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1 /*
2  * Copyright (C) 2005 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_UNICODE_H
18 #define ANDROID_UNICODE_H
19 
20 #include <sys/types.h>
21 #include <stdint.h>
22 
23 extern "C" {
24 
25 // Standard string functions on char16_t strings.
26 int strcmp16(const char16_t *, const char16_t *);
27 int strncmp16(const char16_t *s1, const char16_t *s2, size_t n);
28 size_t strlen16(const char16_t *);
29 size_t strnlen16(const char16_t *, size_t);
30 char16_t *strcpy16(char16_t *, const char16_t *);
31 char16_t *strncpy16(char16_t *, const char16_t *, size_t);
32 
33 // Version of comparison that supports embedded nulls.
34 // This is different than strncmp() because we don't stop
35 // at a nul character and consider the strings to be different
36 // if the lengths are different (thus we need to supply the
37 // lengths of both strings).  This can also be used when
38 // your string is not nul-terminated as it will have the
39 // equivalent result as strcmp16 (unlike strncmp16).
40 int strzcmp16(const char16_t *s1, size_t n1, const char16_t *s2, size_t n2);
41 
42 // Version of strzcmp16 for comparing strings in different endianness.
43 int strzcmp16_h_n(const char16_t *s1H, size_t n1, const char16_t *s2N, size_t n2);
44 
45 // Standard string functions on char32_t strings.
46 size_t strlen32(const char32_t *);
47 size_t strnlen32(const char32_t *, size_t);
48 
49 /**
50  * Measure the length of a UTF-32 string in UTF-8. If the string is invalid
51  * such as containing a surrogate character, -1 will be returned.
52  */
53 ssize_t utf32_to_utf8_length(const char32_t *src, size_t src_len);
54 
55 /**
56  * Stores a UTF-8 string converted from "src" in "dst", if "dst_length" is not
57  * large enough to store the string, the part of the "src" string is stored
58  * into "dst" as much as possible. See the examples for more detail.
59  * Returns the size actually used for storing the string.
60  * dst" is not null-terminated when dst_len is fully used (like strncpy).
61  *
62  * Example 1
63  * "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
64  * "src_len" == 2
65  * "dst_len" >= 7
66  * ->
67  * Returned value == 6
68  * "dst" becomes \xE3\x81\x82\xE3\x81\x84\0
69  * (note that "dst" is null-terminated)
70  *
71  * Example 2
72  * "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
73  * "src_len" == 2
74  * "dst_len" == 5
75  * ->
76  * Returned value == 3
77  * "dst" becomes \xE3\x81\x82\0
78  * (note that "dst" is null-terminated, but \u3044 is not stored in "dst"
79  * since "dst" does not have enough size to store the character)
80  *
81  * Example 3
82  * "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
83  * "src_len" == 2
84  * "dst_len" == 6
85  * ->
86  * Returned value == 6
87  * "dst" becomes \xE3\x81\x82\xE3\x81\x84
88  * (note that "dst" is NOT null-terminated, like strncpy)
89  */
90 void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst, size_t dst_len);
91 
92 /**
93  * Returns the unicode value at "index".
94  * Returns -1 when the index is invalid (equals to or more than "src_len").
95  * If returned value is positive, it is able to be converted to char32_t, which
96  * is unsigned. Then, if "next_index" is not NULL, the next index to be used is
97  * stored in "next_index". "next_index" can be NULL.
98  */
99 int32_t utf32_from_utf8_at(const char *src, size_t src_len, size_t index, size_t *next_index);
100 
101 
102 /**
103  * Returns the UTF-8 length of UTF-16 string "src".
104  */
105 ssize_t utf16_to_utf8_length(const char16_t *src, size_t src_len);
106 
107 /**
108  * Converts a UTF-16 string to UTF-8. The destination buffer must be large
109  * enough to fit the UTF-16 as measured by utf16_to_utf8_length with an added
110  * NULL terminator.
111  */
112 void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst, size_t dst_len);
113 
114 /**
115  * Returns the length of "src" when "src" is valid UTF-8 string.
116  * Returns 0 if src is NULL or 0-length string. Returns -1 when the source
117  * is an invalid string.
118  *
119  * This function should be used to determine whether "src" is valid UTF-8
120  * characters with valid unicode codepoints. "src" must be null-terminated.
121  *
122  * If you are going to use other utf8_to_... functions defined in this header
123  * with string which may not be valid UTF-8 with valid codepoint (form 0 to
124  * 0x10FFFF), you should use this function before calling others, since the
125  * other functions do not check whether the string is valid UTF-8 or not.
126  *
127  * If you do not care whether "src" is valid UTF-8 or not, you should use
128  * strlen() as usual, which should be much faster.
129  */
130 ssize_t utf8_length(const char *src);
131 
132 /**
133  * Measure the length of a UTF-32 string.
134  */
135 size_t utf8_to_utf32_length(const char *src, size_t src_len);
136 
137 /**
138  * Stores a UTF-32 string converted from "src" in "dst". "dst" must be large
139  * enough to store the entire converted string as measured by
140  * utf8_to_utf32_length plus space for a NULL terminator.
141  */
142 void utf8_to_utf32(const char* src, size_t src_len, char32_t* dst);
143 
144 /**
145  * Returns the UTF-16 length of UTF-8 string "src".
146  */
147 ssize_t utf8_to_utf16_length(const uint8_t* src, size_t srcLen);
148 
149 /**
150  * Convert UTF-8 to UTF-16 including surrogate pairs.
151  * Returns a pointer to the end of the string (where a null terminator might go
152  * if you wanted to add one).
153  */
154 char16_t* utf8_to_utf16_no_null_terminator(const uint8_t* src, size_t srcLen, char16_t* dst);
155 
156 /**
157  * Convert UTF-8 to UTF-16 including surrogate pairs. The destination buffer
158  * must be large enough to hold the result as measured by utf8_to_utf16_length
159  * plus an added NULL terminator.
160  */
161 void utf8_to_utf16(const uint8_t* src, size_t srcLen, char16_t* dst);
162 
163 /**
164  * Like utf8_to_utf16_no_null_terminator, but you can supply a maximum length of the
165  * decoded string.  The decoded string will fill up to that length; if it is longer
166  * the returned pointer will be to the character after dstLen.
167  */
168 char16_t* utf8_to_utf16_n(const uint8_t* src, size_t srcLen, char16_t* dst, size_t dstLen);
169 
170 }
171 
172 #endif
173