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Diffstat (limited to 'base/string_piece.h')
-rw-r--r-- | base/string_piece.h | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/base/string_piece.h b/base/string_piece.h new file mode 100644 index 000000000000..278c7b692ae4 --- /dev/null +++ b/base/string_piece.h @@ -0,0 +1,349 @@ +// Copyright (c) 2011 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. +// Copied from strings/stringpiece.h with modifications +// +// A string-like object that points to a sized piece of memory. +// +// Functions or methods may use const StringPiece& parameters to accept either +// a "const char*" or a "string" value that will be implicitly converted to +// a StringPiece. The implicit conversion means that it is often appropriate +// to include this .h file in other files rather than forward-declaring +// StringPiece as would be appropriate for most other Google classes. +// +// Systematic usage of StringPiece is encouraged as it will reduce unnecessary +// conversions from "const char*" to "string" and back again. +// +// StringPiece16 is similar to StringPiece but for base::string16 instead of +// std::string. We do not define as large of a subset of the STL functions +// from basic_string as in StringPiece, but this can be changed if these +// functions (find, find_first_of, etc.) are found to be useful in this context. +// + +#ifndef BASE_STRING_PIECE_H_ +#define BASE_STRING_PIECE_H_ +#pragma once + +#include <string> + +#include "base/base_export.h" +#include "base/basictypes.h" +#include "base/hash_tables.h" +#include "base/string16.h" + +namespace base { + +class BASE_EXPORT StringPiece { + public: + // standard STL container boilerplate + typedef size_t size_type; + typedef char value_type; + typedef const char* pointer; + typedef const char& reference; + typedef const char& const_reference; + typedef ptrdiff_t difference_type; + typedef const char* const_iterator; + typedef const char* iterator; + typedef std::reverse_iterator<const_iterator> const_reverse_iterator; + typedef std::reverse_iterator<iterator> reverse_iterator; + + static const size_type npos; + + public: + // We provide non-explicit singleton constructors so users can pass + // in a "const char*" or a "string" wherever a "StringPiece" is + // expected. + StringPiece() : ptr_(NULL), length_(0) { } + StringPiece(const char* str) + : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { } + StringPiece(const std::string& str) + : ptr_(str.data()), length_(str.size()) { } + StringPiece(const char* offset, size_type len) + : ptr_(offset), length_(len) { } + + // data() may return a pointer to a buffer with embedded NULs, and the + // returned buffer may or may not be null terminated. Therefore it is + // typically a mistake to pass data() to a routine that expects a NUL + // terminated string. + const char* data() const { return ptr_; } + size_type size() const { return length_; } + size_type length() const { return length_; } + bool empty() const { return length_ == 0; } + + void clear() { + ptr_ = NULL; + length_ = 0; + } + void set(const char* data, size_type len) { + ptr_ = data; + length_ = len; + } + void set(const char* str) { + ptr_ = str; + length_ = str ? strlen(str) : 0; + } + void set(const void* data, size_type len) { + ptr_ = reinterpret_cast<const char*>(data); + length_ = len; + } + + char operator[](size_type i) const { return ptr_[i]; } + + void remove_prefix(size_type n) { + ptr_ += n; + length_ -= n; + } + + void remove_suffix(size_type n) { + length_ -= n; + } + + int compare(const StringPiece& x) const { + int r = wordmemcmp( + ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_)); + if (r == 0) { + if (length_ < x.length_) r = -1; + else if (length_ > x.length_) r = +1; + } + return r; + } + + std::string as_string() const { + // std::string doesn't like to take a NULL pointer even with a 0 size. + return std::string(!empty() ? data() : "", size()); + } + + void CopyToString(std::string* target) const; + void AppendToString(std::string* target) const; + + // Does "this" start with "x" + bool starts_with(const StringPiece& x) const { + return ((length_ >= x.length_) && + (wordmemcmp(ptr_, x.ptr_, x.length_) == 0)); + } + + // Does "this" end with "x" + bool ends_with(const StringPiece& x) const { + return ((length_ >= x.length_) && + (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0)); + } + + iterator begin() const { return ptr_; } + iterator end() const { return ptr_ + length_; } + const_reverse_iterator rbegin() const { + return const_reverse_iterator(ptr_ + length_); + } + const_reverse_iterator rend() const { + return const_reverse_iterator(ptr_); + } + + size_type max_size() const { return length_; } + size_type capacity() const { return length_; } + + size_type copy(char* buf, size_type n, size_type pos = 0) const; + + size_type find(const StringPiece& s, size_type pos = 0) const; + size_type find(char c, size_type pos = 0) const; + size_type rfind(const StringPiece& s, size_type pos = npos) const; + size_type rfind(char c, size_type pos = npos) const; + + size_type find_first_of(const StringPiece& s, size_type pos = 0) const; + size_type find_first_of(char c, size_type pos = 0) const { + return find(c, pos); + } + size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const; + size_type find_first_not_of(char c, size_type pos = 0) const; + size_type find_last_of(const StringPiece& s, size_type pos = npos) const; + size_type find_last_of(char c, size_type pos = npos) const { + return rfind(c, pos); + } + size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const; + size_type find_last_not_of(char c, size_type pos = npos) const; + + StringPiece substr(size_type pos, size_type n = npos) const; + + static int wordmemcmp(const char* p, const char* p2, size_type N) { + return memcmp(p, p2, N); + } + + private: + const char* ptr_; + size_type length_; +}; + +class BASE_EXPORT StringPiece16 { + public: + // standard STL container boilerplate + typedef size_t size_type; + typedef char16 value_type; + typedef const char16* pointer; + typedef const char16& reference; + typedef const char16& const_reference; + typedef ptrdiff_t difference_type; + typedef const char16* const_iterator; + typedef const char16* iterator; + typedef std::reverse_iterator<const_iterator> const_reverse_iterator; + typedef std::reverse_iterator<iterator> reverse_iterator; + + public: + // We provide non-explicit singleton constructors so users can pass + // in a "const char16*" or a "string16" wherever a "StringPiece16" is + // expected. + StringPiece16() : ptr_(NULL), length_(0) { } + StringPiece16(const char16* str) + : ptr_(str), + length_((str == NULL) ? 0 : string16::traits_type::length(str)) { } + StringPiece16(const string16& str) + : ptr_(str.data()), length_(str.size()) { } + StringPiece16(const char16* offset, size_type len) + : ptr_(offset), length_(len) { } + + // data() may return a pointer to a buffer with embedded NULs, and the + // returned buffer may or may not be null terminated. Therefore it is + // typically a mistake to pass data() to a routine that expects a NUL + // terminated string. + const char16* data() const { return ptr_; } + size_type size() const { return length_; } + size_type length() const { return length_; } + bool empty() const { return length_ == 0; } + + void clear() { + ptr_ = NULL; + length_ = 0; + } + void set(const char16* data, size_type len) { + ptr_ = data; + length_ = len; + } + void set(const char16* str) { + ptr_ = str; + length_ = str ? string16::traits_type::length(str) : 0; + } + + char16 operator[](size_type i) const { return ptr_[i]; } + + string16 as_string16() const { + // StringPiece claims that this is bad when data() is NULL, but unittesting + // seems to say otherwise. + return string16(data(), size()); + } + + iterator begin() const { return ptr_; } + iterator end() const { return ptr_ + length_; } + const_reverse_iterator rbegin() const { + return const_reverse_iterator(ptr_ + length_); + } + const_reverse_iterator rend() const { + return const_reverse_iterator(ptr_); + } + + size_type max_size() const { return length_; } + size_type capacity() const { return length_; } + + static int wordmemcmp(const char16* p, const char16* p2, size_type N) { + return string16::traits_type::compare(p, p2, N); + } + + private: + const char16* ptr_; + size_type length_; +}; + +BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y); + +inline bool operator!=(const StringPiece& x, const StringPiece& y) { + return !(x == y); +} + +inline bool operator<(const StringPiece& x, const StringPiece& y) { + const int r = StringPiece::wordmemcmp( + x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size())); + return ((r < 0) || ((r == 0) && (x.size() < y.size()))); +} + +inline bool operator>(const StringPiece& x, const StringPiece& y) { + return y < x; +} + +inline bool operator<=(const StringPiece& x, const StringPiece& y) { + return !(x > y); +} + +inline bool operator>=(const StringPiece& x, const StringPiece& y) { + return !(x < y); +} + +inline bool operator==(const StringPiece16& x, const StringPiece16& y) { + if (x.size() != y.size()) + return false; + + return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0; +} + +inline bool operator!=(const StringPiece16& x, const StringPiece16& y) { + return !(x == y); +} + +inline bool operator<(const StringPiece16& x, const StringPiece16& y) { + const int r = StringPiece16::wordmemcmp( + x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size())); + return ((r < 0) || ((r == 0) && (x.size() < y.size()))); +} + +inline bool operator>(const StringPiece16& x, const StringPiece16& y) { + return y < x; +} + +inline bool operator<=(const StringPiece16& x, const StringPiece16& y) { + return !(x > y); +} + +inline bool operator>=(const StringPiece16& x, const StringPiece16& y) { + return !(x < y); +} + +} // namespace base + +// We provide appropriate hash functions so StringPiece and StringPiece16 can +// be used as keys in hash sets and maps. + +// This hash function is copied from base/hash_tables.h. We don't use the +// ones already defined for string and string16 directly because it would +// require the string constructors to be called, which we don't want. +#define HASH_STRING_PIECE(StringPieceType, string_piece) \ + std::size_t result = 0; \ + for (StringPieceType::const_iterator i = string_piece.begin(); \ + i != string_piece.end(); ++i) \ + result = (result * 131) + *i; \ + return result; \ + +namespace BASE_HASH_NAMESPACE { +#if defined(COMPILER_GCC) + +template<> +struct hash<base::StringPiece> { + std::size_t operator()(const base::StringPiece& sp) const { + HASH_STRING_PIECE(base::StringPiece, sp); + } +}; +template<> +struct hash<base::StringPiece16> { + std::size_t operator()(const base::StringPiece16& sp16) const { + HASH_STRING_PIECE(base::StringPiece16, sp16); + } +}; + +#elif defined(COMPILER_MSVC) + +inline size_t hash_value(const base::StringPiece& sp) { + HASH_STRING_PIECE(base::StringPiece, sp); +} +inline size_t hash_value(const base::StringPiece16& sp16) { + HASH_STRING_PIECE(base::StringPiece16, sp16); +} + +#endif // COMPILER + +} // namespace BASE_HASH_NAMESPACE + +#endif // BASE_STRING_PIECE_H_ |