+ image_from_file

requirements.txt

@@ -0,0 +1,3 @@
+libgd2-noxpm-dev
+libgdbm-dev
+libmagic-dev

src/Makefile

@@ -1,7 +1,14 @@
-all:
+CFLAGS=-Wall -Wextra -O0 -g -ggdb -pedantic
+
+all: test-image
+
+%.c: %.h
 
 %.o: %.c
 	gcc -O0 -Wall -Wextra -pedantic -ggdb $< -o $@
 
 clean:
 	rm -f *.o
+
+test-image: image.c test-image.c
+	gcc $(CFLAGS) -lmagic -lgd image.c test-image.c -o $@

src/image.c

@@ -14,12 +14,67 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor Boston, MA 02110-1301,  USA
  */
 
+#include <gd.h>
+#include <magic.h>
+
 #include "main.h"
 #include "image.h"
 
-#include <gd.h>
-
-int image_load(void)
+gdImagePtr
+image_from_file(const char *path, char **errstr)
 {
-  return 1;
+  const char *mimetype;
+  magic_t magic;
+  char err[256] = "\0";
+
+  FILE *in;
+  gdImagePtr (*cb)(FILE *fd);
+  gdImagePtr img;
+
+  if ((magic = magic_open(MAGIC_MIME_TYPE)) == NULL) {
+    snprintf(err, 256, "%s", magic_error(magic));
+    *errstr = err;
+    return NULL;
+  }
+
+  if (magic_load(magic, NULL) < 0) {
+    *errstr = magic_error(magic);
+    magic_close(magic);
+    return NULL;
+  }
+
+  mimetype = magic_file(magic, path);
+  if (mimetype == NULL) {
+    snprintf(err, 256, "%s", magic_error(magic));
+    *errstr = err;
+    magic_close(magic);
+    return NULL;
+  }
+
+  if (strncmp(mimetype, "image/png", 9) == 0) {
+    cb = gdImageCreateFromPng;
+  } else 
+  if (strncmp(mimetype, "image/gif", 9) == 0) {
+    cb = gdImageCreateFromGif;
+  } else
+  if (strncmp(mimetype, "image/jpeg", 10) == 0) {
+    cb = gdImageCreateFromJpeg;
+  } else {
+    snprintf(err, 256, "Can't handle image type '%s'", mimetype);
+    *errstr = err;
+    return NULL;
+  }
+  magic_close(magic);
+
+  in = fopen(path, "rb");
+  if (in == NULL) {
+    snprintf(err, 256, "Can't open file: %s", strerror(errno));
+    *errstr = err;
+    return NULL;
+  }
+
+  img = cb(in);
+  fclose(in);
+
+  return img;
 }

src/image.h

@@ -1 +1,2 @@
-int image_load(void);
+gdImagePtr
+image_from_file(const char *path, char **errstr);

src/test-image.c

@@ -0,0 +1,16 @@
+#include <gd.h>
+
+#include "main.h"
+#include "image.h"
+
+int main(int argc, char **argv) {
+  gdImagePtr img = NULL;
+  char *err;
+
+  img = image_from_file("test.png", &err);
+  if (img == NULL) {
+    printf("%s\n", err);
+    exit(EXIT_FAILURE);
+  }
+  exit(EXIT_SUCCESS);
+}