#include <stdio.h>
#include <stdlib.h>

#define err(x) {printf("\nError: %s... Exiting...\n", x); exit(1);}

static unsigned char pat1[] = {0x99, 0x11, 0x45, 0x27};
static unsigned char pat2[] = {0x73, 0x49};
static unsigned char pat3[] = {0xff, 0x34};
static unsigned char intrim_pat1[][2] = { {0x03, 0x80}, {0x03, 0x81}, {0x03, 0x83}, {0x03, 0x86}, {0x03, 0x87} };
static unsigned char end[] = {0xff, 0x33};

void print_data(const unsigned char *ptr, int len)
{
        int i;
        for(i=0;i<=len;i++)
                printf("%02x ", ptr[i]);
        printf("\n");
        return;
}

void get_len_and_print(FILE *fp, unsigned char *ptr)
{
        int len = 0;

        //only buf[0] is populated at this stage
        if(1 != fread(ptr+1, sizeof(char), 1, fp))
                err("Insufficient data");
        len = *(ptr+1);
        if(len != fread(ptr+2, sizeof(char), len, fp))
                err("Insufficient data");
        print_data(ptr, len+1);
        return;
}

int main(int argc, char **argv)
{

        if(argc < 2)
                err("File name missing");

        char found = 0, more = 0, again = 0;
        unsigned char buf[32];
        unsigned char *ptr = buf;
        int pos = 0, i, len;
        int arr_size = (sizeof(intrim_pat1)/2);

        FILE *fp = fopen(argv[1], "rb");
        if(!fp) err("Unable to open the file");

        while(2 == fread(ptr, sizeof(char), 2, fp)){
                pos = ftell(fp);

                //check for end of file pattern
                if(found && !memcmp(buf, end, 2)){
                        found=0; //start over or stop??
                        continue;
                }

                //check for 0xff 0x34
                if(found && !(memcmp(buf, pat3, 2))){
                        more = 1;
                        continue;
                }

                if(found && more){
                        for(i=0; i < arr_size; i++){
                                // We got the intrim pattern.
                                if(!memcmp(buf, intrim_pat1[i], 2)){
                                        again=1;
                                        more=0;
                                        break;
                                }
                        }
                        if(again) {
                                // Now read the next 1 byte which is actually the size
                                if(1 != fread(ptr+2, sizeof(char), 1, fp))
                                        err("Insufficient data");
                                len = buf[2];
                                if(len != fread(ptr+3, sizeof(char), len, fp))
                                        err("Insufficient data");
                                print_data(ptr, len+2);

                                // Now check for the remaining pattern
                                // Assuming it will be in ascending order
                                // Break even if we dont find the very next pattern
                                // Also, reset the fp. We will flush all the data in buffer
                                // till now, since we have printed them already
                                pos = ftell(fp);

                                if(1 != fread(ptr, sizeof(char), 1, fp))
                                        err("Insufficient data");

                                while(i < arr_size){
                                        if( buf[0] == intrim_pat1[i][1]){
                                                get_len_and_print(fp, ptr);

                                                if(1 != fread(ptr, sizeof(char), 1, fp))
                                                        err("Insufficient data");
                                                pos = ftell(fp);
                                        }
                                        i++;
                                }
                                again=0;
                        }
                }
                if(buf[0] == 0x32){
                        if(18 != fread(ptr+2, sizeof(char), 18, fp))
                                err("Insufficient data");
                        if(memcmp(buf+4, pat1, 4) && memcmp(buf+12, pat2, 2)){
                                fseek(fp, pos, SEEK_SET);
                        }else{
                                found = 1; //found the starting of the block with data
                                print_data(ptr, 19);
                        }
                        continue;
                }
                pos--;
                if(fseek(fp, pos, SEEK_SET))
                        err("Error in seeking");
        }
        return 0;
}