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#include "backend_libpng.h"
#include "backend.h"
#include "source.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <png.h>
struct private {
FILE *file;
png_structp png;
png_infop info;
};
static void source_free(struct imv_source *src)
{
pthread_mutex_lock(&src->busy);
free(src->name);
src->name = NULL;
struct private *private = src->private;
png_destroy_read_struct(&private->png, &private->info, NULL);
if (private->file) {
fclose(private->file);
}
free(src->private);
src->private = NULL;
pthread_mutex_unlock(&src->busy);
pthread_mutex_destroy(&src->busy);
free(src);
}
static struct imv_bitmap *to_imv_bitmap(int width, int height, void *bitmap)
{
struct imv_bitmap *bmp = malloc(sizeof *bmp);
bmp->width = width;
bmp->height = height;
bmp->format = IMV_ABGR;
bmp->data = bitmap;
return bmp;
}
static void report_error(struct imv_source *src)
{
assert(src->callback);
struct imv_source_message msg;
msg.source = src;
msg.user_data = src->user_data;
msg.bitmap = NULL;
msg.error = "Internal error";
pthread_mutex_unlock(&src->busy);
src->callback(&msg);
}
static void send_bitmap(struct imv_source *src, void *bitmap)
{
assert(src->callback);
struct imv_source_message msg;
msg.source = src;
msg.user_data = src->user_data;
msg.bitmap = to_imv_bitmap(src->width, src->height, bitmap);
msg.frametime = 0;
msg.error = NULL;
pthread_mutex_unlock(&src->busy);
src->callback(&msg);
}
static int load_image(struct imv_source *src)
{
/* Don't run if this source is already active */
if (pthread_mutex_trylock(&src->busy)) {
return -1;
}
struct private *private = src->private;
if (setjmp(png_jmpbuf(private->png))) {
report_error(src);
return -1;
}
png_bytep *rows = malloc(sizeof(png_bytep) * src->height);
size_t row_len = png_get_rowbytes(private->png, private->info);
rows[0] = malloc(src->height * row_len);
for (int y = 1; y < src->height; ++y) {
rows[y] = rows[0] + row_len * y;
}
if (setjmp(png_jmpbuf(private->png))) {
free(rows[0]);
free(rows);
report_error(src);
return -1;
}
png_read_image(private->png, rows);
void *bmp = rows[0];
free(rows);
fclose(private->file);
private->file = NULL;
send_bitmap(src, bmp);
return 0;
}
static enum backend_result open_path(const char *path, struct imv_source **src)
{
unsigned char header[8];
FILE *f = fopen(path, "rb");
if (!f) {
return BACKEND_BAD_PATH;
}
fread(header, 1, sizeof header, f);
if (png_sig_cmp(header, 0, sizeof header)) {
fclose(f);
return BACKEND_UNSUPPORTED;
}
struct private *private = malloc(sizeof *private);
private->file = f;
private->png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!private->png) {
fclose(private->file);
free(private);
return BACKEND_UNSUPPORTED;
}
private->info = png_create_info_struct(private->png);
if (!private->info) {
png_destroy_read_struct(&private->png, NULL, NULL);
fclose(private->file);
free(private);
return BACKEND_UNSUPPORTED;
}
if (setjmp(png_jmpbuf(private->png))) {
png_destroy_read_struct(&private->png, &private->info, NULL);
fclose(private->file);
free(private);
return BACKEND_UNSUPPORTED;
}
png_init_io(private->png, private->file);
png_set_sig_bytes(private->png, sizeof header);
png_read_info(private->png, private->info);
/* Tell libpng to give us a consistent output format */
png_set_gray_to_rgb(private->png);
png_set_filler(private->png, 0xff, PNG_FILLER_AFTER);
png_read_update_info(private->png, private->info);
struct imv_source *source = calloc(1, sizeof *source);
source->name = strdup(path);
if (setjmp(png_jmpbuf(private->png))) {
free(source->name);
free(source);
png_destroy_read_struct(&private->png, &private->info, NULL);
fclose(private->file);
free(private);
return BACKEND_UNSUPPORTED;
}
source->width = png_get_image_width(private->png, private->info);
source->height = png_get_image_height(private->png, private->info);
source->num_frames = 1;
source->next_frame = 1;
pthread_mutex_init(&source->busy, NULL);
source->load_first_frame = &load_image;
source->load_next_frame = NULL;
source->free = &source_free;
source->callback = NULL;
source->user_data = NULL;
source->private = private;
*src = source;
return BACKEND_SUCCESS;
}
const struct imv_backend libpng_backend = {
.name = "libpng",
.description = "The official PNG reference implementation",
.website = "http://www.libpng.org/pub/png/libpng.html",
.license = "The libpng license",
.open_path = &open_path,
};
const struct imv_backend *imv_backend_libpng(void)
{
return &libpng_backend;
}
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