Optimize phishing page term feature extraction.

base/wide_string_piece.h

+// 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.
+//
+// WideStringPiece is similar to StringPiece (in base/string_piece.h) 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_WIDE_STRING_PIECE_H_
+#define BASE_WIDE_STRING_PIECE_H_
+#pragma once
+
+#include "base/base_api.h"
+#include "base/hash_tables.h"
+#include "base/string16.h"
+
+namespace base {
+
+class BASE_API WideStringPiece {

[brettw, 2011/08/03 20:47:38]

This should be called StringPiece16. "Wide" is what we use for wchar_t, which is
different on Mac & Linux.

I would actually just put this in string_piece.h header and not bother with a
separate one for the new class.

[Garrett Casto, 2011/08/04 00:03:51]

Done.

+ public:
+  // standard STL container boilerplate
+  typedef size_t size_type;
+  typedef char16 value_type;
+  typedef const char16* pointer;
+  typedef const char16& reference;
+  typedef const char16& const_reference;
+  typedef ptrdiff_t difference_type;
+  typedef const char16* const_iterator;
+  typedef const char16* iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+
+ public:
+  // We provide non-explicit singleton constructors so users can pass
+  // in a "const char16*" or a "string16" wherever a "WideStringPiece" is
+  // expected.
+  WideStringPiece() : ptr_(NULL), length_(0) { }
+  WideStringPiece(const char16* str)
+      : ptr_(str),
+        length_((str == NULL) ? 0 : string16::traits_type::length(str)) { }
+  WideStringPiece(const string16& str)
+      : ptr_(str.data()), length_(str.size()) { }
+  WideStringPiece(const char16* offset, size_type len)
+      : ptr_(offset), length_(len) { }
+
+  // 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 char16* 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 char16* data, size_type len) {
+    ptr_ = data;
+    length_ = len;
+  }
+  void set(const char16* str) {
+    ptr_ = str;
+    length_ = str ? string16::traits_type::length(str) : 0;
+  }
+  void set(const void* data, size_type len) {
+    ptr_ = reinterpret_cast<const char16*>(data);
+    length_ = len;
+  }
+
+  char16 operator[](size_type i) const { return ptr_[i]; }
+
+  string16 as_string16() const {
+    // StringPiece claims that this is bad when data() is NULL, but unittesting
+    // seems to say otherwise.
+    return string16(data(), size());
+  }
+
+  iterator begin() const { return ptr_; }
+  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 char16* p, const char16* p2, size_type N) {
+    return string16::traits_type::compare(p, p2, N);
+  }
+
+ private:
+  const char16*   ptr_;
+  size_type       length_;
+};
+
+inline bool operator==(const WideStringPiece& x, const WideStringPiece& y) {
+  if (x.size() != y.size())
+    return false;
+
+  return WideStringPiece::wordmemcmp(x.data(), y.data(), x.size()) == 0;
+}
+
+inline bool operator!=(const WideStringPiece& x, const WideStringPiece& y) {
+  return !(x == y);
+}
+
+inline bool operator<(const WideStringPiece& x, const WideStringPiece& y) {
+  const int r = WideStringPiece::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 WideStringPiece& x, const WideStringPiece& y) {
+  return y < x;
+}
+
+inline bool operator<=(const WideStringPiece& x, const WideStringPiece& y) {
+  return !(x > y);
+}
+
+inline bool operator>=(const WideStringPiece& x, const WideStringPiece& y) {
+  return !(x < y);
+}
+
+}  // namespace base
+
+// Provide appropriate hash functions so WideStringPiece can be used as a key in
+// hash sets and maps.
+
+// This hash function is copied from base/hash_tables.h. We don't use the
+// already defined string16 directly because it would require the string16
+// constructor to be called, which we don't want.
+#define HASH_WIDE_STRING_PIECE(wsp) \
+  std::size_t result = 0;                                               \
+  for (base::WideStringPiece::const_iterator i = wsp.begin();           \
+       i != wsp.end(); ++i)                                             \
+    result = (result * 131) + *i;                                       \
+  return result;                                                        \
+
+namespace BASE_HASH_NAMESPACE {
+#if defined(COMPILER_GCC)
+
+template<>
+struct hash<base::WideStringPiece> {
+  std::size_t operator()(const base::WideStringPiece& wsp) const {
+    HASH_WIDE_STRING_PIECE(wsp);
+  }
+};
+
+#elif defined(COMPILER_MSVC)
+
+inline size_t hash_value(const base::WideStringPiece& wsp) {
+  HASH_WIDE_STRING_PIECE(wsp);
+}
+
+#endif  // COMPILER
+
+}  // namespace BASE_HASH_NAMESPACE
+
+#undef HASH_WIDE_STRING_PIECE
+
+#endif  // BASE_STRING_PIECE_H_