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Diffstat (limited to 'libcutils/strdup16to8.c')
-rw-r--r--libcutils/strdup16to8.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/libcutils/strdup16to8.c b/libcutils/strdup16to8.c
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1/* libs/cutils/strdup16to8.c
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9** http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include <cutils/jstring.h>
19#include <assert.h>
20#include <stdlib.h>
21
22
23/**
24 * Given a UTF-16 string, compute the length of the corresponding UTF-8
25 * string in bytes.
26 */
27extern size_t strnlen16to8(const char16_t* utf16Str, size_t len)
28{
29 size_t utf8Len = 0;
30
31 while (len--) {
32 unsigned int uic = *utf16Str++;
33
34 if (uic > 0x07ff)
35 utf8Len += 3;
36 else if (uic > 0x7f || uic == 0)
37 utf8Len += 2;
38 else
39 utf8Len++;
40 }
41 return utf8Len;
42}
43
44
45/**
46 * Convert a Java-Style UTF-16 string + length to a JNI-Style UTF-8 string.
47 *
48 * This basically means: embedded \0's in the UTF-16 string are encoded
49 * as "0xc0 0x80"
50 *
51 * Make sure you allocate "utf8Str" with the result of strlen16to8() + 1,
52 * not just "len".
53 *
54 * Please note, a terminated \0 is always added, so your result will always
55 * be "strlen16to8() + 1" bytes long.
56 */
57extern char* strncpy16to8(char* utf8Str, const char16_t* utf16Str, size_t len)
58{
59 char* utf8cur = utf8Str;
60
61 while (len--) {
62 unsigned int uic = *utf16Str++;
63
64 if (uic > 0x07ff) {
65 *utf8cur++ = (uic >> 12) | 0xe0;
66 *utf8cur++ = ((uic >> 6) & 0x3f) | 0x80;
67 *utf8cur++ = (uic & 0x3f) | 0x80;
68 } else if (uic > 0x7f || uic == 0) {
69 *utf8cur++ = (uic >> 6) | 0xc0;
70 *utf8cur++ = (uic & 0x3f) | 0x80;
71 } else {
72 *utf8cur++ = uic;
73
74 if (uic == 0) {
75 break;
76 }
77 }
78 }
79
80 *utf8cur = '\0';
81
82 return utf8Str;
83}
84
85/**
86 * Convert a UTF-16 string to UTF-8.
87 *
88 * Make sure you allocate "dest" with the result of strblen16to8(),
89 * not just "strlen16()".
90 */
91char * strndup16to8 (const char16_t* s, size_t n)
92{
93 char *ret;
94
95 if (s == NULL) {
96 return NULL;
97 }
98
99 ret = malloc(strnlen16to8(s, n) + 1);
100
101 strncpy16to8 (ret, s, n);
102
103 return ret;
104}