michael@0: // Copyright (c) 2012 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 "base/strings/string_piece.h"
michael@0: 
michael@0: #include <algorithm>
michael@0: #include <ostream>
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: // MSVC doesn't like complex extern templates and DLLs.
michael@0: #if !defined(COMPILER_MSVC)
michael@0: namespace internal {
michael@0: template class StringPieceDetail<std::string>;
michael@0: template class StringPieceDetail<string16>;
michael@0: }  // namespace internal
michael@0: 
michael@0: template class BasicStringPiece<string16>;
michael@0: #endif
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: 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: namespace internal {
michael@0: void CopyToString(const StringPiece& self, std::string* target) {
michael@0:   target->assign(!self.empty() ? self.data() : "", self.size());
michael@0: }
michael@0: 
michael@0: void AppendToString(const StringPiece& self, std::string* target) {
michael@0:   if (!self.empty())
michael@0:     target->append(self.data(), self.size());
michael@0: }
michael@0: 
michael@0: StringPiece::size_type copy(const StringPiece& self,
michael@0:                             char* buf,
michael@0:                             StringPiece::size_type n,
michael@0:                             StringPiece::size_type pos) {
michael@0:   StringPiece::size_type ret = std::min(self.size() - pos, n);
michael@0:   memcpy(buf, self.data() + pos, ret);
michael@0:   return ret;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find(const StringPiece& self,
michael@0:                             const StringPiece& s,
michael@0:                             StringPiece::size_type pos) {
michael@0:   if (pos > self.size())
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   StringPiece::const_iterator result =
michael@0:       std::search(self.begin() + pos, self.end(), s.begin(), s.end());
michael@0:   const StringPiece::size_type xpos =
michael@0:     static_cast<size_t>(result - self.begin());
michael@0:   return xpos + s.size() <= self.size() ? xpos : StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find(const StringPiece& self,
michael@0:                             char c,
michael@0:                             StringPiece::size_type pos) {
michael@0:   if (pos >= self.size())
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   StringPiece::const_iterator result =
michael@0:       std::find(self.begin() + pos, self.end(), c);
michael@0:   return result != self.end() ?
michael@0:       static_cast<size_t>(result - self.begin()) : StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type rfind(const StringPiece& self,
michael@0:                              const StringPiece& s,
michael@0:                              StringPiece::size_type pos) {
michael@0:   if (self.size() < s.size())
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   if (s.empty())
michael@0:     return std::min(self.size(), pos);
michael@0: 
michael@0:   StringPiece::const_iterator last =
michael@0:       self.begin() + std::min(self.size() - s.size(), pos) + s.size();
michael@0:   StringPiece::const_iterator result =
michael@0:       std::find_end(self.begin(), last, s.begin(), s.end());
michael@0:   return result != last ?
michael@0:       static_cast<size_t>(result - self.begin()) : StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type rfind(const StringPiece& self,
michael@0:                              char c,
michael@0:                              StringPiece::size_type pos) {
michael@0:   if (self.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) {
michael@0:     if (self.data()[i] == c)
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return StringPiece::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 StringPiece::size_type length = characters_wanted.length();
michael@0:   const char* const data = characters_wanted.data();
michael@0:   for (StringPiece::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: StringPiece::size_type find_first_of(const StringPiece& self,
michael@0:                                      const StringPiece& s,
michael@0:                                      StringPiece::size_type pos) {
michael@0:   if (self.size() == 0 || s.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.size() == 1)
michael@0:     return find(self, s.data()[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (StringPiece::size_type i = pos; i < self.size(); ++i) {
michael@0:     if (lookup[static_cast<unsigned char>(self.data()[i])]) {
michael@0:       return i;
michael@0:     }
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find_first_not_of(const StringPiece& self,
michael@0:                                          const StringPiece& s,
michael@0:                                          StringPiece::size_type pos) {
michael@0:   if (self.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   if (s.size() == 0)
michael@0:     return 0;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.size() == 1)
michael@0:     return find_first_not_of(self, s.data()[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (StringPiece::size_type i = pos; i < self.size(); ++i) {
michael@0:     if (!lookup[static_cast<unsigned char>(self.data()[i])]) {
michael@0:       return i;
michael@0:     }
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find_first_not_of(const StringPiece& self,
michael@0:                                          char c,
michael@0:                                          StringPiece::size_type pos) {
michael@0:   if (self.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   for (; pos < self.size(); ++pos) {
michael@0:     if (self.data()[pos] != c) {
michael@0:       return pos;
michael@0:     }
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find_last_of(const StringPiece& self,
michael@0:                                     const StringPiece& s,
michael@0:                                     StringPiece::size_type pos) {
michael@0:   if (self.size() == 0 || s.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.size() == 1)
michael@0:     return rfind(self, s.data()[0], pos);
michael@0: 
michael@0:   bool lookup[UCHAR_MAX + 1] = { false };
michael@0:   BuildLookupTable(s, lookup);
michael@0:   for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) {
michael@0:     if (lookup[static_cast<unsigned char>(self.data()[i])])
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find_last_not_of(const StringPiece& self,
michael@0:                                         const StringPiece& s,
michael@0:                                         StringPiece::size_type pos) {
michael@0:   if (self.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   StringPiece::size_type i = std::min(pos, self.size() - 1);
michael@0:   if (s.size() == 0)
michael@0:     return i;
michael@0: 
michael@0:   // Avoid the cost of BuildLookupTable() for a single-character search.
michael@0:   if (s.size() == 1)
michael@0:     return find_last_not_of(self, s.data()[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>(self.data()[i])])
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece::size_type find_last_not_of(const StringPiece& self,
michael@0:                                         char c,
michael@0:                                         StringPiece::size_type pos) {
michael@0:   if (self.size() == 0)
michael@0:     return StringPiece::npos;
michael@0: 
michael@0:   for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) {
michael@0:     if (self.data()[i] != c)
michael@0:       return i;
michael@0:     if (i == 0)
michael@0:       break;
michael@0:   }
michael@0:   return StringPiece::npos;
michael@0: }
michael@0: 
michael@0: StringPiece substr(const StringPiece& self,
michael@0:                    StringPiece::size_type pos,
michael@0:                    StringPiece::size_type n) {
michael@0:   if (pos > self.size()) pos = self.size();
michael@0:   if (n > self.size() - pos) n = self.size() - pos;
michael@0:   return StringPiece(self.data() + pos, n);
michael@0: }
michael@0: 
michael@0: }  // namespace internal
michael@0: }  // namespace base