/*
 * Copyright 2004-2008, François Revol, <revol@free.fr>.
 * Distributed under the terms of the MIT License.
 */

#include <ctype.h>
#include <malloc.h>
#include <string.h>
#include "string_utils.h"

//#define TESTME

#ifdef _KERNEL_MODE
#define printf dprintf
#undef TESTME
#endif



char *urlify_string(const char *str)
{
        char *dst, *d;
        const char *p;
        const char *allowed = "abcdefghijklmnopqrstuvwxyz" \
                                                  "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
                                                  "0123456789" \
                                                  "-_.!~*'()"; /* cf. RFC 2396 */
        const char *hex = "0123456789ABCDEF";
        if (!str)
                return NULL;
        // hacky, but safe
        dst = malloc(strlen(str)*3);
        if (!dst)
                return NULL;
        for (p = str, d = dst; *p; p++) {
                if (strchr(allowed, *p))
                        *d++ = *p;
                else if (*p == ' ') {
                        *d++ = '+';
                } else {
                        /* use hex value */
                        *d++ = '%';
                        *d++ = hex[(*(unsigned char *)p >> 4) & 0x0F];
                        *d++ = hex[(*(unsigned char *)p) & 0x0F];
                }
        }
        *d = '\0';
        return dst;
}

// cf. http://www.htmlhelp.com/reference/html40/entities/

static const char *entities_tab[][2] = { 
{ "lt", "<" },
{ "gt", ">" },
{ "amp", "&" },
{ "nbsp", " " },
{ "quot", "\"" },
{ "raquo", "»" },
//{ "laquo", "" },
{ "ccedil", "ç" },
// grave
{ "agrave", "à" },
{ "egrave", "è" },
// acute
//{ "aacute", "" },
{ "eacute", "é" },
// circ
{ "acirc", "â" },
{ "ecirc", "ê" },
{ "icirc", "î" },
{ "ocirc", "ô" },
{ "ucirc", "û" },
{ "copy", "©" },
{ "trade", "™" },
//{ "", "" },
{ NULL, NULL },
};

char *unentitify_string(const char *str)
{
        char *dst, *d;
        const char *p;
        const char *hex = "0123456789abcdef";
        int i;
        if (!str)
                return NULL;
        // hacky, but safe
        dst = malloc(strlen(str)+2);
        if (!dst)
                return NULL;
        for (p = str, d = dst; *p; p++) {
                if (*p != '&')
                        *d++ = *p;
                /* those case convert to binary, but won't check for valid multibyte UTF-8 sequences */
                else if ((p[1] == '#') && p[2] && p[3] && (p[4] == ';') && 
                                isdigit(p[2]) && 
                                isdigit(p[3])) {
                        /* &#nn; */
                        char c = ((p[2]) - '0') * 10 +
                                         ((p[3]) - '0');
                        *d++ = c;
                        p += 4;
                } else if ((p[1] == '#') && p[2] && p[3] && p[4] && (p[5] == ';') && 
                                isdigit(p[2]) && 
                                isdigit(p[3]) && 
                                isdigit(p[4])) {
                        /* &#nnn; */
                        char c = ((p[2]) - '0') * 100 + 
                                         ((p[3]) - '0') * 10 +
                                         ((p[4]) - '0');
                        *d++ = c;
                        p += 5;
                } else if ((p[1] == '#') && (p[2] == 'x') && p[3] && p[4] && (p[5] == ';') && 
                                strchr(hex, tolower(p[3])) && 
                                strchr(hex, tolower(p[4]))) {
                        /* &#xnn; */
                        char c = (strchr(hex, tolower(p[3])) - hex) << 4 |
                                         (strchr(hex, tolower(p[4])) - hex);
                        *d++ = c;
                        p += 5;
                } else {
                        char buf[20];
                        strncpy(buf, p+1, 20);
                        buf[19] = '\0';
                        if (!strchr(buf, ';')) {
                                *d++ = *p;
                                continue;
                        }
                        *(strchr(buf, ';')) = '\0';
                        for (i = 0; entities_tab[i][0]; i++) {
                                if (!strcmp(buf, entities_tab[i][0])) {
                                        strcpy(d, entities_tab[i][1]);
                                        d += strlen(d);
                                        p += strlen(entities_tab[i][0]) + 1;
                                        break;
                                }
                        }
                        if (!entities_tab[i][0]) /* not found */
                                *d++ = '&';
                }
        }
        *d = '\0';
        return dst;
}

#ifdef TESTME
int main(int argc, char **argv)
{
        char *p;
        if (argc < 2)
                return 1;
        p = unentitify_string(argv[1]);
        printf("'%s'\n", p);
        free(p);
        free(malloc(10));
        return 0;
}
#endif