Add -u option for dumpexfat that prints used sectors.

[android-x86/external-exfat.git] / libexfat / cluster.c

diff --git a/libexfat/cluster.c b/libexfat/cluster.c
index fc7dbc5..90db709 100644 (file)
--- a/libexfat/cluster.c
+++ b/libexfat/cluster.c
@@ -50,6 +50,15 @@ off_t exfat_c2o(const struct exfat* ef, cluster_t cluster)
 }
 
 /*
+ * Block to cluster.
+ */
+static cluster_t b2c(const struct exfat* ef, off_t block)
+{
+       return ((block - le32_to_cpu(ef->sb->cluster_block_start)) >>
+                       ef->sb->bpc_bits) + EXFAT_FIRST_DATA_CLUSTER;
+}
+
+/*
  * Size in bytes to size in clusters (rounded upwards).
  */
 static uint32_t bytes2clusters(const struct exfat* ef, uint64_t bytes)
@@ -391,3 +400,45 @@ uint32_t exfat_count_free_clusters(const struct exfat* ef)
                        free_clusters++;
        return free_clusters;
 }
+
+static int find_used_clusters(const struct exfat* ef,
+               cluster_t* a, cluster_t* b)
+{
+       const cluster_t end = le32_to_cpu(ef->sb->cluster_count);
+
+       /* find first used cluster */
+       for (*a = *b + 1; *a < end; (*a)++)
+               if (BMAP_GET(ef->cmap.chunk, *a - EXFAT_FIRST_DATA_CLUSTER))
+                       break;
+       if (*a >= end)
+               return 1;
+
+       /* find last contiguous used cluster */
+       for (*b = *a; *b < end; (*b)++)
+               if (BMAP_GET(ef->cmap.chunk, *b - EXFAT_FIRST_DATA_CLUSTER) == 0)
+               {
+                       (*b)--;
+                       break;
+               }
+
+       return 0;
+}
+
+int exfat_find_used_blocks(const struct exfat* ef, off_t* a, off_t* b)
+{
+       cluster_t ca, cb;
+
+       if (*a == 0 && *b == 0)
+               ca = cb = EXFAT_FIRST_DATA_CLUSTER - 1;
+       else
+       {
+               ca = b2c(ef, *a);
+               cb = b2c(ef, *b);
+       }
+       if (find_used_clusters(ef, &ca, &cb) != 0)
+               return 1;
+       if (*a != 0 || *b != 0)
+               *a = c2b(ef, ca);
+       *b = c2b(ef, cb) + (CLUSTER_SIZE(*ef->sb) - 1) / BLOCK_SIZE(*ef->sb);
+       return 0;
+}