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* Copyright (C) 2005 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <sys/types.h>
#include <stdint.h>
extern "C" {
// Standard string functions on char16_t strings.
int strcmp16(const char16_t *, const char16_t *);
int strncmp16(const char16_t *s1, const char16_t *s2, size_t n);
size_t strlen16(const char16_t *);
size_t strnlen16(const char16_t *, size_t);
char16_t *strcpy16(char16_t *, const char16_t *);
char16_t *strstr16(const char16_t*, const char16_t*);
// Version of comparison that supports embedded NULs.
// This is different than strncmp() because we don't stop
// at a nul character and consider the strings to be different
// if the lengths are different (thus we need to supply the
// lengths of both strings). This can also be used when
// your string is not nul-terminated as it will have the
// equivalent result as strcmp16 (unlike strncmp16).
int strzcmp16(const char16_t *s1, size_t n1, const char16_t *s2, size_t n2);
// Standard string functions on char32_t strings.
size_t strlen32(const char32_t *);
size_t strnlen32(const char32_t *, size_t);
* Measure the length of a UTF-32 string in UTF-8. If the string is invalid
* such as containing a surrogate character, -1 will be returned.
ssize_t utf32_to_utf8_length(const char32_t *src, size_t src_len);
* Stores a UTF-8 string converted from "src" in "dst", if "dst_length" is not
* large enough to store the string, the part of the "src" string is stored
* into "dst" as much as possible. See the examples for more detail.
* Returns the size actually used for storing the string.
* dst" is not nul-terminated when dst_len is fully used (like strncpy).
* \code
* Example 1
* "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
* "src_len" == 2
* "dst_len" >= 7
* ->
* Returned value == 6
* "dst" becomes \xE3\x81\x82\xE3\x81\x84\0
* (note that "dst" is nul-terminated)
* Example 2
* "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
* "src_len" == 2
* "dst_len" == 5
* ->
* Returned value == 3
* "dst" becomes \xE3\x81\x82\0
* (note that "dst" is nul-terminated, but \u3044 is not stored in "dst"
* since "dst" does not have enough size to store the character)
* Example 3
* "src" == \u3042\u3044 (\xE3\x81\x82\xE3\x81\x84)
* "src_len" == 2
* "dst_len" == 6
* ->
* Returned value == 6
* "dst" becomes \xE3\x81\x82\xE3\x81\x84
* (note that "dst" is NOT nul-terminated, like strncpy)
* \endcode
void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst, size_t dst_len);
* Returns the unicode value at "index".
* Returns -1 when the index is invalid (equals to or more than "src_len").
* If returned value is positive, it is able to be converted to char32_t, which
* is unsigned. Then, if "next_index" is not NULL, the next index to be used is
* stored in "next_index". "next_index" can be NULL.
int32_t utf32_from_utf8_at(const char *src, size_t src_len, size_t index, size_t *next_index);
* Returns the UTF-8 length of UTF-16 string "src".
ssize_t utf16_to_utf8_length(const char16_t *src, size_t src_len);
* Converts a UTF-16 string to UTF-8. The destination buffer must be large
* enough to fit the UTF-16 as measured by utf16_to_utf8_length with an added
* NUL terminator.
void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst, size_t dst_len);
* Returns the length of "src" when "src" is valid UTF-8 string.
* Returns 0 if src is NULL or 0-length string. Returns -1 when the source
* is an invalid string.
* This function should be used to determine whether "src" is valid UTF-8
* characters with valid unicode codepoints. "src" must be nul-terminated.
* If you are going to use other utf8_to_... functions defined in this header
* with string which may not be valid UTF-8 with valid codepoint (form 0 to
* 0x10FFFF), you should use this function before calling others, since the
* other functions do not check whether the string is valid UTF-8 or not.
* If you do not care whether "src" is valid UTF-8 or not, you should use
* strlen() as usual, which should be much faster.
ssize_t utf8_length(const char *src);
* Returns the UTF-16 length of UTF-8 string "src". Returns -1 in case
* it's invalid utf8. No buffer over-read occurs because of bound checks. Using overreadIsFatal you
* can ask to log a message and fail in case the invalid utf8 could have caused an override if no
* bound checks were used (otherwise -1 is returned).
ssize_t utf8_to_utf16_length(const uint8_t* src, size_t srcLen, bool overreadIsFatal = false);
* Convert UTF-8 to UTF-16 including surrogate pairs.
* Returns a pointer to the end of the string (where a NUL terminator might go
* if you wanted to add one). At most dstLen characters are written; it won't emit half a surrogate
* pair. If dstLen == 0 nothing is written and dst is returned. If dstLen > SSIZE_MAX it aborts
* (this being probably a negative number returned as an error and casted to unsigned).
char16_t* utf8_to_utf16_no_null_terminator(
const uint8_t* src, size_t srcLen, char16_t* dst, size_t dstLen);
* Convert UTF-8 to UTF-16 including surrogate pairs. At most dstLen - 1
* characters are written; it won't emit half a surrogate pair; and a NUL terminator is appended
* after. dstLen - 1 can be measured beforehand using utf8_to_utf16_length. Aborts if dstLen == 0
* (at least one character is needed for the NUL terminator) or dstLen > SSIZE_MAX (the latter
* case being likely a negative number returned as an error and casted to unsigned) . Returns a
* pointer to the NUL terminator.
char16_t *utf8_to_utf16(
const uint8_t* src, size_t srcLen, char16_t* dst, size_t dstLen);