parslib/tinyparser.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "tinyparser.h"

enum errs err = err_init;
enum states state = state_init;
enum methods method = method_init;
char *uri = NULL; 
char *ver = NULL;
int uri_len = 0;
int ver_len = 0;

int read_line(char **cursor, int cursor_size) {
    int diff = 0; 
    char *match = strchr(*cursor, '\n');

    if (!match)
        match = (*cursor)+cursor_size-1;
        
    diff = match - (*cursor);
    *cursor += diff + 1;
    
    return diff;
}

int cmp_orig(char *ch, char *orig, char *limit) {
    int diff = 0;
    for (; *orig != '\0' && *ch != '\0' && ch < limit; orig++, ch++, diff++) 
        if (*orig != *ch)
            return -1;

    return diff;
}

int cmp_ascii(char *ch, char *limit) {
    int diff = 0; 
    for (; *ch != '\0' && *ch != ' ' && ch < limit; ch++, diff++) {
        if (*ch >= '0' && *ch <= '9')   continue;
        if (*ch >= 'A' && *ch <= 'Z')   continue;
        if (*ch >= 'a' && *ch <= 'z')   continue;
        if (*ch >= '#' && *ch <= '/')   continue;
        if (*ch == '!')                 continue;
        if (*ch == ':')                 continue;
        if (*ch == ';')                 continue;
        if (*ch == '=')                 continue;
        if (*ch == '?')                 continue;
        if (*ch == '@')                 continue;
        if (*ch == '[')                 continue;
        if (*ch == ']')                 continue;
        if (*ch == '_')                 continue;
        if (*ch == '~')                 continue;

        return -1;
    }

    return diff;
}

int parse_title(char *title_offset, int title_len) {
    int title_cursor = 0;

    while (state != state_title_ok && state != state_title_err) {
        if (title_cursor >= title_len) {
            state = state_title_err;
            err = err_parse_title;
        }

        int ret = 0; 
        char *ch = title_offset+title_cursor;
        char *lim = title_offset+title_len-1;

        switch (state) {
        case state_init: 
            state = state_title_method;
            break;
        case state_title_method: 
            if ((ret = cmp_orig(ch, "GET", lim))) {
                title_cursor += ret;
                state = state_title_after_method;
                method = method_get;
                break;
            }
            if ((ret = cmp_orig(ch, "POST", lim))) {
                title_cursor += ret;
                state = state_title_after_method;
                method = method_post;
                break;
            }
            if ((ret = cmp_orig(ch, "HEAD", lim))) {
                title_cursor += ret;
                state = state_title_after_method;
                method = method_head;
                break;
            }

            state = state_title_err;
            err = err_parse_title_method;
            break;
        case state_title_after_method: 
            title_cursor++;
            state = state_title_uri;
            break;
        case state_title_uri: 
            if ((ret = cmp_ascii(ch, lim)) <= 0) {
                state = state_title_err;
                err = err_parse_title_uri;
                break;
            }

            if (!(uri = strndup(ch, ret))) {
                state = state_title_err;
                err = err_memory;
                break;
            }

            uri_len = ret;
            title_cursor += ret;
            state = state_title_after_uri;
            break;
        case state_title_after_uri: 
            title_cursor++; 
            state = state_title_version;
            break;
        case state_title_version: 
            if ((ret = cmp_ascii(ch, lim)) <= 0) {
                state = state_title_err;
                err = err_parse_title_version;
                break;
            }

            if (!(ver = strndup(ch, ret))) {
                state = state_title_err;
                err = err_memory;
                break;
            }

            ver_len = ret;
            title_cursor += ret;
            state = state_title_ok;
            break;
        case state_title_ok: 
            for (;ch < lim;ch++) {
                if (*ch == ' ') continue;
                if (*ch == '\t') continue;
                if (*ch == '\0') continue;

                state = state_title_err;
                err = err_parse_title;
                break;
            }
            break;
        case state_title_err:
            fprintf(stderr, "failed\n");
            return -1;
            break;
        default: 
            break;
        }
    }

    return 0;
}

int parse_request(char *buffer) {
    int ret; 
    int buffer_size = strlen(buffer);

    char *title_offset = buffer;
    int title_len = read_line(&buffer, buffer_size);

    if ((ret = parse_title(title_offset, title_len)) < 0) {
        fprintf(stderr, "Failed parsing title\n");
        return -1;
    }

    return 0;
}

int main(void) {
    int ret; 
    char *str = strdup(TEST_ONE);

    ret = parse_request(str);
    if (ret < 0) {
        fprintf(stderr, "Failed parsing request\n");
        return -1;
    }

    fprintf(stderr, "Finished parsing request\n");

    free(str);
    
    return 0;
}