// Copyright (c) 2005, Google Inc.
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// Author: Sanjay Ghemawat
// Regular-expression based scanner for parsing an input stream.
// Example 1: parse a sequence of "var = number" entries from input:
// Scanner scanner(input);
// scanner.SetSkipExpression("\\s+"); // Skip any white space we encounter
// while (scanner.Consume("(\\w+) = (\\d+)", &var, &number)) {
#include <pcre_stringpiece.h>
class PCRECPP_EXP_DEFN Scanner {
explicit Scanner(const std::string& input);
// Return current line number. The returned line-number is
// one-based. I.e. it returns 1 + the number of consumed newlines.
// Note: this method may be slow. It may take time proportional to
// the size of the input.
// Return the byte-offset that the scanner is looking in the
// Return true iff the start of the remaining input matches "re"
bool LookingAt(const RE& re) const;
// Return true iff all of the following are true
// a. the start of the remaining input matches "re",
// b. if any arguments are supplied, matched sub-patterns can be
// parsed and stored into the arguments.
// If it returns true, it skips over the matched input and any
// following input that matches the "skip" regular expression.
bool Consume(const RE& re,
const Arg& arg0 = RE::no_arg,
const Arg& arg1 = RE::no_arg,
const Arg& arg2 = RE::no_arg
// TODO: Allow more arguments?
// Set the "skip" regular expression. If after consuming some data,
// a prefix of the input matches this RE, it is automatically
// skipped. For example, a programming language scanner would use
// a skip RE that matches white space and comments.
// scanner.SetSkipExpression("\\s+|//.*|/[*](.|\n)*?[*]/");
// Skipping repeats as long as it succeeds. We used to let people do
// this by writing "(...)*" in the regular expression, but that added
// up to lots of recursive calls within the pcre library, so now we
// control repetition explicitly via the function call API.
// You can pass NULL for "re" if you do not want any data to be skipped.
void Skip(const char* re); // DEPRECATED; does *not* repeat
void SetSkipExpression(const char* re);
// Temporarily pause "skip"ing. This
// Skip("Foo"); code ; DisableSkip(); code; EnableSkip()
// Skip("Foo"); code ; Skip(NULL); code ; Skip("Foo");
// but avoids creating/deleting new RE objects.
// Reenable previously paused skipping. Any prefix of the input
// that matches the skip pattern is immediately dropped.
/***** Special wrappers around SetSkip() for some common idioms *****/
// Arranges to skip whitespace, C comments, C++ comments.
// The overall RE is a disjunction of the following REs:
// /[*](.|\n)*?[*]/ C comment (x*? means minimal repetitions of x)
// We get repetition via the semantics of SetSkipExpression, not by using *
SetSkipExpression("\\s|//.*\n|/[*](?:\n|.)*?[*]/");
void set_save_comments(bool comments) {
save_comments_ = comments;
// Append to vector ranges the comments found in the
// byte range [start,end] (inclusive) of the input data.
// Only comments that were extracted entirely within that
// range are returned: no range splitting of atomically-extracted
// comments is performed.
void GetComments(int start, int end, std::vector<StringPiece> *ranges);
// Append to vector ranges the comments added
// since the last time this was called. This
// functionality is provided for efficiency when
// interleaving scanning with parsing.
void GetNextComments(std::vector<StringPiece> *ranges);
std::string data_; // All the input data
StringPiece input_; // Unprocessed input
RE* skip_; // If non-NULL, RE for skipping input
bool should_skip_; // If true, use skip_
bool skip_repeat_; // If true, repeat skip_ as long as it works
bool save_comments_; // If true, aggregate the skip expression
// TODO: later consider requiring that the StringPieces be added
// in order by their start position
std::vector<StringPiece> *comments_;
// the offset into comments_ that has been returned by GetNextComments
// helper function to consume *skip_ and honour
#endif /* _PCRE_SCANNER_H */