string_piece.h revision 72a454cd3513ac24fbdd0e0cb9ad70b86a99b801
13f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen// Copyright (c) 2011 The Chromium Authors. All rights reserved. 2c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Use of this source code is governed by a BSD-style license that can be 3c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// found in the LICENSE file. 4c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Copied from strings/stringpiece.h with modifications 5c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 6c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// A string-like object that points to a sized piece of memory. 7c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 8c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Functions or methods may use const StringPiece& parameters to accept either 9c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// a "const char*" or a "string" value that will be implicitly converted to 10c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// a StringPiece. The implicit conversion means that it is often appropriate 11c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// to include this .h file in other files rather than forward-declaring 12c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// StringPiece as would be appropriate for most other Google classes. 13c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 14c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Systematic usage of StringPiece is encouraged as it will reduce unnecessary 15c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// conversions from "const char*" to "string" and back again. 16c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 17c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 18c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#ifndef BASE_STRING_PIECE_H_ 19c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#define BASE_STRING_PIECE_H_ 203345a6884c488ff3a535c2c9acdd33d74b37e311Iain Merrick#pragma once 21c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 22c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include <string> 23c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 24c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/basictypes.h" 25c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 26c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottnamespace base { 27c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 28c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottclass StringPiece { 29c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 303f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen // standard STL container boilerplate 31c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott typedef size_t size_type; 323f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef char value_type; 333f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef const char* pointer; 343f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef const char& reference; 353f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef const char& const_reference; 363f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef ptrdiff_t difference_type; 373f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef const char* const_iterator; 383f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef const char* iterator; 393f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 403f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen typedef std::reverse_iterator<iterator> reverse_iterator; 41c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 423f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen static const size_type npos; 43c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 44c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 45c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // We provide non-explicit singleton constructors so users can pass 46c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // in a "const char*" or a "string" wherever a "StringPiece" is 47c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // expected. 48c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott StringPiece() : ptr_(NULL), length_(0) { } 49c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott StringPiece(const char* str) 50c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { } 51c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott StringPiece(const std::string& str) 52c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott : ptr_(str.data()), length_(str.size()) { } 53c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott StringPiece(const char* offset, size_type len) 54c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott : ptr_(offset), length_(len) { } 55c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 56c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // data() may return a pointer to a buffer with embedded NULs, and the 57c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // returned buffer may or may not be null terminated. Therefore it is 58c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // typically a mistake to pass data() to a routine that expects a NUL 59c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // terminated string. 60c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott const char* data() const { return ptr_; } 61c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type size() const { return length_; } 62c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type length() const { return length_; } 63c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool empty() const { return length_ == 0; } 64c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 65c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void clear() { 66c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ptr_ = NULL; 67c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ = 0; 68c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 69c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void set(const char* data, size_type len) { 70c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ptr_ = data; 71c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ = len; 72c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 73c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void set(const char* str) { 74c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ptr_ = str; 75c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ = str ? strlen(str) : 0; 76c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 77c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void set(const void* data, size_type len) { 78c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ptr_ = reinterpret_cast<const char*>(data); 79c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ = len; 80c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 81c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 82c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott char operator[](size_type i) const { return ptr_[i]; } 83c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 84c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void remove_prefix(size_type n) { 85c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ptr_ += n; 86c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ -= n; 87c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 88c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 89c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void remove_suffix(size_type n) { 90c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott length_ -= n; 91c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 92c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 93c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott int compare(const StringPiece& x) const { 9472a454cd3513ac24fbdd0e0cb9ad70b86a99b801Kristian Monsen int r = wordmemcmp( 9572a454cd3513ac24fbdd0e0cb9ad70b86a99b801Kristian Monsen ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_)); 96c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (r == 0) { 97c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (length_ < x.length_) r = -1; 98c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott else if (length_ > x.length_) r = +1; 99c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 100c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return r; 101c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 102c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 103c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott std::string as_string() const { 104c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // std::string doesn't like to take a NULL pointer even with a 0 size. 105c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return std::string(!empty() ? data() : "", size()); 106c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 107c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 108c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void CopyToString(std::string* target) const; 109c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void AppendToString(std::string* target) const; 110c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 111c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Does "this" start with "x" 112c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool starts_with(const StringPiece& x) const { 113c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return ((length_ >= x.length_) && 114c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott (wordmemcmp(ptr_, x.ptr_, x.length_) == 0)); 115c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 116c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 117c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Does "this" end with "x" 118c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool ends_with(const StringPiece& x) const { 119c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return ((length_ >= x.length_) && 120c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0)); 121c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 122c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 123c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott iterator begin() const { return ptr_; } 124c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott iterator end() const { return ptr_ + length_; } 125c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott const_reverse_iterator rbegin() const { 126c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return const_reverse_iterator(ptr_ + length_); 127c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 128c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott const_reverse_iterator rend() const { 129c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return const_reverse_iterator(ptr_); 130c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 131c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 132c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type max_size() const { return length_; } 133c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type capacity() const { return length_; } 134c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 135c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type copy(char* buf, size_type n, size_type pos = 0) const; 136c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 137c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find(const StringPiece& s, size_type pos = 0) const; 138c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find(char c, size_type pos = 0) const; 139c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type rfind(const StringPiece& s, size_type pos = npos) const; 140c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type rfind(char c, size_type pos = npos) const; 141c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 142c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_first_of(const StringPiece& s, size_type pos = 0) const; 143c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_first_of(char c, size_type pos = 0) const { 144c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return find(c, pos); 145c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 146c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const; 147c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_first_not_of(char c, size_type pos = 0) const; 148c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_last_of(const StringPiece& s, size_type pos = npos) const; 149c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_last_of(char c, size_type pos = npos) const { 150c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return rfind(c, pos); 151c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 152c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const; 153c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott size_type find_last_not_of(char c, size_type pos = npos) const; 154c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 155c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott StringPiece substr(size_type pos, size_type n = npos) const; 156c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 157c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott static int wordmemcmp(const char* p, const char* p2, size_type N) { 158c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return memcmp(p, p2, N); 159c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 1603f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen 1613f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen private: 1623f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen const char* ptr_; 1633f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen size_type length_; 164c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott}; 165c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 166c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottbool operator==(const StringPiece& x, const StringPiece& y); 167c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 168c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottinline bool operator!=(const StringPiece& x, const StringPiece& y) { 169c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return !(x == y); 170c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 171c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 172c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottinline bool operator<(const StringPiece& x, const StringPiece& y) { 17372a454cd3513ac24fbdd0e0cb9ad70b86a99b801Kristian Monsen const int r = StringPiece::wordmemcmp( 17472a454cd3513ac24fbdd0e0cb9ad70b86a99b801Kristian Monsen x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size())); 175c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return ((r < 0) || ((r == 0) && (x.size() < y.size()))); 176c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 177c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 178c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottinline bool operator>(const StringPiece& x, const StringPiece& y) { 179c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return y < x; 180c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 181c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 182c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottinline bool operator<=(const StringPiece& x, const StringPiece& y) { 183c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return !(x > y); 184c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 185c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 186c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottinline bool operator>=(const StringPiece& x, const StringPiece& y) { 187c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return !(x < y); 188c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 189c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 190c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} // namespace base 191c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 192c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#endif // BASE_STRING_PIECE_H_ 193