base/utf_offset_string_conversions.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_UTF_OFFSET_STRING_CONVERSIONS_H_
   6 #define BASE_UTF_OFFSET_STRING_CONVERSIONS_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/base_export.h"
  12 #include "base/string16.h"
  13 #include "base/string_piece.h"
  14
  15 // Like the conversions in utf_string_conversions.h, but also takes one or more
  16 // offsets (|offset[s]_for_adjustment|) into the source strings, each offset
  17 // will be adjusted to point at the same logical place in the result strings.
  18 // If this isn't possible because an offset points past the end of the source
  19 // strings or into the middle of a multibyte sequence, the offending offset will
  20 // be set to string16::npos. |offset[s]_for_adjustment| may be NULL.
  21 BASE_EXPORT bool UTF8ToUTF16AndAdjustOffset(const char* src,
  22                                             size_t src_len,
  23                                             string16* output,
  24                                             size_t* offset_for_adjustment);
  25 BASE_EXPORT bool UTF8ToUTF16AndAdjustOffsets(
  26     const char* src,
  27     size_t src_len,
  28     string16* output,
  29     std::vector<size_t>* offsets_for_adjustment);
  30
  31 BASE_EXPORT string16 UTF8ToUTF16AndAdjustOffset(const base::StringPiece& utf8,
  32                                                 size_t* offset_for_adjustment);
  33 BASE_EXPORT string16 UTF8ToUTF16AndAdjustOffsets(
  34     const base::StringPiece& utf8,
  35     std::vector<size_t>* offsets_for_adjustment);
  36
  37 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffset(
  38     const base::StringPiece16& utf16,
  39     size_t* offset_for_adjustment);
  40 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffsets(
  41     const base::StringPiece16& utf16,
  42     std::vector<size_t>* offsets_for_adjustment);
  43
  44 // Limiting function callable by std::for_each which will replace any value
  45 // which is equal to or greater than |limit| with npos.
  46 template <typename T>
  47 struct LimitOffset {
  48   explicit LimitOffset(size_t limit)
  49     : limit_(limit) {}
  50
  51   void operator()(size_t& offset) {
  52     if (offset >= limit_)
  53       offset = T::npos;
  54   }
  55
  56   size_t limit_;
  57 };
  58
  59 // Stack object which, on destruction, will update a vector of offsets based on
  60 // any supplied adjustments.  To use, declare one of these, providing the
  61 // address of the offset vector to adjust.  Then Add() any number of Adjustments
  62 // (each Adjustment gives the |original_offset| of a substring and the lengths
  63 // of the substring before and after transforming).  When the OffsetAdjuster
  64 // goes out of scope, all the offsets in the provided vector will be updated.
  65 class BASE_EXPORT OffsetAdjuster {
  66  public:
  67   struct BASE_EXPORT Adjustment {
  68     Adjustment(size_t original_offset,
  69                size_t original_length,
  70                size_t output_length);
  71
  72     size_t original_offset;
  73     size_t original_length;
  74     size_t output_length;
  75   };
  76
  77   explicit OffsetAdjuster(std::vector<size_t>* offsets_for_adjustment);
  78   ~OffsetAdjuster();
  79
  80   void Add(const Adjustment& adjustment);
  81
  82  private:
  83   void AdjustOffset(std::vector<size_t>::iterator offset);
  84
  85   std::vector<size_t>* offsets_for_adjustment_;
  86   std::vector<Adjustment> adjustments_;
  87 };
  88
  89 #endif  // BASE_UTF_OFFSET_STRING_CONVERSIONS_H_