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      1 // Copyright 2003-2010 Google Inc.  All Rights Reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 // This is a variant of PCRE's pcrecpp.h, originally written at Google.
      6 // The main changes are the addition of the HitLimit method and
      7 // compilation as PCRE in namespace re2.
      8 
      9 // C++ interface to the pcre regular-expression library.  PCRE supports
     10 // Perl-style regular expressions (with extensions like \d, \w, \s,
     11 // ...).
     12 //
     13 // -----------------------------------------------------------------------
     14 // REGEXP SYNTAX:
     15 //
     16 // This module uses the pcre library and hence supports its syntax
     17 // for regular expressions:
     18 //
     19 //      http://www.google.com/search?q=pcre
     20 //
     21 // The syntax is pretty similar to Perl's.  For those not familiar
     22 // with Perl's regular expressions, here are some examples of the most
     23 // commonly used extensions:
     24 //
     25 //   "hello (\\w+) world"  -- \w matches a "word" character
     26 //   "version (\\d+)"      -- \d matches a digit
     27 //   "hello\\s+world"      -- \s matches any whitespace character
     28 //   "\\b(\\w+)\\b"        -- \b matches empty string at a word boundary
     29 //   "(?i)hello"           -- (?i) turns on case-insensitive matching
     30 //   "/\\*(.*?)\\*/"       -- .*? matches . minimum no. of times possible
     31 //
     32 // -----------------------------------------------------------------------
     33 // MATCHING INTERFACE:
     34 //
     35 // The "FullMatch" operation checks that supplied text matches a
     36 // supplied pattern exactly.
     37 //
     38 // Example: successful match
     39 //    CHECK(PCRE::FullMatch("hello", "h.*o"));
     40 //
     41 // Example: unsuccessful match (requires full match):
     42 //    CHECK(!PCRE::FullMatch("hello", "e"));
     43 //
     44 // -----------------------------------------------------------------------
     45 // UTF-8 AND THE MATCHING INTERFACE:
     46 //
     47 // By default, pattern and text are plain text, one byte per character.
     48 // The UTF8 flag, passed to the constructor, causes both pattern
     49 // and string to be treated as UTF-8 text, still a byte stream but
     50 // potentially multiple bytes per character. In practice, the text
     51 // is likelier to be UTF-8 than the pattern, but the match returned
     52 // may depend on the UTF8 flag, so always use it when matching
     53 // UTF8 text.  E.g., "." will match one byte normally but with UTF8
     54 // set may match up to three bytes of a multi-byte character.
     55 //
     56 // Example:
     57 //    PCRE re(utf8_pattern, PCRE::UTF8);
     58 //    CHECK(PCRE::FullMatch(utf8_string, re));
     59 //
     60 // -----------------------------------------------------------------------
     61 // MATCHING WITH SUB-STRING EXTRACTION:
     62 //
     63 // You can supply extra pointer arguments to extract matched subpieces.
     64 //
     65 // Example: extracts "ruby" into "s" and 1234 into "i"
     66 //    int i;
     67 //    string s;
     68 //    CHECK(PCRE::FullMatch("ruby:1234", "(\\w+):(\\d+)", &s, &i));
     69 //
     70 // Example: fails because string cannot be stored in integer
     71 //    CHECK(!PCRE::FullMatch("ruby", "(.*)", &i));
     72 //
     73 // Example: fails because there aren't enough sub-patterns:
     74 //    CHECK(!PCRE::FullMatch("ruby:1234", "\\w+:\\d+", &s));
     75 //
     76 // Example: does not try to extract any extra sub-patterns
     77 //    CHECK(PCRE::FullMatch("ruby:1234", "(\\w+):(\\d+)", &s));
     78 //
     79 // Example: does not try to extract into NULL
     80 //    CHECK(PCRE::FullMatch("ruby:1234", "(\\w+):(\\d+)", NULL, &i));
     81 //
     82 // Example: integer overflow causes failure
     83 //    CHECK(!PCRE::FullMatch("ruby:1234567891234", "\\w+:(\\d+)", &i));
     84 //
     85 // -----------------------------------------------------------------------
     86 // PARTIAL MATCHES
     87 //
     88 // You can use the "PartialMatch" operation when you want the pattern
     89 // to match any substring of the text.
     90 //
     91 // Example: simple search for a string:
     92 //      CHECK(PCRE::PartialMatch("hello", "ell"));
     93 //
     94 // Example: find first number in a string
     95 //      int number;
     96 //      CHECK(PCRE::PartialMatch("x*100 + 20", "(\\d+)", &number));
     97 //      CHECK_EQ(number, 100);
     98 //
     99 // -----------------------------------------------------------------------
    100 // PPCRE-COMPILED PCREGULAR EXPPCRESSIONS
    101 //
    102 // PCRE makes it easy to use any string as a regular expression, without
    103 // requiring a separate compilation step.
    104 //
    105 // If speed is of the essence, you can create a pre-compiled "PCRE"
    106 // object from the pattern and use it multiple times.  If you do so,
    107 // you can typically parse text faster than with sscanf.
    108 //
    109 // Example: precompile pattern for faster matching:
    110 //    PCRE pattern("h.*o");
    111 //    while (ReadLine(&str)) {
    112 //      if (PCRE::FullMatch(str, pattern)) ...;
    113 //    }
    114 //
    115 // -----------------------------------------------------------------------
    116 // SCANNING TEXT INCPCREMENTALLY
    117 //
    118 // The "Consume" operation may be useful if you want to repeatedly
    119 // match regular expressions at the front of a string and skip over
    120 // them as they match.  This requires use of the "StringPiece" type,
    121 // which represents a sub-range of a real string.
    122 //
    123 // Example: read lines of the form "var = value" from a string.
    124 //      string contents = ...;          // Fill string somehow
    125 //      StringPiece input(contents);    // Wrap a StringPiece around it
    126 //
    127 //      string var;
    128 //      int value;
    129 //      while (PCRE::Consume(&input, "(\\w+) = (\\d+)\n", &var, &value)) {
    130 //        ...;
    131 //      }
    132 //
    133 // Each successful call to "Consume" will set "var/value", and also
    134 // advance "input" so it points past the matched text.  Note that if the
    135 // regular expression matches an empty string, input will advance
    136 // by 0 bytes.  If the regular expression being used might match
    137 // an empty string, the loop body must check for this case and either
    138 // advance the string or break out of the loop.
    139 //
    140 // The "FindAndConsume" operation is similar to "Consume" but does not
    141 // anchor your match at the beginning of the string.  For example, you
    142 // could extract all words from a string by repeatedly calling
    143 //     PCRE::FindAndConsume(&input, "(\\w+)", &word)
    144 //
    145 // -----------------------------------------------------------------------
    146 // PARSING HEX/OCTAL/C-RADIX NUMBERS
    147 //
    148 // By default, if you pass a pointer to a numeric value, the
    149 // corresponding text is interpreted as a base-10 number.  You can
    150 // instead wrap the pointer with a call to one of the operators Hex(),
    151 // Octal(), or CRadix() to interpret the text in another base.  The
    152 // CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
    153 // prefixes, but defaults to base-10.
    154 //
    155 // Example:
    156 //   int a, b, c, d;
    157 //   CHECK(PCRE::FullMatch("100 40 0100 0x40", "(.*) (.*) (.*) (.*)",
    158 //         Octal(&a), Hex(&b), CRadix(&c), CRadix(&d));
    159 // will leave 64 in a, b, c, and d.
    160 
    161 #include "util/util.h"
    162 #include "re2/stringpiece.h"
    163 
    164 #ifdef USEPCRE
    165 #include <pcre.h>
    166 namespace re2 {
    167 const bool UsingPCRE = true;
    168 }  // namespace re2
    169 #else
    170 namespace re2 {
    171 const bool UsingPCRE = false;
    172 struct pcre;
    173 struct pcre_extra { int flags, match_limit, match_limit_recursion; };
    174 #define pcre_free(x) {}
    175 #define PCRE_EXTRA_MATCH_LIMIT 0
    176 #define PCRE_EXTRA_MATCH_LIMIT_RECURSION 0
    177 #define PCRE_ANCHORED 0
    178 #define PCRE_NOTEMPTY 0
    179 #define PCRE_ERROR_NOMATCH 1
    180 #define PCRE_ERROR_MATCHLIMIT 2
    181 #define PCRE_ERROR_RECURSIONLIMIT 3
    182 #define PCRE_INFO_CAPTURECOUNT 0
    183 #ifndef WIN32
    184 #define pcre_compile(a,b,c,d,e) ({ (void)(a); (void)(b); *(c)=""; *(d)=0; (void)(e); ((pcre*)0); })
    185 #define pcre_exec(a, b, c, d, e, f, g, h) ({ (void)(a); (void)(b); (void)(c); (void)(d); (void)(e); (void)(f); (void)(g); (void)(h); 0; })
    186 #define pcre_fullinfo(a, b, c, d) ({ (void)(a); (void)(b); (void)(c); *(d) = 0; 0; })
    187 #else
    188 #define pcre_compile(a,b,c,d,e) NULL
    189 #define pcre_exec(a, b, c, d, e, f, g, h) NULL
    190 #define pcre_fullinfo(a, b, c, d) NULL
    191 #endif
    192 }  // namespace re2
    193 #endif
    194 
    195 namespace re2 {
    196 
    197 class PCRE_Options;
    198 
    199 // Interface for regular expression matching.  Also corresponds to a
    200 // pre-compiled regular expression.  An "PCRE" object is safe for
    201 // concurrent use by multiple threads.
    202 class PCRE {
    203  public:
    204   // We convert user-passed pointers into special Arg objects
    205   class Arg;
    206 
    207   // Marks end of arg list.
    208   // ONLY USE IN OPTIONAL ARG DEFAULTS.
    209   // DO NOT PASS EXPLICITLY.
    210   static Arg no_more_args;
    211 
    212   // Options are same value as those in pcre.  We provide them here
    213   // to avoid users needing to include pcre.h and also to isolate
    214   // users from pcre should we change the underlying library.
    215   // Only those needed by Google programs are exposed here to
    216   // avoid collision with options employed internally by regexp.cc
    217   // Note that some options have equivalents that can be specified in
    218   // the regexp itself.  For example, prefixing your regexp with
    219   // "(?s)" has the same effect as the PCRE_DOTALL option.
    220   enum Option {
    221     None = 0x0000,
    222     UTF8 = 0x0800,  // == PCRE_UTF8
    223     EnabledCompileOptions = UTF8,
    224     EnabledExecOptions = 0x0000,  // TODO: use to replace anchor flag
    225   };
    226 
    227   // We provide implicit conversions from strings so that users can
    228   // pass in a string or a "const char*" wherever an "PCRE" is expected.
    229   PCRE(const char* pattern);
    230   PCRE(const char* pattern, Option option);
    231   PCRE(const string& pattern);
    232   PCRE(const string& pattern, Option option);
    233   PCRE(const char *pattern, const PCRE_Options& re_option);
    234   PCRE(const string& pattern, const PCRE_Options& re_option);
    235 
    236   ~PCRE();
    237 
    238   // The string specification for this PCRE.  E.g.
    239   //   PCRE re("ab*c?d+");
    240   //   re.pattern();    // "ab*c?d+"
    241   const string& pattern() const { return pattern_; }
    242 
    243   // If PCRE could not be created properly, returns an error string.
    244   // Else returns the empty string.
    245   const string& error() const { return *error_; }
    246 
    247   // Whether the PCRE has hit a match limit during execution.
    248   // Not thread safe.  Intended only for testing.
    249   // If hitting match limits is a problem,
    250   // you should be using PCRE2 (re2/re2.h)
    251   // instead of checking this flag.
    252   bool HitLimit();
    253   void ClearHitLimit();
    254 
    255   /***** The useful part: the matching interface *****/
    256 
    257   // Matches "text" against "pattern".  If pointer arguments are
    258   // supplied, copies matched sub-patterns into them.
    259   //
    260   // You can pass in a "const char*" or a "string" for "text".
    261   // You can pass in a "const char*" or a "string" or a "PCRE" for "pattern".
    262   //
    263   // The provided pointer arguments can be pointers to any scalar numeric
    264   // type, or one of:
    265   //    string          (matched piece is copied to string)
    266   //    StringPiece     (StringPiece is mutated to point to matched piece)
    267   //    T               (where "bool T::ParseFrom(const char*, int)" exists)
    268   //    (void*)NULL     (the corresponding matched sub-pattern is not copied)
    269   //
    270   // Returns true iff all of the following conditions are satisfied:
    271   //   a. "text" matches "pattern" exactly
    272   //   b. The number of matched sub-patterns is >= number of supplied pointers
    273   //   c. The "i"th argument has a suitable type for holding the
    274   //      string captured as the "i"th sub-pattern.  If you pass in
    275   //      NULL for the "i"th argument, or pass fewer arguments than
    276   //      number of sub-patterns, "i"th captured sub-pattern is
    277   //      ignored.
    278   //
    279   // CAVEAT: An optional sub-pattern that does not exist in the
    280   // matched string is assigned the empty string.  Therefore, the
    281   // following will return false (because the empty string is not a
    282   // valid number):
    283   //    int number;
    284   //    PCRE::FullMatch("abc", "[a-z]+(\\d+)?", &number);
    285   struct FullMatchFunctor {
    286     bool operator ()(const StringPiece& text, const PCRE& re, // 3..16 args
    287                      const Arg& ptr1 = no_more_args,
    288                      const Arg& ptr2 = no_more_args,
    289                      const Arg& ptr3 = no_more_args,
    290                      const Arg& ptr4 = no_more_args,
    291                      const Arg& ptr5 = no_more_args,
    292                      const Arg& ptr6 = no_more_args,
    293                      const Arg& ptr7 = no_more_args,
    294                      const Arg& ptr8 = no_more_args,
    295                      const Arg& ptr9 = no_more_args,
    296                      const Arg& ptr10 = no_more_args,
    297                      const Arg& ptr11 = no_more_args,
    298                      const Arg& ptr12 = no_more_args,
    299                      const Arg& ptr13 = no_more_args,
    300                      const Arg& ptr14 = no_more_args,
    301                      const Arg& ptr15 = no_more_args,
    302                      const Arg& ptr16 = no_more_args) const;
    303   };
    304 
    305   static const FullMatchFunctor FullMatch;
    306 
    307   // Exactly like FullMatch(), except that "pattern" is allowed to match
    308   // a substring of "text".
    309   struct PartialMatchFunctor {
    310     bool operator ()(const StringPiece& text, const PCRE& re, // 3..16 args
    311                      const Arg& ptr1 = no_more_args,
    312                      const Arg& ptr2 = no_more_args,
    313                      const Arg& ptr3 = no_more_args,
    314                      const Arg& ptr4 = no_more_args,
    315                      const Arg& ptr5 = no_more_args,
    316                      const Arg& ptr6 = no_more_args,
    317                      const Arg& ptr7 = no_more_args,
    318                      const Arg& ptr8 = no_more_args,
    319                      const Arg& ptr9 = no_more_args,
    320                      const Arg& ptr10 = no_more_args,
    321                      const Arg& ptr11 = no_more_args,
    322                      const Arg& ptr12 = no_more_args,
    323                      const Arg& ptr13 = no_more_args,
    324                      const Arg& ptr14 = no_more_args,
    325                      const Arg& ptr15 = no_more_args,
    326                      const Arg& ptr16 = no_more_args) const;
    327   };
    328 
    329   static const PartialMatchFunctor PartialMatch;
    330 
    331   // Like FullMatch() and PartialMatch(), except that pattern has to
    332   // match a prefix of "text", and "input" is advanced past the matched
    333   // text.  Note: "input" is modified iff this routine returns true.
    334   struct ConsumeFunctor {
    335     bool operator ()(StringPiece* input, const PCRE& pattern, // 3..16 args
    336                      const Arg& ptr1 = no_more_args,
    337                      const Arg& ptr2 = no_more_args,
    338                      const Arg& ptr3 = no_more_args,
    339                      const Arg& ptr4 = no_more_args,
    340                      const Arg& ptr5 = no_more_args,
    341                      const Arg& ptr6 = no_more_args,
    342                      const Arg& ptr7 = no_more_args,
    343                      const Arg& ptr8 = no_more_args,
    344                      const Arg& ptr9 = no_more_args,
    345                      const Arg& ptr10 = no_more_args,
    346                      const Arg& ptr11 = no_more_args,
    347                      const Arg& ptr12 = no_more_args,
    348                      const Arg& ptr13 = no_more_args,
    349                      const Arg& ptr14 = no_more_args,
    350                      const Arg& ptr15 = no_more_args,
    351                      const Arg& ptr16 = no_more_args) const;
    352   };
    353 
    354   static const ConsumeFunctor Consume;
    355 
    356   // Like Consume(..), but does not anchor the match at the beginning of the
    357   // string.  That is, "pattern" need not start its match at the beginning of
    358   // "input".  For example, "FindAndConsume(s, "(\\w+)", &word)" finds the next
    359   // word in "s" and stores it in "word".
    360   struct FindAndConsumeFunctor {
    361     bool operator ()(StringPiece* input, const PCRE& pattern,
    362                      const Arg& ptr1 = no_more_args,
    363                      const Arg& ptr2 = no_more_args,
    364                      const Arg& ptr3 = no_more_args,
    365                      const Arg& ptr4 = no_more_args,
    366                      const Arg& ptr5 = no_more_args,
    367                      const Arg& ptr6 = no_more_args,
    368                      const Arg& ptr7 = no_more_args,
    369                      const Arg& ptr8 = no_more_args,
    370                      const Arg& ptr9 = no_more_args,
    371                      const Arg& ptr10 = no_more_args,
    372                      const Arg& ptr11 = no_more_args,
    373                      const Arg& ptr12 = no_more_args,
    374                      const Arg& ptr13 = no_more_args,
    375                      const Arg& ptr14 = no_more_args,
    376                      const Arg& ptr15 = no_more_args,
    377                      const Arg& ptr16 = no_more_args) const;
    378   };
    379 
    380   static const FindAndConsumeFunctor FindAndConsume;
    381 
    382   // Replace the first match of "pattern" in "str" with "rewrite".
    383   // Within "rewrite", backslash-escaped digits (\1 to \9) can be
    384   // used to insert text matching corresponding parenthesized group
    385   // from the pattern.  \0 in "rewrite" refers to the entire matching
    386   // text.  E.g.,
    387   //
    388   //   string s = "yabba dabba doo";
    389   //   CHECK(PCRE::Replace(&s, "b+", "d"));
    390   //
    391   // will leave "s" containing "yada dabba doo"
    392   //
    393   // Returns true if the pattern matches and a replacement occurs,
    394   // false otherwise.
    395   static bool Replace(string *str,
    396                       const PCRE& pattern,
    397                       const StringPiece& rewrite);
    398 
    399   // Like Replace(), except replaces all occurrences of the pattern in
    400   // the string with the rewrite.  Replacements are not subject to
    401   // re-matching.  E.g.,
    402   //
    403   //   string s = "yabba dabba doo";
    404   //   CHECK(PCRE::GlobalReplace(&s, "b+", "d"));
    405   //
    406   // will leave "s" containing "yada dada doo"
    407   //
    408   // Returns the number of replacements made.
    409   static int GlobalReplace(string *str,
    410                            const PCRE& pattern,
    411                            const StringPiece& rewrite);
    412 
    413   // Like Replace, except that if the pattern matches, "rewrite"
    414   // is copied into "out" with substitutions.  The non-matching
    415   // portions of "text" are ignored.
    416   //
    417   // Returns true iff a match occurred and the extraction happened
    418   // successfully;  if no match occurs, the string is left unaffected.
    419   static bool Extract(const StringPiece &text,
    420                       const PCRE& pattern,
    421                       const StringPiece &rewrite,
    422                       string *out);
    423 
    424   // Check that the given @p rewrite string is suitable for use with
    425   // this PCRE.  It checks that:
    426   //   * The PCRE has enough parenthesized subexpressions to satisfy all
    427   //       of the \N tokens in @p rewrite, and
    428   //   * The @p rewrite string doesn't have any syntax errors
    429   //       ('\' followed by anything besides [0-9] and '\').
    430   // Making this test will guarantee that "replace" and "extract"
    431   // operations won't LOG(ERROR) or fail because of a bad rewrite
    432   // string.
    433   // @param rewrite The proposed rewrite string.
    434   // @param error An error message is recorded here, iff we return false.
    435   //              Otherwise, it is unchanged.
    436   // @return true, iff @p rewrite is suitable for use with the PCRE.
    437   bool CheckRewriteString(const StringPiece& rewrite, string* error) const;
    438 
    439   // Returns a copy of 'unquoted' with all potentially meaningful
    440   // regexp characters backslash-escaped.  The returned string, used
    441   // as a regular expression, will exactly match the original string.
    442   // For example,
    443   //           1.5-2.0?
    444   //  becomes:
    445   //           1\.5\-2\.0\?
    446   static string QuoteMeta(const StringPiece& unquoted);
    447 
    448   /***** Generic matching interface (not so nice to use) *****/
    449 
    450   // Type of match (TODO: Should be restructured as an Option)
    451   enum Anchor {
    452     UNANCHORED,         // No anchoring
    453     ANCHOR_START,       // Anchor at start only
    454     ANCHOR_BOTH,        // Anchor at start and end
    455   };
    456 
    457   // General matching routine.  Stores the length of the match in
    458   // "*consumed" if successful.
    459   bool DoMatch(const StringPiece& text,
    460                Anchor anchor,
    461                int* consumed,
    462                const Arg* const* args, int n) const;
    463 
    464   // Return the number of capturing subpatterns, or -1 if the
    465   // regexp wasn't valid on construction.
    466   int NumberOfCapturingGroups() const;
    467 
    468  private:
    469   void Init(const char* pattern, Option option, int match_limit,
    470             int stack_limit, bool report_errors);
    471 
    472   // Match against "text", filling in "vec" (up to "vecsize" * 2/3) with
    473   // pairs of integers for the beginning and end positions of matched
    474   // text.  The first pair corresponds to the entire matched text;
    475   // subsequent pairs correspond, in order, to parentheses-captured
    476   // matches.  Returns the number of pairs (one more than the number of
    477   // the last subpattern with a match) if matching was successful
    478   // and zero if the match failed.
    479   // I.e. for PCRE("(foo)|(bar)|(baz)") it will return 2, 3, and 4 when matching
    480   // against "foo", "bar", and "baz" respectively.
    481   // When matching PCRE("(foo)|hello") against "hello", it will return 1.
    482   // But the values for all subpattern are filled in into "vec".
    483   int TryMatch(const StringPiece& text,
    484                int startpos,
    485                Anchor anchor,
    486                bool empty_ok,
    487                int *vec,
    488                int vecsize) const;
    489 
    490   // Append the "rewrite" string, with backslash subsitutions from "text"
    491   // and "vec", to string "out".
    492   bool Rewrite(string *out,
    493                const StringPiece &rewrite,
    494                const StringPiece &text,
    495                int *vec,
    496                int veclen) const;
    497 
    498   // internal implementation for DoMatch
    499   bool DoMatchImpl(const StringPiece& text,
    500                    Anchor anchor,
    501                    int* consumed,
    502                    const Arg* const args[],
    503                    int n,
    504                    int* vec,
    505                    int vecsize) const;
    506 
    507   // Compile the regexp for the specified anchoring mode
    508   pcre* Compile(Anchor anchor);
    509 
    510   string            pattern_;
    511   Option            options_;
    512   pcre*             re_full_;        // For full matches
    513   pcre*             re_partial_;     // For partial matches
    514   const string*     error_;          // Error indicator (or empty string)
    515   bool              report_errors_;  // Silences error logging if false
    516   int               match_limit_;    // Limit on execution resources
    517   int               stack_limit_;    // Limit on stack resources (bytes)
    518   mutable int32_t  hit_limit_;  // Hit limit during execution (bool)?
    519   DISALLOW_EVIL_CONSTRUCTORS(PCRE);
    520 };
    521 
    522 // PCRE_Options allow you to set the PCRE::Options, plus any pcre
    523 // "extra" options.  The only extras are match_limit, which limits
    524 // the CPU time of a match, and stack_limit, which limits the
    525 // stack usage.  Setting a limit to <= 0 lets PCRE pick a sensible default
    526 // that should not cause too many problems in production code.
    527 // If PCRE hits a limit during a match, it may return a false negative,
    528 // but (hopefully) it won't crash.
    529 //
    530 // NOTE: If you are handling regular expressions specified by
    531 // (external or internal) users, rather than hard-coded ones,
    532 // you should be using PCRE2, which uses an alternate implementation
    533 // that avoids these issues.  See http://go/re2quick.
    534 class PCRE_Options {
    535  public:
    536   // constructor
    537   PCRE_Options() : option_(PCRE::None), match_limit_(0), stack_limit_(0), report_errors_(true) {}
    538   // accessors
    539   PCRE::Option option() const { return option_; }
    540   void set_option(PCRE::Option option) {
    541     option_ = option;
    542   }
    543   int match_limit() const { return match_limit_; }
    544   void set_match_limit(int match_limit) {
    545     match_limit_ = match_limit;
    546   }
    547   int stack_limit() const { return stack_limit_; }
    548   void set_stack_limit(int stack_limit) {
    549     stack_limit_ = stack_limit;
    550   }
    551 
    552   // If the regular expression is malformed, an error message will be printed
    553   // iff report_errors() is true.  Default: true.
    554   bool report_errors() const { return report_errors_; }
    555   void set_report_errors(bool report_errors) {
    556     report_errors_ = report_errors;
    557   }
    558  private:
    559   PCRE::Option option_;
    560   int match_limit_;
    561   int stack_limit_;
    562   bool report_errors_;
    563 };
    564 
    565 
    566 /***** Implementation details *****/
    567 
    568 // Hex/Octal/Binary?
    569 
    570 // Special class for parsing into objects that define a ParseFrom() method
    571 template <class T>
    572 class _PCRE_MatchObject {
    573  public:
    574   static inline bool Parse(const char* str, int n, void* dest) {
    575     if (dest == NULL) return true;
    576     T* object = reinterpret_cast<T*>(dest);
    577     return object->ParseFrom(str, n);
    578   }
    579 };
    580 
    581 class PCRE::Arg {
    582  public:
    583   // Empty constructor so we can declare arrays of PCRE::Arg
    584   Arg();
    585 
    586   // Constructor specially designed for NULL arguments
    587   Arg(void*);
    588 
    589   typedef bool (*Parser)(const char* str, int n, void* dest);
    590 
    591 // Type-specific parsers
    592 #define MAKE_PARSER(type,name) \
    593   Arg(type* p) : arg_(p), parser_(name) { } \
    594   Arg(type* p, Parser parser) : arg_(p), parser_(parser) { } \
    595 
    596 
    597   MAKE_PARSER(char,               parse_char);
    598   MAKE_PARSER(unsigned char,      parse_uchar);
    599   MAKE_PARSER(short,              parse_short);
    600   MAKE_PARSER(unsigned short,     parse_ushort);
    601   MAKE_PARSER(int,                parse_int);
    602   MAKE_PARSER(unsigned int,       parse_uint);
    603   MAKE_PARSER(long,               parse_long);
    604   MAKE_PARSER(unsigned long,      parse_ulong);
    605   MAKE_PARSER(long long,          parse_longlong);
    606   MAKE_PARSER(unsigned long long, parse_ulonglong);
    607   MAKE_PARSER(float,              parse_float);
    608   MAKE_PARSER(double,             parse_double);
    609   MAKE_PARSER(string,             parse_string);
    610   MAKE_PARSER(StringPiece,        parse_stringpiece);
    611 
    612 #undef MAKE_PARSER
    613 
    614   // Generic constructor
    615   template <class T> Arg(T*, Parser parser);
    616   // Generic constructor template
    617   template <class T> Arg(T* p)
    618     : arg_(p), parser_(_PCRE_MatchObject<T>::Parse) {
    619   }
    620 
    621   // Parse the data
    622   bool Parse(const char* str, int n) const;
    623 
    624  private:
    625   void*         arg_;
    626   Parser        parser_;
    627 
    628   static bool parse_null          (const char* str, int n, void* dest);
    629   static bool parse_char          (const char* str, int n, void* dest);
    630   static bool parse_uchar         (const char* str, int n, void* dest);
    631   static bool parse_float         (const char* str, int n, void* dest);
    632   static bool parse_double        (const char* str, int n, void* dest);
    633   static bool parse_string        (const char* str, int n, void* dest);
    634   static bool parse_stringpiece   (const char* str, int n, void* dest);
    635 
    636 #define DECLARE_INTEGER_PARSER(name)                                        \
    637  private:                                                                   \
    638   static bool parse_ ## name(const char* str, int n, void* dest);           \
    639   static bool parse_ ## name ## _radix(                                     \
    640     const char* str, int n, void* dest, int radix);                         \
    641  public:                                                                    \
    642   static bool parse_ ## name ## _hex(const char* str, int n, void* dest);   \
    643   static bool parse_ ## name ## _octal(const char* str, int n, void* dest); \
    644   static bool parse_ ## name ## _cradix(const char* str, int n, void* dest)
    645 
    646   DECLARE_INTEGER_PARSER(short);
    647   DECLARE_INTEGER_PARSER(ushort);
    648   DECLARE_INTEGER_PARSER(int);
    649   DECLARE_INTEGER_PARSER(uint);
    650   DECLARE_INTEGER_PARSER(long);
    651   DECLARE_INTEGER_PARSER(ulong);
    652   DECLARE_INTEGER_PARSER(longlong);
    653   DECLARE_INTEGER_PARSER(ulonglong);
    654 
    655 #undef DECLARE_INTEGER_PARSER
    656 };
    657 
    658 inline PCRE::Arg::Arg() : arg_(NULL), parser_(parse_null) { }
    659 inline PCRE::Arg::Arg(void* p) : arg_(p), parser_(parse_null) { }
    660 
    661 inline bool PCRE::Arg::Parse(const char* str, int n) const {
    662   return (*parser_)(str, n, arg_);
    663 }
    664 
    665 // This part of the parser, appropriate only for ints, deals with bases
    666 #define MAKE_INTEGER_PARSER(type, name) \
    667   inline PCRE::Arg Hex(type* ptr) { \
    668     return PCRE::Arg(ptr, PCRE::Arg::parse_ ## name ## _hex); } \
    669   inline PCRE::Arg Octal(type* ptr) { \
    670     return PCRE::Arg(ptr, PCRE::Arg::parse_ ## name ## _octal); } \
    671   inline PCRE::Arg CRadix(type* ptr) { \
    672     return PCRE::Arg(ptr, PCRE::Arg::parse_ ## name ## _cradix); }
    673 
    674 MAKE_INTEGER_PARSER(short,              short);
    675 MAKE_INTEGER_PARSER(unsigned short,     ushort);
    676 MAKE_INTEGER_PARSER(int,                int);
    677 MAKE_INTEGER_PARSER(unsigned int,       uint);
    678 MAKE_INTEGER_PARSER(long,               long);
    679 MAKE_INTEGER_PARSER(unsigned long,      ulong);
    680 MAKE_INTEGER_PARSER(long long,          longlong);
    681 MAKE_INTEGER_PARSER(unsigned long long, ulonglong);
    682 
    683 #undef MAKE_INTEGER_PARSER
    684 
    685 }  // namespace re2
    686