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68 lines
1.7 KiB
68 lines
1.7 KiB
/* |
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* bitstream.h |
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* |
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* Copyright (C) Aaron Holtzman - Dec 1999 |
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* |
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* This file is part of ac3dec, a free AC-3 audio decoder |
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* |
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* ac3dec is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2, or (at your option) |
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* any later version. |
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* |
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* ac3dec is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with GNU Make; see the file COPYING. If not, write to |
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
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* |
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*/ |
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//My new and improved vego-matic endian swapping routine |
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//(stolen from the kernel) |
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#ifdef WORDS_BIGENDIAN |
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# define swab32(x) (x) |
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#else |
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# if defined (__i386__) |
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# define swab32(x) __i386_swab32(x) |
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static inline const uint32_t __i386_swab32(uint32_t x) |
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{ |
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__asm__("bswap %0" : "=r" (x) : "0" (x)); |
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return x; |
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} |
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# else |
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# define swab32(x)\ |
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((((uint8_t*)&x)[0] << 24) | (((uint8_t*)&x)[1] << 16) | \ |
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(((uint8_t*)&x)[2] << 8) | (((uint8_t*)&x)[3])) |
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# endif |
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#endif |
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extern uint32_t bits_left; |
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extern uint32_t current_word; |
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void bitstream_set_ptr (uint8_t * buf); |
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uint32_t bitstream_get_bh(uint32_t num_bits); |
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static inline uint32_t |
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bitstream_get(uint32_t num_bits) |
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{ |
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uint32_t result; |
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if(num_bits < bits_left) { |
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result = (current_word << (32 - bits_left)) >> (32 - num_bits); |
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bits_left -= num_bits; |
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return result; |
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} |
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return bitstream_get_bh(num_bits); |
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}
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