parslib/tinyparser.c

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

extern char *headers;
extern char *methods;

int method = 0;
char *uri = NULL; 
char *ver = NULL;
int uri_len = 0;
int ver_len = 0;

struct nod *header_tree = NULL; 
struct nod *method_tree = NULL;
struct point *header_table = NULL; 

int read_line(char **buffer, char **buffer_limit) {
    int diff = 0; 
    if ((*buffer) >= (*buffer_limit)) {
        return diff;
    }

    int ret = 0; 
    char *match = strstr(*buffer, "\r\n");
    if (match) {
        ret = match-(*buffer);
        *buffer += 2;
    } else {
        ret = (*buffer_limit)-(*buffer);
    }
    *buffer += ret;
    return ret;
}

int parse_header(char *offset, int len) {
    int key = 0; 
    int ret = 0; 
    int diff = 0; 

    char *cursor = offset;
    char *cursor_lim = offset+len;

    // header title
    char *htitle_lim = strchr(cursor, ':');
    if (!htitle_lim) {
        return -1;
    }
    if (htitle_lim > cursor_lim) {
        return -1;
    }

    diff = htitle_lim-cursor;
    ret = streencmp(header_tree, cursor, diff);
    if (!ret) {
        return -1;
    }

    key = ret;
    cursor += diff;

    // white space and seperators 
_loop: 
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ':') {
        cursor++; 
        goto _loop; 
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop;
    }

    // header value
    diff = cursor_lim-cursor;

    header_table[key].er = cursor;
    header_table[key].len = diff;

    return 0;
}

int parse_title(char *offset, int len) {
    int ret = 0; 
    int diff = 0; 
    char *cursor = offset;
    char *cursor_lim = cursor+len;

    // method
    char *method_lim = strchr(offset, ' ');
    if (!method_lim) {
        return -1;
    }
    if (method_lim > cursor_lim) {
        return -1;
    }

    diff = method_lim-cursor;
    ret = streencmp(method_tree, cursor, diff);
    if (ret == 0) {
        return -1;
    }

    method = ret;
    cursor += diff;

    // white space 
_loop1: 
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop1;
    }

    // uri 
    char *uri_lim = strchr(cursor, ' ');
    if (!uri_lim) {
        return -1;
    }
    if (uri_lim > cursor_lim) {
        return -1;
    }

    diff = uri_lim-cursor;
    uri = cursor;
    uri_len = diff;

    cursor += diff;
    
    // white space 
_loop2:
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop2;
    }

    // ver
    diff = cursor_lim-cursor;
    ver = cursor;
    ver_len = diff;

    cursor += diff;

    return 0;
}

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

    char *title_offset = buffer;
    int title_len = read_line(&buffer, &buffer_limit);
    if ((ret = parse_title(title_offset, title_len)) < 0) {
        fprintf(stderr, "Failed parsing title\n");
        return -1;
    }

    for (int bound = 0; bound < MAX_BOUND; bound++) {
        char *header_offset = buffer; 
        int header_len = read_line(&buffer, &buffer_limit);
        char *header_limit = header_offset+header_len;
        
        // IF END OF MESSAGE
        if (!header_len) {
            break;
        }

        if ((ret = parse_header(header_offset, header_len)) < 0) {
            fprintf(stderr, "Failed parsing header\n");
            return -1;
        }
    }

    return 0;
}

void debug_stats(void) {
    fprintf(stderr, "\tstats:\n"
                    "\t\tmethod\t: %d\n"
                    "\t\turi\t: %.*s\n"
                    "\t\tver\t: %.*s\n",
                    method, uri_len, uri, ver_len, ver
            );

    fprintf(stdout, "\theaders:\n");
    for (int i = 0; i < header_count; i++) {
        struct point *pnt = &header_table[i]; 
        if (!pnt->er) {
            continue;
        }

        fprintf(stdout, "\t\t%d\t: %.*s\n", i, pnt->len, pnt->er);
    }
}

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

    header_table = (struct point *) calloc(header_count, sizeof(struct point));
    if (!header_table) {
        fprintf(stderr, "Not enough dynamic memory\n");
        return -1;
    }

    header_tree = allocnod();
    if (!header_tree) {
        fprintf(stderr, "Not enough dynamic memory\n");
        return -1;
    }

    method_tree = allocnod();
    if (!method_tree) {
        fprintf(stderr, "Not enough dynamic memory\n");
        return -1;
    }

    ret = gentree(header_tree, headers, NULL);
    if (ret < 0) {
        fprintf(stderr, "Failed generating the header comparison tree\n");
        return -1;
    }

    ret = gentree(method_tree, methods, NULL);
    if (ret < 0) {
        fprintf(stderr, "Failed generating the header comparison tree\n");
        return -1;
    }

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

    fprintf(stdout, "++Successfully parsed data++\n");
    debug_stats();

    frenod(method_tree);
    frenod(header_tree);
    free(header_table);
    free(str);
    
    return 0;
}