85 lines
1.6 KiB
C
85 lines
1.6 KiB
C
#include "ff.h"
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#include <arpa/inet.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#define MAGIC "farbfeld"
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#define MAGICLEN 8
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#define BUFSIZE 4096
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#define MIN(x, y) ((x) < (y) ? (x) : (y))
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static uint8_t buf[BUFSIZE];
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static uint8_t *loadpix(uint8_t *p, const pix_t *pix, unsigned n)
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{
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for (unsigned i = 0; i < n; ++i) {
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*((uint16_t *)p) = htons(pix[i].r);
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p += sizeof(uint16_t);
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*((uint16_t *)p) = htons(pix[i].g);
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p += sizeof(uint16_t);
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*((uint16_t *)p) = htons(pix[i].b);
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p += sizeof(uint16_t);
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*((uint16_t *)p) = htons(pix[i].a);
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p += sizeof(uint16_t);
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}
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return p;
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}
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static void writebuf(int fd, size_t size)
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{
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while (1) {
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errno = 0;
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const ssize_t res = write(fd, buf, size);
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if (res == (ssize_t)size) {
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return;
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} else if (res > 0) {
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fputs(
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"Error writing image: Couldn't write entire buffer"
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" (storage may be full)\n",
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stderr);
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exit(1);
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} else {
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if (errno == EINTR) {
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continue;
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} else {
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perror("Error writing image");
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exit(1);
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}
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}
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}
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}
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void ff_write(int fd, img_t img)
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{
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uint8_t *p = buf;
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memcpy(p, MAGIC, MAGICLEN);
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p += MAGICLEN;
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*((uint32_t *)p) = htonl(img.w);
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p += sizeof(uint32_t);
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*((uint32_t *)p) = htonl(img.h);
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p += sizeof(uint32_t);
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const pix_t *pix = img.pix;
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unsigned rem = img.w * img.h;
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while (rem > 0) {
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const unsigned cap = (BUFSIZE - (p - buf)) / sizeof(pix_t);
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const unsigned n = MIN(rem, cap);
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p = loadpix(p, pix, n);
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pix += n;
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rem -= n;
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writebuf(fd, p - buf);
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p = buf;
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}
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}
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