Thread: make: *** [transform] Error 1

Please help ive been working on this for two weeks and I'm having this error and every time I try to run it to print the new image I get a seg fault I commented out my mirror() function so I know its not causing it. Its something in my main or readImage() function. This is the error I get if I compile without make:

[17:53:59] cehutto@hornet19:~/asg21 [39] gcc transform.h transform.c parset.c print.c
/tmp/ccoTPJTA.o: In function `main':
transform.c.text+0x8f): undefined reference to `mirror'
collect2: ld returned 1 exit status

Header File:

Code:

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

#define CREATOR "Cody Hutto"
#define RGB_COMPONENT_COLOR 255


typedef struct PPMPixel {

    unsigned char r, g, b;

}PPMPixel;

typedef struct PPMImage {

    int x, y;
    PPMPixel *data;
    int g_width, g_height;

}PPMImage;



PPMImage *readPPM(const char *filename);


// other function prototypes here
void writePPM(const char *filename, PPMImage *img);
void mirror(PPMImage *img);

This is my main:

Code:

#include "transform.h"
#include <string.h>

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

    FILE *inFile;
    int c;
        

    //open input file
    inFile = fopen("tiger.ppm", "r");
    if (inFile == NULL) {
        fprintf(stderr,"Output failure. Exiting program");
        exit(0);
    }


    PPMImage *image;
    image = readPPM("tiger.ppm");

    c = atoi(argv[1]);

    
    if(c == 1){
        mirror(image);
        writePPM("tiger1.ppm", image); 
    }
    else if(c == 2){

        //flipImage(image);
        writePPM("tiger2.ppm", image);
    }
    else if(c == 3){
        
        //rotate(image);
        writePPM("tiger3.ppm", image);
    }



    return (1);
}

This is a parser for the ppm:

Code:

#include "transform.h"
#include <errno.h>
#include <string.h>



PPMImage *readPPM(const char *filename) {
    
    char buff[16];
    PPMImage *img;
    FILE *fp;
    char *resultstr;
    int c, rgb_comp_color;
    
    //open PPM file for reading
    fp = fopen(filename, "rb");
    if (!fp) {
        fprintf(stderr, "Unable to open file '%s'\n", filename);
        exit(1);
    }
    
         //read image format
         if (!(resultstr = fgets(buff, sizeof(buff), fp))) {
        fprintf(stderr, "echo %s\n", buff);              
        //perror(strerror(errno));
                  fprintf(stderr, "error(%d): %s\n", errno, strerror(errno));
        exit(1);
         }
    
    //check the image format
    if (buff[0] != 'P' || buff[1] != '6') {
        fprintf(stderr, "Invalid image format (must be 'P6')\n");
        exit(1);
    }
    
    //alloc memory form image
    img = (PPMImage *)malloc(sizeof(PPMImage));
    if (!img) {
    fprintf(stderr, "Unable to allocate memory\n");
    exit(1);
    }
    
    //check for comments
    c = getc(fp);
    while (c == '#') {
    while (getc(fp) != '\n') ;
    c = getc(fp);
    }

    ungetc(c, fp);
    //read image size information
    if (fscanf(fp, "%d %d", &img->x, &img->y) != 2) {
        fprintf(stderr, "Invalid image size (error loading '%s')\n",             filename);
             exit(1);
    }

    //read rgb component
    if (fscanf(fp, "%d", &rgb_comp_color) != 1) {
        fprintf(stderr, "Invalid rgb component (error loading '%s')\n",         filename);
        exit(1);
    }
    
    //check rgb component depth
    if (rgb_comp_color!= RGB_COMPONENT_COLOR) {
        fprintf(stderr, "'%s' does not have 8-bits components\n", filename);
        exit(1);
    }

    while (fgetc(fp) != '\n') ;
    //memory allocation for pixel data
    img->data = (PPMPixel*)malloc(img->x* img->y * sizeof(PPMPixel));
    
    if (!img) {
        fprintf(stderr, "Unable to allocate memory\n");
        exit(1);
    }

    //read pixel data from file
    if (fread(img->data, 3 * img->x, img->y, fp) != img->y)         {
        fprintf(stderr, "Error loading image '%s'\n", filename);
        exit(1);
    }

    fclose(fp);
    return img;
}

I'm most certainly not missing it. However I got rid of the error but now I get a seg fault

Code:

#include "transform.h" 
#include <stdio.h> 
 
void mirror(PPMImage *img) { 
 
    int y, x; 
    const int middleX = img->x/2; 
    PPMImage tmp; 
    fprintf(stderr, "%d %d\n", img->x, img->y); 
    for(y=0; y<img->y; y++){ 
 
        //img = img->data + y * img->x; 
        for(x=0; x<middleX; x++) { 
 
            tmp = img[x + (img->x * y)]; 
            img[x + (img->x * y)] = img[img->x - 1 - x + (img->x * y)]; 
            img[img->x - 1 - x + (img->x * y)] = tmp; 
        } 
    } 
}

Originally Posted by Salem

> gcc transform.h transform.c parset.c print.c
You don't pass .h files to the compiler.

You've got this
void mirror(PPMImage *img);

What you're missing is the implementation - it's the thing that actually DOES the work.

Code:

void mirror(PPMImage *img) {
  // your code here
}

This is the full code and my new seg fault:

Code:

#include<stdio.h> 
#include<stdlib.h> 
 
typedef struct { 
     unsigned char r,g,b; 
} PPMPixel; 
 
typedef struct { 
     int x, y; 
     PPMPixel *data; 
} PPMImage; 
 
#define CREATOR "Cody Hutto" 
#define RGB_COMPONENT_COLOR 255 
 
static PPMImage *readPPM(const char *filename) 
{ 
         char buff[100]; 
         PPMImage *img; 
         FILE *fp; 
         int c, rgb_comp_color; 
         //open PPM file for reading 
         fp = fopen(filename, "rb"); 
         if (!fp) { 
              fprintf(stderr, "Unable to open file '%s'\n", filename); 
              exit(1); 
         } 
 
         //read image format 
         if (!fgets(buff, sizeof(buff), fp)) { 
              perror(filename); 
              exit(1); 
         } 
 
    //check the image format 
    if (buff[0] != 'P' || buff[1] != '6') { 
         fprintf(stderr, "Invalid image format (must be 'P6')\n"); 
         exit(1); 
    } 
 
    //alloc memory form image 
    img = (PPMImage *)malloc(sizeof(PPMImage)); 
    if (!img) { 
         fprintf(stderr, "Unable to allocate memory\n"); 
         exit(1); 
    } 
 
    //check for comments 
    c = getc(fp); 
    while (c == '#') { 
    while (getc(fp) != '\n') ; 
         c = getc(fp); 
    } 
 
    ungetc(c, fp); 
    //read image size information 
    if (fscanf(fp, "%d %d", &img->x, &img->y) != 2) { 
         fprintf(stderr, "Invalid image size (error loading '%s')\n", filename); 
         exit(1); 
    } 
 
    //read rgb component 
    if (fscanf(fp, "%d", &rgb_comp_color) != 1) { 
         fprintf(stderr, "Invalid rgb component (error loading '%s')\n", filename); 
         exit(1); 
    } 
 
    //check rgb component depth 
    if (rgb_comp_color!= RGB_COMPONENT_COLOR) { 
         fprintf(stderr, "'%s' does not have 8-bits components\n", filename); 
         exit(1); 
    } 
 
    while (fgetc(fp) != '\n') ; 
    //memory allocation for pixel data 
    img->data = (PPMPixel*)malloc(img->x * img->y * sizeof(PPMPixel)); 
 
    if (!img) { 
         fprintf(stderr, "Unable to allocate memory\n"); 
         exit(1); 
    } 
 
    //read pixel data from file 
    if (fread(img->data, 3 * img->x, img->y, fp) != img->y) { 
         fprintf(stderr, "Error loading image '%s'\n", filename); 
         exit(1); 
    } 
 
    fclose(fp); 
    return img; 
} 
void writePPM(const char *filename, PPMImage *img) 
{ 
    FILE *fp; 
    //open file for output 
    fp = fopen(filename, "wb"); 
    if (!fp) { 
         fprintf(stderr, "Unable to open file '%s'\n", filename); 
         exit(1); 
    } 
 
    //write the header file 
    //image format 
    fprintf(fp, "P6\n"); 
 
    //comments 
    fprintf(fp, "# Created by %s\n",CREATOR); 
 
    //image size 
    fprintf(fp, "%d %d\n",img->x,img->y); 
 
    // rgb component depth 
    fprintf(fp, "%d\n",RGB_COMPONENT_COLOR); 
 
    // pixel data 
    fwrite(img->data, 3 * img->x, img->y, fp); 
    fclose(fp); 
} 
 
void mirror(PPMImage *img) { 
 
    int y, x; 
    const int middleX = img->x/2; 
    PPMImage tmp; 
    fprintf(stderr, "%d %d\n", img->x, img->y); 
    for(y=0; y<img->y; y++){ 
 
        //img = img->data + y * img->x; 
        for(x=0; x<middleX; x++) { 
 
            tmp = img[x + (img->x * y)]; 
            img[x + (img->x * y)] = img[img->x - 1 - x + (img->x * y)]; 
            img[img->x - 1 - x + (img->x * y)] = tmp; 
        } 
    } 
} 
 
 
int main(){ 
    PPMImage *image; 
    image = readPPM("tiger.ppm"); 
    mirror(image); 
    writePPM("tiger2.ppm",image); 
    printf("Press any key..."); 
    getchar(); 
}

Seg Fault;

[18:43:38] cehutto@hornet19:~/101/lab12 [162] ./a.out
690 461
Segmentation fault

I have done this but still cannot figure out the error. Although it points here

img[img->x - 1 - x + (img->x * y)] = tmp;

Line 133

Originally Posted by Salem

Like I said - learn some tools.

$ gcc -g transform.c parset.c print.c
The -g flag adds debug information to the program

$ gdb -q ./a.out
Load the program into gdb

(gdb) run
Run the program

690 461
Segmentation fault

(gdb) bt
Display a stack trace from the point of the crash all the way back to main.

The next useful commands are 'up' 'down' and 'print'

My math is correct even my teacher said so.

is img an array ?

I get the x to loop till the mid point but y will not go past seven please help me I have been at this for a week with nothing to show.

Code:

void mirror(PPMImage *img) {

    int y, x;
    const int middleX = img->x/2;
    PPMImage tmp;
    
    for(y=0; y<img->y; y++){
    
        //img = img->data + y * img->x;
        for(x=0; x<middleX; x++) {
                     
            tmp = img[x + (img->x * y)];

        img[x + (img->x * y)] = img[img->x  -  x + (img->x * y)];
            //fprintf(stderr, "y = %d\n ", tmp[y]);
            img[img->x  -  x + (img->x * y)] = tmp;
            fprintf(stderr, "img->x = %d\n", img->x);
            fprintf(stderr, "img->y = %d\n", img->y);
            fprintf(stderr, "middle= %d\n", middleX);
            fprintf(stderr, "y = %d\n ", y);
            fprintf(stderr, "x = %d\n ", x);
        }
    }
}