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