X-Git-Url: https://git.sven.stormbind.net/?p=sven%2Fexfat-utils.git;a=blobdiff_plain;f=libexfat%2Fcluster.c;fp=libexfat%2Fcluster.c;h=980e1cd5358b4fb8f6efdf5ff01f5cfae5aee2e6;hp=0418932ec802f66590fcf29139a2d075aa64e335;hb=4efb596cee7f7cc961990f8dffc3b210e579e49c;hpb=70a4b10edcf53a90140e6dd80ccaa045f3647ad7

diff --git a/libexfat/cluster.c b/libexfat/cluster.c
index 0418932..980e1cd 100644
--- a/libexfat/cluster.c
+++ b/libexfat/cluster.c
@@ -2,7 +2,7 @@
 	cluster.c (03.09.09)
 	exFAT file system implementation library.
 
-	Copyright (C) 2010-2012  Andrew Nayenko
+	Copyright (C) 2010-2013  Andrew Nayenko
 
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
@@ -99,47 +99,31 @@ cluster_t exfat_advance_cluster(const struct exfat* ef,
 	{
 		node->fptr_cluster = exfat_next_cluster(ef, node, node->fptr_cluster);
 		if (CLUSTER_INVALID(node->fptr_cluster))
-			break;
+			break; /* the caller should handle this and print appropriate 
+			          error message */
 	}
 	node->fptr_index = count;
 	return node->fptr_cluster;
 }
 
-static cluster_t find_bit_and_set(uint8_t* bitmap, cluster_t start,
-		cluster_t end)
+static cluster_t find_bit_and_set(uint8_t* bitmap, size_t start, size_t end)
 {
-	const cluster_t mid_start = (start + 7) / 8 * 8;
-	const cluster_t mid_end = end / 8 * 8;
-	cluster_t c;
-	cluster_t byte;
-
-	for (c = start; c < mid_start; c++)
-		if (BMAP_GET(bitmap, c) == 0)
-		{
-			BMAP_SET(bitmap, c);
-			return c + EXFAT_FIRST_DATA_CLUSTER;
-		}
-
-	for (byte = mid_start / 8; byte < mid_end / 8; byte++)
-		if (bitmap[byte] != 0xff)
-		{
-			cluster_t bit;
-
-			for (bit = 0; bit < 8; bit++)
-				if (!(bitmap[byte] & (1u << bit)))
-				{
-					bitmap[byte] |= (1u << bit);
-					return byte * 8 + bit + EXFAT_FIRST_DATA_CLUSTER;
-				}
-		}
-
-	for (c = mid_end; c < end; c++)
-		if (BMAP_GET(bitmap, c) == 0)
-		{
-			BMAP_SET(bitmap, c);
-			return c + EXFAT_FIRST_DATA_CLUSTER;
-		}
+	const size_t start_index = start / 8;
+	const size_t end_index = DIV_ROUND_UP(end, 8);
+	size_t i;
+	size_t c;
 
+	for (i = start_index; i < end_index; i++)
+	{
+		if (bitmap[i] == 0xff)
+			continue;
+		for (c = MAX(i * 8, start); c < MIN((i + 1) * 8, end); c++)
+			if (BMAP_GET(bitmap, c) == 0)
+			{
+				BMAP_SET(bitmap, c);
+				return c + EXFAT_FIRST_DATA_CLUSTER;
+			}
+	}
 	return EXFAT_CLUSTER_END;
 }
 
@@ -147,7 +131,7 @@ void exfat_flush_cmap(struct exfat* ef)
 {
 	exfat_pwrite(ef->dev, ef->cmap.chunk, (ef->cmap.chunk_size + 7) / 8,
 			exfat_c2o(ef, ef->cmap.start_cluster));
-	ef->cmap.dirty = 0;
+	ef->cmap.dirty = false;
 }
 
 static void set_next_cluster(const struct exfat* ef, int contiguous,
@@ -181,20 +165,20 @@ static cluster_t allocate_cluster(struct exfat* ef, cluster_t hint)
 		return EXFAT_CLUSTER_END;
 	}
 
-	ef->cmap.dirty = 1;
+	ef->cmap.dirty = true;
 	return cluster;
 }
 
 static void free_cluster(struct exfat* ef, cluster_t cluster)
 {
 	if (CLUSTER_INVALID(cluster))
-		exfat_bug("attempting to free invalid cluster");
-	if (cluster < EXFAT_FIRST_DATA_CLUSTER ||
-		cluster - EXFAT_FIRST_DATA_CLUSTER >= ef->cmap.size)
-		exfat_bug("bad cluster 0x%x (0x%x)", cluster, ef->cmap.size);
+		exfat_bug("freeing invalid cluster 0x%x", cluster);
+	if (cluster - EXFAT_FIRST_DATA_CLUSTER >= ef->cmap.size)
+		exfat_bug("freeing non-existing cluster 0x%x (0x%x)", cluster,
+				ef->cmap.size);
 
 	BMAP_CLR(ef->cmap.chunk, cluster - EXFAT_FIRST_DATA_CLUSTER);
-	ef->cmap.dirty = 1;
+	ef->cmap.dirty = true;
 }
 
 static void make_noncontiguous(const struct exfat* ef, cluster_t first,
@@ -225,7 +209,7 @@ static int grow_file(struct exfat* ef, struct exfat_node* node,
 		previous = exfat_advance_cluster(ef, node, current - 1);
 		if (CLUSTER_INVALID(previous))
 		{
-			exfat_error("invalid cluster in file");
+			exfat_error("invalid cluster 0x%x while growing", previous);
 			return -EIO;
 		}
 	}
@@ -290,7 +274,7 @@ static int shrink_file(struct exfat* ef, struct exfat_node* node,
 				current - difference - 1);
 		if (CLUSTER_INVALID(last))
 		{
-			exfat_error("invalid cluster in file");
+			exfat_error("invalid cluster 0x%x while shrinking", last);
 			return -EIO;
 		}
 		previous = exfat_next_cluster(ef, node, last);
@@ -309,7 +293,8 @@ static int shrink_file(struct exfat* ef, struct exfat_node* node,
 	{
 		if (CLUSTER_INVALID(previous))
 		{
-			exfat_error("invalid cluster in file");
+			exfat_error("invalid cluster 0x%x while freeing after shrink",
+					previous);
 			return -EIO;
 		}
 		next = exfat_next_cluster(ef, node, previous);
@@ -340,7 +325,7 @@ static int erase_range(struct exfat* ef, struct exfat_node* node,
 			begin / CLUSTER_SIZE(*ef->sb));
 	if (CLUSTER_INVALID(cluster))
 	{
-		exfat_error("invalid cluster in file");
+		exfat_error("invalid cluster 0x%x while erasing", cluster);
 		return -EIO;
 	}
 	/* erase from the beginning to the closest cluster boundary */
@@ -352,7 +337,7 @@ static int erase_range(struct exfat* ef, struct exfat_node* node,
 		cluster = exfat_next_cluster(ef, node, cluster);
 		/* the cluster cannot be invalid because we have just allocated it */
 		if (CLUSTER_INVALID(cluster))
-			exfat_bug("invalid cluster in file");
+			exfat_bug("invalid cluster 0x%x after allocation", cluster);
 		erase_raw(ef, CLUSTER_SIZE(*ef->sb), exfat_c2o(ef, cluster));
 		cluster_boundary += CLUSTER_SIZE(*ef->sb);
 	}