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reformatting: parse_string

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This commit is contained in:
Max Bruckner 2016-09-28 01:34:47 +07:00
parent 2e2dc873b2
commit c88d045888
1 changed files with 165 additions and 66 deletions
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231
cJSON.c
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@ -443,76 +443,175 @@ static const unsigned char firstByteMark[7] =
};
/* Parse the input text into an unescaped cstring, and populate item. */
static const char *parse_string(cJSON *item,const char *str,const char **ep)
static const char *parse_string(cJSON *item, const char *str, const char **ep)
{
const char *ptr=str+1,*end_ptr=str+1;char *ptr2;char *out;int len=0;unsigned uc,uc2;
if (*str!='\"') {*ep=str;return 0;} /* not a string! */
const char *ptr = str + 1;
const char *end_ptr =str + 1;
char *ptr2;
char *out;
int len = 0;
unsigned uc;
unsigned uc2;
while (*end_ptr!='\"' && *end_ptr && ++len)
{
if (*end_ptr++ == '\\')
{
if (*end_ptr == '\0')
{
/* prevent buffer overflow when last input character is a backslash */
return 0;
}
end_ptr++; /* Skip escaped quotes. */
}
}
/* not a string! */
if (*str != '\"')
{
*ep = str;
return 0;
}
out=(char*)cJSON_malloc(len+1); /* This is how long we need for the string, roughly. */
if (!out) return 0;
item->valuestring=out; /* assign here so out will be deleted during cJSON_Delete() later */
item->type=cJSON_String;
ptr=str+1;ptr2=out;
while (ptr < end_ptr)
{
if (*ptr!='\\') *ptr2++=*ptr++;
else
{
ptr++;
switch (*ptr)
{
case 'b': *ptr2++='\b'; break;
case 'f': *ptr2++='\f'; break;
case 'n': *ptr2++='\n'; break;
case 'r': *ptr2++='\r'; break;
case 't': *ptr2++='\t'; break;
case 'u': /* transcode utf16 to utf8. */
uc=parse_hex4(ptr+1);ptr+=4; /* get the unicode char. */
if (ptr >= end_ptr) {*ep=str;return 0;} /* invalid */
if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0) {*ep=str;return 0;} /* check for invalid. */
if (uc>=0xD800 && uc<=0xDBFF) /* UTF16 surrogate pairs. */
{
if (ptr+6 > end_ptr) {*ep=str;return 0;} /* invalid */
if (ptr[1]!='\\' || ptr[2]!='u') {*ep=str;return 0;} /* missing second-half of surrogate. */
uc2=parse_hex4(ptr+3);ptr+=6;
if (uc2<0xDC00 || uc2>0xDFFF) {*ep=str;return 0;} /* invalid second-half of surrogate. */
uc=0x10000 + (((uc&0x3FF)<<10) | (uc2&0x3FF));
}
while ((*end_ptr != '\"') && *end_ptr && ++len)
{
if (*end_ptr++ == '\\')
{
if (*end_ptr == '\0')
{
/* prevent buffer overflow when last input character is a backslash */
return 0;
}
/* Skip escaped quotes. */
end_ptr++;
}
}
len=4;if (uc<0x80) len=1;else if (uc<0x800) len=2;else if (uc<0x10000) len=3; ptr2+=len;
switch (len) {
case 4: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
case 3: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
case 2: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
case 1: *--ptr2 =(uc | firstByteMark[len]);
}
ptr2+=len;
break;
default: *ptr2++=*ptr; break;
}
ptr++;
}
}
*ptr2=0;
if (*ptr=='\"') ptr++;
return ptr;
/* This is at most how long we need for the string, roughly. */
out = (char*)cJSON_malloc(len + 1);
if (!out)
{
return 0;
}
item->valuestring = out; /* assign here so out will be deleted during cJSON_Delete() later */
item->type = cJSON_String;
ptr = str + 1;
ptr2 = out;
/* loop through the string literal */
while (ptr < end_ptr)
{
if (*ptr != '\\')
{
*ptr2++ = *ptr++;
}
/* escape sequence */
else
{
ptr++;
switch (*ptr)
{
case 'b':
*ptr2++ = '\b';
break;
case 'f':
*ptr2++ = '\f';
break;
case 'n':
*ptr2++ = '\n';
break;
case 'r':
*ptr2++ = '\r';
break;
case 't':
*ptr2++ = '\t';
break;
case 'u':
/* transcode utf16 to utf8. See RFC2781 and RFC3629. */
uc = parse_hex4(ptr + 1); /* get the unicode char. */
ptr += 4;
if (ptr >= end_ptr)
{
/* invalid */
*ep = str;
return 0;
}
/* check for invalid. */
if (((uc >= 0xDC00) && (uc <= 0xDFFF)) || (uc == 0))
{
*ep = str;
return 0;
}
/* UTF16 surrogate pairs. */
if ((uc >= 0xD800) && (uc<=0xDBFF))
{
if ((ptr + 6) > end_ptr)
{
/* invalid */
*ep = str;
return 0;
}
if ((ptr[1] != '\\') || (ptr[2] != 'u'))
{
/* missing second-half of surrogate. */
*ep = str;
return 0;
}
uc2 = parse_hex4(ptr + 3);
ptr += 6; /* \uXXXX */
if ((uc2 < 0xDC00) || (uc2 > 0xDFFF))
{
/* invalid second-half of surrogate. */
*ep = str;
return 0;
}
/* calculate unicode codepoint from the surrogate pair */
uc = 0x10000 + (((uc & 0x3FF) << 10) | (uc2 & 0x3FF));
}
/* encode as UTF8
* takes at maximum 4 bytes to encode:
* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
len = 4;
if (uc < 0x80)
{
/* normal ascii, encoding 0xxxxxxx */
len = 1;
}
else if (uc < 0x800)
{
/* two bytes, encoding 110xxxxx 10xxxxxx */
len = 2;
}
else if (uc < 0x10000)
{
/* three bytes, encoding 1110xxxx 10xxxxxx 10xxxxxx */
len = 3;
}
ptr2 += len;
switch (len) {
case 4:
/* 10xxxxxx */
*--ptr2 = ((uc | 0x80) & 0xBF);
uc >>= 6;
case 3:
/* 10xxxxxx */
*--ptr2 = ((uc | 0x80) & 0xBF);
uc >>= 6;
case 2:
/* 10xxxxxx */
*--ptr2 = ((uc | 0x80) & 0xBF);
uc >>= 6;
case 1:
/* depending on the length in bytes this determines the
* encoding ofthe first UTF8 byte */
*--ptr2 = (uc | firstByteMark[len]);
}
ptr2 += len;
break;
default:
*ptr2++ = *ptr;
break;
}
ptr++;
}
}
*ptr2 = '\0';
if (*ptr == '\"')
{
ptr++;
}
return ptr;
}
/* Render the cstring provided to an escaped version that can be printed. */