~bzr-pqm/bzr/bzr.dev : contents of bzrlib/delta.h at revision 6500

~bzr-pqm/bzr/bzr.dev : (revision 6500)

0.17.31 by John Arbash Meinel Bring in the 'rabin' experiment.	1	/*
	2	* delta.h: headers for delta functionality
	3	*
	4	* Adapted from GIT for Bazaar by
	5	* John Arbash Meinel <john@arbash-meinel.com> (C) 2009
	6	*
	7	* This code is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	11	#ifndef DELTA_H
	12	#define DELTA_H
	13
	14	/* opaque object for delta index */
	15	struct delta_index;
	16
0.23.42 by John Arbash Meinel Change the code around again.	17	struct source_info {
0.23.57 by John Arbash Meinel Change the formatting, replace \t with spaces to be consistent with bzr coding.	18	const void buf; / Pointer to the beginning of source data */
	19	unsigned long size; /* Total length of source data */
	20	unsigned long agg_offset; /* Start of source data as part of the
	21	aggregate source */
0.23.42 by John Arbash Meinel Change the code around again.	22	};
0.23.42 by John Arbash Meinel Change the code around again.	23
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	24	/* result type for functions that have multiple failure modes */
	25	typedef enum {
	26	DELTA_OK, /* Success */
	27	DELTA_OUT_OF_MEMORY, /* Could not allocate required memory */
	28	DELTA_INDEX_NEEDED, /* A delta_index must be passed */
	29	DELTA_SOURCE_EMPTY, /* A source_info had no content */
	30	DELTA_SOURCE_BAD, /* A source_info had invalid or corrupt content */
5698.2.6 by Martin Also adapt create_delta to the return code interface as it uses malloc	31	DELTA_BUFFER_EMPTY, /* A buffer pointer and size */
5698.2.7 by Martin Non-code fixes noticed looking at full diff	32	DELTA_SIZE_TOO_BIG, /* Delta data is larger than the max requested */
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	33	} delta_result;
	34
	35
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	36	/*
	37	* create_delta_index: compute index data from given buffer
	38	*
5698.2.8 by Martin Tweak function descriptions in delta header for clarity	39	* Returns a delta_result status, when DELTA_OK then *fresh is set to a struct
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	40	* delta_index that should be passed to subsequent create_delta() calls, or to
5698.2.8 by Martin Tweak function descriptions in delta header for clarity	41	* free_delta_index(). Other values are a failure, and *fresh is unset.
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	42	* The given buffer must not be freed nor altered before free_delta_index() is
	43	* called. The resultant struct must be freed using free_delta_index().
5755.2.3 by John Arbash Meinel Add a max_entries_per_source to DeltaIndex	44	*
5755.2.8 by John Arbash Meinel Do a lot of renaming.	45	* :param max_bytes_to_index: Limit the number of regions to sample to this
	46	* amount of text. We will store at most max_bytes_to_index / RABIN_WINDOW
	47	* pointers into the source text. Useful if src can be unbounded in size,
	48	* and you are willing to trade match accuracy for peak memory.
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	49	*/
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	50	extern delta_result
0.23.43 by John Arbash Meinel Change the internals to allow delta indexes to be expanded with new source data.	51	create_delta_index(const struct source_info *src,
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	52	struct delta_index *old,
5755.2.3 by John Arbash Meinel Add a max_entries_per_source to DeltaIndex	53	struct delta_index **fresh,
5755.2.10 by John Arbash Meinel Merge Martin gz's tweaks for signed vs unsigned, but tweak them a bit further.	54	int max_bytes_to_index);
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	55
0.23.45 by John Arbash Meinel Add a function that updates the index for delta bytes.	56
	57	/*
	58	* create_delta_index_from_delta: compute index data from given buffer
	59	*
5698.2.8 by Martin Tweak function descriptions in delta header for clarity	60	* Returns a delta_result status, when DELTA_OK then *fresh is set to a struct
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	61	* delta_index that should be passed to subsequent create_delta() calls, or to
5698.2.8 by Martin Tweak function descriptions in delta header for clarity	62	* free_delta_index(). Other values are a failure, and *fresh is unset.
0.23.45 by John Arbash Meinel Add a function that updates the index for delta bytes.	63	* The bytes must be in the form of a delta structure, as generated by
	64	* create_delta(). The generated index will only index the insert bytes, and
	65	* not any of the control structures.
	66	*/
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	67	extern delta_result
0.23.45 by John Arbash Meinel Add a function that updates the index for delta bytes.	68	create_delta_index_from_delta(const struct source_info *delta,
5698.2.5 by Martin Switch approach to delta function interfaces and use a return code and outparam	69	struct delta_index *old,
	70	struct delta_index **fresh);
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	71	/*
	72	* free_delta_index: free the index created by create_delta_index()
	73	*
	74	* Given pointer must be what create_delta_index() returned, or NULL.
	75	*/
	76	extern void free_delta_index(struct delta_index *index);
	77
	78	/*
	79	* sizeof_delta_index: returns memory usage of delta index
	80	*
	81	* Given pointer must be what create_delta_index() returned, or NULL.
	82	*/
	83	extern unsigned long sizeof_delta_index(struct delta_index *index);
	84
	85	/*
	86	* create_delta: create a delta from given index for the given buffer
	87	*
	88	* This function may be called multiple times with different buffers using
	89	* the same delta_index pointer. If max_delta_size is non-zero and the
5698.2.6 by Martin Also adapt create_delta to the return code interface as it uses malloc	90	* resulting delta is to be larger than max_delta_size then DELTA_SIZE_TOO_BIG
5698.2.8 by Martin Tweak function descriptions in delta header for clarity	91	* is returned. Otherwise on success, DELTA_OK is returned and *delta_data is
	92	* set to a new buffer with the delta data and *delta_size is updated with its
	93	* size. That buffer must be freed by the caller.
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	94	*/
5698.2.6 by Martin Also adapt create_delta to the return code interface as it uses malloc	95	extern delta_result
0.23.44 by John Arbash Meinel Remove the multi-index handling now that we have index combining instead.	96	create_delta(const struct delta_index *index,
5698.2.6 by Martin Also adapt create_delta to the return code interface as it uses malloc	97	const void *buf, unsigned long bufsize,
	98	unsigned long *delta_size, unsigned long max_delta_size,
	99	void **delta_data);
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	100
3735.38.1 by John Arbash Meinel Change the delta byte stream to remove the 'source length' entry.	101	/* the smallest possible delta size is 3 bytes
	102	* Target size, Copy command, Copy length
	103	*/
	104	#define DELTA_SIZE_MIN 3
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	105
	106	/*
	107	* This must be called twice on the delta data buffer, first to get the
	108	* expected source buffer size, and again to get the target buffer size.
	109	*/
3735.36.7 by John Arbash Meinel Get rid of inline and const, to reduce warnings and errors.	110	static unsigned long
	111	get_delta_hdr_size(unsigned char *datap, const unsigned char top)
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	112	{
3735.36.7 by John Arbash Meinel Get rid of inline and const, to reduce warnings and errors.	113	unsigned char data = datap;
0.23.57 by John Arbash Meinel Change the formatting, replace \t with spaces to be consistent with bzr coding.	114	unsigned char cmd;
	115	unsigned long size = 0;
	116	int i = 0;
	117	do {
	118	cmd = *data++;
	119	size \|= (cmd & ~0x80) << i;
	120	i += 7;
	121	} while (cmd & 0x80 && data < top);
	122	*datap = data;
	123	return size;
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	124	}
	125
5755.2.3 by John Arbash Meinel Add a max_entries_per_source to DeltaIndex	126	/*
	127	* Return the basic information about a given delta index.
	128	* :param index: The delta_index object
	129	* :param pos: The offset in the entry list. Start at 0, and walk until you get
	130	* 0 as a return code.
	131	* :param global_offset: return value, distance to the beginning of all sources
	132	* :param hash_val: return value, the RABIN hash associated with this pointer
	133	* :param hash_offset: Location for this entry in the hash array.
	134	* :return: 1 if pos != -1 (there was data produced)
	135	*/
	136	extern int
	137	get_entry_summary(const struct delta_index *index, int pos,
	138	unsigned int text_offset, unsigned int hash_val);
	139
	140	/*
	141	* Determine what entry index->hash[X] points to.
	142	*/
	143	extern int
	144	get_hash_offset(const struct delta_index *index, int pos,
	145	unsigned int *entry_offset);
	146
	147	/*
	148	* Compute the rabin_hash of the given data, it is assumed the data is at least
	149	* RABIN_WINDOW wide (16 bytes).
	150	*/
	151	extern unsigned int
5755.2.10 by John Arbash Meinel Merge Martin gz's tweaks for signed vs unsigned, but tweak them a bit further.	152	rabin_hash(const unsigned char *data);
5755.2.3 by John Arbash Meinel Add a max_entries_per_source to DeltaIndex	153
0.23.5 by John Arbash Meinel Minor changes to get diff-delta.c and patch-delta.c to compile.	154	#endif