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* Add handling of surrogate pairs

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git-svn-id: http://svn.metaparadigm.com/svn/json-c/trunk@53 327403b1-1117-474d-bef2-5cb71233fd97
This commit is contained in:
Brent Miller
2009-08-20 06:50:22 +00:00
parent f8663fc16f
commit 126ad95fc4
4 changed files with 133 additions and 20 deletions
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102
json_tokener.c
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@@ -58,6 +58,12 @@ const char* json_tokener_errors[] = {
"expected comment",
};
/* Stuff for decoding unicode sequences */
#define IS_HIGH_SURROGATE(uc) (((uc) & 0xFC00) == 0xD800)
#define IS_LOW_SURROGATE(uc) (((uc) & 0xFC00) == 0xDC00)
#define DECODE_SURROGATE_PAIR(hi,lo) ((((hi) & 0x3FF) << 10) + ((lo) & 0x3FF) + 0x10000)
static unsigned char utf8_replacement_char[3] = { 0xEF, 0xBF, 0xBD };
struct json_tokener* json_tokener_new(void)
{
@@ -176,6 +182,7 @@ char* strndup(const char* str, size_t n)
#define ADVANCE_CHAR(str, tok) \
( ++(str), ((tok)->char_offset)++, c)
/* End optimization macro defs */
@@ -398,40 +405,97 @@ struct json_object* json_tokener_parse_ex(struct json_tokener *tok,
break;
case json_tokener_state_escape_unicode:
/* Note that the following code is inefficient for handling large
* chunks of extended chars, calling printbuf_memappend() once
* for each multi-byte character of input.
* This is a good area for future optimization.
*/
{
/* Advance until we change state */
unsigned int got_hi_surrogate = 0;
/* Handle a 4-byte sequence, or two sequences if a surrogate pair */
while(1) {
if(strchr(json_hex_chars, c)) {
tok->ucs_char += ((unsigned int)hexdigit(c) << ((3-tok->st_pos++)*4));
if(tok->st_pos == 4) {
unsigned char utf_out[3];
unsigned char unescaped_utf[4];
if (got_hi_surrogate) {
if (IS_LOW_SURROGATE(tok->ucs_char)) {
/* Recalculate the ucs_char, then fall thru to process normally */
tok->ucs_char = DECODE_SURROGATE_PAIR(got_hi_surrogate, tok->ucs_char);
} else {
/* Hi surrogate was not followed by a low surrogate */
/* Replace the hi and process the rest normally */
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
}
got_hi_surrogate = 0;
}
if (tok->ucs_char < 0x80) {
utf_out[0] = tok->ucs_char;
printbuf_memappend_fast(tok->pb, (char*)utf_out, 1);
unescaped_utf[0] = tok->ucs_char;
printbuf_memappend_fast(tok->pb, (char*)unescaped_utf, 1);
} else if (tok->ucs_char < 0x800) {
utf_out[0] = 0xc0 | (tok->ucs_char >> 6);
utf_out[1] = 0x80 | (tok->ucs_char & 0x3f);
printbuf_memappend_fast(tok->pb, (char*)utf_out, 2);
unescaped_utf[0] = 0xc0 | (tok->ucs_char >> 6);
unescaped_utf[1] = 0x80 | (tok->ucs_char & 0x3f);
printbuf_memappend_fast(tok->pb, (char*)unescaped_utf, 2);
} else if (IS_HIGH_SURROGATE(tok->ucs_char)) {
/* Got a high surrogate. Remember it and look for the
* the beginning of another sequence, which should be the
* low surrogate.
*/
got_hi_surrogate = tok->ucs_char;
/* Not at end, and the next two chars should be "\u" */
if ((tok->char_offset+1 != len) &&
(tok->char_offset+2 != len) &&
(str[1] == '\\') &&
(str[2] == 'u'))
{
ADVANCE_CHAR(str, tok);
ADVANCE_CHAR(str, tok);
/* Advance to the first char of the next sequence and
* continue processing with the next sequence.
*/
if (!ADVANCE_CHAR(str, tok) || !POP_CHAR(c, tok)) {
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
goto out;
}
tok->ucs_char = 0;
tok->st_pos = 0;
continue; /* other json_tokener_state_escape_unicode */
} else {
/* Got a high surrogate without another sequence following
* it. Put a replacement char in for the hi surrogate
* and pretend we finished.
*/
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
}
} else if (IS_LOW_SURROGATE(tok->ucs_char)) {
/* Got a low surrogate not preceded by a high */
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
} else if (tok->ucs_char < 0x10000) {
unescaped_utf[0] = 0xe0 | (tok->ucs_char >> 12);
unescaped_utf[1] = 0x80 | ((tok->ucs_char >> 6) & 0x3f);
unescaped_utf[2] = 0x80 | (tok->ucs_char & 0x3f);
printbuf_memappend_fast(tok->pb, (char*)unescaped_utf, 3);
} else if (tok->ucs_char < 0x110000) {
unescaped_utf[0] = 0xf0 | ((tok->ucs_char >> 18) & 0x07);
unescaped_utf[1] = 0x80 | ((tok->ucs_char >> 12) & 0x3f);
unescaped_utf[2] = 0x80 | ((tok->ucs_char >> 6) & 0x3f);
unescaped_utf[3] = 0x80 | (tok->ucs_char & 0x3f);
printbuf_memappend_fast(tok->pb, (char*)unescaped_utf, 4);
} else {
utf_out[0] = 0xe0 | (tok->ucs_char >> 12);
utf_out[1] = 0x80 | ((tok->ucs_char >> 6) & 0x3f);
utf_out[2] = 0x80 | (tok->ucs_char & 0x3f);
printbuf_memappend_fast(tok->pb, (char*)utf_out, 3);
}
/* Don't know what we got--insert the replacement char */
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
}
state = saved_state;
break;
}
} else {
tok->err = json_tokener_error_parse_string;
goto out;
}
if (!ADVANCE_CHAR(str, tok) || !POP_CHAR(c, tok))
}
if (!ADVANCE_CHAR(str, tok) || !POP_CHAR(c, tok)) {
if (got_hi_surrogate) /* Clean up any pending chars */
printbuf_memappend_fast(tok->pb, (char*)utf8_replacement_char, 3);
goto out;
}
}
}
break;