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#include "ppm.h"
static void read_header(FILE *fp, char ppm_type[2], int img_size[3]);
static void read_p6_data(FILE *fp, Image *img);
void
ppm_write(const char *file, Image *img)
{
/*
* Write a ppm file
*/
FILE *fp = fopen(file, "w");
if (fp == NULL) {
perror("ppm_read() Error");
exit(1);
}
size_t n_pixels = img->width * img->height * 3;
fprintf(fp, "P6\n%d %d\n%d\n", img->width, img->height, img->pixel_bits);
fwrite(img->data, n_pixels, sizeof(uint8_t), fp);
fclose(fp);
}
void
ppm_read(const char *file, Image *img)
/*
* Read a ppm file
*/
{
FILE *fp = fopen(file, "r");
if (fp == NULL) {
perror("ppm_read() Error");
exit(1);
}
char ppm_type[3];
int img_size[3];
read_header(fp, ppm_type, img_size);
img->width = img_size[0];
img->height = img_size[1];
img->pixel_bits = img_size[2];
if (!strcmp(ppm_type, "P6")) read_p6_data(fp, img);
else {
fprintf(stderr, "ppm_read() Error: %s format not supported\n", ppm_type);
fclose(fp);
exit(1);
}
fclose(fp);
}
void
read_header(FILE *fp, char ppm_type[2], int img_size[3])
{
int i, n, ret;
char line_buffer[70], *buffer;
buffer = fgets(line_buffer, 70, fp);
for (i = n = 0; i < 4; ) {
if (i == 0) {
sscanf(line_buffer, "%2s%n", ppm_type, &n);
buffer += n;
i++;
}
else if (i > 0) {
ret = sscanf(buffer, "%d%n", img_size + i - 1, &n);
if (ret >= 1) {
buffer += n;
i++;
} else buffer = fgets(line_buffer, 70, fp);
}
}
}
void
read_p6_data(FILE *fp, Image *img)
{
int n_pixels = img->width * img->height * 3;
img->data = calloc(n_pixels, sizeof(uint8_t));
if (img->data == NULL) {
perror("read_p6_data() Error");
exit(1);
}
fread(img->data, n_pixels, sizeof(uint8_t), fp);
if (ferror(fp)) {
perror("read_p6_data() Error");
exit(1);
}
}
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