/* bijou HTTP server for plan 9 by sean caron (scaron@umich.edu) */

#include "main.h"

int uri_encode(char *ip, char **op) {
    int i, j, t;
    char temp[4];
    int ol;

    ol = strlen(ip);

    *op = malloc ( sizeof(char) * (ol+1) );

    if (*op == 0) {
        exits("MALLOC");
    }

    i = 0;
    j = 0;

    /* catch null input */
    if (strlen(ip) == 0) {
        strcpy(*op, "");
        return 0;
    }

    while (1) {
        /* just pass unreserved characters through with no encoding */

        if (((ip[i] >= 43) && (ip[i] <= 47)) || (ip[i] == 95) || (ip[i] == 126) || ((ip[i] >= 48) && (ip[i] <= 57)) || ((ip[i] >= 65) && (ip[i] <= 90)) || ((ip[i] >= 97) && (ip[i] <= 122))) {
            *(*op+j) = ip[i];

            i = i + 1;
            j = j + 1;
        }

        /* otherwise express it in the uri encoded format */
        else {
            ol = ol + 3;

            *op = realloc(*op, sizeof(char)*(ol+1) );

            if (*op == 0) {
                exits("REALLOC");
            }

            sprintf(temp, "%2.0x", ip[i] );

            *(*op+j) = '%';
            *(*op+j+1) = temp[0];
            *(*op+j+2) = temp[1];

            i = i + 1;
            j = j + 3;
        }

        if (i == strlen(ip)) {
            break;
        }
    }

    *(*op+j) = '\0';

    return 0;
}

int uri_decode(char *ip, char **op) {
    int i, j, t;
    char temp[4];

    *op = malloc ( sizeof(char) * (strlen(ip)+1) );

    if (*op == 0) {
        exits("MALLOC");
    }

    i = 0;
    j = 0;

    /* catch null input */
    if (strlen(ip) == 0) {
        strcpy(*op, "");
        return 0;
    }

    while (1) {
        if ((ip[i] == '%') && isxdigit(ip[i+1]) && isxdigit(ip[i+2])) {
            // ascii value of the encoded char is in ip[i+1] and ip[i+2] in hex; ip[i+1] is MSB.
            sprintf(temp, "%c%c", ip[i+1], ip[i+2] );

            t = (int)strtol(temp, (char**)NULL, 16);

            *(*op+j) = (char)t;

            i = i + 3;
            j = j + 1;
        }

        else {
            *(*op+j) = ip[i];

            i = i + 1;
            j = j + 1;
        }

        if (i == strlen(ip)) {
            break;
        }
    }

    *(*op+j) = '\0';

    return 0;
}