From: resver@gmail.com <resver@gmail.com@60bc1c72-a15a-11de-b98f-4500b42dc123>
Date: Sat, 3 Aug 2013 13:25:28 +0000 (+0000)
Subject: Address clusters bitmap using size_t-sized blocks instead of bytes. This should be... 
X-Git-Url: http://git.osdn.net/view?p=android-x86%2Fexternal-exfat.git;a=commitdiff_plain;h=db8d13fe0464766b33ddaf99711d679bdf2b16c4

Address clusters bitmap using size_t-sized blocks instead of bytes. This should be a bit faster.

git-svn-id: http://exfat.googlecode.com/svn/trunk@371 60bc1c72-a15a-11de-b98f-4500b42dc123
---

diff --git a/libexfat/cluster.c b/libexfat/cluster.c
index 5a13d23..e84e581 100644
--- a/libexfat/cluster.c
+++ b/libexfat/cluster.c
@@ -108,18 +108,22 @@ cluster_t exfat_advance_cluster(const struct exfat* ef,
 	return node->fptr_cluster;
 }
 
-static cluster_t find_bit_and_set(uint8_t* bitmap, size_t start, size_t end)
+static cluster_t find_bit_and_set(bitmap_t* bitmap, size_t start, size_t end)
 {
-	const size_t start_index = start / 8;
-	const size_t end_index = DIV_ROUND_UP(end, 8);
+	const size_t start_index = start / sizeof(bitmap_t) / 8;
+	const size_t end_index = DIV_ROUND_UP(end, sizeof(bitmap_t) * 8);
 	size_t i;
+	size_t start_bitindex;
+	size_t end_bitindex;
 	size_t c;
 
 	for (i = start_index; i < end_index; i++)
 	{
-		if (bitmap[i] == 0xff)
+		if (bitmap[i] == ~((bitmap_t) 0))
 			continue;
-		for (c = MAX(i * 8, start); c < MIN((i + 1) * 8, end); c++)
+		start_bitindex = MAX(i * sizeof(bitmap_t) * 8, start);
+		end_bitindex = MIN((i + 1) * sizeof(bitmap_t) * 8, end);
+		for (c = start_bitindex; c < end_bitindex; c++)
 			if (BMAP_GET(bitmap, c) == 0)
 			{
 				BMAP_SET(bitmap, c);
@@ -133,7 +137,7 @@ void exfat_flush(struct exfat* ef)
 {
 	if (ef->cmap.dirty)
 	{
-		exfat_pwrite(ef->dev, ef->cmap.chunk, (ef->cmap.chunk_size + 7) / 8,
+		exfat_pwrite(ef->dev, ef->cmap.chunk, BMAP_SIZE(ef->cmap.chunk_size),
 				exfat_c2o(ef, ef->cmap.start_cluster));
 		ef->cmap.dirty = false;
 	}
diff --git a/libexfat/exfat.h b/libexfat/exfat.h
index f7825d3..4b0ebc9 100644
--- a/libexfat/exfat.h
+++ b/libexfat/exfat.h
@@ -51,12 +51,16 @@
 #define ROUND_UP(x, d) (DIV_ROUND_UP(x, d) * (d))
 #define UTF8_BYTES(c) ((c) * 6) /* UTF-8 character can occupy up to 6 bytes */
 
+typedef size_t bitmap_t;
+#define BMAP_SIZE(count) (ROUND_UP(count, sizeof(bitmap_t) * 8) / 8)
+#define BMAP_BLOCK(index) ((index) / sizeof(bitmap_t) / 8)
+#define BMAP_MASK(index) ((bitmap_t) 1 << ((index) % (sizeof(bitmap_t) * 8)))
 #define BMAP_GET(bitmap, index) \
-	(((uint8_t*) bitmap)[(index) / 8] & (1u << ((index) % 8)))
+	((bitmap)[BMAP_BLOCK(index)] & BMAP_MASK(index))
 #define BMAP_SET(bitmap, index) \
-	((uint8_t*) bitmap)[(index) / 8] |= (1u << ((index) % 8))
+	((bitmap)[BMAP_BLOCK(index)] |= BMAP_MASK(index))
 #define BMAP_CLR(bitmap, index) \
-	((uint8_t*) bitmap)[(index) / 8] &= ~(1u << ((index) % 8))
+	((bitmap)[BMAP_BLOCK(index)] &= ~BMAP_MASK(index))
 
 struct exfat_node
 {
@@ -97,7 +101,7 @@ struct exfat
 	{
 		cluster_t start_cluster;
 		uint32_t size;				/* in bits */
-		uint8_t* chunk;
+		bitmap_t* chunk;
 		uint32_t chunk_size;		/* in bits */
 		bool dirty;
 	}
diff --git a/libexfat/node.c b/libexfat/node.c
index 9eaf0d7..e83ec9e 100644
--- a/libexfat/node.c
+++ b/libexfat/node.c
@@ -368,16 +368,17 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 			}
 			ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 				EXFAT_FIRST_DATA_CLUSTER;
-			if (le64_to_cpu(bitmap->size) < (ef->cmap.size + 7) / 8)
+			if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 			{
 				exfat_error("invalid clusters bitmap size: %"PRIu64
 						" (expected at least %u)",
-						le64_to_cpu(bitmap->size), (ef->cmap.size + 7) / 8);
+						le64_to_cpu(bitmap->size),
+						DIV_ROUND_UP(ef->cmap.size, 8));
 				goto error;
 			}
 			/* FIXME bitmap can be rather big, up to 512 MB */
 			ef->cmap.chunk_size = ef->cmap.size;
-			ef->cmap.chunk = malloc(le64_to_cpu(bitmap->size));
+			ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 			if (ef->cmap.chunk == NULL)
 			{
 				exfat_error("failed to allocate clusters bitmap chunk "
@@ -386,7 +387,8 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 				goto error;
 			}
 
-			exfat_pread(ef->dev, ef->cmap.chunk, le64_to_cpu(bitmap->size),
+			exfat_pread(ef->dev, ef->cmap.chunk,
+					BMAP_SIZE(ef->cmap.chunk_size),
 					exfat_c2o(ef, ef->cmap.start_cluster));
 			break;