commit acf7073c322f297f89a531271169a5603253ed53
parent 1a5017f69e05703dabe5a06e17450422f09c24bf
Author: phoebos <ben@bvnf.space>
Date: Wed, 1 Sep 2021 22:59:44 +0100
format
Diffstat:
| M | gif.c | | | 115 | +++++++++++++++++++++++++++++++++++++++++-------------------------------------- |
1 file changed, 59 insertions(+), 56 deletions(-)
diff --git a/gif.c b/gif.c
@@ -5,10 +5,10 @@
* where each pixel is a number corresponding to the index of the color.
*/
-#include <math.h>
#include <fcntl.h>
-#include <stdio.h>
+#include <math.h>
#include <stdint.h>
+#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
@@ -26,13 +26,13 @@ struct Gif {
char version[3]; /* 87a or 89a */
uint16_t width;
uint16_t height;
- unsigned char flags; /* ABBBCDDD
- A: global colour table [GCT] flag
- B+1: colour resolution (bits per primary colour)
- C: GCT sort flag (89a+ only)
- D+1: bits used per pixel in GCT
- */
- unsigned char background; /* color index in GCT of screen background */
+ unsigned char flags; /* ABBBCDDD
+ A: global colour table [GCT] flag
+ B+1: colour resolution (bits per primary colour)
+ C: GCT sort flag (89a+ only)
+ D+1: bits used per pixel in GCT
+ */
+ unsigned char background; /* color index in GCT of screen background */
unsigned char aspect_ratio; /* 89a+ only */
struct Color_table *gct;
unsigned char *pixels; /* array of indices to colors */
@@ -51,11 +51,11 @@ struct Image {
};
void
-print_colortable(struct Color_table *c){
- for (int i = 0; i < c->len; i++){
- printf("%d: \033[48;2;%d;%d;%dm(%02x;%02x;%02x)\033[0m\n",
- i, c->table[i][0], c->table[i][1], c->table[i][2],
- c->table[i][0], c->table[i][1], c->table[i][2]);
+print_colortable(struct Color_table *c) {
+ for (int i = 0; i < c->len; i++) {
+ printf("%d: \033[48;2;%d;%d;%dm(%02x;%02x;%02x)\033[0m\n", i,
+ c->table[i][0], c->table[i][1], c->table[i][2], c->table[i][0],
+ c->table[i][1], c->table[i][2]);
}
}
@@ -63,8 +63,9 @@ print_colortable(struct Color_table *c){
* character, ','. gct should be a pointer to the global color table.
*/
int
-gif_decode_image(struct Image *img, struct Color_table *gct, unsigned char *buf){
- if (*buf++ != ','){
+gif_decode_image(struct Image *img, struct Color_table *gct,
+ unsigned char *buf) {
+ if (*buf++ != ',') {
fprintf(stderr, "not an image block\n");
return FAIL_GIF;
}
@@ -113,8 +114,8 @@ gif_decode_image(struct Image *img, struct Color_table *gct, unsigned char *buf)
}
int
-gif_decode(unsigned char *buf, size_t len){
- struct Gif g = {0 };
+gif_decode(unsigned char *buf, size_t len) {
+ struct Gif g = {0};
g.gct = malloc(sizeof(struct Color_table));
if (g.gct == NULL) {
perror("malloc");
@@ -126,7 +127,8 @@ gif_decode(unsigned char *buf, size_t len){
cur_block = HEAD;
(void)cur_block;
- if (strncmp((char *)buf, "GIF", 3)) return FAIL_GIF;
+ if (strncmp((char *)buf, "GIF", 3))
+ return FAIL_GIF;
buf += 3;
len -= 3;
strncpy(g.version, (char *)buf, 3);
@@ -150,13 +152,13 @@ gif_decode(unsigned char *buf, size_t len){
g.background = *buf++;
g.aspect_ratio = *buf++;
- g.gct->len = (int)pow(2.0, (double) (g.flags & 7U) + 1);
+ g.gct->len = (int)pow(2.0, (double)(g.flags & 7U) + 1);
fprintf(stderr, "%d colors in GCT\n", g.gct->len);
/* if GCT... */
if (g.flags & 0x80) {
/* TODO: gif87a.txt L 336? */
- for (int i = 0; i < g.gct->len; i+=1) {
+ for (int i = 0; i < g.gct->len; i += 1) {
rgb c = {*buf++, *buf++, *buf++};
memcpy(g.gct->table[i], c, sizeof(rgb));
}
@@ -169,31 +171,31 @@ gif_decode(unsigned char *buf, size_t len){
while (--len) {
++buf;
switch (*buf) {
- case '!':
- if (cur_block != SPEC) {
- cur_block = SPEC;
+ case '!':
+ if (cur_block != SPEC) {
+ cur_block = SPEC;
+ }
+ break;
+ case ',':
+ if (cur_block != IMGE) {
+ cur_block = IMGE;
+ img = malloc(sizeof(struct Image));
+ if (img == NULL) {
+ perror("malloc");
+ exit(FAIL_SYS);
}
- break;
- case ',':
- if (cur_block != IMGE) {
- cur_block = IMGE;
- img = malloc(sizeof(struct Image));
- if (img == NULL) {
- perror("malloc");
- exit(FAIL_SYS);
- }
- img->lct = malloc(sizeof(struct Color_table));
- if (img->lct == NULL) {
- perror("malloc");
- exit(FAIL_SYS);
- }
- img->lct->len = g.gct->len;
- gif_decode_image(img, g.gct, buf);
+ img->lct = malloc(sizeof(struct Color_table));
+ if (img->lct == NULL) {
+ perror("malloc");
+ exit(FAIL_SYS);
}
- break;
- case ';':
- /* last char of image section */
- return 0;
+ img->lct->len = g.gct->len;
+ gif_decode_image(img, g.gct, buf);
+ }
+ break;
+ case ';':
+ /* last char of image section */
+ return 0;
}
}
free(img);
@@ -202,7 +204,7 @@ gif_decode(unsigned char *buf, size_t len){
}
int
-main(int argc, char **argv){
+main(int argc, char **argv) {
int fd;
/* only work on one file */
@@ -213,7 +215,8 @@ main(int argc, char **argv){
++argv;
/* stdin */
- if (argc == 1 || **argv == '-') fd = 0;
+ if (argc == 1 || **argv == '-')
+ fd = 0;
else {
/* open named file */
fd = open(*argv, O_RDONLY);
@@ -224,7 +227,7 @@ main(int argc, char **argv){
}
unsigned char *buf;
- buf = (unsigned char *) malloc(BUF_SIZE);
+ buf = malloc(BUF_SIZE);
if (buf == NULL) {
perror("malloc");
exit(FAIL_SYS);
@@ -250,7 +253,8 @@ main(int argc, char **argv){
buf = tmp;
}
bytes = read(fd, buf + used, BUF_SIZE);
- if (bytes == 0) break; /* EOF */
+ if (bytes == 0)
+ break; /* EOF */
if (bytes < 0) {
perror("read");
return FAIL_SYS;
@@ -265,16 +269,15 @@ main(int argc, char **argv){
int ret = gif_decode(buf, used);
switch (ret) {
- case FAIL_GIF:
- fprintf(stderr, "error: invalid GIF format\n");
- return FAIL_GIF;
- case 0:
- break;
- default:
- return ret;
+ case FAIL_GIF:
+ fprintf(stderr, "error: invalid GIF format\n");
+ return FAIL_GIF;
+ case 0:
+ break;
+ default:
+ return ret;
}
-
free(buf);
return 0;
}
