args[n++] = &a7; 
  if (&a8 == &no_more_args)  goto done; args[n++] = &a8; 
  if (&a9 == &no_more_args)  goto done; args[n++] = &a9; 
  if (&a10 == &no_more_args) goto done; args[n++] = &a10; 
  if (&a11 == &no_more_args) goto done; args[n++] = &a11; 
  if (&a12 == &no_more_args) goto done; args[n++] = &a12; 
  if (&a13 == &no_more_args) goto done; args[n++] = &a13; 
  if (&a14 == &no_more_args) goto done; args[n++] = &a14; 
  if (&a15 == &no_more_args) goto done; args[n++] = &a15; 
done: 
 
  size_t consumed; 
  int vec[kVecSize] = {}; 
  return re.DoMatchImpl(text, ANCHOR_BOTH, &consumed, args, n, vec, kVecSize); 
} 
 
bool PCRE::PartialMatchFunctor::operator ()(const StringPiece& text, 
                                          const PCRE& re, 
                                          const Arg& a0, 
                                          const Arg& a1, 
                                          const Arg& a2, 
                                          const Arg& a3, 
                                          const Arg& a4, 
                                          const Arg& a5, 
                                          const Arg& a6, 
                                          const Arg& a7, 
                                          const Arg& a8, 
                                          const Arg& a9, 
                                          const Arg& a10, 
                                          const Arg& a11, 
                                          const Arg& a12, 
                                          const Arg& a13, 
                                          const Arg& a14, 
                                          const Arg& a15) const { 
  const Arg* args[kMaxArgs]; 
  int n = 0; 
  if (&a0 == &no_more_args)  goto done; args[n++] = &a0; 
  if (&a1 == &no_more_args)  goto done; args[n++] = &a1; 
  if (&a2 == &no_more_args)  goto done; args[n++] = &a2; 
  if (&a3 == &no_more_args)  goto done; args[n++] = &a3; 
  if (&a4 == &no_more_args)  goto done; args[n++] = &a4; 
  if (&a5 == &no_more_args)  goto done; args[n++] = &a5; 
  if (&a6 == &no_more_args)  goto done; args[n++] = &a6; 
  if (&a7 == &no_more_args)  goto done; args[n++] = &a7; 
  if (&a8 == &no_more_args)  goto done; args[n++] = &a8; 
  if (&a9 == &no_more_args)  goto done; args[n++] = &a9; 
  if (&a10 == &no_more_args) goto done; args[n++] = &a10; 
  if (&a11 == &no_more_args) goto done; args[n++] = &a11; 
  if (&a12 == &no_more_args) goto done; args[n++] = &a12; 
  if (&a13 == &no_more_args) goto done; args[n++] = &a13; 
  if (&a14 == &no_more_args) goto done; args[n++] = &a14; 
  if (&a15 == &no_more_args) goto done; args[n++] = &a15; 
done: 
 
  size_t consumed; 
  int vec[kVecSize] = {}; 
  return re.DoMatchImpl(text, UNANCHORED, &consumed, args, n, vec, kVecSize); 
} 
 
bool PCRE::ConsumeFunctor::operator ()(StringPiece* input, 
                                     const PCRE& pattern, 
                                     const Arg& a0, 
                                     const Arg& a1, 
                                     const Arg& a2, 
                                     const Arg& a3, 
                                     const Arg& a4, 
                                     const Arg& a5, 
                                     const Arg& a6, 
                                     const Arg& a7, 
                                     const Arg& a8, 
                                     const Arg& a9, 
                                     const Arg& a10, 
                                     const Arg& a11, 
                                     const Arg& a12, 
                                     const Arg& a13, 
                                     const Arg& a14, 
                                     const Arg& a15) const { 
  const Arg* args[kMaxArgs]; 
  int n = 0; 
  if (&a0 == &no_more_args)  goto done; args[n++] = &a0; 
  if (&a1 == &no_more_args)  goto done; args[n++] = &a1; 
  if (&a2 == &no_more_args)  goto done; args[n++] = &a2; 
  if (&a3 == &no_more_args)  goto done; args[n++] = &a3; 
  if (&a4 == &no_more_args)  goto done; args[n++] = &a4; 
  if (&a5 == &no_more_args)  goto done; args[n++] = &a5; 
  if (&a6 == &no_more_args)  goto done; args[n++] = &a6; 
  if (&a7 == &no_more_args)  goto done; args[n++] = &a7; 
  if (&a8 == &no_more_args)  goto done; args[n++] = &a8; 
  if (&a9 == &no_more_args)  goto done; args[n++] = &a9; 
  if (&a10 == &no_more_args) goto done; args[n++] = &a10; 
  if (&a11 == &no_more_args) goto done; args[n++] = &a11; 
  if (&a12 == &no_more_args) goto done; args[n++] = &a12; 
  if (&a13 == &no_more_args) goto done; args[n++] = &a13; 
  if (&a14 == &no_more_args) goto done; args[n++] = &a14; 
  if (&a15 == &no_more_args) goto done; args[n++] = &a15; 
done: 
 
  size_t consumed; 
  int vec[kVecSize] = {}; 
  if (pattern.DoMatchImpl(*input, ANCHOR_START, &consumed, 
                          args, n, vec, kVecSize)) { 
    input->remove_prefix(consumed); 
    return true; 
  } else { 
    return false; 
  } 
} 
 
bool PCRE::FindAndConsumeFunctor::operator ()(StringPiece* input, 
                                            const PCRE& pattern, 
                                            const Arg& a0, 
                                            const Arg& a1, 
                                            const Arg& a2, 
                                            const Arg& a3, 
                                            const Arg& a4, 
                                            const Arg& a5, 
                                            const Arg& a6, 
                                            const Arg& a7, 
                                            const Arg& a8, 
                                            const Arg& a9, 
                                            const Arg& a10, 
                                            const Arg& a11, 
                                            const Arg& a12, 
                                            const Arg& a13, 
                                            const Arg& a14, 
                                            const Arg& a15) const { 
  const Arg* args[kMaxArgs]; 
  int n = 0; 
  if (&a0 == &no_more_args)  goto done; args[n++] = &a0; 
  if (&a1 == &no_more_args)  goto done; args[n++] = &a1; 
  if (&a2 == &no_more_args)  goto done; args[n++] = &a2; 
  if (&a3 == &no_more_args)  goto done; args[n++] = &a3; 
  if (&a4 == &no_more_args)  goto done; args[n++] = &a4; 
  if (&a5 == &no_more_args)  goto done; args[n++] = &a5; 
  if (&a6 == &no_more_args)  goto done; args[n++] = &a6; 
  if (&a7 == &no_more_args)  goto done; args[n++] = &a7; 
  if (&a8 == &no_more_args)  goto done; args[n++] = &a8; 
  if (&a9 == &no_more_args)  goto done; args[n++] = &a9; 
  if (&a10 == &no_more_args) goto done; args[n++] = &a10; 
  if (&a11 == &no_more_args) goto done; args[n++] = &a11; 
  if (&a12 == &no_more_args) goto done; args[n++] = &a12; 
  if (&a13 == &no_more_args) goto done; args[n++] = &a13; 
  if (&a14 == &no_more_args) goto done; args[n++] = &a14; 
  if (&a15 == &no_more_args) goto done; args[n++] = &a15; 
done: 
 
  size_t consumed; 
  int vec[kVecSize] = {}; 
  if (pattern.DoMatchImpl(*input, UNANCHORED, &consumed, 
                          args, n, vec, kVecSize)) { 
    input->remove_prefix(consumed); 
    return true; 
  } else { 
    return false; 
  } 
} 
 
bool PCRE::Replace(std::string *str, 
                 const PCRE& pattern, 
                 const StringPiece& rewrite) { 
  int vec[kVecSize] = {}; 
  int matches = pattern.TryMatch(*str, 0, UNANCHORED, true, vec, kVecSize); 
  if (matches == 0) 
    return false; 
 
  std::string s; 
  if (!pattern.Rewrite(&s, rewrite, *str, vec, matches)) 
    return false; 
 
  assert(vec[0] >= 0); 
  assert(vec[1] >= 0); 
  str->replace(vec[0], vec[1] - vec[0], s); 
  return true; 
} 
 
int PCRE::GlobalReplace(std::string *str, 
                      const PCRE& pattern, 
                      const StringPiece& rewrite) { 
  int count = 0; 
  int vec[kVecSize] = {}; 
  std::string out; 
  size_t start = 0; 
  bool last_match_was_empty_string = false; 
 
  while (start <= str->size()) { 
    // If the previous match was for the empty string, we shouldn't 
    // just match again: we'll match in the same way and get an 
    // infinite loop.  Instead, we do the match in a special way: 
    // anchored -- to force another try at the same position -- 
    // and with a flag saying that this time, ignore empty matches. 
    // If this special match returns, that means there's a non-empty 
    // match at this position as well, and we can continue.  If not, 
    // we do what perl does, and just advance by one. 
    // Notice that perl prints '@@@' for this; 
    //    perl -le '$_ = "aa"; s/b*|aa/@/g; print' 
    int matches; 
    if (last_match_was_empty_string) { 
      matches = pattern.TryMatch(*str, start, ANCHOR_START, false, 
                                 vec, kVecSize); 
      if (matches <= 0) { 
        if (start < str->size()) 
          out.push_back((*str)[start]); 
        start++; 
        last_match_was_empty_string = false; 
        continue; 
      } 
    } else { 
      matches = pattern.TryMatch(*str, start, UNANCHORED, true, 
                                 vec, kVecSize); 
      if (matches <= 0) 
        break; 
    } 
    size_t matchstart = vec[0], matchend = vec[1]; 
    assert(matchstart >= start); 
    assert(matchend >= matchstart); 
 
    out.append(*str, start, matchstart - start); 
    pattern.Rewrite(&out, rewrite, *str, vec, matches); 
    start = matchend; 
    count++; 
    last_match_was_empty_string = (matchstart == matchend); 
  } 
 
  if (count == 0) 
    return 0; 
 
  if (start < str->size()) 
    out.append(*str, start, str->size() - start); 
  using std::swap; 
  swap(out, *str); 
  return count; 
} 
 
bool PCRE::Extract(const StringPiece &text, 
                 const PCRE& pattern, 
                 const StringPiece &rewrite, 
                 std::string *out) { 
  int vec[kVecSize] = {}; 
  int matches = pattern.TryMatch(text, 0, UNANCHORED, true, vec, kVecSize); 
  if (matches == 0) 
    return false; 
  out->clear(); 
  return pattern.Rewrite(out, rewrite, text, vec, matches); 
} 
 
std::string PCRE::QuoteMeta(const StringPiece& unquoted) { 
  std::string result; 
  result.reserve(unquoted.size() << 1); 
 
  // Escape any ascii character not in [A-Za-z_0-9]. 
  // 
  // Note that it's legal to escape a character even if it has no 
  // special meaning in a regular expression -- so this function does 
  // that.  (This also makes it identical to the perl function of the 
  // same name except for the null-character special case; 
  // see `perldoc -f quotemeta`.) 
  for (size_t ii = 0; ii < unquoted.size(); ++ii) { 
    // Note that using 'isalnum' here raises the benchmark time from 
    // 32ns to 58ns: 
    if ((unquoted[ii] < 'a' || unquoted[ii] > 'z') && 
        (unquoted[ii] < 'A' || unquoted[ii] > 'Z') && 
        (unquoted[ii] < '0' || unquoted[ii] > '9') && 
        unquoted[ii] != '_' && 
        // If this is the part of a UTF8 or Latin1 character, we need 
        // to copy this byte without escaping.  Experimentally this is 
        // what works correctly with the regexp library. 
        !(unquoted[ii] & 128)) { 
      if (unquoted[ii] == '\0') {  // Special handling for null chars. 
        // Can't use "\\0" since the next character might be a digit. 
        result += "\\x00"; 
        continue; 
      } 
      result += '\\'; 
    } 
    result += unquoted[ii]; 
  } 
 
  return result; 
} 
 
/***** Actual matching and rewriting code *****/ 
 
bool PCRE::HitLimit() { 
  return hit_limit_ != 0; 
} 
 
void PCRE::ClearHitLimit() { 
  hit_limit_ = 0; 
} 
 
int PCRE::TryMatch(const StringPiece& text, 
                   size_t startpos, 
                   Anchor anchor, 
                   bool empty_ok, 
                   int *vec, 
                   int vecsize) const { 
  pcre* re = (anchor == ANCHOR_BOTH) ? re_full_ : re_partial_; 
  if (re == NULL) { 
    PCREPORT(ERROR) << "Matching against invalid re: " << *error_; 
    return 0; 
  } 
 
  int match_limit = match_limit_; 
  if (match_limit <= 0) { 
    match_limit = GetFlag(FLAGS_regexp_match_limit); 
  } 
 
  int stack_limit = stack_limit_; 
  if (stack_limit <= 0) { 
    stack_limit = GetFlag(FLAGS_regexp_stack_limit); 
  } 
 
  pcre_extra extra = { 0 }; 
  if (match_limit > 0) { 
    extra.flags |= PCRE_EXTRA_MATCH_LIMIT; 
    extra.match_limit = match_limit; 
  } 
  if (stack_limit > 0) { 
    extra.flags |= PCRE_EXTRA_MATCH_LIMIT_RECURSION; 
    extra.match_limit_recursion = stack_limit / kPCREFrameSize; 
  } 
 
  int options = 0; 
  if (anchor != UNANCHORED) 
    options |= PCRE_ANCHORED; 
  if (!empty_ok) 
    options |= PCRE_NOTEMPTY; 
 
  int rc = pcre_exec(re,              // The regular expression object 
                     &extra, 
                     (text.data() == NULL) ? "" : text.data(), 
                     static_cast<int>(text.size()), 
                     static_cast<int>(startpos), 
                     options, 
                     vec, 
                     vecsize); 
 
  // Handle errors 
  if (rc == 0) { 
    // pcre_exec() returns 0 as a special case when the number of 
    // capturing subpatterns exceeds the size of the vector. 
    // When this happens, there is a match and the output vector 
    // is filled, but we miss out on the positions of the extra subpatterns. 
    rc = vecsize / 2; 
  } else if (rc < 0) { 
    switch (rc) { 
      case PCRE_ERROR_NOMATCH: 
        return 0; 
      case PCRE_ERROR_MATCHLIMIT: 
        // Writing to hit_limit is not safe if multiple threads 
        // are using the PCRE, but the flag is only intended 
        // for use by unit tests anyway, so we let it go. 
        hit_limit_ = true; 
        PCREPORT(WARNING) << "Exceeded match limit of " << match_limit 
                        << " when matching '" << pattern_ << "'" 
                        << " against text that is " << text.size() << " bytes."; 
        return 0; 
      case PCRE_ERROR_RECURSIONLIMIT: 
        // See comment about hit_limit above. 
        hit_limit_ = true; 
        PCREPORT(WARNING) << "Exceeded stack limit of " << stack_limit 
                        << " when matching '" << pattern_ << "'" 
                        << " against text that is " << text.size() << " bytes."; 
        return 0; 
      default: 
        // There are other return codes from pcre.h : 
        // PCRE_ERROR_NULL           (-2) 
        // PCRE_ERROR_BADOPTION      (-3) 
        // PCRE_ERROR_BADMAGIC       (-4) 
        // PCRE_ERROR_UNKNOWN_NODE   (-5) 
        // PCRE_ERROR_NOMEMORY       (-6) 
        // PCRE_ERROR_NOSUBSTRING    (-7) 
        // ... 
        PCREPORT(ERROR) << "Unexpected return code: " << rc 
                      << " when matching '" << pattern_ << "'" 
                      << ", re=" << re 
                      << ", text=" << text 
                      << ", vec=" << vec 
                      << ", vecsize=" << vecsize; 
        return 0; 
    } 
  } 
 
  return rc; 
} 
 
bool PCRE::DoMatchImpl(const StringPiece& text, 
                       Anchor anchor, 
                       size_t* consumed, 
                       const Arg* const* args, 
                       int n, 
                       int* vec, 
                       int vecsize) const { 
  assert((1 + n) * 3 <= vecsize);  // results + PCRE workspace 
  if (NumberOfCapturingGroups() < n) { 
    // RE has fewer capturing groups than number of Arg pointers passed in. 
    return false; 
  } 
 
  int matches = TryMatch(text, 0, anchor, true, vec, vecsize); 
  assert(matches >= 0);  // TryMatch never returns negatives 
  if (matches == 0) 
    return false; 
 
  *consumed = vec[1]; 
 
  if (n == 0 || args == NULL) { 
    // We are not interested in results 
    return true; 
  } 
 
  // If we got here, we must have matched the whole pattern. 
  // We do not need (can not do) any more checks on the value of 'matches' here 
  // -- see the comment for TryMatch. 
  for (int i = 0; i < n; i++) { 
    const int start = vec[2*(i+1)]; 
    const int limit = vec[2*(i+1)+1]; 
 
    // Avoid invoking undefined behavior when text.data() happens 
    // to be null and start happens to be -1, the latter being the 
    // case for an unmatched subexpression. Even if text.data() is 
    // not null, pointing one byte before was a longstanding bug. 
    const char* addr = NULL; 
    if (start != -1) { 
      addr = text.data() + start; 
    } 
 
    if (!args[i]->Parse(addr, limit-start)) { 
      // TODO: Should we indicate what the error was? 
      return false; 
    } 
  } 
 
  return true; 
} 
 
bool PCRE::DoMatch(const StringPiece& text, 
                   Anchor anchor, 
                   size_t* consumed, 
                   const Arg* const args[], 
                   int n) const { 
  assert(n >= 0); 
  const int vecsize = (1 + n) * 3;  // results + PCRE workspace 
                                    // (as for kVecSize) 
  int* vec = new int[vecsize]; 
  bool b = DoMatchImpl(text, anchor, consumed, args, n, vec, vecsize); 
  delete[] vec; 
  return b; 
} 
 
bool PCRE::Rewrite(std::string *out, const StringPiece &rewrite, 
                 const StringPiece &text, int *vec, int veclen) const { 
  int number_of_capturing_groups = NumberOfCapturingGroups(); 
  for (const char *s = rewrite.data(), *end = s + rewrite.size(); 
       s < end; s++) { 
    int c = *s; 
    if (c == '\\') { 
      c = *++s; 
      if (isdigit(c)) { 
        int n = (c - '0'); 
        if (n >= veclen) { 
          if (n <= number_of_capturing_groups) { 
            // unmatched optional capturing group. treat 
            // its value as empty string; i.e., nothing to append. 
          } else { 
            PCREPORT(ERROR) << "requested group " << n 
                          << " in regexp " << rewrite.data(); 
            return false; 
          } 
        } 
        int start = vec[2 * n]; 
        if (start >= 0) 
          out->append(text.data() + start, vec[2 * n + 1] - start); 
      } else if (c == '\\') { 
        out->push_back('\\'); 
      } else { 
        PCREPORT(ERROR) << "invalid rewrite pattern: " << rewrite.data(); 
        return false; 
      } 
    } else { 
      out->push_back(c); 
    } 
  } 
  return true; 
} 
 
bool PCRE::CheckRewriteString(const StringPiece& rewrite, 
                              std::string* error) const { 
  int max_token = -1; 
  for (const char *s = rewrite.data(), *end = s + rewrite.size(); 
       s < end; s++) { 
    int c = *s; 
    if (c != '\\') { 
      continue; 
    } 
    if (++s == end) { 
      *error = "Rewrite schema error: '\\' not allowed at end."; 
      return false; 
    } 
    c = *s; 
    if (c == '\\') { 
      continue; 
    } 
    if (!isdigit(c)) { 
      *error = "Rewrite schema error: " 
               "'\\' must be followed by a digit or '\\'."; 
      return false; 
    } 
    int n = (c - '0'); 
    if (max_token < n) { 
      max_token = n; 
    } 
  } 
 
  if (max_token > NumberOfCapturingGroups()) { 
    *error = StringPrintf( 
        "Rewrite schema requests %d matches, but the regexp only has %d " 
        "parenthesized subexpressions.", 
        max_token, NumberOfCapturingGroups()); 
    return false; 
  } 
  return true; 
} 
 
 
// Return the number of capturing subpatterns, or -1 if the 
// regexp wasn't valid on construction. 
int PCRE::NumberOfCapturingGroups() const { 
  if (re_partial_ == NULL) return -1; 
 
  int result; 
  int rc = pcre_fullinfo(re_partial_,       // The regular expression object 
                         NULL,              // We did not study the pattern 
                         PCRE_INFO_CAPTURECOUNT, 
                         &result); 
  if (rc != 0) { 
    PCREPORT(ERROR) << "Unexpected return code: " << rc; 
    return -1; 
  } 
  return result; 
} 
 
 
/***** Parsers for various types *****/ 
 
bool PCRE::Arg::parse_null(const char* str, size_t n, void* dest) { 
  // We fail if somebody asked us to store into a non-NULL void* pointer 
  return (dest == NULL); 
} 
 
bool PCRE::Arg::parse_string(const char* str, size_t n, void* dest) { 
  if (dest == NULL) return true; 
  reinterpret_cast<std::string*>(dest)->assign(str, n); 
  return true; 
} 
 
bool PCRE::Arg::parse_stringpiece(const char* str, size_t n, void* dest) { 
  if (dest == NULL) return true; 
  *(reinterpret_cast<StringPiece*>(dest)) = StringPiece(str, n); 
  return true; 
} 
 
bool PCRE::Arg::parse_char(const char* str, size_t n, void* dest) { 
  if (n != 1) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<char*>(dest)) = str[0]; 
  return true; 
} 
 
bool PCRE::Arg::parse_schar(const char* str, size_t n, void* dest) { 
  if (n != 1) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<signed char*>(dest)) = str[0]; 
  return true; 
} 
 
bool PCRE::Arg::parse_uchar(const char* str, size_t n, void* dest) { 
  if (n != 1) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<unsigned char*>(dest)) = str[0]; 
  return true; 
} 
 
// Largest number spec that we are willing to parse 
static const int kMaxNumberLength = 32; 
 
// PCREQUIPCRES "buf" must have length at least kMaxNumberLength+1 
// PCREQUIPCRES "n > 0" 
// Copies "str" into "buf" and null-terminates if necessary. 
// Returns one of: 
//      a. "str" if no termination is needed 
//      b. "buf" if the string was copied and null-terminated 
//      c. "" if the input was invalid and has no hope of being parsed 
static const char* TerminateNumber(char* buf, const char* str, size_t n) { 
  if ((n > 0) && isspace(*str)) { 
    // We are less forgiving than the strtoxxx() routines and do not 
    // allow leading spaces. 
    return ""; 
  } 
 
  // See if the character right after the input text may potentially 
  // look like a digit. 
  if (isdigit(str[n]) || 
      ((str[n] >= 'a') && (str[n] <= 'f')) || 
      ((str[n] >= 'A') && (str[n] <= 'F'))) { 
    if (n > kMaxNumberLength) return ""; // Input too big to be a valid number 
    memcpy(buf, str, n); 
    buf[n] = '\0'; 
    return buf; 
  } else { 
    // We can parse right out of the supplied string, so return it. 
    return str; 
  } 
} 
 
bool PCRE::Arg::parse_long_radix(const char* str, 
                                 size_t n, 
                                 void* dest, 
                                 int radix) { 
  if (n == 0) return false; 
  char buf[kMaxNumberLength+1]; 
  str = TerminateNumber(buf, str, n); 
  char* end; 
  errno = 0; 
  long r = strtol(str, &end, radix); 
  if (end != str + n) return false;   // Leftover junk 
  if (errno) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<long*>(dest)) = r; 
  return true; 
} 
 
bool PCRE::Arg::parse_ulong_radix(const char* str, 
                                  size_t n, 
                                  void* dest, 
                                  int radix) { 
  if (n == 0) return false; 
  char buf[kMaxNumberLength+1]; 
  str = TerminateNumber(buf, str, n); 
  if (str[0] == '-') { 
    // strtoul() will silently accept negative numbers and parse 
    // them.  This module is more strict and treats them as errors. 
    return false; 
  } 
 
  char* end; 
  errno = 0; 
  unsigned long r = strtoul(str, &end, radix); 
  if (end != str + n) return false;   // Leftover junk 
  if (errno) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<unsigned long*>(dest)) = r; 
  return true; 
} 
 
bool PCRE::Arg::parse_short_radix(const char* str, 
                                  size_t n, 
                                  void* dest, 
                                  int radix) { 
  long r; 
  if (!parse_long_radix(str, n, &r, radix)) return false;  // Could not parse 
  if ((short)r != r) return false;                         // Out of range 
  if (dest == NULL) return true; 
  *(reinterpret_cast<short*>(dest)) = (short)r; 
  return true; 
} 
 
bool PCRE::Arg::parse_ushort_radix(const char* str, 
                                   size_t n, 
                                   void* dest, 
                                   int radix) { 
  unsigned long r; 
  if (!parse_ulong_radix(str, n, &r, radix)) return false;  // Could not parse 
  if ((unsigned short)r != r) return false;                 // Out of range 
  if (dest == NULL) return true; 
  *(reinterpret_cast<unsigned short*>(dest)) = (unsigned short)r; 
  return true; 
} 
 
bool PCRE::Arg::parse_int_radix(const char* str, 
                                size_t n, 
                                void* dest, 
                                int radix) { 
  long r; 
  if (!parse_long_radix(str, n, &r, radix)) return false;  // Could not parse 
  if ((int)r != r) return false;                           // Out of range 
  if (dest == NULL) return true; 
  *(reinterpret_cast<int*>(dest)) = (int)r; 
  return true; 
} 
 
bool PCRE::Arg::parse_uint_radix(const char* str, 
                                 size_t n, 
                                 void* dest, 
                                 int radix) { 
  unsigned long r; 
  if (!parse_ulong_radix(str, n, &r, radix)) return false;  // Could not parse 
  if ((unsigned int)r != r) return false;                   // Out of range 
  if (dest == NULL) return true; 
  *(reinterpret_cast<unsigned int*>(dest)) = (unsigned int)r; 
  return true; 
} 
 
bool PCRE::Arg::parse_longlong_radix(const char* str, 
                                     size_t n, 
                                     void* dest, 
                                     int radix) { 
  if (n == 0) return false; 
  char buf[kMaxNumberLength+1]; 
  str = TerminateNumber(buf, str, n); 
  char* end; 
  errno = 0; 
  long long r = strtoll(str, &end, radix); 
  if (end != str + n) return false;   // Leftover junk 
  if (errno) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<long long*>(dest)) = r; 
  return true; 
} 
 
bool PCRE::Arg::parse_ulonglong_radix(const char* str, 
                                      size_t n, 
                                      void* dest, 
                                      int radix) { 
  if (n == 0) return false; 
  char buf[kMaxNumberLength+1]; 
  str = TerminateNumber(buf, str, n); 
  if (str[0] == '-') { 
    // strtoull() will silently accept negative numbers and parse 
    // them.  This module is more strict and treats them as errors. 
    return false; 
  } 
  char* end; 
  errno = 0; 
  unsigned long long r = strtoull(str, &end, radix); 
  if (end != str + n) return false;   // Leftover junk 
  if (errno) return false; 
  if (dest == NULL) return true; 
  *(reinterpret_cast<unsigned long long*>(dest)) = r; 
  return true; 
} 
 
static bool parse_double_float(const char* str, size_t n, bool isfloat, 
                               void* dest) { 
  if (n == 0) return false; 
  static const int kMaxLength = 200; 
  char buf[kMaxLength]; 
  if (n >= kMaxLength) return false; 
  memcpy(buf, str, n); 
  buf[n] = '\0'; 
  char* end; 
  errno = 0; 
  double r; 
  if (isfloat) { 
    r = strtof(buf, &end); 
  } else { 
    r = strtod(buf, &end); 
  } 
  if (end != buf + n) return false;   // Leftover junk 
  if (errno) return false; 
  if (dest == NULL) return true; 
  if (isfloat) { 
    *(reinterpret_cast<float*>(dest)) = (float)r; 
  } else { 
    *(reinterpret_cast<double*>(dest)) = r; 
  } 
  return true; 
} 
 
bool PCRE::Arg::parse_double(const char* str, size_t n, void* dest) { 
  return parse_double_float(str, n, false, dest); 
} 
 
bool PCRE::Arg::parse_float(const char* str, size_t n, void* dest) { 
  return parse_double_float(str, n, true, dest); 
} 
 
#define DEFINE_INTEGER_PARSER(name)                                           \ 
  bool PCRE::Arg::parse_##name(const char* str, size_t n, void* dest) {       \ 
    return parse_##name##_radix(str, n, dest, 10);                            \ 
  }                                                                           \ 
  bool PCRE::Arg::parse_##name##_hex(const char* str, size_t n, void* dest) { \ 
    return parse_##name##_radix(str, n, dest, 16);                            \ 
  }                                                                           \ 
  bool PCRE::Arg::parse_##name##_octal(const char* str, size_t n,             \ 
                                       void* dest) {                          \ 
    return parse_##name##_radix(str, n, dest, 8);                             \ 
  }                                                                           \ 
  bool PCRE::Arg::parse_##name##_cradix(const char* str, size_t n,            \ 
                                        void* dest) {                         \ 
    return parse_##name##_radix(str, n, dest, 0);                             \ 
  } 
 
DEFINE_INTEGER_PARSER(short); 
DEFINE_INTEGER_PARSER(ushort); 
DEFINE_INTEGER_PARSER(int); 
DEFINE_INTEGER_PARSER(uint); 
DEFINE_INTEGER_PARSER(long); 
DEFINE_INTEGER_PARSER(ulong); 
DEFINE_INTEGER_PARSER(longlong); 
DEFINE_INTEGER_PARSER(ulonglong); 
 
#undef DEFINE_INTEGER_PARSER 
 
}  // namespace re2