Current File : //opt/alt/ruby32/include/ruby/internal/core/rmatch.h
#ifndef RBIMPL_RMATCH_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_RMATCH_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Defines struct ::RMatch.
*/
#include "ruby/internal/attr/artificial.h"
#include "ruby/internal/attr/pure.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/core/rbasic.h"
#include "ruby/internal/value.h"
#include "ruby/internal/value_type.h"
#include "ruby/assert.h"
/**
* Convenient casting macro.
*
* @param obj An object, which is in fact an ::RMatch.
* @return The passed object casted to ::RMatch.
*/
#define RMATCH(obj) RBIMPL_CAST((struct RMatch *)(obj))
/** @cond INTERNAL_MACRO */
#define RMATCH_REGS RMATCH_REGS
/** @endcond */
struct re_patter_buffer; /* a.k.a. OnigRegexType, defined in onigmo.h */
struct re_registers; /* Also in onigmo.h */
/**
* @old{re_pattern_buffer}
*
* @internal
*
* @shyouhei wonders: is anyone actively using this typedef ...?
*/
typedef struct re_pattern_buffer Regexp;
/**
* Represents the region of a capture group. This is basically for caching
* purpose. re_registers have similar concepts (`beg` and `end`) but they are
* in `ptrdiff_t*`. In order for us to implement `MatchData#offset` that info
* has to be converted to offset integers. This is the struct to hold such
* things.
*
* @internal
*
* But why on earth it has to be visible from extension libraries?
*/
struct rmatch_offset {
long beg; /**< Beginning of a group. */
long end; /**< End of a group. */
};
/** Represents a match. */
struct rmatch {
/**
* "Registers" of a match. This is a quasi-opaque struct that holds
* execution result of a match. Roughly resembles `&~`.
*/
struct re_registers regs;
/** Capture group offsets, in C array. */
struct rmatch_offset *char_offset;
/** Number of ::rmatch_offset that ::rmatch::char_offset holds. */
int char_offset_num_allocated;
};
/**
* Regular expression execution context. When a regular expression "matches"
* to a string, it generates capture groups etc. This struct holds that info.
* Visible from Ruby as an instance of `MatchData`.
*
* @note There is no way for extension libraries to manually generate this
* struct except by actually exercising the match operation of a regular
* expression.
*/
struct RMatch {
/** Basic part, including flags and class. */
struct RBasic basic;
/**
* The target string that the match was made against.
*/
VALUE str;
/**
* The result of this match.
*/
struct rmatch *rmatch;
/**
* The expression of this match.
*/
VALUE regexp; /* RRegexp */
};
RBIMPL_ATTR_PURE_UNLESS_DEBUG()
RBIMPL_ATTR_ARTIFICIAL()
/**
* Queries the raw ::re_registers.
*
* @param[in] match A match object
* @pre `match` must be of ::RMatch.
* @return Its execution result.
* @note Good. So you are aware of the fact that it could return NULL.
* Yes. It actually does. This is a really bizarre thing. The
* situation is about `String#gsub` and its family. They take
* strings as arguments, like `"foo".sub("bar", "baz")`. On such
* situations, in order to optimise memory allocations, these
* methods do not involve regular expressions at all. They just
* sequentially scan the receiver. Okay. The story begins here.
* Even when they do not kick our regexp engine, there must be
* backref objects e.g. `$&`. But how? You know what? Ruby fakes
* them. It allocates an empty ::RMatch and behaves as if there
* were execution contexts. In reality there weren't. No
* ::re_registers are allocated then. There is no way for this
* function but to return NULL for those fake ::RMatch. This is
* the reason for the nullability of this function.
*/
static inline struct re_registers *
RMATCH_REGS(VALUE match)
{
RBIMPL_ASSERT_TYPE(match, RUBY_T_MATCH);
RBIMPL_ASSERT_OR_ASSUME(RMATCH(match)->rmatch != NULL);
return &RMATCH(match)->rmatch->regs;
}
#endif /* RBIMPL_RMATCH_H */
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