Add libjpeg-turbo backend

1 files changed, 181 insertions, 0 deletions

diff --git a/src/backend_libjpeg.c b/src/backend_libjpeg.c
new file mode 100644
index 0000000..acbd6b3
--- /dev/null
+++ b/src/backend_libjpeg.c
@@ -0,0 +1,181 @@
+#include "backend_libjpeg.h"
+#include "backend.h"
+#include "source.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#ifdef IMV_BACKEND_LIBJPEG
+
+#include <turbojpeg.h>
+
+struct private {
+  int fd;
+  void *data;
+  size_t len;
+  tjhandle jpeg;
+};
+
+static void source_free(struct imv_source *src)
+{
+  free(src->name);
+  src->name = NULL;
+
+  struct private *private = src->private;
+  tjDestroy(private->jpeg);
+  munmap(private->data, private->len);
+  private->data = NULL;
+  close(private->fd);
+
+  free(src->private);
+  src->private = NULL;
+
+  free(src);
+}
+
+static struct imv_bitmap *to_imv_bitmap(int width, int height, void *bitmap)
+{
+  struct imv_bitmap *bmp = malloc(sizeof(struct imv_bitmap));
+  bmp->width = width;
+  bmp->height = height;
+  bmp->format = IMV_ABGR;
+  bmp->data = bitmap;
+  return bmp;
+}
+
+static void report_error(struct imv_source *src)
+{
+  if (!src->callback) {
+    fprintf(stderr, "imv_source(%s) has no callback configured. "
+                    "Discarding error.\n", src->name);
+    return;
+  }
+
+  struct imv_source_message msg;
+  msg.source = src;
+  msg.user_data = src->user_data;
+  msg.bitmap = NULL;
+  msg.error = "Internal error";
+
+  src->callback(&msg);
+}
+
+static void send_bitmap(struct imv_source *src, void *bitmap)
+{
+  if (!src->callback) {
+    fprintf(stderr, "imv_source(%s) has no callback configured. "
+                    "Discarding result.\n", src->name);
+    return;
+  }
+
+  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;
+
+  src->callback(&msg);
+}
+
+static void load_image(struct imv_source *src)
+{
+  struct private *private = src->private;
+
+  void *bitmap = malloc(src->height * src->width * 4);
+  int rcode = tjDecompress2(private->jpeg, private->data, private->len,
+      bitmap, src->width, 0, src->height, TJPF_RGBA, TJFLAG_FASTDCT);
+
+  if (!rcode) {
+    send_bitmap(src, bitmap);
+  } else {
+    free(bitmap);
+    report_error(src);
+    return;
+  }
+}
+
+static enum backend_result open_path(const char *path, struct imv_source **src)
+{
+  struct private private;
+
+  private.fd = open(path, O_RDONLY);
+  if (private.fd < 0) {
+    return BACKEND_BAD_PATH;
+  }
+
+  off_t len = lseek(private.fd, 0, SEEK_END);
+  if (len < 0) {
+    close(private.fd);
+    return BACKEND_BAD_PATH;
+  }
+
+  private.len = len;
+
+  private.data = mmap(NULL, private.len, PROT_READ, MAP_PRIVATE, private.fd, 0);
+  if (!private.data) {
+    close(private.fd);
+    return BACKEND_BAD_PATH;
+  }
+
+  private.jpeg = tjInitDecompress();
+  if (!private.jpeg) {
+    munmap(private.data, private.len);
+    close(private.fd);
+    return BACKEND_UNSUPPORTED;
+  }
+
+  int width, height;
+  int rcode = tjDecompressHeader(private.jpeg, private.data, private.len,
+      &width, &height);
+  if (rcode) {
+    tjDestroy(private.jpeg);
+    munmap(private.data, private.len);
+    close(private.fd);
+    return BACKEND_UNSUPPORTED;
+  }
+
+  struct imv_source *source = calloc(1, sizeof(struct imv_source));
+  source->name = strdup(path);
+  source->width = width;
+  source->height = height;
+  source->num_frames = 1;
+  source->next_frame = 1;
+  source->load_first_frame = &load_image;
+  source->load_next_frame = NULL;
+  source->free = &source_free;
+  source->callback = NULL;
+  source->user_data = NULL;
+  source->private = malloc(sizeof private);
+  memcpy(source->private, &private, sizeof private);
+
+  *src = source;
+  return BACKEND_SUCCESS;
+}
+
+const struct imv_backend libjpeg_backend = {
+  .name = "libjpeg-turbo",
+  .description = "Fast JPEG codec based on libjpeg. "
+                 "This software is based in part on the work "
+                 "of the Independent JPEG Group.",
+  .website = "https://libjpeg-turbo.org/",
+  .license = "The Modified BSD License",
+  .open_path = &open_path,
+};
+
+const struct imv_backend *imv_backend_libjpeg(void)
+{
+  return &libjpeg_backend;
+}
+
+#else
+
+const struct imv_backend *imv_backend_libjpeg(void)
+{
+  return NULL;
+}
+
+#endif