FastDup/ext/htslib/htscodecs/htscodecs/rle.h

96 lines
3.7 KiB
C

/*
* Copyright (c) 2019 Genome Research Ltd.
* Author(s): James Bonfield
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* 3. Neither the names Genome Research Ltd and Wellcome Trust Sanger
* Institute nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY GENOME RESEARCH LTD AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GENOME RESEARCH
* LTD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef HTS_RLE_H
#define HTS_RLE_H
#ifdef __cplusplus
extern "C" {
#endif
/*
* Performs run length encoding of a byte stream, turning it into a
* list of lengths and a list of literals.
*
* The method used is a bit different to traditional run length
* encoding. It always outputs run-lengths for symbols in the
* 'rle_syms' list (even if that length is +0 more), and never outputs
* lengths for symbols not in that list.
*
* "run" should be preallocated to be large enough;
* e.g at least data_len bytes long as a worse case.
* "rle_syms" should be allocated to be at least 256 bytes.
*
* If *rle_nsyms is zero this function will survey the input data
* first to choose symbols automatically, writing back to rle_syms and
* rle_nsyms.
*
* The "out" buffer may be passed in as NULL in which case it is
* allocated and returned (and is up to the caller to free).
* Otherwise if specified as non-NULL it will be written to, but
* it is up to the caller to ensure the buffer size is large enough.
* A worst case scenario is 2*data_len.
*
* Returns the literal buffer on success with new length in out_len,
* also fills out run buffer and run_len, and potentially
* updates rle_syms / rle_nsyms too.
* Returns NULL of failure
*/
uint8_t *hts_rle_encode(uint8_t *data, uint64_t data_len,
uint8_t *run, uint64_t *run_len,
uint8_t *rle_syms, int *rle_nsyms,
uint8_t *out, uint64_t *out_len);
/*
* Expands a run lengthed data steam from a pair of literal and
* run-length buffers.
*
* On input *out_len holds the length of the supplied out
* buffer. On exit, it holds the used portion of this buffer.
*
* Returns uncompressed data (out) on success,
* NULL on failure.
*/
uint8_t *hts_rle_decode(uint8_t *lit, uint64_t lit_len,
uint8_t *run, uint64_t run_len,
uint8_t *rle_syms, int rle_nsyms,
uint8_t *out, uint64_t *out_len);
// TODO: Add rle scanning func to compute rle_syms.
#ifdef __cplusplus
}
#endif
#endif /* HTS_RLE_H */