trying count lines from memory buffer

//-std=c99 -Wall -Wextra -Wpedantic -Wshadow

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

int main () {

    FILE *fp;
    unsigned int fileSize;
    char *buffer;
    size_t result;
    unsigned int numOfLines = 0;
    char *cur, *end;
    bool befNotEmpty = false;

    //#define STRSIZE 1024
    //static char str[STRSIZE];

    fp = fopen("file.txt" , "r");

    if(fp == NULL)
    {
        printf("Error opening file");
        return -1;
    }

/*
if(fseek(fp, 0L, SEEK_SET) != 0 )
{
  //Handle error
}
*/

    //obtain file size:
    fseek(fp, 0 , SEEK_END);
    fileSize = ftell(fp);
    fseek(fp, 0, SEEK_SET);

    buffer = malloc(fileSize);

    if (buffer == NULL)
    {
        fclose(fp);
        printf("Memory error\n");
        return -1;
    }

    result = fread(buffer, 1, fileSize, fp);

    if(result != fileSize)
    {
        free(buffer);
        fclose(fp);
        printf("Reading error\n");
        return -1;
    }

    /*
        OD
        OA
        ODOA

        0A0D

        0A0A0A0A..., 0D0D0D0D...

        can be badly formatted

        can end without line terminator

    */

    end = buffer + fileSize;
    cur = buffer;

    while(1)
    {
        if(!(end-cur))
        {
            if(befNotEmpty) numOfLines++;
            break;
        }

        if(*cur == '\r')
        {
            befNotEmpty = false;
            numOfLines++;

            if (++cur < end)
            {
                if(*cur == '\n')
                {
                    cur++;
                    continue;
                }
                else if(*cur == '\r')
                {
                    numOfLines++;
                    cur++;
                    continue;
                }
            }
            else break;
        }
        else if(*cur == '\n')
        {
            befNotEmpty = false;
            numOfLines++;

            if (++cur < end)
            {
                if(*cur == '\r')
                {
                    cur++;
                    continue;
                }
                else if(*cur == '\n')
                {
                    numOfLines++;
                    cur++;
                    continue;
                }
            }
            else break;
        }
        else befNotEmpty = true;

        cur++;
    }



    printf("Number of lines: %d\n", numOfLines);

    free(buffer);
    fclose(fp);

    printf("Bye bye.\n");

    return 0;
}