tor-browser

string_piece.cc (5947B)

---

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2006-2008 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 <algorithm>
#include <ostream>

#include "base/string_piece.h"

typedef StringPiece::size_type size_type;

std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
 o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
 return o;
}

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;
}

void StringPiece::CopyToString(std::string* target) const {
 target->assign(!empty() ? data() : "", size());
}

void StringPiece::AppendToString(std::string* target) const {
 if (!empty()) target->append(data(), size());
}

size_type StringPiece::copy(char* buf, size_type n, size_type pos) const {
 size_type ret = std::min(length_ - pos, n);
 memcpy(buf, ptr_ + pos, ret);
 return ret;
}

size_type StringPiece::find(const StringPiece& s, size_type pos) const {
 if (pos > length_) return npos;

 const char* result =
     std::search(ptr_ + pos, ptr_ + length_, s.ptr_, s.ptr_ + s.length_);
 const size_type xpos = result - ptr_;
 return xpos + s.length_ <= length_ ? xpos : npos;
}

size_type StringPiece::find(char c, size_type pos) const {
 if (pos >= length_) return npos;

 const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
 return result != ptr_ + length_ ? result - ptr_ : npos;
}

size_type StringPiece::rfind(const StringPiece& s, size_type pos) const {
 if (length_ < s.length_) return npos;

 if (s.empty()) return std::min(length_, pos);

 const char* last = ptr_ + std::min(length_ - s.length_, pos) + s.length_;
 const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
 return result != last ? result - ptr_ : npos;
}

size_type StringPiece::rfind(char c, size_type pos) const {
 if (length_ == 0) return npos;

 for (size_type i = std::min(pos, length_ - 1);; --i) {
   if (ptr_[i] == c) return i;
   if (i == 0) break;
 }
 return 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 size_type length = characters_wanted.length();
 const char* const data = characters_wanted.data();
 for (size_type i = 0; i < length; ++i) {
   table[static_cast<unsigned char>(data[i])] = true;
 }
}

size_type StringPiece::find_first_of(const StringPiece& s,
                                    size_type pos) const {
 if (length_ == 0 || s.length_ == 0) return npos;

 // Avoid the cost of BuildLookupTable() for a single-character search.
 if (s.length_ == 1) return find_first_of(s.ptr_[0], pos);

 bool lookup[UCHAR_MAX + 1] = {false};
 BuildLookupTable(s, lookup);
 for (size_type i = pos; i < length_; ++i) {
   if (lookup[static_cast<unsigned char>(ptr_[i])]) {
     return i;
   }
 }
 return npos;
}

size_type StringPiece::find_first_not_of(const StringPiece& s,
                                        size_type pos) const {
 if (length_ == 0) return npos;

 if (s.length_ == 0) return 0;

 // Avoid the cost of BuildLookupTable() for a single-character search.
 if (s.length_ == 1) return find_first_not_of(s.ptr_[0], pos);

 bool lookup[UCHAR_MAX + 1] = {false};
 BuildLookupTable(s, lookup);
 for (size_type i = pos; i < length_; ++i) {
   if (!lookup[static_cast<unsigned char>(ptr_[i])]) {
     return i;
   }
 }
 return npos;
}

size_type StringPiece::find_first_not_of(char c, size_type pos) const {
 if (length_ == 0) return npos;

 for (; pos < length_; ++pos) {
   if (ptr_[pos] != c) {
     return pos;
   }
 }
 return npos;
}

size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const {
 if (length_ == 0 || s.length_ == 0) return npos;

 // Avoid the cost of BuildLookupTable() for a single-character search.
 if (s.length_ == 1) return find_last_of(s.ptr_[0], pos);

 bool lookup[UCHAR_MAX + 1] = {false};
 BuildLookupTable(s, lookup);
 for (size_type i = std::min(pos, length_ - 1);; --i) {
   if (lookup[static_cast<unsigned char>(ptr_[i])]) return i;
   if (i == 0) break;
 }
 return npos;
}

size_type StringPiece::find_last_not_of(const StringPiece& s,
                                       size_type pos) const {
 if (length_ == 0) return npos;

 size_type i = std::min(pos, length_ - 1);
 if (s.length_ == 0) return i;

 // Avoid the cost of BuildLookupTable() for a single-character search.
 if (s.length_ == 1) return find_last_not_of(s.ptr_[0], pos);

 bool lookup[UCHAR_MAX + 1] = {false};
 BuildLookupTable(s, lookup);
 for (;; --i) {
   if (!lookup[static_cast<unsigned char>(ptr_[i])]) return i;
   if (i == 0) break;
 }
 return npos;
}

size_type StringPiece::find_last_not_of(char c, size_type pos) const {
 if (length_ == 0) return npos;

 for (size_type i = std::min(pos, length_ - 1);; --i) {
   if (ptr_[i] != c) return i;
   if (i == 0) break;
 }
 return npos;
}

StringPiece StringPiece::substr(size_type pos, size_type n) const {
 if (pos > length_) pos = length_;
 if (n > length_ - pos) n = length_ - pos;
 return StringPiece(ptr_ + pos, n);
}

const StringPiece::size_type StringPiece::npos = size_type(-1);