Coverage Report

Created: 2024-01-20 12:39

/src/re2/re2/re2.h
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// Copyright 2003-2009 The RE2 Authors.  All Rights Reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#ifndef RE2_RE2_H_
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#define RE2_RE2_H_
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// C++ interface to the re2 regular-expression library.
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// RE2 supports Perl-style regular expressions (with extensions like
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// \d, \w, \s, ...).
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//
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// -----------------------------------------------------------------------
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// REGEXP SYNTAX:
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//
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// This module uses the re2 library and hence supports
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// its syntax for regular expressions, which is similar to Perl's with
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// some of the more complicated things thrown away.  In particular,
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// backreferences and generalized assertions are not available, nor is \Z.
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//
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// See https://github.com/google/re2/wiki/Syntax for the syntax
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// supported by RE2, and a comparison with PCRE and PERL regexps.
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//
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// For those not familiar with Perl's regular expressions,
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// here are some examples of the most commonly used extensions:
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//
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//   "hello (\\w+) world"  -- \w matches a "word" character
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//   "version (\\d+)"      -- \d matches a digit
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//   "hello\\s+world"      -- \s matches any whitespace character
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//   "\\b(\\w+)\\b"        -- \b matches non-empty string at word boundary
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//   "(?i)hello"           -- (?i) turns on case-insensitive matching
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//   "/\\*(.*?)\\*/"       -- .*? matches . minimum no. of times possible
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//
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// The double backslashes are needed when writing C++ string literals.
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// However, they should NOT be used when writing C++11 raw string literals:
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//
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//   R"(hello (\w+) world)"  -- \w matches a "word" character
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//   R"(version (\d+))"      -- \d matches a digit
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//   R"(hello\s+world)"      -- \s matches any whitespace character
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//   R"(\b(\w+)\b)"          -- \b matches non-empty string at word boundary
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//   R"((?i)hello)"          -- (?i) turns on case-insensitive matching
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//   R"(/\*(.*?)\*/)"        -- .*? matches . minimum no. of times possible
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//
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// When using UTF-8 encoding, case-insensitive matching will perform
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// simple case folding, not full case folding.
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//
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// -----------------------------------------------------------------------
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// MATCHING INTERFACE:
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//
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// The "FullMatch" operation checks that supplied text matches a
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// supplied pattern exactly.
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//
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// Example: successful match
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//    CHECK(RE2::FullMatch("hello", "h.*o"));
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//
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// Example: unsuccessful match (requires full match):
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//    CHECK(!RE2::FullMatch("hello", "e"));
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//
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// -----------------------------------------------------------------------
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// UTF-8 AND THE MATCHING INTERFACE:
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//
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// By default, the pattern and input text are interpreted as UTF-8.
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// The RE2::Latin1 option causes them to be interpreted as Latin-1.
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//
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// Example:
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//    CHECK(RE2::FullMatch(utf8_string, RE2(utf8_pattern)));
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//    CHECK(RE2::FullMatch(latin1_string, RE2(latin1_pattern, RE2::Latin1)));
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//
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// -----------------------------------------------------------------------
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// SUBMATCH EXTRACTION:
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//
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// You can supply extra pointer arguments to extract submatches.
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// On match failure, none of the pointees will have been modified.
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// On match success, the submatches will be converted (as necessary) and
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// their values will be assigned to their pointees until all conversions
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// have succeeded or one conversion has failed.
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// On conversion failure, the pointees will be in an indeterminate state
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// because the caller has no way of knowing which conversion failed.
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// However, conversion cannot fail for types like string and StringPiece
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// that do not inspect the submatch contents. Hence, in the common case
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// where all of the pointees are of such types, failure is always due to
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// match failure and thus none of the pointees will have been modified.
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//
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// Example: extracts "ruby" into "s" and 1234 into "i"
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//    int i;
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//    std::string s;
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//    CHECK(RE2::FullMatch("ruby:1234", "(\\w+):(\\d+)", &s, &i));
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//
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// Example: fails because string cannot be stored in integer
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//    CHECK(!RE2::FullMatch("ruby", "(.*)", &i));
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//
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// Example: fails because there aren't enough sub-patterns
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//    CHECK(!RE2::FullMatch("ruby:1234", "\\w+:\\d+", &s));
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//
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// Example: does not try to extract any extra sub-patterns
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//    CHECK(RE2::FullMatch("ruby:1234", "(\\w+):(\\d+)", &s));
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//
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// Example: does not try to extract into NULL
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//    CHECK(RE2::FullMatch("ruby:1234", "(\\w+):(\\d+)", NULL, &i));
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//
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// Example: integer overflow causes failure
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//    CHECK(!RE2::FullMatch("ruby:1234567891234", "\\w+:(\\d+)", &i));
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//
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// NOTE(rsc): Asking for submatches slows successful matches quite a bit.
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// This may get a little faster in the future, but right now is slower
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// than PCRE.  On the other hand, failed matches run *very* fast (faster
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// than PCRE), as do matches without submatch extraction.
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//
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// -----------------------------------------------------------------------
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// PARTIAL MATCHES
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//
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// You can use the "PartialMatch" operation when you want the pattern
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// to match any substring of the text.
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//
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// Example: simple search for a string:
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//      CHECK(RE2::PartialMatch("hello", "ell"));
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//
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// Example: find first number in a string
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//      int number;
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//      CHECK(RE2::PartialMatch("x*100 + 20", "(\\d+)", &number));
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//      CHECK_EQ(number, 100);
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//
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// -----------------------------------------------------------------------
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// PRE-COMPILED REGULAR EXPRESSIONS
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//
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// RE2 makes it easy to use any string as a regular expression, without
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// requiring a separate compilation step.
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//
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// If speed is of the essence, you can create a pre-compiled "RE2"
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// object from the pattern and use it multiple times.  If you do so,
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// you can typically parse text faster than with sscanf.
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//
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// Example: precompile pattern for faster matching:
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//    RE2 pattern("h.*o");
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//    while (ReadLine(&str)) {
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//      if (RE2::FullMatch(str, pattern)) ...;
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//    }
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//
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// -----------------------------------------------------------------------
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// SCANNING TEXT INCREMENTALLY
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//
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// The "Consume" operation may be useful if you want to repeatedly
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// match regular expressions at the front of a string and skip over
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// them as they match.  This requires use of the "StringPiece" type,
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// which represents a sub-range of a real string.
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//
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// Example: read lines of the form "var = value" from a string.
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//      std::string contents = ...;     // Fill string somehow
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//      StringPiece input(contents);    // Wrap a StringPiece around it
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//
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//      std::string var;
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//      int value;
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//      while (RE2::Consume(&input, "(\\w+) = (\\d+)\n", &var, &value)) {
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//        ...;
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//      }
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//
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// Each successful call to "Consume" will set "var/value", and also
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// advance "input" so it points past the matched text.  Note that if the
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// regular expression matches an empty string, input will advance
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// by 0 bytes.  If the regular expression being used might match
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// an empty string, the loop body must check for this case and either
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// advance the string or break out of the loop.
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//
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// The "FindAndConsume" operation is similar to "Consume" but does not
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// anchor your match at the beginning of the string.  For example, you
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// could extract all words from a string by repeatedly calling
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//     RE2::FindAndConsume(&input, "(\\w+)", &word)
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//
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// -----------------------------------------------------------------------
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// USING VARIABLE NUMBER OF ARGUMENTS
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//
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// The above operations require you to know the number of arguments
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// when you write the code.  This is not always possible or easy (for
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// example, the regular expression may be calculated at run time).
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// You can use the "N" version of the operations when the number of
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// match arguments are determined at run time.
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//
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// Example:
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//   const RE2::Arg* args[10];
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//   int n;
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//   // ... populate args with pointers to RE2::Arg values ...
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//   // ... set n to the number of RE2::Arg objects ...
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//   bool match = RE2::FullMatchN(input, pattern, args, n);
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//
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// The last statement is equivalent to
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//
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//   bool match = RE2::FullMatch(input, pattern,
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//                               *args[0], *args[1], ..., *args[n - 1]);
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//
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// -----------------------------------------------------------------------
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// PARSING HEX/OCTAL/C-RADIX NUMBERS
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//
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// By default, if you pass a pointer to a numeric value, the
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// corresponding text is interpreted as a base-10 number.  You can
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// instead wrap the pointer with a call to one of the operators Hex(),
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// Octal(), or CRadix() to interpret the text in another base.  The
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// CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
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// prefixes, but defaults to base-10.
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//
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// Example:
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//   int a, b, c, d;
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//   CHECK(RE2::FullMatch("100 40 0100 0x40", "(.*) (.*) (.*) (.*)",
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//         RE2::Octal(&a), RE2::Hex(&b), RE2::CRadix(&c), RE2::CRadix(&d));
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// will leave 64 in a, b, c, and d.
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#include <stddef.h>
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#include <stdint.h>
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#include <algorithm>
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#include <map>
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#include <mutex>
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#include <string>
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#include <type_traits>
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#include <vector>
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#if defined(__APPLE__)
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#include <TargetConditionals.h>
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#endif
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#include "re2/stringpiece.h"
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namespace re2 {
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class Prog;
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class Regexp;
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}  // namespace re2
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namespace re2 {
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// Interface for regular expression matching.  Also corresponds to a
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// pre-compiled regular expression.  An "RE2" object is safe for
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// concurrent use by multiple threads.
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class RE2 {
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 public:
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  // We convert user-passed pointers into special Arg objects
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  class Arg;
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  class Options;
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  // Defined in set.h.
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  class Set;
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  enum ErrorCode {
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    NoError = 0,
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    // Unexpected error
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    ErrorInternal,
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    // Parse errors
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    ErrorBadEscape,          // bad escape sequence
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    ErrorBadCharClass,       // bad character class
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    ErrorBadCharRange,       // bad character class range
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    ErrorMissingBracket,     // missing closing ]
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    ErrorMissingParen,       // missing closing )
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    ErrorUnexpectedParen,    // unexpected closing )
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    ErrorTrailingBackslash,  // trailing \ at end of regexp
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    ErrorRepeatArgument,     // repeat argument missing, e.g. "*"
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    ErrorRepeatSize,         // bad repetition argument
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    ErrorRepeatOp,           // bad repetition operator
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    ErrorBadPerlOp,          // bad perl operator
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    ErrorBadUTF8,            // invalid UTF-8 in regexp
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    ErrorBadNamedCapture,    // bad named capture group
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    ErrorPatternTooLarge     // pattern too large (compile failed)
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  };
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  // Predefined common options.
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  // If you need more complicated things, instantiate
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  // an Option class, possibly passing one of these to
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  // the Option constructor, change the settings, and pass that
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  // Option class to the RE2 constructor.
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  enum CannedOptions {
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    DefaultOptions = 0,
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    Latin1, // treat input as Latin-1 (default UTF-8)
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    POSIX, // POSIX syntax, leftmost-longest match
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    Quiet // do not log about regexp parse errors
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  };
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  // Need to have the const char* and const std::string& forms for implicit
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  // conversions when passing string literals to FullMatch and PartialMatch.
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  // Otherwise the StringPiece form would be sufficient.
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  RE2(const char* pattern);
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  RE2(const std::string& pattern);
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  RE2(const StringPiece& pattern);
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  RE2(const StringPiece& pattern, const Options& options);
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  ~RE2();
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  // Not copyable.
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  // RE2 objects are expensive. You should probably use std::shared_ptr<RE2>
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  // instead. If you really must copy, RE2(first.pattern(), first.options())
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  // effectively does so: it produces a second object that mimics the first.
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  RE2(const RE2&) = delete;
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  RE2& operator=(const RE2&) = delete;
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  // Not movable.
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  // RE2 objects are thread-safe and logically immutable. You should probably
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  // use std::unique_ptr<RE2> instead. Otherwise, consider std::deque<RE2> if
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  // direct emplacement into a container is desired. If you really must move,
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  // be prepared to submit a design document along with your feature request.
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  RE2(RE2&&) = delete;
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  RE2& operator=(RE2&&) = delete;
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  // Returns whether RE2 was created properly.
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  bool ok() const { return error_code() == NoError; }
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  // The string specification for this RE2.  E.g.
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  //   RE2 re("ab*c?d+");
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  //   re.pattern();    // "ab*c?d+"
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0
  const std::string& pattern() const { return *pattern_; }
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  // If RE2 could not be created properly, returns an error string.
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  // Else returns the empty string.
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  const std::string& error() const { return *error_; }
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  // If RE2 could not be created properly, returns an error code.
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  // Else returns RE2::NoError (== 0).
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140k
  ErrorCode error_code() const { return error_code_; }
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  // If RE2 could not be created properly, returns the offending
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  // portion of the regexp.
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0
  const std::string& error_arg() const { return *error_arg_; }
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  // Returns the program size, a very approximate measure of a regexp's "cost".
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  // Larger numbers are more expensive than smaller numbers.
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  int ProgramSize() const;
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  int ReverseProgramSize() const;
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  // If histogram is not null, outputs the program fanout
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  // as a histogram bucketed by powers of 2.
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  // Returns the number of the largest non-empty bucket.
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  int ProgramFanout(std::vector<int>* histogram) const;
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  int ReverseProgramFanout(std::vector<int>* histogram) const;
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  // Returns the underlying Regexp; not for general use.
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  // Returns entire_regexp_ so that callers don't need
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  // to know about prefix_ and prefix_foldcase_.
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0
  re2::Regexp* Regexp() const { return entire_regexp_; }
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  /***** The array-based matching interface ******/
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  // The functions here have names ending in 'N' and are used to implement
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  // the functions whose names are the prefix before the 'N'. It is sometimes
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  // useful to invoke them directly, but the syntax is awkward, so the 'N'-less
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  // versions should be preferred.
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  static bool FullMatchN(const StringPiece& text, const RE2& re,
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                         const Arg* const args[], int n);
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  static bool PartialMatchN(const StringPiece& text, const RE2& re,
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                            const Arg* const args[], int n);
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  static bool ConsumeN(StringPiece* input, const RE2& re,
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                       const Arg* const args[], int n);
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  static bool FindAndConsumeN(StringPiece* input, const RE2& re,
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                              const Arg* const args[], int n);
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 private:
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  template <typename F, typename SP>
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  static inline bool Apply(F f, SP sp, const RE2& re) {
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41.8k
    return f(sp, re, NULL, 0);
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  }
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  template <typename F, typename SP, typename... A>
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  static inline bool Apply(F f, SP sp, const RE2& re, const A&... a) {
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    const Arg* const args[] = {&a...};
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    const int n = sizeof...(a);
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    return f(sp, re, args, n);
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  }
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 public:
362
  // In order to allow FullMatch() et al. to be called with a varying number
363
  // of arguments of varying types, we use two layers of variadic templates.
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  // The first layer constructs the temporary Arg objects. The second layer
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  // (above) constructs the array of pointers to the temporary Arg objects.
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  /***** The useful part: the matching interface *****/
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  // Matches "text" against "re".  If pointer arguments are
370
  // supplied, copies matched sub-patterns into them.
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  //
372
  // You can pass in a "const char*" or a "std::string" for "text".
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  // You can pass in a "const char*" or a "std::string" or a "RE2" for "re".
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  //
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  // The provided pointer arguments can be pointers to any scalar numeric
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  // type, or one of:
377
  //    std::string     (matched piece is copied to string)
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  //    StringPiece     (StringPiece is mutated to point to matched piece)
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  //    T               (where "bool T::ParseFrom(const char*, size_t)" exists)
380
  //    (void*)NULL     (the corresponding matched sub-pattern is not copied)
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  //
382
  // Returns true iff all of the following conditions are satisfied:
383
  //   a. "text" matches "re" fully - from the beginning to the end of "text".
384
  //   b. The number of matched sub-patterns is >= number of supplied pointers.
385
  //   c. The "i"th argument has a suitable type for holding the
386
  //      string captured as the "i"th sub-pattern.  If you pass in
387
  //      NULL for the "i"th argument, or pass fewer arguments than
388
  //      number of sub-patterns, the "i"th captured sub-pattern is
389
  //      ignored.
390
  //
391
  // CAVEAT: An optional sub-pattern that does not exist in the
392
  // matched string is assigned the empty string.  Therefore, the
393
  // following will return false (because the empty string is not a
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  // valid number):
395
  //    int number;
396
  //    RE2::FullMatch("abc", "[a-z]+(\\d+)?", &number);
397
  template <typename... A>
398
41.8k
  static bool FullMatch(const StringPiece& text, const RE2& re, A&&... a) {
399
41.8k
    return Apply(FullMatchN, text, re, Arg(std::forward<A>(a))...);
400
41.8k
  }
401
402
  // Like FullMatch(), except that "re" is allowed to match a substring
403
  // of "text".
404
  //
405
  // Returns true iff all of the following conditions are satisfied:
406
  //   a. "text" matches "re" partially - for some substring of "text".
407
  //   b. The number of matched sub-patterns is >= number of supplied pointers.
408
  //   c. The "i"th argument has a suitable type for holding the
409
  //      string captured as the "i"th sub-pattern.  If you pass in
410
  //      NULL for the "i"th argument, or pass fewer arguments than
411
  //      number of sub-patterns, the "i"th captured sub-pattern is
412
  //      ignored.
413
  template <typename... A>
414
  static bool PartialMatch(const StringPiece& text, const RE2& re, A&&... a) {
415
    return Apply(PartialMatchN, text, re, Arg(std::forward<A>(a))...);
416
  }
417
418
  // Like FullMatch() and PartialMatch(), except that "re" has to match
419
  // a prefix of the text, and "input" is advanced past the matched
420
  // text.  Note: "input" is modified iff this routine returns true
421
  // and "re" matched a non-empty substring of "input".
422
  //
423
  // Returns true iff all of the following conditions are satisfied:
424
  //   a. "input" matches "re" partially - for some prefix of "input".
425
  //   b. The number of matched sub-patterns is >= number of supplied pointers.
426
  //   c. The "i"th argument has a suitable type for holding the
427
  //      string captured as the "i"th sub-pattern.  If you pass in
428
  //      NULL for the "i"th argument, or pass fewer arguments than
429
  //      number of sub-patterns, the "i"th captured sub-pattern is
430
  //      ignored.
431
  template <typename... A>
432
  static bool Consume(StringPiece* input, const RE2& re, A&&... a) {
433
    return Apply(ConsumeN, input, re, Arg(std::forward<A>(a))...);
434
  }
435
436
  // Like Consume(), but does not anchor the match at the beginning of
437
  // the text.  That is, "re" need not start its match at the beginning
438
  // of "input".  For example, "FindAndConsume(s, "(\\w+)", &word)" finds
439
  // the next word in "s" and stores it in "word".
440
  //
441
  // Returns true iff all of the following conditions are satisfied:
442
  //   a. "input" matches "re" partially - for some substring of "input".
443
  //   b. The number of matched sub-patterns is >= number of supplied pointers.
444
  //   c. The "i"th argument has a suitable type for holding the
445
  //      string captured as the "i"th sub-pattern.  If you pass in
446
  //      NULL for the "i"th argument, or pass fewer arguments than
447
  //      number of sub-patterns, the "i"th captured sub-pattern is
448
  //      ignored.
449
  template <typename... A>
450
  static bool FindAndConsume(StringPiece* input, const RE2& re, A&&... a) {
451
    return Apply(FindAndConsumeN, input, re, Arg(std::forward<A>(a))...);
452
  }
453
454
  // Replace the first match of "re" in "str" with "rewrite".
455
  // Within "rewrite", backslash-escaped digits (\1 to \9) can be
456
  // used to insert text matching corresponding parenthesized group
457
  // from the pattern.  \0 in "rewrite" refers to the entire matching
458
  // text.  E.g.,
459
  //
460
  //   std::string s = "yabba dabba doo";
461
  //   CHECK(RE2::Replace(&s, "b+", "d"));
462
  //
463
  // will leave "s" containing "yada dabba doo"
464
  //
465
  // Returns true if the pattern matches and a replacement occurs,
466
  // false otherwise.
467
  static bool Replace(std::string* str,
468
                      const RE2& re,
469
                      const StringPiece& rewrite);
470
471
  // Like Replace(), except replaces successive non-overlapping occurrences
472
  // of the pattern in the string with the rewrite. E.g.
473
  //
474
  //   std::string s = "yabba dabba doo";
475
  //   CHECK(RE2::GlobalReplace(&s, "b+", "d"));
476
  //
477
  // will leave "s" containing "yada dada doo"
478
  // Replacements are not subject to re-matching.
479
  //
480
  // Because GlobalReplace only replaces non-overlapping matches,
481
  // replacing "ana" within "banana" makes only one replacement, not two.
482
  //
483
  // Returns the number of replacements made.
484
  static int GlobalReplace(std::string* str,
485
                           const RE2& re,
486
                           const StringPiece& rewrite);
487
488
  // Like Replace, except that if the pattern matches, "rewrite"
489
  // is copied into "out" with substitutions.  The non-matching
490
  // portions of "text" are ignored.
491
  //
492
  // Returns true iff a match occurred and the extraction happened
493
  // successfully;  if no match occurs, the string is left unaffected.
494
  //
495
  // REQUIRES: "text" must not alias any part of "*out".
496
  static bool Extract(const StringPiece& text,
497
                      const RE2& re,
498
                      const StringPiece& rewrite,
499
                      std::string* out);
500
501
  // Escapes all potentially meaningful regexp characters in
502
  // 'unquoted'.  The returned string, used as a regular expression,
503
  // will match exactly the original string.  For example,
504
  //           1.5-2.0?
505
  // may become:
506
  //           1\.5\-2\.0\?
507
  static std::string QuoteMeta(const StringPiece& unquoted);
508
509
  // Computes range for any strings matching regexp. The min and max can in
510
  // some cases be arbitrarily precise, so the caller gets to specify the
511
  // maximum desired length of string returned.
512
  //
513
  // Assuming PossibleMatchRange(&min, &max, N) returns successfully, any
514
  // string s that is an anchored match for this regexp satisfies
515
  //   min <= s && s <= max.
516
  //
517
  // Note that PossibleMatchRange() will only consider the first copy of an
518
  // infinitely repeated element (i.e., any regexp element followed by a '*' or
519
  // '+' operator). Regexps with "{N}" constructions are not affected, as those
520
  // do not compile down to infinite repetitions.
521
  //
522
  // Returns true on success, false on error.
523
  bool PossibleMatchRange(std::string* min, std::string* max,
524
                          int maxlen) const;
525
526
  // Generic matching interface
527
528
  // Type of match.
529
  enum Anchor {
530
    UNANCHORED,         // No anchoring
531
    ANCHOR_START,       // Anchor at start only
532
    ANCHOR_BOTH         // Anchor at start and end
533
  };
534
535
  // Return the number of capturing subpatterns, or -1 if the
536
  // regexp wasn't valid on construction.  The overall match ($0)
537
  // does not count: if the regexp is "(a)(b)", returns 2.
538
83.6k
  int NumberOfCapturingGroups() const { return num_captures_; }
539
540
  // Return a map from names to capturing indices.
541
  // The map records the index of the leftmost group
542
  // with the given name.
543
  // Only valid until the re is deleted.
544
  const std::map<std::string, int>& NamedCapturingGroups() const;
545
546
  // Return a map from capturing indices to names.
547
  // The map has no entries for unnamed groups.
548
  // Only valid until the re is deleted.
549
  const std::map<int, std::string>& CapturingGroupNames() const;
550
551
  // General matching routine.
552
  // Match against text starting at offset startpos
553
  // and stopping the search at offset endpos.
554
  // Returns true if match found, false if not.
555
  // On a successful match, fills in submatch[] (up to nsubmatch entries)
556
  // with information about submatches.
557
  // I.e. matching RE2("(foo)|(bar)baz") on "barbazbla" will return true, with
558
  // submatch[0] = "barbaz", submatch[1].data() = NULL, submatch[2] = "bar",
559
  // submatch[3].data() = NULL, ..., up to submatch[nsubmatch-1].data() = NULL.
560
  // Caveat: submatch[] may be clobbered even on match failure.
561
  //
562
  // Don't ask for more match information than you will use:
563
  // runs much faster with nsubmatch == 1 than nsubmatch > 1, and
564
  // runs even faster if nsubmatch == 0.
565
  // Doesn't make sense to use nsubmatch > 1 + NumberOfCapturingGroups(),
566
  // but will be handled correctly.
567
  //
568
  // Passing text == StringPiece(NULL, 0) will be handled like any other
569
  // empty string, but note that on return, it will not be possible to tell
570
  // whether submatch i matched the empty string or did not match:
571
  // either way, submatch[i].data() == NULL.
572
  bool Match(const StringPiece& text,
573
             size_t startpos,
574
             size_t endpos,
575
             Anchor re_anchor,
576
             StringPiece* submatch,
577
             int nsubmatch) const;
578
579
  // Check that the given rewrite string is suitable for use with this
580
  // regular expression.  It checks that:
581
  //   * The regular expression has enough parenthesized subexpressions
582
  //     to satisfy all of the \N tokens in rewrite
583
  //   * The rewrite string doesn't have any syntax errors.  E.g.,
584
  //     '\' followed by anything other than a digit or '\'.
585
  // A true return value guarantees that Replace() and Extract() won't
586
  // fail because of a bad rewrite string.
587
  bool CheckRewriteString(const StringPiece& rewrite,
588
                          std::string* error) const;
589
590
  // Returns the maximum submatch needed for the rewrite to be done by
591
  // Replace(). E.g. if rewrite == "foo \\2,\\1", returns 2.
592
  static int MaxSubmatch(const StringPiece& rewrite);
593
594
  // Append the "rewrite" string, with backslash subsitutions from "vec",
595
  // to string "out".
596
  // Returns true on success.  This method can fail because of a malformed
597
  // rewrite string.  CheckRewriteString guarantees that the rewrite will
598
  // be sucessful.
599
  bool Rewrite(std::string* out,
600
               const StringPiece& rewrite,
601
               const StringPiece* vec,
602
               int veclen) const;
603
604
  // Constructor options
605
  class Options {
606
   public:
607
    // The options are (defaults in parentheses):
608
    //
609
    //   utf8             (true)  text and pattern are UTF-8; otherwise Latin-1
610
    //   posix_syntax     (false) restrict regexps to POSIX egrep syntax
611
    //   longest_match    (false) search for longest match, not first match
612
    //   log_errors       (true)  log syntax and execution errors to ERROR
613
    //   max_mem          (see below)  approx. max memory footprint of RE2
614
    //   literal          (false) interpret string as literal, not regexp
615
    //   never_nl         (false) never match \n, even if it is in regexp
616
    //   dot_nl           (false) dot matches everything including new line
617
    //   never_capture    (false) parse all parens as non-capturing
618
    //   case_sensitive   (true)  match is case-sensitive (regexp can override
619
    //                              with (?i) unless in posix_syntax mode)
620
    //
621
    // The following options are only consulted when posix_syntax == true.
622
    // When posix_syntax == false, these features are always enabled and
623
    // cannot be turned off; to perform multi-line matching in that case,
624
    // begin the regexp with (?m).
625
    //   perl_classes     (false) allow Perl's \d \s \w \D \S \W
626
    //   word_boundary    (false) allow Perl's \b \B (word boundary and not)
627
    //   one_line         (false) ^ and $ only match beginning and end of text
628
    //
629
    // The max_mem option controls how much memory can be used
630
    // to hold the compiled form of the regexp (the Prog) and
631
    // its cached DFA graphs.  Code Search placed limits on the number
632
    // of Prog instructions and DFA states: 10,000 for both.
633
    // In RE2, those limits would translate to about 240 KB per Prog
634
    // and perhaps 2.5 MB per DFA (DFA state sizes vary by regexp; RE2 does a
635
    // better job of keeping them small than Code Search did).
636
    // Each RE2 has two Progs (one forward, one reverse), and each Prog
637
    // can have two DFAs (one first match, one longest match).
638
    // That makes 4 DFAs:
639
    //
640
    //   forward, first-match    - used for UNANCHORED or ANCHOR_START searches
641
    //                               if opt.longest_match() == false
642
    //   forward, longest-match  - used for all ANCHOR_BOTH searches,
643
    //                               and the other two kinds if
644
    //                               opt.longest_match() == true
645
    //   reverse, first-match    - never used
646
    //   reverse, longest-match  - used as second phase for unanchored searches
647
    //
648
    // The RE2 memory budget is statically divided between the two
649
    // Progs and then the DFAs: two thirds to the forward Prog
650
    // and one third to the reverse Prog.  The forward Prog gives half
651
    // of what it has left over to each of its DFAs.  The reverse Prog
652
    // gives it all to its longest-match DFA.
653
    //
654
    // Once a DFA fills its budget, it flushes its cache and starts over.
655
    // If this happens too often, RE2 falls back on the NFA implementation.
656
657
    // For now, make the default budget something close to Code Search.
658
    static const int kDefaultMaxMem = 8<<20;
659
660
    enum Encoding {
661
      EncodingUTF8 = 1,
662
      EncodingLatin1
663
    };
664
665
    Options() :
666
      max_mem_(kDefaultMaxMem),
667
      encoding_(EncodingUTF8),
668
      posix_syntax_(false),
669
      longest_match_(false),
670
      log_errors_(true),
671
      literal_(false),
672
      never_nl_(false),
673
      dot_nl_(false),
674
      never_capture_(false),
675
      case_sensitive_(true),
676
      perl_classes_(false),
677
      word_boundary_(false),
678
114k
      one_line_(false) {
679
114k
    }
680
681
    /*implicit*/ Options(CannedOptions);
682
683
42.7k
    int64_t max_mem() const { return max_mem_; }
684
0
    void set_max_mem(int64_t m) { max_mem_ = m; }
685
686
57.1k
    Encoding encoding() const { return encoding_; }
687
40.8k
    void set_encoding(Encoding encoding) { encoding_ = encoding; }
688
689
57.1k
    bool posix_syntax() const { return posix_syntax_; }
690
57.1k
    void set_posix_syntax(bool b) { posix_syntax_ = b; }
691
692
57.1k
    bool longest_match() const { return longest_match_; }
693
57.1k
    void set_longest_match(bool b) { longest_match_ = b; }
694
695
19.7k
    bool log_errors() const { return log_errors_; }
696
57.1k
    void set_log_errors(bool b) { log_errors_ = b; }
697
698
57.1k
    bool literal() const { return literal_; }
699
57.1k
    void set_literal(bool b) { literal_ = b; }
700
701
57.1k
    bool never_nl() const { return never_nl_; }
702
57.1k
    void set_never_nl(bool b) { never_nl_ = b; }
703
704
57.1k
    bool dot_nl() const { return dot_nl_; }
705
57.1k
    void set_dot_nl(bool b) { dot_nl_ = b; }
706
707
57.1k
    bool never_capture() const { return never_capture_; }
708
57.1k
    void set_never_capture(bool b) { never_capture_ = b; }
709
710
57.1k
    bool case_sensitive() const { return case_sensitive_; }
711
57.1k
    void set_case_sensitive(bool b) { case_sensitive_ = b; }
712
713
57.1k
    bool perl_classes() const { return perl_classes_; }
714
57.1k
    void set_perl_classes(bool b) { perl_classes_ = b; }
715
716
57.1k
    bool word_boundary() const { return word_boundary_; }
717
57.1k
    void set_word_boundary(bool b) { word_boundary_ = b; }
718
719
57.1k
    bool one_line() const { return one_line_; }
720
57.1k
    void set_one_line(bool b) { one_line_ = b; }
721
722
57.1k
    void Copy(const Options& src) {
723
57.1k
      *this = src;
724
57.1k
    }
725
726
    int ParseFlags() const;
727
728
   private:
729
    int64_t max_mem_;
730
    Encoding encoding_;
731
    bool posix_syntax_;
732
    bool longest_match_;
733
    bool log_errors_;
734
    bool literal_;
735
    bool never_nl_;
736
    bool dot_nl_;
737
    bool never_capture_;
738
    bool case_sensitive_;
739
    bool perl_classes_;
740
    bool word_boundary_;
741
    bool one_line_;
742
  };
743
744
  // Returns the options set in the constructor.
745
0
  const Options& options() const { return options_; }
746
747
  // Argument converters; see below.
748
  template <typename T>
749
  static Arg CRadix(T* ptr);
750
  template <typename T>
751
  static Arg Hex(T* ptr);
752
  template <typename T>
753
  static Arg Octal(T* ptr);
754
755
  // Controls the maximum count permitted by GlobalReplace(); -1 is unlimited.
756
  // FOR FUZZING ONLY.
757
  static void FUZZING_ONLY_set_maximum_global_replace_count(int i);
758
759
 private:
760
  void Init(const StringPiece& pattern, const Options& options);
761
762
  bool DoMatch(const StringPiece& text,
763
               Anchor re_anchor,
764
               size_t* consumed,
765
               const Arg* const args[],
766
               int n) const;
767
768
  re2::Prog* ReverseProg() const;
769
770
  // First cache line is relatively cold fields.
771
  const std::string* pattern_;    // string regular expression
772
  Options options_;               // option flags
773
  re2::Regexp* entire_regexp_;    // parsed regular expression
774
  re2::Regexp* suffix_regexp_;    // parsed regular expression, prefix_ removed
775
  const std::string* error_;      // error indicator (or points to empty string)
776
  const std::string* error_arg_;  // fragment of regexp showing error (or ditto)
777
778
  // Second cache line is relatively hot fields.
779
  // These are ordered oddly to pack everything.
780
  int num_captures_;              // number of capturing groups
781
  ErrorCode error_code_ : 29;     // error code (29 bits is more than enough)
782
  bool longest_match_ : 1;        // cached copy of options_.longest_match()
783
  bool is_one_pass_ : 1;          // can use prog_->SearchOnePass?
784
  bool prefix_foldcase_ : 1;      // prefix_ is ASCII case-insensitive
785
  std::string prefix_;            // required prefix (before suffix_regexp_)
786
  re2::Prog* prog_;               // compiled program for regexp
787
788
  // Reverse Prog for DFA execution only
789
  mutable re2::Prog* rprog_;
790
  // Map from capture names to indices
791
  mutable const std::map<std::string, int>* named_groups_;
792
  // Map from capture indices to names
793
  mutable const std::map<int, std::string>* group_names_;
794
795
  mutable std::once_flag rprog_once_;
796
  mutable std::once_flag named_groups_once_;
797
  mutable std::once_flag group_names_once_;
798
};
799
800
/***** Implementation details *****/
801
802
namespace re2_internal {
803
804
// Types for which the 3-ary Parse() function template has specializations.
805
template <typename T> struct Parse3ary : public std::false_type {};
806
template <> struct Parse3ary<void> : public std::true_type {};
807
template <> struct Parse3ary<std::string> : public std::true_type {};
808
template <> struct Parse3ary<StringPiece> : public std::true_type {};
809
template <> struct Parse3ary<char> : public std::true_type {};
810
template <> struct Parse3ary<signed char> : public std::true_type {};
811
template <> struct Parse3ary<unsigned char> : public std::true_type {};
812
template <> struct Parse3ary<float> : public std::true_type {};
813
template <> struct Parse3ary<double> : public std::true_type {};
814
815
template <typename T>
816
bool Parse(const char* str, size_t n, T* dest);
817
818
// Types for which the 4-ary Parse() function template has specializations.
819
template <typename T> struct Parse4ary : public std::false_type {};
820
template <> struct Parse4ary<long> : public std::true_type {};
821
template <> struct Parse4ary<unsigned long> : public std::true_type {};
822
template <> struct Parse4ary<short> : public std::true_type {};
823
template <> struct Parse4ary<unsigned short> : public std::true_type {};
824
template <> struct Parse4ary<int> : public std::true_type {};
825
template <> struct Parse4ary<unsigned int> : public std::true_type {};
826
template <> struct Parse4ary<long long> : public std::true_type {};
827
template <> struct Parse4ary<unsigned long long> : public std::true_type {};
828
829
template <typename T>
830
bool Parse(const char* str, size_t n, T* dest, int radix);
831
832
}  // namespace re2_internal
833
834
class RE2::Arg {
835
 private:
836
  template <typename T>
837
  using CanParse3ary = typename std::enable_if<
838
      re2_internal::Parse3ary<T>::value,
839
      int>::type;
840
841
  template <typename T>
842
  using CanParse4ary = typename std::enable_if<
843
      re2_internal::Parse4ary<T>::value,
844
      int>::type;
845
846
#if !defined(_MSC_VER)
847
  template <typename T>
848
  using CanParseFrom = typename std::enable_if<
849
      std::is_member_function_pointer<
850
          decltype(static_cast<bool (T::*)(const char*, size_t)>(
851
              &T::ParseFrom))>::value,
852
      int>::type;
853
#endif
854
855
 public:
856
0
  Arg() : Arg(nullptr) {}
857
0
  Arg(std::nullptr_t ptr) : arg_(ptr), parser_(DoNothing) {}
858
859
  template <typename T, CanParse3ary<T> = 0>
860
  Arg(T* ptr) : arg_(ptr), parser_(DoParse3ary<T>) {}
861
862
  template <typename T, CanParse4ary<T> = 0>
863
  Arg(T* ptr) : arg_(ptr), parser_(DoParse4ary<T>) {}
864
865
#if !defined(_MSC_VER)
866
  template <typename T, CanParseFrom<T> = 0>
867
  Arg(T* ptr) : arg_(ptr), parser_(DoParseFrom<T>) {}
868
#endif
869
870
  typedef bool (*Parser)(const char* str, size_t n, void* dest);
871
872
  template <typename T>
873
  Arg(T* ptr, Parser parser) : arg_(ptr), parser_(parser) {}
874
875
0
  bool Parse(const char* str, size_t n) const {
876
0
    return (*parser_)(str, n, arg_);
877
0
  }
878
879
 private:
880
0
  static bool DoNothing(const char* /*str*/, size_t /*n*/, void* /*dest*/) {
881
0
    return true;
882
0
  }
883
884
  template <typename T>
885
  static bool DoParse3ary(const char* str, size_t n, void* dest) {
886
    return re2_internal::Parse(str, n, reinterpret_cast<T*>(dest));
887
  }
888
889
  template <typename T>
890
  static bool DoParse4ary(const char* str, size_t n, void* dest) {
891
    return re2_internal::Parse(str, n, reinterpret_cast<T*>(dest), 10);
892
  }
893
894
#if !defined(_MSC_VER)
895
  template <typename T>
896
  static bool DoParseFrom(const char* str, size_t n, void* dest) {
897
    if (dest == NULL) return true;
898
    return reinterpret_cast<T*>(dest)->ParseFrom(str, n);
899
  }
900
#endif
901
902
  void*         arg_;
903
  Parser        parser_;
904
};
905
906
template <typename T>
907
inline RE2::Arg RE2::CRadix(T* ptr) {
908
  return RE2::Arg(ptr, [](const char* str, size_t n, void* dest) -> bool {
909
    return re2_internal::Parse(str, n, reinterpret_cast<T*>(dest), 0);
910
  });
911
}
912
913
template <typename T>
914
inline RE2::Arg RE2::Hex(T* ptr) {
915
  return RE2::Arg(ptr, [](const char* str, size_t n, void* dest) -> bool {
916
    return re2_internal::Parse(str, n, reinterpret_cast<T*>(dest), 16);
917
  });
918
}
919
920
template <typename T>
921
inline RE2::Arg RE2::Octal(T* ptr) {
922
  return RE2::Arg(ptr, [](const char* str, size_t n, void* dest) -> bool {
923
    return re2_internal::Parse(str, n, reinterpret_cast<T*>(dest), 8);
924
  });
925
}
926
927
// Silence warnings about missing initializers for members of LazyRE2.
928
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 6
929
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
930
#endif
931
932
// Helper for writing global or static RE2s safely.
933
// Write
934
//     static LazyRE2 re = {".*"};
935
// and then use *re instead of writing
936
//     static RE2 re(".*");
937
// The former is more careful about multithreaded
938
// situations than the latter.
939
//
940
// N.B. This class never deletes the RE2 object that
941
// it constructs: that's a feature, so that it can be used
942
// for global and function static variables.
943
class LazyRE2 {
944
 private:
945
  struct NoArg {};
946
947
 public:
948
  typedef RE2 element_type;  // support std::pointer_traits
949
950
  // Constructor omitted to preserve braced initialization in C++98.
951
952
  // Pretend to be a pointer to Type (never NULL due to on-demand creation):
953
0
  RE2& operator*() const { return *get(); }
954
0
  RE2* operator->() const { return get(); }
955
956
  // Named accessor/initializer:
957
0
  RE2* get() const {
958
0
    std::call_once(once_, &LazyRE2::Init, this);
959
0
    return ptr_;
960
0
  }
961
962
  // All data fields must be public to support {"foo"} initialization.
963
  const char* pattern_;
964
  RE2::CannedOptions options_;
965
  NoArg barrier_against_excess_initializers_;
966
967
  mutable RE2* ptr_;
968
  mutable std::once_flag once_;
969
970
 private:
971
0
  static void Init(const LazyRE2* lazy_re2) {
972
0
    lazy_re2->ptr_ = new RE2(lazy_re2->pattern_, lazy_re2->options_);
973
0
  }
974
975
  void operator=(const LazyRE2&);  // disallowed
976
};
977
978
namespace hooks {
979
980
// Most platforms support thread_local. Older versions of iOS don't support
981
// thread_local, but for the sake of brevity, we lump together all versions
982
// of Apple platforms that aren't macOS. If an iOS application really needs
983
// the context pointee someday, we can get more specific then...
984
//
985
// As per https://github.com/google/re2/issues/325, thread_local support in
986
// MinGW seems to be buggy. (FWIW, Abseil folks also avoid it.)
987
#define RE2_HAVE_THREAD_LOCAL
988
#if (defined(__APPLE__) && !(defined(TARGET_OS_OSX) && TARGET_OS_OSX)) || defined(__MINGW32__)
989
#undef RE2_HAVE_THREAD_LOCAL
990
#endif
991
992
// A hook must not make any assumptions regarding the lifetime of the context
993
// pointee beyond the current invocation of the hook. Pointers and references
994
// obtained via the context pointee should be considered invalidated when the
995
// hook returns. Hence, any data about the context pointee (e.g. its pattern)
996
// would have to be copied in order for it to be kept for an indefinite time.
997
//
998
// A hook must not use RE2 for matching. Control flow reentering RE2::Match()
999
// could result in infinite mutual recursion. To discourage that possibility,
1000
// RE2 will not maintain the context pointer correctly when used in that way.
1001
#ifdef RE2_HAVE_THREAD_LOCAL
1002
extern thread_local const RE2* context;
1003
#endif
1004
1005
struct DFAStateCacheReset {
1006
  int64_t state_budget;
1007
  size_t state_cache_size;
1008
};
1009
1010
struct DFASearchFailure {
1011
  // Nothing yet...
1012
};
1013
1014
#define DECLARE_HOOK(type)                  \
1015
  using type##Callback = void(const type&); \
1016
  void Set##type##Hook(type##Callback* cb); \
1017
  type##Callback* Get##type##Hook();
1018
1019
DECLARE_HOOK(DFAStateCacheReset)
1020
DECLARE_HOOK(DFASearchFailure)
1021
1022
#undef DECLARE_HOOK
1023
1024
}  // namespace hooks
1025
1026
}  // namespace re2
1027
1028
using re2::RE2;
1029
using re2::LazyRE2;
1030
1031
#endif  // RE2_RE2_H_