De-duplicate common code from StringPiece, StringPiece16, and their tests.

base/string_piece.cc

 // Copyright (c) 2011 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"
 
 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<std::string>;
+template class BasicStringPiece<string16>;
+#endif
+
 typedef StringPiece::size_type size_type;
 
 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 {
+void BasicStringPiece<std::string>::CopyToString(std::string* target) const {
   target->assign(!empty() ? data() : "", size());
 }
 
-void StringPiece::AppendToString(std::string* target) const {
+void BasicStringPiece<std::string>::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 BasicStringPiece<std::string>::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 {
+size_type BasicStringPiece<std::string>::find(const BasicStringPiece& 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 {
+size_type BasicStringPiece<std::string>::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_ ? static_cast<size_t>(result - ptr_) : npos;
 }
 
-size_type StringPiece::rfind(const StringPiece& s, size_type pos) const {
+size_type BasicStringPiece<std::string>::rfind(const BasicStringPiece& 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 ? static_cast<size_t>(result - ptr_) : npos;
 }
 
-size_type StringPiece::rfind(char c, size_type pos) const {
+size_type BasicStringPiece<std::string>::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 {
+size_type BasicStringPiece<std::string>::find_first_of(
+    const BasicStringPiece& 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 {
+size_type BasicStringPiece<std::string>::find_first_not_of(
+    const BasicStringPiece& 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 {
+size_type BasicStringPiece<std::string>::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 {
+size_type BasicStringPiece<std::string>::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 {
+size_type BasicStringPiece<std::string>::find_last_not_of(
+    const BasicStringPiece& 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 {
+size_type BasicStringPiece<std::string>::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 {
+BasicStringPiece<std::string> BasicStringPiece<std::string>::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);
-
 }  // namespace base