labyrinth
annotate src/image.c @ 0:8ba79034e8a6
labyrinth example initial commit
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Thu, 15 Jan 2015 14:59:38 +0200 |
| parents | |
| children |
| rev | line source |
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| nuclear@0 | 1 #include <stdio.h> |
| nuclear@0 | 2 #include <stdlib.h> |
| nuclear@0 | 3 #include <string.h> |
| nuclear@0 | 4 #include <errno.h> |
| nuclear@0 | 5 #include "image.h" |
| nuclear@0 | 6 |
| nuclear@0 | 7 struct image *load_image(const char *fname) |
| nuclear@0 | 8 { |
| nuclear@0 | 9 FILE *fp; |
| nuclear@0 | 10 int i, hdrline = 0; |
| nuclear@0 | 11 struct image *img = 0; |
| nuclear@0 | 12 |
| nuclear@0 | 13 if(!(fp = fopen(fname, "rb"))) { |
| nuclear@0 | 14 fprintf(stderr, "failed to open pixmap: %s: %s\n", fname, strerror(errno)); |
| nuclear@0 | 15 return 0; |
| nuclear@0 | 16 } |
| nuclear@0 | 17 |
| nuclear@0 | 18 if(!(img = malloc(sizeof *img))) { |
| nuclear@0 | 19 perror("failed to allocate image structure"); |
| nuclear@0 | 20 goto err; |
| nuclear@0 | 21 } |
| nuclear@0 | 22 |
| nuclear@0 | 23 /* read ppm header */ |
| nuclear@0 | 24 while(hdrline < 3) { |
| nuclear@0 | 25 char buf[64]; |
| nuclear@0 | 26 |
| nuclear@0 | 27 if(!fgets(buf, sizeof buf, fp)) { |
| nuclear@0 | 28 goto err; |
| nuclear@0 | 29 } |
| nuclear@0 | 30 |
| nuclear@0 | 31 /* skip comments */ |
| nuclear@0 | 32 if(buf[0] == '#') |
| nuclear@0 | 33 continue; |
| nuclear@0 | 34 |
| nuclear@0 | 35 switch(hdrline++) { |
| nuclear@0 | 36 case 0: |
| nuclear@0 | 37 /* first header line should be P6 */ |
| nuclear@0 | 38 if(strcmp(buf, "P6\n") != 0) { |
| nuclear@0 | 39 goto err; |
| nuclear@0 | 40 } |
| nuclear@0 | 41 break; |
| nuclear@0 | 42 |
| nuclear@0 | 43 case 1: |
| nuclear@0 | 44 /* second header line contains the pixmap dimensions */ |
| nuclear@0 | 45 if(sscanf(buf, "%d %d", &img->width, &img->height) != 2) { |
| nuclear@0 | 46 goto err; |
| nuclear@0 | 47 } |
| nuclear@0 | 48 break; |
| nuclear@0 | 49 } |
| nuclear@0 | 50 } |
| nuclear@0 | 51 |
| nuclear@0 | 52 /* allocate the image (each pixel is 3 bytes r, g, and b) */ |
| nuclear@0 | 53 if(!(img->pixels = malloc(img->width * img->height * 3))) { |
| nuclear@0 | 54 goto err; |
| nuclear@0 | 55 } |
| nuclear@0 | 56 |
| nuclear@0 | 57 /* read all pixels */ |
| nuclear@0 | 58 for(i=0; i<img->width * img->height * 3; i++) { |
| nuclear@0 | 59 int c = fgetc(fp); |
| nuclear@0 | 60 if(c < 0) { |
| nuclear@0 | 61 goto err; |
| nuclear@0 | 62 } |
| nuclear@0 | 63 img->pixels[i] = c; |
| nuclear@0 | 64 } |
| nuclear@0 | 65 fclose(fp); |
| nuclear@0 | 66 |
| nuclear@0 | 67 return img; |
| nuclear@0 | 68 |
| nuclear@0 | 69 err: |
| nuclear@0 | 70 fprintf(stderr, "failed to load pixmap: %s\n", fname); |
| nuclear@0 | 71 if(img) { |
| nuclear@0 | 72 free(img->pixels); |
| nuclear@0 | 73 free(img); |
| nuclear@0 | 74 } |
| nuclear@0 | 75 if(fp) { |
| nuclear@0 | 76 fclose(fp); |
| nuclear@0 | 77 } |
| nuclear@0 | 78 return 0; |
| nuclear@0 | 79 } |
| nuclear@0 | 80 |
| nuclear@0 | 81 |
| nuclear@0 | 82 void free_image(struct image *img) |
| nuclear@0 | 83 { |
| nuclear@0 | 84 if(img) { |
| nuclear@0 | 85 free(img->pixels); |
| nuclear@0 | 86 free(img); |
| nuclear@0 | 87 } |
| nuclear@0 | 88 } |