Index: fmap.c |
diff --git a/fmap.c b/fmap.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..2cdc5dd5f4bdbe2b88b4898d0869a2aac1e269c5 |
--- /dev/null |
+++ b/fmap.c |
@@ -0,0 +1,85 @@ |
+/* Copyright 2010, Google Inc. |
+ * All rights reserved. |
+ * |
+ * Redistribution and use in source and binary forms, with or without |
+ * modification, are permitted provided that the following conditions are |
+ * met: |
+ * |
+ * * Redistributions of source code must retain the above copyright |
+ * notice, this list of conditions and the following disclaimer. |
+ * * Redistributions in binary form must reproduce the above |
+ * copyright notice, this list of conditions and the following disclaimer |
+ * in the documentation and/or other materials provided with the |
+ * distribution. |
+ * * Neither the name of Google Inc. nor the names of its |
+ * contributors may be used to endorse or promote products derived from |
+ * this software without specific prior written permission. |
+ * |
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
+ * |
+ * Alternatively, this software may be distributed under the terms of the |
+ * GNU General Public License ("GPL") version 2 as published by the Free |
+ * Software Foundation. |
+ * |
+ * This is ported from the flashmap utility: http://flashmap.googlecode.com |
+ */ |
+ |
+#include <stdlib.h> |
+#include <string.h> |
+ |
+#include "flash.h" /* for ARRAY_SIZE macro */ |
+#include "fmap.h" |
+ |
+long int fmap_find(const uint8_t *image, size_t image_len) |
+{ |
+ long int offset = -1; |
+ uint64_t sig; |
+ int i; |
+ /* Note: keep the strides sorted in largest to smallest order for |
+ efficient operation below. Strides should all be powers of 2. */ |
+ unsigned int strides[] = { 64 * 1024, 4 * 1024, 64 }; |
+ |
+ memcpy(&sig, FMAP_SIGNATURE, strlen(FMAP_SIGNATURE)); |
+ |
+ /* |
+ * Find FMAP signature within image. The alignment requirements |
+ * increased over time due to speed concerns, so we'll use an array to |
+ * represent the strides we wish to attempt to use. |
+ * |
+ * For efficient operation, we start with the largest stride possible |
+ * and then decrease the stride on each iteration. We will check for a |
+ * remainder when modding the offset with the previous stride. This |
+ * makes it so that each offset is only checked once. |
+ */ |
+ for (i = 0; i < ARRAY_SIZE(strides); i++) { |
+ for (offset = 0; |
+ offset + sizeof(sig) <= image_len; |
+ offset += strides[i]) { |
+ if (i > 0) { |
+ if (offset % strides[i-1] == 0) |
Louis
2011/03/04 11:01:13
Awesome! Much better than my stupid bitarray appro
|
+ continue; |
+ } |
+ |
+ if (!memcmp(&image[offset], &sig, sizeof(sig))) { |
+ goto fmap_find_exit; |
+ } |
+ } |
+ } |
+ |
+fmap_find_exit: |
+ msg_gdbg("%s: fmap_offset: 0x%lx\n", __func__, offset); |
+ if (offset + sizeof(sig) <= image_len) |
+ return offset; |
+ else |
+ return -1; |
+} |