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Diffstat (limited to 'base/strings/string_piece.cc')
-rw-r--r-- | base/strings/string_piece.cc | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/base/strings/string_piece.cc b/base/strings/string_piece.cc new file mode 100644 index 0000000..79a42d7 --- /dev/null +++ b/base/strings/string_piece.cc @@ -0,0 +1,255 @@ +// Copyright (c) 2012 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.cc with modifications + +#include "base/strings/string_piece.h" + +#include <algorithm> +#include <ostream> + +namespace base { + +// MSVC doesn't like complex extern templates and DLLs. +#if !defined(COMPILER_MSVC) +namespace internal { +template class StringPieceDetail<std::string>; +template class StringPieceDetail<string16>; +} // namespace internal + +template class BasicStringPiece<string16>; +#endif + +bool operator==(const StringPiece& x, const StringPiece& y) { + if (x.size() != y.size()) + return false; + + return StringPiece::wordmemcmp(x.data(), y.data(), x.size()) == 0; +} + +std::ostream& operator<<(std::ostream& o, const StringPiece& piece) { + o.write(piece.data(), static_cast<std::streamsize>(piece.size())); + return o; +} + +namespace internal { +void CopyToString(const StringPiece& self, std::string* target) { + target->assign(!self.empty() ? self.data() : "", self.size()); +} + +void AppendToString(const StringPiece& self, std::string* target) { + if (!self.empty()) + target->append(self.data(), self.size()); +} + +StringPiece::size_type copy(const StringPiece& self, + char* buf, + StringPiece::size_type n, + StringPiece::size_type pos) { + StringPiece::size_type ret = std::min(self.size() - pos, n); + memcpy(buf, self.data() + pos, ret); + return ret; +} + +StringPiece::size_type find(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (pos > self.size()) + return StringPiece::npos; + + StringPiece::const_iterator result = + std::search(self.begin() + pos, self.end(), s.begin(), s.end()); + const StringPiece::size_type xpos = + static_cast<size_t>(result - self.begin()); + return xpos + s.size() <= self.size() ? xpos : StringPiece::npos; +} + +StringPiece::size_type find(const StringPiece& self, + char c, + StringPiece::size_type pos) { + if (pos >= self.size()) + return StringPiece::npos; + + StringPiece::const_iterator result = + std::find(self.begin() + pos, self.end(), c); + return result != self.end() ? + static_cast<size_t>(result - self.begin()) : StringPiece::npos; +} + +StringPiece::size_type rfind(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (self.size() < s.size()) + return StringPiece::npos; + + if (s.empty()) + return std::min(self.size(), pos); + + StringPiece::const_iterator last = + self.begin() + std::min(self.size() - s.size(), pos) + s.size(); + StringPiece::const_iterator result = + std::find_end(self.begin(), last, s.begin(), s.end()); + return result != last ? + static_cast<size_t>(result - self.begin()) : StringPiece::npos; +} + +StringPiece::size_type rfind(const StringPiece& self, + char c, + StringPiece::size_type pos) { + if (self.size() == 0) + return StringPiece::npos; + + for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) { + if (self.data()[i] == c) + return i; + if (i == 0) + break; + } + return StringPiece::npos; +} + +// For each character in characters_wanted, sets the index corresponding +// to the ASCII code of that character to 1 in table. This is used by +// the find_.*_of methods below to tell whether or not a character is in +// the lookup table in constant time. +// The argument `table' must be an array that is large enough to hold all +// the possible values of an unsigned char. Thus it should be be declared +// as follows: +// bool table[UCHAR_MAX + 1] +static inline void BuildLookupTable(const StringPiece& characters_wanted, + bool* table) { + const StringPiece::size_type length = characters_wanted.length(); + const char* const data = characters_wanted.data(); + for (StringPiece::size_type i = 0; i < length; ++i) { + table[static_cast<unsigned char>(data[i])] = true; + } +} + +StringPiece::size_type find_first_of(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (self.size() == 0 || s.size() == 0) + return StringPiece::npos; + + // Avoid the cost of BuildLookupTable() for a single-character search. + if (s.size() == 1) + return find(self, s.data()[0], pos); + + bool lookup[UCHAR_MAX + 1] = { false }; + BuildLookupTable(s, lookup); + for (StringPiece::size_type i = pos; i < self.size(); ++i) { + if (lookup[static_cast<unsigned char>(self.data()[i])]) { + return i; + } + } + return StringPiece::npos; +} + +StringPiece::size_type find_first_not_of(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (self.size() == 0) + return StringPiece::npos; + + if (s.size() == 0) + return 0; + + // Avoid the cost of BuildLookupTable() for a single-character search. + if (s.size() == 1) + return find_first_not_of(self, s.data()[0], pos); + + bool lookup[UCHAR_MAX + 1] = { false }; + BuildLookupTable(s, lookup); + for (StringPiece::size_type i = pos; i < self.size(); ++i) { + if (!lookup[static_cast<unsigned char>(self.data()[i])]) { + return i; + } + } + return StringPiece::npos; +} + +StringPiece::size_type find_first_not_of(const StringPiece& self, + char c, + StringPiece::size_type pos) { + if (self.size() == 0) + return StringPiece::npos; + + for (; pos < self.size(); ++pos) { + if (self.data()[pos] != c) { + return pos; + } + } + return StringPiece::npos; +} + +StringPiece::size_type find_last_of(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (self.size() == 0 || s.size() == 0) + return StringPiece::npos; + + // Avoid the cost of BuildLookupTable() for a single-character search. + if (s.size() == 1) + return rfind(self, s.data()[0], pos); + + bool lookup[UCHAR_MAX + 1] = { false }; + BuildLookupTable(s, lookup); + for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) { + if (lookup[static_cast<unsigned char>(self.data()[i])]) + return i; + if (i == 0) + break; + } + return StringPiece::npos; +} + +StringPiece::size_type find_last_not_of(const StringPiece& self, + const StringPiece& s, + StringPiece::size_type pos) { + if (self.size() == 0) + return StringPiece::npos; + + StringPiece::size_type i = std::min(pos, self.size() - 1); + if (s.size() == 0) + return i; + + // Avoid the cost of BuildLookupTable() for a single-character search. + if (s.size() == 1) + return find_last_not_of(self, s.data()[0], pos); + + bool lookup[UCHAR_MAX + 1] = { false }; + BuildLookupTable(s, lookup); + for (; ; --i) { + if (!lookup[static_cast<unsigned char>(self.data()[i])]) + return i; + if (i == 0) + break; + } + return StringPiece::npos; +} + +StringPiece::size_type find_last_not_of(const StringPiece& self, + char c, + StringPiece::size_type pos) { + if (self.size() == 0) + return StringPiece::npos; + + for (StringPiece::size_type i = std::min(pos, self.size() - 1); ; --i) { + if (self.data()[i] != c) + return i; + if (i == 0) + break; + } + return StringPiece::npos; +} + +StringPiece substr(const StringPiece& self, + StringPiece::size_type pos, + StringPiece::size_type n) { + if (pos > self.size()) pos = self.size(); + if (n > self.size() - pos) n = self.size() - pos; + return StringPiece(self.data() + pos, n); +} + +} // namespace internal +} // namespace base |