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* delta.h: headers for delta functionality
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* Adapted from GIT for Bazaar by
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* John Arbash Meinel <john@arbash-meinel.com> (C) 2009
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* This code is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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/* opaque object for delta index */
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const void *buf; /* Pointer to the beginning of source data */
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unsigned long size; /* Total length of source data */
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unsigned long agg_offset; /* Start of source data as part of the
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* create_delta_index: compute index data from given buffer
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* This returns a pointer to a struct delta_index that should be passed to
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* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
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* is returned on failure. The given buffer must not be freed nor altered
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* before free_delta_index() is called. The returned pointer must be freed
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* using free_delta_index().
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extern struct delta_index *
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create_delta_index(const struct source_info *src,
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struct delta_index *old);
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* create_delta_index_from_delta: compute index data from given buffer
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* This returns a pointer to a struct delta_index that should be passed to
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* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
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* is returned on failure.
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* The bytes must be in the form of a delta structure, as generated by
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* create_delta(). The generated index will only index the insert bytes, and
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* not any of the control structures.
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extern struct delta_index *
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create_delta_index_from_delta(const struct source_info *delta,
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struct delta_index *old);
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* free_delta_index: free the index created by create_delta_index()
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* Given pointer must be what create_delta_index() returned, or NULL.
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extern void free_delta_index(struct delta_index *index);
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* sizeof_delta_index: returns memory usage of delta index
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* Given pointer must be what create_delta_index() returned, or NULL.
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extern unsigned long sizeof_delta_index(struct delta_index *index);
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* create_delta: create a delta from given index for the given buffer
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* This function may be called multiple times with different buffers using
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* the same delta_index pointer. If max_delta_size is non-zero and the
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* resulting delta is to be larger than max_delta_size then NULL is returned.
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* On success, a non-NULL pointer to the buffer with the delta data is
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* returned and *delta_size is updated with its size. The returned buffer
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* must be freed by the caller.
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create_delta(const struct delta_index *index,
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const void *buf, unsigned long bufsize,
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unsigned long *delta_size, unsigned long max_delta_size);
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/* the smallest possible delta size is 3 bytes
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* Target size, Copy command, Copy length
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#define DELTA_SIZE_MIN 3
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* This must be called twice on the delta data buffer, first to get the
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* expected source buffer size, and again to get the target buffer size.
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get_delta_hdr_size(unsigned char **datap, const unsigned char *top)
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unsigned char *data = *datap;
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unsigned long size = 0;
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size |= (cmd & ~0x80) << i;
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} while (cmd & 0x80 && data < top);
added
removed
bzrlib/delta.h
