Support associating a user pointer with data blocks

This commit modifies the block processor to support associating a user
data pointer with data blocks that it forwards to the block writer,
which is modified to accept an optional user data pointer.

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

2 files changed, 10 insertions, 4 deletions

diff --git a/include/sqfs/block_processor.h b/include/sqfs/block_processor.h
index c88e3df..5c77155 100644
--- a/include/sqfs/block_processor.h
+++ b/include/sqfs/block_processor.h
@@ -168,6 +168,8 @@ sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
  * @param inode An optional pointer to a pointer to an inode. If not NULL, the
  *              block processor creates a file inode and stores a pointer to
  *              it here and keeps updating the inode as the file grows.
+ * @param user An optional user data pointer that is passed to the
+ *             the @ref sqfs_block_writer_t for each file data block.
  * @param flags A combination of @ref SQFS_BLK_FLAGS that can be used to
  *              micro manage how the data is processed.
  *
@@ -175,7 +177,7 @@ sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
  */
 SQFS_API int sqfs_block_processor_begin_file(sqfs_block_processor_t *proc,
 					     sqfs_inode_generic_t **inode,
-					     sqfs_u32 flags);
+					     void *user, sqfs_u32 flags);
 
 /**
  * @brief Append data to the current file.
diff --git a/include/sqfs/block_writer.h b/include/sqfs/block_writer.h
index f8bc671..6352f4d 100644
--- a/include/sqfs/block_writer.h
+++ b/include/sqfs/block_writer.h
@@ -58,6 +58,9 @@ struct sqfs_block_writer_t {
 	 * @ref SQFS_BLK_LAST_BLOCK flag, the padding is added afterwards.
 	 *
 	 * @param wr A pointer to a block writer.
+	 * @param user An optional user data pointer.
+	 *             The @ref sqfs_block_processor_t can be told to pass this
+	 *             on to the block writer for each block.
 	 * @param size The size of the block to write.
 	 * @param checksum A 32 bit checksum of the block data.
 	 * @param flags A combination of @ref SQFS_BLK_FLAGS flag bits
@@ -70,9 +73,10 @@ struct sqfs_block_writer_t {
 	 *
 	 * @return Zero on success, an @ref SQFS_ERROR error on failure.
 	 */
-	int (*write_data_block)(sqfs_block_writer_t *wr, sqfs_u32 size,
-				sqfs_u32 checksum, sqfs_u32 flags,
-				const sqfs_u8 *data, sqfs_u64 *location);
+	int (*write_data_block)(sqfs_block_writer_t *wr, void *user,
+				sqfs_u32 size, sqfs_u32 checksum,
+				sqfs_u32 flags, const sqfs_u8 *data,
+				sqfs_u64 *location);
 
 	/**
 	 * @brief Get the number of blocks actually written to disk.