Function parse__escape

extern/editline/src/parse.c:138–233

parse__escape(): * Parse a string of the form ^ \ \ \U+xxxx and return * the appropriate character or -1 if the escape is not valid */

 *	the appropriate character or -1 if the escape is not valid
 */
protected int
parse__escape(const Char **ptr)
{
	const Char *p;
	Int c;

	p = *ptr;

	if (p[1] == 0)
		return -1;

	if (*p == '\\') {
		p++;
		switch (*p) {
		case 'a':
			c = '\007';	/* Bell */
			break;
		case 'b':
			c = '\010';	/* Backspace */
			break;
		case 't':
			c = '\011';	/* Horizontal Tab */
			break;
		case 'n':
			c = '\012';	/* New Line */
			break;
		case 'v':
			c = '\013';	/* Vertical Tab */
			break;
		case 'f':
			c = '\014';	/* Form Feed */
			break;
		case 'r':
			c = '\015';	/* Carriage Return */
			break;
		case 'e':
			c = '\033';	/* Escape */
			break;
                case 'U':               /* Unicode \U+xxxx or \U+xxxxx format */
                {
                        int i;
                        const Char hex[] = STR("0123456789ABCDEF");
                        const Char *h;
                        ++p;
                        if (*p++ != '+')
                                return -1;
			c = 0;
                        for (i = 0; i < 5; ++i) {
                                h = Strchr(hex, *p++);
                                if (!h && i < 4)
                                        return -1;
                                else if (h)
                                        c = (c << 4) | ((int)(h - hex));
                                else
                                        --p;
                        }
                        if (c > 0x10FFFF) /* outside valid character range */
                                return -1;