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 #include "base/i18n/case_conversion.h"
6
7 #include <stdint.h>
8
9 #include "base/numerics/safe_conversions.h"
10 #include "base/strings/string16.h"
11 #include "base/strings/string_util.h"
12 #include "third_party/icu/source/common/unicode/uchar.h"
13 #include "third_party/icu/source/common/unicode/unistr.h"
14 #include "third_party/icu/source/common/unicode/ustring.h"
15
16 namespace base {
17 namespace i18n {
18
19 namespace {
20
21 // Provides a uniform interface for upper/lower/folding which take take
22 // slightly varying parameters.
23 typedef int32_t (*CaseMapperFunction)(UChar* dest, int32_t dest_capacity,
24 const UChar* src, int32_t src_length,
25 UErrorCode* error);
26
ToUpperMapper(UChar * dest,int32_t dest_capacity,const UChar * src,int32_t src_length,UErrorCode * error)27 int32_t ToUpperMapper(UChar* dest, int32_t dest_capacity,
28 const UChar* src, int32_t src_length,
29 UErrorCode* error) {
30 // Use default locale.
31 return u_strToUpper(dest, dest_capacity, src, src_length, nullptr, error);
32 }
33
ToLowerMapper(UChar * dest,int32_t dest_capacity,const UChar * src,int32_t src_length,UErrorCode * error)34 int32_t ToLowerMapper(UChar* dest, int32_t dest_capacity,
35 const UChar* src, int32_t src_length,
36 UErrorCode* error) {
37 // Use default locale.
38 return u_strToLower(dest, dest_capacity, src, src_length, nullptr, error);
39 }
40
FoldCaseMapper(UChar * dest,int32_t dest_capacity,const UChar * src,int32_t src_length,UErrorCode * error)41 int32_t FoldCaseMapper(UChar* dest, int32_t dest_capacity,
42 const UChar* src, int32_t src_length,
43 UErrorCode* error) {
44 return u_strFoldCase(dest, dest_capacity, src, src_length,
45 U_FOLD_CASE_DEFAULT, error);
46 }
47
48 // Provides similar functionality as UnicodeString::caseMap but on string16.
CaseMap(StringPiece16 string,CaseMapperFunction case_mapper)49 string16 CaseMap(StringPiece16 string, CaseMapperFunction case_mapper) {
50 string16 dest;
51 if (string.empty())
52 return dest;
53
54 // Provide an initial guess that the string length won't change. The typical
55 // strings we use will very rarely change length in this process, so don't
56 // optimize for that case.
57 dest.resize(string.size());
58
59 UErrorCode error;
60 do {
61 error = U_ZERO_ERROR;
62
63 // ICU won't terminate the string if there's not enough room for the null
64 // terminator, but will otherwise. So we don't need to save room for that.
65 // Don't use WriteInto, which assumes null terminators.
66 int32_t new_length = case_mapper(
67 &dest[0], saturated_cast<int32_t>(dest.size()),
68 string.data(), saturated_cast<int32_t>(string.size()),
69 &error);
70 dest.resize(new_length);
71 } while (error == U_BUFFER_OVERFLOW_ERROR);
72 return dest;
73 }
74
75 } // namespace
76
ToLower(StringPiece16 string)77 string16 ToLower(StringPiece16 string) {
78 return CaseMap(string, &ToLowerMapper);
79 }
80
ToUpper(StringPiece16 string)81 string16 ToUpper(StringPiece16 string) {
82 return CaseMap(string, &ToUpperMapper);
83 }
84
FoldCase(StringPiece16 string)85 string16 FoldCase(StringPiece16 string) {
86 return CaseMap(string, &FoldCaseMapper);
87 }
88
89 } // namespace i18n
90 } // namespace base
91