michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: // Copied from strings/stringpiece.cc with modifications
michael@0: 
michael@0: #include <algorithm>
michael@0: #include <ostream>
michael@0: 
michael@0: #include "base/string_piece.h"
michael@0: 
michael@0: typedef StringPiece::size_type size_type;
michael@0: 
michael@0: std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
michael@0:   o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
michael@0:   return o;
michael@0: }
michael@0: 
michael@0: bool operator==(const StringPiece& x, const StringPiece& y) {
michael@0:   if (x.size() != y.size())
michael@0:     return false;
michael@0: 
michael@0:   return StringPiece::wordmemcmp(x.data(), y.data(), x.size()) == 0;
michael@0: }
michael@0: 
michael@0: void StringPiece::CopyToString(std::string* target) const {
michael@0:   target->assign(!empty() ? data() : "", size());
michael@0: }
michael@0: 
michael@0: void StringPiece::AppendToString(std::string* target) const {
michael@0:   if (!empty())
michael@0:     target->append(data(), size());
michael@0: }
michael@0: 
michael@0: size_type StringPiece::copy(char* buf, size_type n, size_type pos) const {
michael@0:   size_type ret = std::min(length_ - pos, n);
michael@0:   memcpy(buf, ptr_ + pos, ret);
michael@0:   return ret;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find(const StringPiece& s, size_type pos) const {
michael@0:   if (pos > length_)
michael@0:     return npos;
michael@0: 
michael@0:   const char* result = std::search(ptr_ + pos, ptr_ + length_,
michael@0:                                    s.ptr_, s.ptr_ + s.length_);
michael@0:   const size_type xpos = result - ptr_;
michael@0:   return xpos + s.length_ <= length_ ? xpos : npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find(char c, size_type pos) const {
michael@0:   if (pos >= length_)
michael@0:     return npos;
michael@0: 
michael@0:   const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
michael@0:   return result != ptr_ + length_ ? result - ptr_ : npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::rfind(const StringPiece& s, size_type pos) const {
michael@0:   if (length_ < s.length_)
michael@0:     return npos;
michael@0: 
michael@0:   if (s.empty())
michael@0:     return std::min(length_, pos);
michael@0: 
michael@0:   const char* last = ptr_ + std::min(length_ - s.length_, pos) + s.length_;
michael@0:   const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
michael@0:   return result != last ? result - ptr_ : npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::rfind(char c, size_type pos) const {
michael@0:   if (length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   for (size_type i = std::min(pos, length_ - 1); ; --i) {
michael@0:     if (ptr_[i] == c)
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: // For each character in characters_wanted, sets the index corresponding
michael@0: // to the ASCII code of that character to 1 in table.  This is used by
michael@0: // the find_.*_of methods below to tell whether or not a character is in
michael@0: // the lookup table in constant time.
michael@0: // The argument `table' must be an array that is large enough to hold all
michael@0: // the possible values of an unsigned char.  Thus it should be be declared
michael@0: // as follows:
michael@0: //   bool table[UCHAR_MAX + 1]
michael@0: static inline void BuildLookupTable(const StringPiece& characters_wanted,
michael@0:                                     bool* table) {
michael@0:   const size_type length = characters_wanted.length();
michael@0:   const char* const data = characters_wanted.data();
michael@0:   for (size_type i = 0; i < length; ++i) {
michael@0:     table[static_cast<unsigned char>(data[i])] = true;
michael@0:   }
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_first_of(const StringPiece& s,
michael@0:                                      size_type pos) const {
michael@0:   if (length_ == 0 || s.length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.length_ == 1)
michael@0:     return find_first_of(s.ptr_[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (size_type i = pos; i < length_; ++i) {
michael@0:     if (lookup[static_cast<unsigned char>(ptr_[i])]) {
michael@0:       return i;
michael@0:     }
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_first_not_of(const StringPiece& s,
michael@0:                                          size_type pos) const {
michael@0:   if (length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   if (s.length_ == 0)
michael@0:     return 0;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.length_ == 1)
michael@0:     return find_first_not_of(s.ptr_[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (size_type i = pos; i < length_; ++i) {
michael@0:     if (!lookup[static_cast<unsigned char>(ptr_[i])]) {
michael@0:       return i;
michael@0:     }
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_first_not_of(char c, size_type pos) const {
michael@0:   if (length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   for (; pos < length_; ++pos) {
michael@0:     if (ptr_[pos] != c) {
michael@0:       return pos;
michael@0:     }
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const {
michael@0:   if (length_ == 0 || s.length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.length_ == 1)
michael@0:     return find_last_of(s.ptr_[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (size_type i = std::min(pos, length_ - 1); ; --i) {
michael@0:     if (lookup[static_cast<unsigned char>(ptr_[i])])
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_last_not_of(const StringPiece& s,
michael@0:                                         size_type pos) const {
michael@0:   if (length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   size_type i = std::min(pos, length_ - 1);
michael@0:   if (s.length_ == 0)
michael@0:     return i;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.length_ == 1)
michael@0:     return find_last_not_of(s.ptr_[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (; ; --i) {
michael@0:     if (!lookup[static_cast<unsigned char>(ptr_[i])])
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: size_type StringPiece::find_last_not_of(char c, size_type pos) const {
michael@0:   if (length_ == 0)
michael@0:     return npos;
michael@0: 
michael@0:   for (size_type i = std::min(pos, length_ - 1); ; --i) {
michael@0:     if (ptr_[i] != c)
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return npos;
michael@0: }
michael@0: 
michael@0: StringPiece StringPiece::substr(size_type pos, size_type n) const {
michael@0:   if (pos > length_) pos = length_;
michael@0:   if (n > length_ - pos) n = length_ - pos;
michael@0:   return StringPiece(ptr_ + pos, n);
michael@0: }
michael@0: 
michael@0: const StringPiece::size_type StringPiece::npos = size_type(-1);