chujowo

#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
//map2=replace(map, reversed, torev);
    char* replace(const char *str, const char *oldstr, const char *newstr)
    {

        int lengthstr= strlen(oldstr); //strlen(oldstr)=strlen(newstr)

        char *result;
        result = (char *)malloc(strlen(str)+1);

        char *space;
        space = (char *)malloc(lengthstr+3);
        space[0]=' ';
        strncpy(&space[1], oldstr, lengthstr-1);
        space[strlen(space)]=' ';
        space[strlen(space)-1]=' ';
        space[strlen(space)-2]=' ';

        char *newline;
        newline = (char *)malloc(lengthstr+3);
        newline[0]='\n';
        newline[strlen(newline)-1]=' ';
        strncpy(&newline[1], oldstr, lengthstr);

        char *first;
        first = (char *)malloc(lengthstr+2);
        strncpy(&first[0], oldstr, lengthstr);
        first[strlen(first)-1]=' ';


        int i = 0;
            while (*str)
            {
            if (i==0 && strstr(str, first) == str)
                {
                    result[i+lengthstr]=' ';
                    strcpy(&result[i], newstr);
                    i += lengthstr;
                    str += lengthstr;
                }
            else if (strstr(str, space) == str)
                {
                    result[i]=' ';
                    result[i+lengthstr]=' ';
                    strcpy(&result[i]+1, newstr);
                    i += lengthstr+1;
                    str += lengthstr+1;
                }
            else if (strstr(str, newline) == str)
                {
                    result[i]='\n';
                    result[i+lengthstr]=' ';
                    strcpy(&result[i]+1, newstr);
                    i += lengthstr+1;
                    str += lengthstr+1;
                }
            else
            result[i++] = *str++;
            }
            return result;
}

int main(int argc, char *argv[])
{
    char *torev, *file;
    int fd;
    struct stat inode;
    void *map, *map2;

    switch(argc)
    {
    case 3:
        file = argv[1];
        torev=argv[2];
        break;
    default :
        printf("You should write:\t%s file word\n", argv[0]);
        return 1;
    }

    char reversed[strlen(torev)+1];
    strcpy(reversed, torev);

    if ((fd = open(argv[1], O_RDWR)) == -1)
    {
        perror("Error opening file for writing");
        return 2;
    }

    if (fstat(fd, &inode))
    {
        perror("Error fstat");
        return 3;
    }

    if ((map = mmap(NULL, inode.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0))==(void *)-1)
    {
        perror("Error mmapping the file");
        return 4;
    }

    int i;
    int x= strlen(torev)/2;
    for (i = 0; i<x; i++)
    {
        //torev[i] = toupper(torev[i]);
        char tmp= torev[i];
        torev[i]=torev[strlen(torev)-1-i];
        torev[strlen(torev)-1-i]=tmp;
    }


    map2=replace(map, reversed, torev);

    memcpy(map, map2, inode.st_size);

    msync(map, inode.st_size, MS_SYNC);

    munmap(map, inode.st_size);

    close(fd);

    return 0;
}