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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/strings/string_piece.h"
#include <algorithm>
#include <climits>
#include <limits>
#include <ostream>
#include <string>
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
namespace base {
namespace {
// 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]
inline void BuildLookupTable(StringPiece characters_wanted, bool* table) {
const size_t length = characters_wanted.length();
const char* const data = characters_wanted.data();
for (size_t i = 0; i < length; ++i) {
table[static_cast<unsigned char>(data[i])] = true;
}
}
} // namespace
// MSVC doesn't like complex extern templates and DLLs.
#if !defined(COMPILER_MSVC)
template class BasicStringPiece<char>;
template class BasicStringPiece<char16_t>;
template class BasicStringPiece<wchar_t>;
#endif
std::ostream& operator<<(std::ostream& o, StringPiece piece) {
o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
return o;
}
std::ostream& operator<<(std::ostream& o, StringPiece16 piece) {
return o << UTF16ToUTF8(piece);
}
std::ostream& operator<<(std::ostream& o, WStringPiece piece) {
return o << WideToUTF8(piece);
}
namespace internal {
template <typename T, typename CharT = typename T::value_type>
size_t findT(T self, T s, size_t pos) {
if (pos > self.size())
return BasicStringPiece<CharT>::npos;
typename BasicStringPiece<CharT>::const_iterator result =
std::search(self.begin() + pos, self.end(), s.begin(), s.end());
const size_t xpos =
static_cast<size_t>(result - self.begin());
return xpos + s.size() <= self.size() ? xpos : BasicStringPiece<CharT>::npos;
}
size_t find(StringPiece self, StringPiece s, size_t pos) {
return findT(self, s, pos);
}
size_t find(StringPiece16 self, StringPiece16 s, size_t pos) {
return findT(self, s, pos);
}
template <typename T, typename CharT = typename T::value_type>
size_t rfindT(T self, T s, size_t pos) {
if (self.size() < s.size())
return BasicStringPiece<CharT>::npos;
if (s.empty())
return std::min(self.size(), pos);
typename BasicStringPiece<CharT>::const_iterator last =
self.begin() + std::min(self.size() - s.size(), pos) + s.size();
typename BasicStringPiece<CharT>::const_iterator result =
std::find_end(self.begin(), last, s.begin(), s.end());
return result != last ? static_cast<size_t>(result - self.begin())
: BasicStringPiece<CharT>::npos;
}
size_t rfind(StringPiece self, StringPiece s, size_t pos) {
return rfindT(self, s, pos);
}
size_t rfind(StringPiece16 self, StringPiece16 s, size_t pos) {
return rfindT(self, s, pos);
}
// 8-bit version using lookup table.
size_t find_first_of(StringPiece self, StringPiece s, size_t 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 self.find(s.data()[0], pos);
bool lookup[UCHAR_MAX + 1] = { false };
BuildLookupTable(s, lookup);
for (size_t i = pos; i < self.size(); ++i) {
if (lookup[static_cast<unsigned char>(self.data()[i])]) {
return i;
}
}
return StringPiece::npos;
}
// Generic brute force version.
template <typename T, typename CharT = typename T::value_type>
size_t find_first_ofT(T self, T s, size_t pos) {
// Use the faster std::find() if searching for a single character.
typename BasicStringPiece<CharT>::const_iterator found =
s.size() == 1 ? std::find(self.begin() + pos, self.end(), s[0])
: std::find_first_of(self.begin() + pos, self.end(),
s.begin(), s.end());
if (found == self.end())
return BasicStringPiece<CharT>::npos;
return static_cast<size_t>(found - self.begin());
}
size_t find_first_of(StringPiece16 self, StringPiece16 s, size_t pos) {
return find_first_ofT(self, s, pos);
}
// 8-bit version using lookup table.
size_t find_first_not_of(StringPiece self, StringPiece s, size_t pos) {
if (pos >= self.size())
return StringPiece::npos;
if (s.size() == 0)
return pos;
// Avoid the cost of BuildLookupTable() for a single-character search.
if (s.size() == 1)
return self.find_first_not_of(s.data()[0], pos);
bool lookup[UCHAR_MAX + 1] = { false };
BuildLookupTable(s, lookup);
for (size_t i = pos; i < self.size(); ++i) {
if (!lookup[static_cast<unsigned char>(self.data()[i])]) {
return i;
}
}
return StringPiece::npos;
}
// Generic brute-force version.
template <typename T, typename CharT = typename T::value_type>
size_t find_first_not_ofT(T self, T s, size_t pos) {
if (self.size() == 0)
return BasicStringPiece<CharT>::npos;
for (size_t self_i = pos; self_i < self.size(); ++self_i) {
bool found = false;
for (auto c : s) {
if (self[self_i] == c) {
found = true;
break;
}
}
if (!found)
return self_i;
}
return BasicStringPiece<CharT>::npos;
}
size_t find_first_not_of(StringPiece16 self, StringPiece16 s, size_t pos) {
return find_first_not_ofT(self, s, pos);
}
// 8-bit version using lookup table.
size_t find_last_of(StringPiece self, StringPiece s, size_t 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 self.rfind(s.data()[0], pos);
bool lookup[UCHAR_MAX + 1] = { false };
BuildLookupTable(s, lookup);
for (size_t 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;
}
// Generic brute-force version.
template <typename T, typename CharT = typename T::value_type>
size_t find_last_ofT(T self, T s, size_t pos) {
if (self.size() == 0)
return BasicStringPiece<CharT>::npos;
for (size_t self_i = std::min(pos, self.size() - 1); ;
--self_i) {
for (auto c : s) {
if (self.data()[self_i] == c)
return self_i;
}
if (self_i == 0)
break;
}
return BasicStringPiece<CharT>::npos;
}
size_t find_last_of(StringPiece16 self, StringPiece16 s, size_t pos) {
return find_last_ofT(self, s, pos);
}
// 8-bit version using lookup table.
size_t find_last_not_of(StringPiece self, StringPiece s, size_t pos) {
if (self.size() == 0)
return StringPiece::npos;
size_t 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 self.find_last_not_of(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;
}
// Generic brute-force version.
template <typename T, typename CharT = typename T::value_type>
size_t find_last_not_ofT(T self, T s, size_t pos) {
if (self.size() == 0)
return StringPiece::npos;
for (size_t self_i = std::min(pos, self.size() - 1); ; --self_i) {
bool found = false;
for (auto c : s) {
if (self.data()[self_i] == c) {
found = true;
break;
}
}
if (!found)
return self_i;
if (self_i == 0)
break;
}
return BasicStringPiece<CharT>::npos;
}
size_t find_last_not_of(StringPiece16 self, StringPiece16 s, size_t pos) {
return find_last_not_ofT(self, s, pos);
}
size_t find(WStringPiece self, WStringPiece s, size_t pos) {
return findT(self, s, pos);
}
size_t rfind(WStringPiece self, WStringPiece s, size_t pos) {
return rfindT(self, s, pos);
}
size_t find_first_of(WStringPiece self, WStringPiece s, size_t pos) {
return find_first_ofT(self, s, pos);
}
size_t find_first_not_of(WStringPiece self, WStringPiece s, size_t pos) {
return find_first_not_ofT(self, s, pos);
}
size_t find_last_of(WStringPiece self, WStringPiece s, size_t pos) {
return find_last_ofT(self, s, pos);
}
size_t find_last_not_of(WStringPiece self, WStringPiece s, size_t pos) {
return find_last_not_ofT(self, s, pos);
}
} // namespace internal
} // namespace base