#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>

#define felder 45

#ifdef _WIN32
#define strtok_r strtok_s
__inline char *stpcpy(char *a, const char *b)
{
    size_t n, m;

    n = strlen(a);
    m = strlen(b);
    a += n;
    memcpy(a, b, m + 1);
    return a + m;
}
#endif

size_t getFilesize(const char *filename)
{
    struct stat st;

    stat(filename, &st);
    return st.st_size;
}

void parsedata(char **buffer, char **outpbuff);

static unsigned long intsize = 4194304;

int main()
{
    char *outbuff = malloc(intsize);
    char *buffer = malloc(intsize);
    unsigned long cnt = 0;
    unsigned long seekoff = 0;
    unsigned long tiles = 0;
    unsigned long fsize = (int)getFilesize("list.txt");
    FILE *fp = fopen("list.txt", "rb");
    FILE *fp2 = fopen("nodup.txt", "w");
    unsigned long lastblock;
    int nlpos;

    buffer[intsize - 1] = '\0';

    setvbuf(fp2, NULL, _IOFBF, intsize);

    while (fread(buffer, intsize - 1, 1, fp)) {
        cnt++;
        seekoff = ftell(fp);
        nlpos = intsize - 1UL;
        while (buffer[nlpos] != '\n') {
            nlpos--;
            seekoff = seekoff - 1UL;
        }
        fseek(fp, seekoff, SEEK_SET);
        buffer[nlpos - 1] = '\0';
        buffer[intsize] = '\0';
        parsedata(&buffer, &outbuff);
        tiles = ftell(fp);
        //fwrite(outbuff, intsize, 1, fp2);
        fprintf(fp2, outbuff);
    }

    lastblock = fsize - tiles;
    buffer[lastblock - 1] = '\0';
    fread(buffer, lastblock + 1, 1, fp);
    parsedata(&buffer, &outbuff);
    fprintf(fp2, outbuff);
    fprintf(fp2, "%c", '\n');
    fflush(fp2);
    fclose(fp);
    fclose(fp2);
}


void parsedata(char **buffer, char **outpbuff)
{
    int ignore = 3;
    char *cols[felder];
    char *backup = NULL;
    int n = 0;
    size_t seps = 0;
    char *last = NULL;
    char *lastconcat = NULL;
    char *p;
    int x, first = 1;

    *outpbuff[0] = 0;
    lastconcat = *outpbuff;

    for (p = strtok_r(*buffer, ";", &backup); p != NULL;
            p = strtok_r(NULL, ";", &backup))
    {
        seps = p - last;
        if (first == 1)
            first = 0;
        else
            while (seps > 0) {
                seps--;
                cols[n++] = "";
                lastconcat = stpcpy(lastconcat, ";");	//(*outpbuff, ";");
                if (n > felder - 1)
                    n = 0;
            }
        if (n <= ignore) {
            // printf("%s",p);
            lastconcat = stpcpy(lastconcat, p);
            lastconcat = stpcpy(lastconcat, ";");
        }
        else if (n > ignore && n < felder + 1) {
            for (x = n - 1; x >= ignore; x--) {
                if (strcmp(cols[x], p) == 0)
                    break;
                else if (x <= ignore)
                    lastconcat = stpcpy(lastconcat, p);
            }
            lastconcat = stpcpy(lastconcat, ";");
        }
        if (n > felder - 1)
            n = 0;
        cols[n++] = p;
        last = backup;
    }

    while (n < felder)
    {
        lastconcat = stpcpy(lastconcat, ";");
        n++;
    }
}