block: adding lzfse decompressing support as a module.

QEMU dmg support includes zlib and bzip2, but it does not contains lzfse
support. This commit adds the source file to extend compression support
for new DMGs.

Signed-off-by: Julio Faracco <jcfaracco@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/dmg-lzfse.c

@@ -0,0 +1,49 @@
+/*
+ * DMG lzfse uncompression
+ *
+ * Copyright (c) 2018 Julio Cesar Faracco
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "dmg.h"
+#include <lzfse.h>
+
+static int dmg_uncompress_lzfse_do(char *next_in, unsigned int avail_in,
+                                   char *next_out, unsigned int avail_out)
+{
+    size_t out_size = lzfse_decode_buffer((uint8_t *) next_out, avail_out,
+                                          (uint8_t *) next_in, avail_in,
+                                          NULL);
+
+    /* We need to decode the single chunk only. */
+    /* So, out_size == avail_out is not an error here. */
+    if (out_size > 0) {
+        return out_size;
+    }
+    return -1;
+}
+
+__attribute__((constructor))
+static void dmg_lzfse_init(void)
+{
+    assert(!dmg_uncompress_lzfse);
+    dmg_uncompress_lzfse = dmg_uncompress_lzfse_do;
+}