add example_util.[hc]

moves ReadFile to a common location

Change-Id: Ia81230671f16d7d4d218b9954a5be55577a85413

examples/example_util.c

@@ -0,0 +1,59 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the example programs.
+//
+
+#include "./example_util.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+// -----------------------------------------------------------------------------
+// File I/O
+
+int ExUtilReadFile(const char* const file_name,
+                   const uint8_t** data, size_t* data_size) {
+  int ok;
+  void* file_data;
+  size_t file_size;
+  FILE* in;
+
+  if (file_name == NULL || data == NULL || data_size == NULL) return 0;
+  *data = NULL;
+  *data_size = 0;
+
+  in = fopen(file_name, "rb");
+  if (in == NULL) {
+    fprintf(stderr, "cannot open input file '%s'\n", file_name);
+    return 0;
+  }
+  fseek(in, 0, SEEK_END);
+  file_size = ftell(in);
+  fseek(in, 0, SEEK_SET);
+  file_data = malloc(file_size);
+  if (file_data == NULL) return 0;
+  ok = (fread(file_data, file_size, 1, in) == 1);
+  fclose(in);
+
+  if (!ok) {
+    fprintf(stderr, "Could not read %zu bytes of data from file %s\n",
+            file_size, file_name);
+    free(file_data);
+    return 0;
+  }
+  *data = (uint8_t*)file_data;
+  *data_size = file_size;
+  return 1;
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif