Block processor: add flags to manage hashing & sparse block detection

This commit adds 2 new user settable flags to the block processor:
 - A flag to ignore sparse blocks and treat them like normal
   data blocks.
 - A flag to disable checksum computation altogether.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/sqfs/block_processor/common.c b/lib/sqfs/block_processor/common.c
index bfcc3d5..b40ec0f 100644
--- a/lib/sqfs/block_processor/common.c
+++ b/lib/sqfs/block_processor/common.c
@@ -144,12 +144,17 @@ static int process_block(sqfs_block_t *block, sqfs_compressor_t *cmp,
 		}
 	}
 
-	if (is_zero_block(block->data, block->size)) {
+	if (!(block->flags & SQFS_BLK_IGNORE_SPARSE) &&
+	    is_zero_block(block->data, block->size)) {
 		block->flags |= SQFS_BLK_IS_SPARSE;
 		return 0;
 	}
 
-	block->checksum = xxh32(block->data, block->size);
+	if (block->flags & SQFS_BLK_DONT_HASH) {
+		block->checksum = 0;
+	} else {
+		block->checksum = xxh32(block->data, block->size);
+	}
 
 	if (block->flags & (SQFS_BLK_IS_FRAGMENT | SQFS_BLK_DONT_COMPRESS))
 		return 0;