+static int do_unescape(const char*s, const char*end, char*n)
+{
+ char*o = n;
+ int len=0;
+ while(s<end) {
+ if(*s!='\\') {
+ if(o) o[len] = *s;len++;
+ s++;
+ continue;
+ }
+ s++; //skip past '\'
+ if(s==end) syntaxerror("invalid \\ at end of string");
+
+ /* handle the various line endings (mac, dos, unix) */
+ if(*s=='\r') {
+ s++;
+ if(s==end) break;
+ if(*s=='\n')
+ s++;
+ continue;
+ }
+ if(*s=='\n') {
+ s++;
+ continue;
+ }
+ switch(*s) {
+ case '\\': if(o) o[len] = '\\';s++;len++; break;
+ case '"': if(o) o[len] = '"';s++;len++; break;
+ case 'b': if(o) o[len] = '\b';s++;len++; break;
+ case 'f': if(o) o[len] = '\f';s++;len++; break;
+ case 'n': if(o) o[len] = '\n';s++;len++; break;
+ case 'r': if(o) o[len] = '\r';s++;len++; break;
+ case 't': if(o) o[len] = '\t';s++;len++; break;
+ case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': {
+ unsigned int num=0;
+ int nr = 0;
+ while(strchr("01234567", *s) && nr<3 && s<end) {
+ num <<= 3;
+ num |= *s-'0';
+ nr++;
+ s++;
+ }
+ if(num>256)
+ syntaxerror("octal number out of range (0-255): %d", num);
+ if(o) o[len] = num;len++;
+ continue;
+ }
+ case 'x': case 'u': {
+ int max=2;
+ char bracket = 0;
+ char unicode = 0;
+ if(*s == 'u') {
+ max = 6;
+ unicode = 1;
+ }
+ s++;
+ if(s==end) syntaxerror("invalid \\u or \\x at end of string");
+ if(*s == '{') {
+ s++;
+ if(s==end) syntaxerror("invalid \\u{ at end of string");
+ bracket=1;
+ }
+ unsigned int num=0;
+ int nr = 0;
+ while(strchr("0123456789abcdefABCDEF", *s) && (bracket || nr < max) && s<end) {
+ num <<= 4;
+ if(*s>='0' && *s<='9') num |= *s - '0';
+ if(*s>='a' && *s<='f') num |= *s - 'a' + 10;
+ if(*s>='A' && *s<='F') num |= *s - 'A' + 10;
+ nr++;
+ s++;
+ }
+ if(bracket) {
+ if(*s=='}' && s<end) {
+ s++;
+ } else {
+ syntaxerror("missing terminating '}'");
+ }
+ }
+ if(unicode) {
+ char*utf8 = getUTF8(num);
+ while(*utf8) {
+ if(o) o[len] = *utf8;utf8++;len++;
+ }
+ } else {
+ if(num>256)
+ syntaxerror("byte out of range (0-255): %d", num);
+ if(o) o[len] = num;len++;
+ }
+ break;
+ }
+ default:
+ syntaxerror("unknown escape sequence: \"\\%c\"", *s);
+ }
+ }
+ if(o) o[len]=0;
+ return len;
+}
+
+static string_t string_unescape(const char*in, int l)
+{
+ const char*s = in;
+ const char*end = &in[l];
+
+ int len = do_unescape(s, end, 0);
+ char*n = (char*)malloc(len+1);
+ do_unescape(s, end, n);
+ string_t out = string_new(n, len);
+ return out;
+}
+