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115 lines
5.0 KiB
115 lines
5.0 KiB
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
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#define BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
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#include <stddef.h>
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#include <string>
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#include <vector>
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#include "base/base_export.h"
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#include "base/strings/string16.h"
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#include "base/strings/string_piece.h"
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namespace base {
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// A helper class and associated data structures to adjust offsets into a
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// string in response to various adjustments one might do to that string
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// (e.g., eliminating a range). For details on offsets, see the comments by
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// the AdjustOffsets() function below.
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class BASE_EXPORT OffsetAdjuster {
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public:
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struct BASE_EXPORT Adjustment {
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Adjustment(size_t original_offset,
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size_t original_length,
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size_t output_length);
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size_t original_offset;
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size_t original_length;
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size_t output_length;
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};
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typedef std::vector<Adjustment> Adjustments;
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// Adjusts all offsets in |offsets_for_adjustment| to reflect the adjustments
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// recorded in |adjustments|. Adjusted offsets greater than |limit| will be
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// set to string16::npos.
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//
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// Offsets represents insertion/selection points between characters: if |src|
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// is "abcd", then 0 is before 'a', 2 is between 'b' and 'c', and 4 is at the
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// end of the string. Valid input offsets range from 0 to |src_len|. On
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// exit, each offset will have been modified to point at the same logical
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// position in the output string. If an offset cannot be successfully
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// adjusted (e.g., because it points into the middle of a multibyte sequence),
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// it will be set to string16::npos.
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static void AdjustOffsets(const Adjustments& adjustments,
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std::vector<size_t>* offsets_for_adjustment,
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size_t limit = string16::npos);
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// Adjusts the single |offset| to reflect the adjustments recorded in
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// |adjustments|.
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static void AdjustOffset(const Adjustments& adjustments,
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size_t* offset,
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size_t limit = string16::npos);
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// Adjusts all offsets in |offsets_for_unadjustment| to reflect the reverse
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// of the adjustments recorded in |adjustments|. In other words, the offsets
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// provided represent offsets into an adjusted string and the caller wants
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// to know the offsets they correspond to in the original string. If an
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// offset cannot be successfully unadjusted (e.g., because it points into
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// the middle of a multibyte sequence), it will be set to string16::npos.
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static void UnadjustOffsets(const Adjustments& adjustments,
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std::vector<size_t>* offsets_for_unadjustment);
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// Adjusts the single |offset| to reflect the reverse of the adjustments
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// recorded in |adjustments|.
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static void UnadjustOffset(const Adjustments& adjustments,
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size_t* offset);
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// Combines two sequential sets of adjustments, storing the combined revised
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// adjustments in |adjustments_on_adjusted_string|. That is, suppose a
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// string was altered in some way, with the alterations recorded as
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// adjustments in |first_adjustments|. Then suppose the resulting string is
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// further altered, with the alterations recorded as adjustments scored in
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// |adjustments_on_adjusted_string|, with the offsets recorded in these
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// adjustments being with respect to the intermediate string. This function
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// combines the two sets of adjustments into one, storing the result in
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// |adjustments_on_adjusted_string|, whose offsets are correct with respect
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// to the original string.
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//
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// Assumes both parameters are sorted by increasing offset.
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//
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// WARNING: Only supports |first_adjustments| that involve collapsing ranges
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// of text, not expanding ranges.
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static void MergeSequentialAdjustments(
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const Adjustments& first_adjustments,
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Adjustments* adjustments_on_adjusted_string);
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};
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// Like the conversions in utf_string_conversions.h, but also fills in an
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// |adjustments| parameter that reflects the alterations done to the string.
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// It may be NULL.
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BASE_EXPORT bool UTF8ToUTF16WithAdjustments(
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const char* src,
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size_t src_len,
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string16* output,
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base::OffsetAdjuster::Adjustments* adjustments);
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BASE_EXPORT string16 UTF8ToUTF16WithAdjustments(
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const base::StringPiece& utf8,
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base::OffsetAdjuster::Adjustments* adjustments);
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// As above, but instead internally examines the adjustments and applies them
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// to |offsets_for_adjustment|. Input offsets greater than the length of the
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// input string will be set to string16::npos. See comments by AdjustOffsets().
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BASE_EXPORT string16 UTF8ToUTF16AndAdjustOffsets(
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const base::StringPiece& utf8,
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std::vector<size_t>* offsets_for_adjustment);
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BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffsets(
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const base::StringPiece16& utf16,
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std::vector<size_t>* offsets_for_adjustment);
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} // namespace base
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#endif // BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
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