kopia lustrzana https://github.com/F5OEO/tstools
124 wiersze
3.5 KiB
C
124 wiersze
3.5 KiB
C
/*
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* Infrastructure to handle byte data as bit data, and particularly to read
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* Exp-Golomb encoded data.
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*
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* See H.264 clause 10.
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the MPEG TS, PS and ES tools.
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*
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* The Initial Developer of the Original Code is Amino Communications Ltd.
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* Portions created by the Initial Developer are Copyright (C) 2008
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Amino Communications Ltd, Swavesey, Cambridge UK
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*
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* ***** END LICENSE BLOCK *****
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*/
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#ifndef _bitdata_fns
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#define _bitdata_fns
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#include "bitdata_defns.h"
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/*
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* Build a new bitdata datastructure.
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*
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* - `data` is the byte array we're extracting bits from.
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* - `data_len` is its length (in bytes).
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*
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* Returns 0 if it succeeds, 1 if some error occurs.
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*/
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extern int build_bitdata(bitdata_p *bitdata,
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byte data[],
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int data_len);
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/*
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* Tidy up and free a bitdata datastructure after we've finished with it.
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*
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* Clears the bitdata datastructure, frees it, and sets `bitdata` to NULL.
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*/
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extern void free_bitdata(bitdata_p *bitdata);
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/*
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* Return the next bit from the data.
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*
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* Returns 0 if it reads the bit correctly, 1 if there are no more
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* bits to be read.
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*/
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extern int read_bit(bitdata_p bitdata,
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byte *bit);
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/*
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* Reads `count` bits from the data.
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*
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* Note it is asserted that `count` must be in the range 0..32.
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*
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* Returns 0 if all went well, 1 if there were not enough bits in the data.
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*/
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extern int read_bits(bitdata_p bitdata,
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int count,
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u_int32 *bits);
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/*
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* Reads `count` bits from the data, into a byte.
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*
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* Note it is asserted that `count` must be in the range 0..8.
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*
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* Returns 0 if all went well, 1 if there were not enough bits in the data.
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*/
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extern int read_bits_into_byte(bitdata_p bitdata,
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int count,
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byte *bits);
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/*
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* Read zero bits, counting them. Stop at the first non-zero bit.
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*
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* Returns the number of zero bits. Note that the non-zero bit is not
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* "unread" in any way, so reading another bit will retrieve the first bit
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* thereafter.
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*/
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extern int count_zero_bits(bitdata_p bitdata);
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/*
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* Read and decode an Exp-Golomb code.
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*
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* Reference H.264 10.1 for an explanation.
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*
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* Returns 0 if all went well, 1 if there were not enough bits in the data.
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*/
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extern int read_exp_golomb(bitdata_p bitdata,
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u_int32 *result);
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/*
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* Read and decode a signed Exp-Golomb code.
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*
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* Reference H.264 10.1 sqq for an explanation.
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*
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* Returns 0 if all went well, 1 if there were not enough bits in the data.
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*/
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extern int read_signed_exp_golomb(bitdata_p bitdata,
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int32 *result);
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#endif // _bitdata_fns
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// Local Variables:
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// tab-width: 8
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// indent-tabs-mode: nil
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// c-basic-offset: 2
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// End:
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// vim: set tabstop=8 shiftwidth=2 expandtab:
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