Move string_piece.h to base/strings.

This keeps a forwarding header and does not update any code to use the new location. This will be updated in a later pass.

BUG=

Review URL: https://codereview.chromium.org/12982018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@191206 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 460 insertions, 454 deletions

diff --git a/base/base.gyp b/base/base.gyp
index a120182..ff74605 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -562,10 +562,10 @@
         'shared_memory_unittest.cc',
         'stl_util_unittest.cc',
         'string16_unittest.cc',
-        'string_piece_unittest.cc',
         'string_util_unittest.cc',
         'stringprintf_unittest.cc',
         'strings/string_number_conversions_unittest.cc',
+        'strings/string_piece_unittest.cc',
         'strings/string_split_unittest.cc',
         'strings/string_tokenizer_unittest.cc',
         'strings/stringize_macros_unittest.cc',
diff --git a/base/base.gypi b/base/base.gypi
index ce7f7e8..9f91b16 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -390,8 +390,6 @@
           'shared_memory_win.cc',
           'single_thread_task_runner.h',
           'stl_util.h',
-          'string_piece.cc',
-          'string_piece.h',
           'string_util.cc',
           'string_util.h',
           'string_util_posix.h',
@@ -404,6 +402,8 @@
           'strings/string_split.h',
           'strings/string_number_conversions.cc',
           'strings/string_number_conversions.h',
+          'strings/string_piece.cc',
+          'strings/string_piece.h',
           'strings/string_tokenizer.h',
           'strings/stringize_macros.h',
           'strings/sys_string_conversions.h',
diff --git a/base/string_piece.h b/base/string_piece.h
index 416fca8..12b9a34 100644
--- a/base/string_piece.h
+++ b/base/string_piece.h
@@ -1,451 +1,6 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 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.h with modifications
-//
-// A string-like object that points to a sized piece of memory.
-//
-// Functions or methods may use const StringPiece& parameters to accept either
-// a "const char*" or a "string" value that will be implicitly converted to
-// a StringPiece.  The implicit conversion means that it is often appropriate
-// to include this .h file in other files rather than forward-declaring
-// StringPiece as would be appropriate for most other Google classes.
-//
-// Systematic usage of StringPiece is encouraged as it will reduce unnecessary
-// conversions from "const char*" to "string" and back again.
-//
-// StringPiece16 is similar to StringPiece but for base::string16 instead of
-// std::string. We do not define as large of a subset of the STL functions
-// from basic_string as in StringPiece, but this can be changed if these
-// functions (find, find_first_of, etc.) are found to be useful in this context.
-//
 
-#ifndef BASE_STRING_PIECE_H_
-#define BASE_STRING_PIECE_H_
-
-#include <stddef.h>
-
-#include <iosfwd>
-#include <string>
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/hash_tables.h"
-#include "base/string16.h"
-
-namespace base {
-
-template <typename STRING_TYPE> class BasicStringPiece;
-typedef BasicStringPiece<std::string> StringPiece;
-typedef BasicStringPiece<string16> StringPiece16;
-
-namespace internal {
-
-// Defines the types, methods, operators, and data members common to both
-// StringPiece and StringPiece16. Do not refer to this class directly, but
-// rather to BasicStringPiece, StringPiece, or StringPiece16.
-template <typename STRING_TYPE> class StringPieceDetail {
- public:
-  // standard STL container boilerplate
-  typedef size_t size_type;
-  typedef typename STRING_TYPE::value_type value_type;
-  typedef const value_type* pointer;
-  typedef const value_type& reference;
-  typedef const value_type& const_reference;
-  typedef ptrdiff_t difference_type;
-  typedef const value_type* const_iterator;
-  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
-
-  static const size_type npos;
-
- public:
-  // We provide non-explicit singleton constructors so users can pass
-  // in a "const char*" or a "string" wherever a "StringPiece" is
-  // expected (likewise for char16, string16, StringPiece16).
-  StringPieceDetail() : ptr_(NULL), length_(0) {}
-  StringPieceDetail(const value_type* str)
-      : ptr_(str),
-        length_((str == NULL) ? 0 : STRING_TYPE::traits_type::length(str)) {}
-  StringPieceDetail(const STRING_TYPE& str)
-      : ptr_(str.data()), length_(str.size()) {}
-  StringPieceDetail(const value_type* offset, size_type len)
-      : ptr_(offset), length_(len) {}
-  StringPieceDetail(const typename STRING_TYPE::const_iterator& begin,
-                    const typename STRING_TYPE::const_iterator& end)
-      : ptr_((end > begin) ? &(*begin) : NULL),
-        length_((end > begin) ? (size_type)(end - begin) : 0) {}
-
-  // data() may return a pointer to a buffer with embedded NULs, and the
-  // returned buffer may or may not be null terminated.  Therefore it is
-  // typically a mistake to pass data() to a routine that expects a NUL
-  // terminated string.
-  const value_type* data() const { return ptr_; }
-  size_type size() const { return length_; }
-  size_type length() const { return length_; }
-  bool empty() const { return length_ == 0; }
-
-  void clear() {
-    ptr_ = NULL;
-    length_ = 0;
-  }
-  void set(const value_type* data, size_type len) {
-    ptr_ = data;
-    length_ = len;
-  }
-  void set(const value_type* str) {
-    ptr_ = str;
-    length_ = str ? STRING_TYPE::traits_type::length(str) : 0;
-  }
-
-  value_type operator[](size_type i) const { return ptr_[i]; }
-
-  void remove_prefix(size_type n) {
-    ptr_ += n;
-    length_ -= n;
-  }
-
-  void remove_suffix(size_type n) {
-    length_ -= n;
-  }
-
-  int compare(const BasicStringPiece<STRING_TYPE>& x) const {
-    int r = wordmemcmp(
-        ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
-    if (r == 0) {
-      if (length_ < x.length_) r = -1;
-      else if (length_ > x.length_) r = +1;
-    }
-    return r;
-  }
-
-  STRING_TYPE as_string() const {
-    // std::string doesn't like to take a NULL pointer even with a 0 size.
-    return empty() ? STRING_TYPE() : STRING_TYPE(data(), size());
-  }
-
-  const_iterator begin() const { return ptr_; }
-  const_iterator end() const { return ptr_ + length_; }
-  const_reverse_iterator rbegin() const {
-    return const_reverse_iterator(ptr_ + length_);
-  }
-  const_reverse_iterator rend() const {
-    return const_reverse_iterator(ptr_);
-  }
-
-  size_type max_size() const { return length_; }
-  size_type capacity() const { return length_; }
-
-  static int wordmemcmp(const value_type* p,
-                        const value_type* p2,
-                        size_type N) {
-    return STRING_TYPE::traits_type::compare(p, p2, N);
-  }
-
- protected:
-  const value_type* ptr_;
-  size_type     length_;
-};
-
-template <typename STRING_TYPE>
-const typename StringPieceDetail<STRING_TYPE>::size_type
-StringPieceDetail<STRING_TYPE>::npos =
-    typename StringPieceDetail<STRING_TYPE>::size_type(-1);
-
-// MSVC doesn't like complex extern templates and DLLs.
-#if !defined(COMPILER_MSVC)
-extern template class BASE_EXPORT StringPieceDetail<std::string>;
-extern template class BASE_EXPORT StringPieceDetail<string16>;
-#endif
-
-BASE_EXPORT void CopyToString(const StringPiece& self, std::string* target);
-BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target);
-BASE_EXPORT StringPieceDetail<std::string>::size_type copy(
-    const StringPiece& self,
-    char* buf,
-    StringPieceDetail<std::string>::size_type n,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find(
-    const StringPiece& self,
-    char c,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type rfind(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type rfind(
-    const StringPiece& self,
-    char c,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_of(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_not_of(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_not_of(
-    const StringPiece& self,
-    char c,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_of(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_of(
-    const StringPiece& self,
-    char c,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_not_of(
-    const StringPiece& self,
-    const StringPiece& s,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_not_of(
-    const StringPiece& self,
-    char c,
-    StringPieceDetail<std::string>::size_type pos);
-BASE_EXPORT StringPiece substr(const StringPiece& self,
-                               StringPieceDetail<std::string>::size_type pos,
-                               StringPieceDetail<std::string>::size_type n);
-}  // namespace internal
-
-// Defines the template type that is instantiated as either StringPiece or
-// StringPiece16.
-template <typename STRING_TYPE> class BasicStringPiece :
-    public internal::StringPieceDetail<STRING_TYPE> {
- public:
-  typedef typename internal::StringPieceDetail<STRING_TYPE>::value_type
-      value_type;
-  typedef typename internal::StringPieceDetail<STRING_TYPE>::size_type
-      size_type;
-
-  BasicStringPiece() {}
-  BasicStringPiece(const value_type*str)
-      : internal::StringPieceDetail<STRING_TYPE>(str) {}
-  BasicStringPiece(const STRING_TYPE& str)
-      : internal::StringPieceDetail<STRING_TYPE>(str) {}
-  BasicStringPiece(const value_type* offset, size_type len)
-      : internal::StringPieceDetail<STRING_TYPE>(offset, len) {}
-  BasicStringPiece(const typename STRING_TYPE::const_iterator& begin,
-                   const typename STRING_TYPE::const_iterator& end)
-      : internal::StringPieceDetail<STRING_TYPE>(begin, end) {}
-};
-
-// Specializes BasicStringPiece for std::string to add a few operations that
-// are not needed for string16.
-template <> class BasicStringPiece<std::string> :
-    public internal::StringPieceDetail<std::string> {
- public:
-  BasicStringPiece() {}
-  BasicStringPiece(const char* str)
-      : internal::StringPieceDetail<std::string>(str) {}
-  BasicStringPiece(const std::string& str)
-      : internal::StringPieceDetail<std::string>(str) {}
-  BasicStringPiece(const char* offset, size_type len)
-      : internal::StringPieceDetail<std::string>(offset, len) {}
-  BasicStringPiece(const std::string::const_iterator& begin,
-                   const std::string::const_iterator& end)
-      : internal::StringPieceDetail<std::string>(begin, end) {}
-
-  // Prevent the following overload of set() from hiding the definitions in the
-  // base class.
-  using internal::StringPieceDetail<std::string>::set;
-
-  void set(const void* data, size_type len) {
-    ptr_ = reinterpret_cast<const value_type*>(data);
-    length_ = len;
-  }
-
-  void CopyToString(std::string* target) const {
-    internal::CopyToString(*this, target);
-  }
-
-  void AppendToString(std::string* target) const {
-    internal::AppendToString(*this, target);
-  }
-
-  // Does "this" start with "x"
-  bool starts_with(const BasicStringPiece& x) const {
-    return ((length_ >= x.length_) &&
-            (wordmemcmp(ptr_, x.ptr_, x.length_) == 0));
-  }
-
-  // Does "this" end with "x"
-  bool ends_with(const BasicStringPiece& x) const {
-    return ((length_ >= x.length_) &&
-            (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0));
-  }
-
-  size_type copy(char* buf, size_type n, size_type pos = 0) const {
-    return internal::copy(*this, buf, n, pos);
-  }
-
-  size_type find(const BasicStringPiece& s, size_type pos = 0) const {
-    return internal::find(*this, s, pos);
-  }
-
-  size_type find(char c, size_type pos = 0) const {
-    return internal::find(*this, c, pos);
-  }
-
-  size_type rfind(const BasicStringPiece& s, size_type pos = npos) const {
-    return internal::rfind(*this, s, pos);
-  }
-
-  size_type rfind(char c, size_type pos = npos) const {
-    return internal::rfind(*this, c, pos);
-  }
-
-  size_type find_first_of(const BasicStringPiece& s, size_type pos = 0) const {
-    return internal::find_first_of(*this, s, pos);
-  }
-
-  size_type find_first_of(char c, size_type pos = 0) const {
-    return find(c, pos);
-  }
-
-  size_type find_first_not_of(const BasicStringPiece& s,
-                              size_type pos = 0) const {
-    return internal::find_first_not_of(*this, s, pos);
-  }
-
-  size_type find_first_not_of(char c, size_type pos = 0) const {
-    return internal::find_first_not_of(*this, c, pos);
-  }
-
-  size_type find_last_of(const BasicStringPiece& s,
-                         size_type pos = npos) const {
-    return internal::find_last_of(*this, s, pos);
-  }
-
-  size_type find_last_of(char c, size_type pos = npos) const {
-    return rfind(c, pos);
-  }
-
-  size_type find_last_not_of(const BasicStringPiece& s,
-                             size_type pos = npos) const {
-    return internal::find_last_not_of(*this, s, pos);
-  }
-
-  size_type find_last_not_of(char c, size_type pos = npos) const {
-    return internal::find_last_not_of(*this, c, pos);
-  }
-
-  BasicStringPiece substr(size_type pos, size_type n = npos) const {
-    return internal::substr(*this, pos, n);
-  }
-};
-
-// MSVC doesn't like complex extern templates and DLLs.
-#if !defined(COMPILER_MSVC)
-// We can't explicitly declare the std::string instantiation here because it was
-// already instantiated when specialized, above. Not only is it a no-op, but
-// currently it also crashes Clang (see http://crbug.com/107412).
-extern template class BASE_EXPORT BasicStringPiece<string16>;
-#endif
-
-BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y);
-
-inline bool operator!=(const StringPiece& x, const StringPiece& y) {
-  return !(x == y);
-}
-
-inline bool operator<(const StringPiece& x, const StringPiece& y) {
-  const int r = StringPiece::wordmemcmp(
-      x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
-  return ((r < 0) || ((r == 0) && (x.size() < y.size())));
-}
-
-inline bool operator>(const StringPiece& x, const StringPiece& y) {
-  return y < x;
-}
-
-inline bool operator<=(const StringPiece& x, const StringPiece& y) {
-  return !(x > y);
-}
-
-inline bool operator>=(const StringPiece& x, const StringPiece& y) {
-  return !(x < y);
-}
-
-inline bool operator==(const StringPiece16& x, const StringPiece16& y) {
-  if (x.size() != y.size())
-    return false;
-
-  return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0;
-}
-
-inline bool operator!=(const StringPiece16& x, const StringPiece16& y) {
-  return !(x == y);
-}
-
-inline bool operator<(const StringPiece16& x, const StringPiece16& y) {
-  const int r = StringPiece16::wordmemcmp(
-      x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
-  return ((r < 0) || ((r == 0) && (x.size() < y.size())));
-}
-
-inline bool operator>(const StringPiece16& x, const StringPiece16& y) {
-  return y < x;
-}
-
-inline bool operator<=(const StringPiece16& x, const StringPiece16& y) {
-  return !(x > y);
-}
-
-inline bool operator>=(const StringPiece16& x, const StringPiece16& y) {
-  return !(x < y);
-}
-
-BASE_EXPORT std::ostream& operator<<(std::ostream& o,
-                                     const StringPiece& piece);
-
-}  // namespace base
-
-// We provide appropriate hash functions so StringPiece and StringPiece16 can
-// be used as keys in hash sets and maps.
-
-// This hash function is copied from base/hash_tables.h. We don't use the
-// ones already defined for string and string16 directly because it would
-// require the string constructors to be called, which we don't want.
-#define HASH_STRING_PIECE(StringPieceType, string_piece)                \
-  std::size_t result = 0;                                               \
-  for (StringPieceType::const_iterator i = string_piece.begin();        \
-       i != string_piece.end(); ++i)                                    \
-    result = (result * 131) + *i;                                       \
-  return result;                                                        \
-
-namespace BASE_HASH_NAMESPACE {
-#if defined(COMPILER_GCC)
-
-template<>
-struct hash<base::StringPiece> {
-  std::size_t operator()(const base::StringPiece& sp) const {
-    HASH_STRING_PIECE(base::StringPiece, sp);
-  }
-};
-template<>
-struct hash<base::StringPiece16> {
-  std::size_t operator()(const base::StringPiece16& sp16) const {
-    HASH_STRING_PIECE(base::StringPiece16, sp16);
-  }
-};
-
-#elif defined(COMPILER_MSVC)
-
-inline size_t hash_value(const base::StringPiece& sp) {
-  HASH_STRING_PIECE(base::StringPiece, sp);
-}
-inline size_t hash_value(const base::StringPiece16& sp16) {
-  HASH_STRING_PIECE(base::StringPiece16, sp16);
-}
-
-#endif  // COMPILER
-
-}  // namespace BASE_HASH_NAMESPACE
-
-#endif  // BASE_STRING_PIECE_H_
+// TODO(brettw) move callers to using the new location
+#include "base/strings/string_piece.h"
diff --git a/base/string_piece.cc b/base/strings/string_piece.cc
index 7a41361..79a42d7 100644
--- a/base/string_piece.cc
+++ b/base/strings/string_piece.cc
@@ -3,11 +3,11 @@
 // found in the LICENSE file.
 // Copied from strings/stringpiece.cc with modifications
 
+#include "base/strings/string_piece.h"
+
 #include <algorithm>
 #include <ostream>
 
-#include "base/string_piece.h"
-
 namespace base {
 
 // MSVC doesn't like complex extern templates and DLLs.
diff --git a/base/strings/string_piece.h b/base/strings/string_piece.h
new file mode 100644
index 0000000..13ca009
--- /dev/null
+++ b/base/strings/string_piece.h
@@ -0,0 +1,451 @@
+// 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.h with modifications
+//
+// A string-like object that points to a sized piece of memory.
+//
+// Functions or methods may use const StringPiece& parameters to accept either
+// a "const char*" or a "string" value that will be implicitly converted to
+// a StringPiece.  The implicit conversion means that it is often appropriate
+// to include this .h file in other files rather than forward-declaring
+// StringPiece as would be appropriate for most other Google classes.
+//
+// Systematic usage of StringPiece is encouraged as it will reduce unnecessary
+// conversions from "const char*" to "string" and back again.
+//
+// StringPiece16 is similar to StringPiece but for base::string16 instead of
+// std::string. We do not define as large of a subset of the STL functions
+// from basic_string as in StringPiece, but this can be changed if these
+// functions (find, find_first_of, etc.) are found to be useful in this context.
+//
+
+#ifndef BASE_STRINGS_STRING_PIECE_H_
+#define BASE_STRINGS_STRING_PIECE_H_
+
+#include <stddef.h>
+
+#include <iosfwd>
+#include <string>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+#include "base/hash_tables.h"
+#include "base/string16.h"
+
+namespace base {
+
+template <typename STRING_TYPE> class BasicStringPiece;
+typedef BasicStringPiece<std::string> StringPiece;
+typedef BasicStringPiece<string16> StringPiece16;
+
+namespace internal {
+
+// Defines the types, methods, operators, and data members common to both
+// StringPiece and StringPiece16. Do not refer to this class directly, but
+// rather to BasicStringPiece, StringPiece, or StringPiece16.
+template <typename STRING_TYPE> class StringPieceDetail {
+ public:
+  // standard STL container boilerplate
+  typedef size_t size_type;
+  typedef typename STRING_TYPE::value_type value_type;
+  typedef const value_type* pointer;
+  typedef const value_type& reference;
+  typedef const value_type& const_reference;
+  typedef ptrdiff_t difference_type;
+  typedef const value_type* const_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+  static const size_type npos;
+
+ public:
+  // We provide non-explicit singleton constructors so users can pass
+  // in a "const char*" or a "string" wherever a "StringPiece" is
+  // expected (likewise for char16, string16, StringPiece16).
+  StringPieceDetail() : ptr_(NULL), length_(0) {}
+  StringPieceDetail(const value_type* str)
+      : ptr_(str),
+        length_((str == NULL) ? 0 : STRING_TYPE::traits_type::length(str)) {}
+  StringPieceDetail(const STRING_TYPE& str)
+      : ptr_(str.data()), length_(str.size()) {}
+  StringPieceDetail(const value_type* offset, size_type len)
+      : ptr_(offset), length_(len) {}
+  StringPieceDetail(const typename STRING_TYPE::const_iterator& begin,
+                    const typename STRING_TYPE::const_iterator& end)
+      : ptr_((end > begin) ? &(*begin) : NULL),
+        length_((end > begin) ? (size_type)(end - begin) : 0) {}
+
+  // data() may return a pointer to a buffer with embedded NULs, and the
+  // returned buffer may or may not be null terminated.  Therefore it is
+  // typically a mistake to pass data() to a routine that expects a NUL
+  // terminated string.
+  const value_type* data() const { return ptr_; }
+  size_type size() const { return length_; }
+  size_type length() const { return length_; }
+  bool empty() const { return length_ == 0; }
+
+  void clear() {
+    ptr_ = NULL;
+    length_ = 0;
+  }
+  void set(const value_type* data, size_type len) {
+    ptr_ = data;
+    length_ = len;
+  }
+  void set(const value_type* str) {
+    ptr_ = str;
+    length_ = str ? STRING_TYPE::traits_type::length(str) : 0;
+  }
+
+  value_type operator[](size_type i) const { return ptr_[i]; }
+
+  void remove_prefix(size_type n) {
+    ptr_ += n;
+    length_ -= n;
+  }
+
+  void remove_suffix(size_type n) {
+    length_ -= n;
+  }
+
+  int compare(const BasicStringPiece<STRING_TYPE>& x) const {
+    int r = wordmemcmp(
+        ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
+    if (r == 0) {
+      if (length_ < x.length_) r = -1;
+      else if (length_ > x.length_) r = +1;
+    }
+    return r;
+  }
+
+  STRING_TYPE as_string() const {
+    // std::string doesn't like to take a NULL pointer even with a 0 size.
+    return empty() ? STRING_TYPE() : STRING_TYPE(data(), size());
+  }
+
+  const_iterator begin() const { return ptr_; }
+  const_iterator end() const { return ptr_ + length_; }
+  const_reverse_iterator rbegin() const {
+    return const_reverse_iterator(ptr_ + length_);
+  }
+  const_reverse_iterator rend() const {
+    return const_reverse_iterator(ptr_);
+  }
+
+  size_type max_size() const { return length_; }
+  size_type capacity() const { return length_; }
+
+  static int wordmemcmp(const value_type* p,
+                        const value_type* p2,
+                        size_type N) {
+    return STRING_TYPE::traits_type::compare(p, p2, N);
+  }
+
+ protected:
+  const value_type* ptr_;
+  size_type     length_;
+};
+
+template <typename STRING_TYPE>
+const typename StringPieceDetail<STRING_TYPE>::size_type
+StringPieceDetail<STRING_TYPE>::npos =
+    typename StringPieceDetail<STRING_TYPE>::size_type(-1);
+
+// MSVC doesn't like complex extern templates and DLLs.
+#if !defined(COMPILER_MSVC)
+extern template class BASE_EXPORT StringPieceDetail<std::string>;
+extern template class BASE_EXPORT StringPieceDetail<string16>;
+#endif
+
+BASE_EXPORT void CopyToString(const StringPiece& self, std::string* target);
+BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target);
+BASE_EXPORT StringPieceDetail<std::string>::size_type copy(
+    const StringPiece& self,
+    char* buf,
+    StringPieceDetail<std::string>::size_type n,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find(
+    const StringPiece& self,
+    char c,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type rfind(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type rfind(
+    const StringPiece& self,
+    char c,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_of(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_not_of(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_first_not_of(
+    const StringPiece& self,
+    char c,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_of(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_of(
+    const StringPiece& self,
+    char c,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_not_of(
+    const StringPiece& self,
+    const StringPiece& s,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPieceDetail<std::string>::size_type find_last_not_of(
+    const StringPiece& self,
+    char c,
+    StringPieceDetail<std::string>::size_type pos);
+BASE_EXPORT StringPiece substr(const StringPiece& self,
+                               StringPieceDetail<std::string>::size_type pos,
+                               StringPieceDetail<std::string>::size_type n);
+}  // namespace internal
+
+// Defines the template type that is instantiated as either StringPiece or
+// StringPiece16.
+template <typename STRING_TYPE> class BasicStringPiece :
+    public internal::StringPieceDetail<STRING_TYPE> {
+ public:
+  typedef typename internal::StringPieceDetail<STRING_TYPE>::value_type
+      value_type;
+  typedef typename internal::StringPieceDetail<STRING_TYPE>::size_type
+      size_type;
+
+  BasicStringPiece() {}
+  BasicStringPiece(const value_type*str)
+      : internal::StringPieceDetail<STRING_TYPE>(str) {}
+  BasicStringPiece(const STRING_TYPE& str)
+      : internal::StringPieceDetail<STRING_TYPE>(str) {}
+  BasicStringPiece(const value_type* offset, size_type len)
+      : internal::StringPieceDetail<STRING_TYPE>(offset, len) {}
+  BasicStringPiece(const typename STRING_TYPE::const_iterator& begin,
+                   const typename STRING_TYPE::const_iterator& end)
+      : internal::StringPieceDetail<STRING_TYPE>(begin, end) {}
+};
+
+// Specializes BasicStringPiece for std::string to add a few operations that
+// are not needed for string16.
+template <> class BasicStringPiece<std::string> :
+    public internal::StringPieceDetail<std::string> {
+ public:
+  BasicStringPiece() {}
+  BasicStringPiece(const char* str)
+      : internal::StringPieceDetail<std::string>(str) {}
+  BasicStringPiece(const std::string& str)
+      : internal::StringPieceDetail<std::string>(str) {}
+  BasicStringPiece(const char* offset, size_type len)
+      : internal::StringPieceDetail<std::string>(offset, len) {}
+  BasicStringPiece(const std::string::const_iterator& begin,
+                   const std::string::const_iterator& end)
+      : internal::StringPieceDetail<std::string>(begin, end) {}
+
+  // Prevent the following overload of set() from hiding the definitions in the
+  // base class.
+  using internal::StringPieceDetail<std::string>::set;
+
+  void set(const void* data, size_type len) {
+    ptr_ = reinterpret_cast<const value_type*>(data);
+    length_ = len;
+  }
+
+  void CopyToString(std::string* target) const {
+    internal::CopyToString(*this, target);
+  }
+
+  void AppendToString(std::string* target) const {
+    internal::AppendToString(*this, target);
+  }
+
+  // Does "this" start with "x"
+  bool starts_with(const BasicStringPiece& x) const {
+    return ((length_ >= x.length_) &&
+            (wordmemcmp(ptr_, x.ptr_, x.length_) == 0));
+  }
+
+  // Does "this" end with "x"
+  bool ends_with(const BasicStringPiece& x) const {
+    return ((length_ >= x.length_) &&
+            (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0));
+  }
+
+  size_type copy(char* buf, size_type n, size_type pos = 0) const {
+    return internal::copy(*this, buf, n, pos);
+  }
+
+  size_type find(const BasicStringPiece& s, size_type pos = 0) const {
+    return internal::find(*this, s, pos);
+  }
+
+  size_type find(char c, size_type pos = 0) const {
+    return internal::find(*this, c, pos);
+  }
+
+  size_type rfind(const BasicStringPiece& s, size_type pos = npos) const {
+    return internal::rfind(*this, s, pos);
+  }
+
+  size_type rfind(char c, size_type pos = npos) const {
+    return internal::rfind(*this, c, pos);
+  }
+
+  size_type find_first_of(const BasicStringPiece& s, size_type pos = 0) const {
+    return internal::find_first_of(*this, s, pos);
+  }
+
+  size_type find_first_of(char c, size_type pos = 0) const {
+    return find(c, pos);
+  }
+
+  size_type find_first_not_of(const BasicStringPiece& s,
+                              size_type pos = 0) const {
+    return internal::find_first_not_of(*this, s, pos);
+  }
+
+  size_type find_first_not_of(char c, size_type pos = 0) const {
+    return internal::find_first_not_of(*this, c, pos);
+  }
+
+  size_type find_last_of(const BasicStringPiece& s,
+                         size_type pos = npos) const {
+    return internal::find_last_of(*this, s, pos);
+  }
+
+  size_type find_last_of(char c, size_type pos = npos) const {
+    return rfind(c, pos);
+  }
+
+  size_type find_last_not_of(const BasicStringPiece& s,
+                             size_type pos = npos) const {
+    return internal::find_last_not_of(*this, s, pos);
+  }
+
+  size_type find_last_not_of(char c, size_type pos = npos) const {
+    return internal::find_last_not_of(*this, c, pos);
+  }
+
+  BasicStringPiece substr(size_type pos, size_type n = npos) const {
+    return internal::substr(*this, pos, n);
+  }
+};
+
+// MSVC doesn't like complex extern templates and DLLs.
+#if !defined(COMPILER_MSVC)
+// We can't explicitly declare the std::string instantiation here because it was
+// already instantiated when specialized, above. Not only is it a no-op, but
+// currently it also crashes Clang (see http://crbug.com/107412).
+extern template class BASE_EXPORT BasicStringPiece<string16>;
+#endif
+
+BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y);
+
+inline bool operator!=(const StringPiece& x, const StringPiece& y) {
+  return !(x == y);
+}
+
+inline bool operator<(const StringPiece& x, const StringPiece& y) {
+  const int r = StringPiece::wordmemcmp(
+      x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
+  return ((r < 0) || ((r == 0) && (x.size() < y.size())));
+}
+
+inline bool operator>(const StringPiece& x, const StringPiece& y) {
+  return y < x;
+}
+
+inline bool operator<=(const StringPiece& x, const StringPiece& y) {
+  return !(x > y);
+}
+
+inline bool operator>=(const StringPiece& x, const StringPiece& y) {
+  return !(x < y);
+}
+
+inline bool operator==(const StringPiece16& x, const StringPiece16& y) {
+  if (x.size() != y.size())
+    return false;
+
+  return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0;
+}
+
+inline bool operator!=(const StringPiece16& x, const StringPiece16& y) {
+  return !(x == y);
+}
+
+inline bool operator<(const StringPiece16& x, const StringPiece16& y) {
+  const int r = StringPiece16::wordmemcmp(
+      x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
+  return ((r < 0) || ((r == 0) && (x.size() < y.size())));
+}
+
+inline bool operator>(const StringPiece16& x, const StringPiece16& y) {
+  return y < x;
+}
+
+inline bool operator<=(const StringPiece16& x, const StringPiece16& y) {
+  return !(x > y);
+}
+
+inline bool operator>=(const StringPiece16& x, const StringPiece16& y) {
+  return !(x < y);
+}
+
+BASE_EXPORT std::ostream& operator<<(std::ostream& o,
+                                     const StringPiece& piece);
+
+}  // namespace base
+
+// We provide appropriate hash functions so StringPiece and StringPiece16 can
+// be used as keys in hash sets and maps.
+
+// This hash function is copied from base/hash_tables.h. We don't use the
+// ones already defined for string and string16 directly because it would
+// require the string constructors to be called, which we don't want.
+#define HASH_STRING_PIECE(StringPieceType, string_piece)                \
+  std::size_t result = 0;                                               \
+  for (StringPieceType::const_iterator i = string_piece.begin();        \
+       i != string_piece.end(); ++i)                                    \
+    result = (result * 131) + *i;                                       \
+  return result;                                                        \
+
+namespace BASE_HASH_NAMESPACE {
+#if defined(COMPILER_GCC)
+
+template<>
+struct hash<base::StringPiece> {
+  std::size_t operator()(const base::StringPiece& sp) const {
+    HASH_STRING_PIECE(base::StringPiece, sp);
+  }
+};
+template<>
+struct hash<base::StringPiece16> {
+  std::size_t operator()(const base::StringPiece16& sp16) const {
+    HASH_STRING_PIECE(base::StringPiece16, sp16);
+  }
+};
+
+#elif defined(COMPILER_MSVC)
+
+inline size_t hash_value(const base::StringPiece& sp) {
+  HASH_STRING_PIECE(base::StringPiece, sp);
+}
+inline size_t hash_value(const base::StringPiece16& sp16) {
+  HASH_STRING_PIECE(base::StringPiece16, sp16);
+}
+
+#endif  // COMPILER
+
+}  // namespace BASE_HASH_NAMESPACE
+
+#endif  // BASE_STRINGS_STRING_PIECE_H_
diff --git a/base/string_piece_unittest.cc b/base/strings/string_piece_unittest.cc
index e93dba8..6265888 100644
--- a/base/string_piece_unittest.cc
+++ b/base/strings/string_piece_unittest.cc
@@ -5,7 +5,7 @@
 #include <string>
 
 #include "base/string16.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "base/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"