base/strings/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_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
   6 #define BASE_STRINGS_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 namespace base {
  16
  17 // Like the conversions in utf_string_conversions.h, but also takes one or more
  18 // offsets (|offset[s]_for_adjustment|) into the source strings, each offset
  19 // will be adjusted to point at the same logical place in the result strings.
  20 // If this isn't possible because an offset points past the end of the source
  21 // strings or into the middle of a multibyte sequence, the offending offset will
  22 // be set to string16::npos. |offset[s]_for_adjustment| may be NULL.
  23 BASE_EXPORT bool UTF8ToUTF16AndAdjustOffset(const char* src,
  24                                             size_t src_len,
  25                                             string16* output,
  26                                             size_t* offset_for_adjustment);
  27 BASE_EXPORT bool UTF8ToUTF16AndAdjustOffsets(
  28     const char* src,
  29     size_t src_len,
  30     string16* output,
  31     std::vector<size_t>* offsets_for_adjustment);
  32
  33 BASE_EXPORT string16 UTF8ToUTF16AndAdjustOffset(const base::StringPiece& utf8,
  34                                                 size_t* offset_for_adjustment);
  35 BASE_EXPORT string16 UTF8ToUTF16AndAdjustOffsets(
  36     const base::StringPiece& utf8,
  37     std::vector<size_t>* offsets_for_adjustment);
  38
  39 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffset(
  40     const base::StringPiece16& utf16,
  41     size_t* offset_for_adjustment);
  42 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffsets(
  43     const base::StringPiece16& utf16,
  44     std::vector<size_t>* offsets_for_adjustment);
  45
  46 // Limiting function callable by std::for_each which will replace any value
  47 // which is equal to or greater than |limit| with npos.
  48 template <typename T>
  49 struct LimitOffset {
  50   explicit LimitOffset(size_t limit)
  51     : limit_(limit) {}
  52
  53   void operator()(size_t& offset) {
  54     if (offset >= limit_)
  55       offset = T::npos;
  56   }
  57
  58   size_t limit_;
  59 };
  60
  61 // Stack object which, on destruction, will update a vector of offsets based on
  62 // any supplied adjustments.  To use, declare one of these, providing the
  63 // address of the offset vector to adjust.  Then Add() any number of Adjustments
  64 // (each Adjustment gives the |original_offset| of a substring and the lengths
  65 // of the substring before and after transforming).  When the OffsetAdjuster
  66 // goes out of scope, all the offsets in the provided vector will be updated.
  67 class BASE_EXPORT OffsetAdjuster {
  68  public:
  69   struct BASE_EXPORT Adjustment {
  70     Adjustment(size_t original_offset,
  71                size_t original_length,
  72                size_t output_length);
  73
  74     size_t original_offset;
  75     size_t original_length;
  76     size_t output_length;
  77   };
  78
  79   explicit OffsetAdjuster(std::vector<size_t>* offsets_for_adjustment);
  80   ~OffsetAdjuster();
  81
  82   void Add(const Adjustment& adjustment);
  83
  84  private:
  85   void AdjustOffset(std::vector<size_t>::iterator offset);
  86
  87   std::vector<size_t>* offsets_for_adjustment_;
  88   std::vector<Adjustment> adjustments_;
  89 };
  90
  91 }  // namespace base
  92
  93 #endif  // BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_