blob: d1e51b9caa3777ec52bda11c121cc1301f106721 [file] [log] [blame]
/* libs/cutils/strdup8to16.c
**
** Copyright 2006, 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
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include <cutils/jstring.h>
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
/* See http://www.unicode.org/reports/tr22/ for discussion
* on invalid sequences
*/
#define UTF16_REPLACEMENT_CHAR 0xfffd
/* Clever trick from Dianne that returns 1-4 depending on leading bit sequence*/
#define UTF8_SEQ_LENGTH(ch) (((0xe5000000 >> (((ch) >> 3) & 0x1e)) & 3) + 1)
/* note: macro expands to multiple lines */
#define UTF8_SHIFT_AND_MASK(unicode, byte) \
(unicode)<<=6; (unicode) |= (0x3f & (byte));
#define UNICODE_UPPER_LIMIT 0x10fffd
/**
* out_len is an out parameter (which may not be null) containing the
* length of the UTF-16 string (which may contain embedded \0's)
*/
extern char16_t * strdup8to16 (const char* s, size_t *out_len)
{
char16_t *ret;
size_t len;
if (s == NULL) return NULL;
len = strlen8to16(s);
// fail on overflow
if (len && SIZE_MAX/len < sizeof(char16_t))
return NULL;
// no plus-one here. UTF-16 strings are not null terminated
ret = (char16_t *) malloc (sizeof(char16_t) * len);
return strcpy8to16 (ret, s, out_len);
}
/**
* Like "strlen", but for strings encoded with Java's modified UTF-8.
*
* The value returned is the number of UTF-16 characters required
* to represent this string.
*/
extern size_t strlen8to16 (const char* utf8Str)
{
size_t len = 0;
int ic;
int expected = 0;
while ((ic = *utf8Str++) != '\0') {
/* bytes that start 0? or 11 are lead bytes and count as characters.*/
/* bytes that start 10 are extention bytes and are not counted */
if ((ic & 0xc0) == 0x80) {
/* count the 0x80 extention bytes. if we have more than
* expected, then start counting them because strcpy8to16
* will insert UTF16_REPLACEMENT_CHAR's
*/
expected--;
if (expected < 0) {
len++;
}
} else {
len++;
expected = UTF8_SEQ_LENGTH(ic) - 1;
/* this will result in a surrogate pair */
if (expected == 3) {
len++;
}
}
}
return len;
}
/*
* Retrieve the next UTF-32 character from a UTF-8 string.
*
* Stops at inner \0's
*
* Returns UTF16_REPLACEMENT_CHAR if an invalid sequence is encountered
*
* Advances "*pUtf8Ptr" to the start of the next character.
*/
static inline uint32_t getUtf32FromUtf8(const char** pUtf8Ptr)
{
uint32_t ret;
int seq_len;
int i;
/* Mask for leader byte for lengths 1, 2, 3, and 4 respectively*/
static const unsigned char leaderMask[4] = {0xff, 0x1f, 0x0f, 0x07};
/* Bytes that start with bits "10" are not leading characters. */
if (((**pUtf8Ptr) & 0xc0) == 0x80) {
(*pUtf8Ptr)++;
return UTF16_REPLACEMENT_CHAR;
}
/* note we tolerate invalid leader 11111xxx here */
seq_len = UTF8_SEQ_LENGTH(**pUtf8Ptr);
ret = (**pUtf8Ptr) & leaderMask [seq_len - 1];
if (**pUtf8Ptr == '\0') return ret;
(*pUtf8Ptr)++;
for (i = 1; i < seq_len ; i++, (*pUtf8Ptr)++) {
if ((**pUtf8Ptr) == '\0') return UTF16_REPLACEMENT_CHAR;
if (((**pUtf8Ptr) & 0xc0) != 0x80) return UTF16_REPLACEMENT_CHAR;
UTF8_SHIFT_AND_MASK(ret, **pUtf8Ptr);
}
return ret;
}
/**
* out_len is an out parameter (which may not be null) containing the
* length of the UTF-16 string (which may contain embedded \0's)
*/
extern char16_t * strcpy8to16 (char16_t *utf16Str, const char*utf8Str,
size_t *out_len)
{
char16_t *dest = utf16Str;
while (*utf8Str != '\0') {
uint32_t ret;
ret = getUtf32FromUtf8(&utf8Str);
if (ret <= 0xffff) {
*dest++ = (char16_t) ret;
} else if (ret <= UNICODE_UPPER_LIMIT) {
/* Create surrogate pairs */
/* See http://en.wikipedia.org/wiki/UTF-16/UCS-2#Method_for_code_points_in_Plane_1.2C_Plane_2 */
*dest++ = 0xd800 | ((ret - 0x10000) >> 10);
*dest++ = 0xdc00 | ((ret - 0x10000) & 0x3ff);
} else {
*dest++ = UTF16_REPLACEMENT_CHAR;
}
}
*out_len = dest - utf16Str;
return utf16Str;
}
/**
* length is the number of characters in the UTF-8 string.
* out_len is an out parameter (which may not be null) containing the
* length of the UTF-16 string (which may contain embedded \0's)
*/
extern char16_t * strcpylen8to16 (char16_t *utf16Str, const char*utf8Str,
int length, size_t *out_len)
{
/* TODO: Share more of this code with the method above. Only 2 lines changed. */
char16_t *dest = utf16Str;
const char *end = utf8Str + length; /* This line */
while (utf8Str < end) { /* and this line changed. */
uint32_t ret;
ret = getUtf32FromUtf8(&utf8Str);
if (ret <= 0xffff) {
*dest++ = (char16_t) ret;
} else if (ret <= UNICODE_UPPER_LIMIT) {
/* Create surrogate pairs */
/* See http://en.wikipedia.org/wiki/UTF-16/UCS-2#Method_for_code_points_in_Plane_1.2C_Plane_2 */
*dest++ = 0xd800 | ((ret - 0x10000) >> 10);
*dest++ = 0xdc00 | ((ret - 0x10000) & 0x3ff);
} else {
*dest++ = UTF16_REPLACEMENT_CHAR;
}
}
*out_len = dest - utf16Str;
return utf16Str;
}