| // Copyright 2001-2010 The RE2 Authors. All Rights Reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // 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. |
| // |
| // |
| // Arghh! I wish C++ literals were "string". |
| |
| #ifndef STRINGS_STRINGPIECE_H__ |
| #define STRINGS_STRINGPIECE_H__ |
| |
| #include <string.h> |
| #include <cstddef> |
| #include <iosfwd> |
| #include <string> |
| |
| namespace re2 { |
| |
| class StringPiece { |
| private: |
| const char* ptr_; |
| int length_; |
| |
| 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 : static_cast<int>(strlen(str))) { } |
| StringPiece(const std::string& str) |
| : ptr_(str.data()), length_(static_cast<int>(str.size())) { } |
| StringPiece(const char* offset, int 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_; } |
| int size() const { return length_; } |
| int length() const { return length_; } |
| bool empty() const { return length_ == 0; } |
| |
| void clear() { ptr_ = NULL; length_ = 0; } |
| void set(const char* data, int len) { ptr_ = data; length_ = len; } |
| void set(const char* str) { |
| ptr_ = str; |
| if (str != NULL) |
| length_ = static_cast<int>(strlen(str)); |
| else |
| length_ = 0; |
| } |
| void set(const void* data, int len) { |
| ptr_ = reinterpret_cast<const char*>(data); |
| length_ = len; |
| } |
| |
| char operator[](int i) const { return ptr_[i]; } |
| |
| void remove_prefix(int n) { |
| ptr_ += n; |
| length_ -= n; |
| } |
| |
| void remove_suffix(int n) { |
| length_ -= n; |
| } |
| |
| int compare(const StringPiece& x) const { |
| int r = memcmp(ptr_, x.ptr_, std::min(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 { |
| return std::string(data(), size()); |
| } |
| // We also define ToString() here, since many other string-like |
| // interfaces name the routine that converts to a C++ string |
| // "ToString", and it's confusing to have the method that does that |
| // for a StringPiece be called "as_string()". We also leave the |
| // "as_string()" method defined here for existing code. |
| std::string ToString() const { |
| return std::string(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_) && |
| (memcmp(ptr_, x.ptr_, x.length_) == 0)); |
| } |
| |
| // Does "this" end with "x" |
| bool ends_with(const StringPiece& x) const { |
| return ((length_ >= x.length_) && |
| (memcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0)); |
| } |
| |
| // standard STL container boilerplate |
| typedef char value_type; |
| typedef const char* pointer; |
| typedef const char& reference; |
| typedef const char& const_reference; |
| typedef size_t size_type; |
| typedef ptrdiff_t difference_type; |
| static const size_type npos; |
| 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; |
| 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_); |
| } |
| // STLS says return size_type, but Google says return int |
| int max_size() const { return length_; } |
| int capacity() const { return length_; } |
| |
| int copy(char* buf, size_type n, size_type pos = 0) const; |
| |
| int find(const StringPiece& s, size_type pos = 0) const; |
| int find(char c, size_type pos = 0) const; |
| int rfind(const StringPiece& s, size_type pos = npos) const; |
| int rfind(char c, size_type pos = npos) const; |
| |
| StringPiece substr(size_type pos, size_type n = npos) const; |
| |
| static bool _equal(const StringPiece&, const StringPiece&); |
| }; |
| |
| inline bool operator==(const StringPiece& x, const StringPiece& y) { |
| return StringPiece::_equal(x, 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 = memcmp(x.data(), y.data(), |
| std::min(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); |
| } |
| |
| } // namespace re2 |
| |
| // allow StringPiece to be logged |
| extern std::ostream& operator<<(std::ostream& o, const re2::StringPiece& piece); |
| |
| #endif // STRINGS_STRINGPIECE_H__ |