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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-08-13 14:11:25 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-08-18 22:44:39 +0200
commit7ca19d23cb4913b5dabfdf3469852ec9f2c0f8d7 (patch)
treeacfff19efd250a37e9eec15be80aa1e743b78bc9 /include/block_processor.h
parent2f22a35e843a24f0ad5f31644133d64648fe4efc (diff)
Add block processor data structure
The interface is designed for parallel, asynchronuous processing of data blocks with an I/O callback that handles the serialized result. The underlying implementation is currently still synchronuous. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'include/block_processor.h')
-rw-r--r--include/block_processor.h111
1 files changed, 111 insertions, 0 deletions
diff --git a/include/block_processor.h b/include/block_processor.h
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+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * block_processor.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef BLOCK_PROCESSOR_H
+#define BLOCK_PROCESSOR_H
+
+#include "config.h"
+#include "compress.h"
+
+enum {
+ /* only calculate checksum, do NOT compress the data */
+ BLK_DONT_COMPRESS = 0x0001,
+
+ /* set by compressor worker if the block was actually compressed */
+ BLK_IS_COMPRESSED = 0x0002,
+
+ /* do not calculate block checksum */
+ BLK_DONT_CHECKSUM = 0x0004,
+
+ /* set by compressor worker if compression failed */
+ BLK_COMPRESS_ERROR = 0x0008,
+
+ /* first user setable block flag */
+ BLK_USER = 0x0080
+};
+
+typedef struct block_t {
+ /* used internally, ignored and overwritten when enqueueing blocks */
+ struct block_t *next;
+ uint32_t sequence_number;
+
+ /* Size of the data area */
+ uint32_t size;
+
+ /* checksum of the input data */
+ uint32_t checksum;
+
+ /* user settable file block index */
+ uint32_t index;
+
+ /* user pointer associated with the block */
+ void *user;
+
+ /* user settable flag field */
+ uint32_t flags;
+
+ /* raw data to be processed */
+ uint8_t data[];
+} block_t;
+
+typedef struct block_processor_t block_processor_t;
+
+/*
+ Gets called for each processed block. May be called from a different thread
+ than the one that calls enqueue, but only from one thread at a time.
+ Guaranteed to be called on blocks in the order that they are submitted
+ to enqueue.
+
+ A non-zero return value is interpreted as fatal error.
+ */
+typedef int (*block_cb)(void *user, block_t *blk);
+
+block_processor_t *block_processor_create(size_t max_block_size,
+ compressor_t *cmp,
+ unsigned int num_workers,
+ void *user,
+ block_cb callback);
+
+void block_processor_destroy(block_processor_t *proc);
+
+/*
+ Add a block to be processed. Returns non-zero on error and prints a message
+ to stderr.
+
+ The function takes over ownership of the submitted block. It is freed with
+ a after processing and calling the block callback.
+
+ Even on failure, the workers may still be running and
+ block_processor_finish must be called before cleaning up.
+*/
+int block_processor_enqueue(block_processor_t *proc, block_t *block);
+
+/*
+ Wait for the compressor workers to finish. Returns zero on success, non-zero
+ if an internal error occoured or one of the block callbacks returned a
+ non-zero value.
+ */
+int block_processor_finish(block_processor_t *proc);
+
+/*
+ Convenience function to create a block structure and optionally fill it with
+ content.
+
+ filename is used for printing error messages. If fd is a valid file
+ descriptor (>= 0), the function attempts to populate the payload data
+ from the input file.
+ */
+block_t *create_block(const char *filename, int fd, size_t size,
+ void *user, uint32_t flags);
+
+/*
+ Convenience function to process a data block. Returns 0 on success,
+ prints to stderr on failure.
+ */
+int process_block(block_t *block, compressor_t *cmp,
+ uint8_t *scratch, size_t scratch_size);
+
+#endif /* BLOCK_PROCESSOR_H */