Implement cmdutils.c:read_file(), and use it in ffmpeg.c for reading

the second pass encoding log file.

Originally committed as revision 22769 to svn://svn.ffmpeg.org/ffmpeg/trunk

cmdutils.c

@@ -639,3 +639,27 @@ int read_yesno(void)
 
     return yesno;
 }
+
+int read_file(const char *filename, char **bufptr, size_t *size)
+{
+    FILE *f = fopen(filename, "r");
+
+    if (!f) {
+        fprintf(stderr, "Cannot read file '%s': %s\n", filename, strerror(errno));
+        return AVERROR(errno);
+    }
+    fseek(f, 0, SEEK_END);
+    *size = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    *bufptr = av_malloc(*size + 1);
+    if (!*bufptr) {
+        fprintf(stderr, "Could not allocate file buffer\n");
+        fclose(f);
+        return AVERROR(ENOMEM);
+    }
+    fread(*bufptr, 1, *size, f);
+    (*bufptr)[*size++] = '\0';
+
+    fclose(f);
+    return 0;
+}