From f40bfc9267b13b54e6379dfe7539447662879d24 Mon Sep 17 00:00:00 2001 From: Sean Bartell Date: Sat, 25 Jun 2011 21:32:25 -0400 Subject: Add codecs to librbcodec. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius Tested-by: Nils Wallménius --- lib/rbcodec/codecs/liba52/bitstream.c | 97 +++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 lib/rbcodec/codecs/liba52/bitstream.c (limited to 'lib/rbcodec/codecs/liba52/bitstream.c') diff --git a/lib/rbcodec/codecs/liba52/bitstream.c b/lib/rbcodec/codecs/liba52/bitstream.c new file mode 100644 index 0000000000..155368f1ed --- /dev/null +++ b/lib/rbcodec/codecs/liba52/bitstream.c @@ -0,0 +1,97 @@ +/* + * bitstream.c + * Copyright (C) 2000-2003 Michel Lespinasse + * Copyright (C) 1999-2000 Aaron Holtzman + * + * This file is part of a52dec, a free ATSC A-52 stream decoder. + * See http://liba52.sourceforge.net/ for updates. + * + * a52dec is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * a52dec is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include "config-a52.h" + +#include + +#include "a52.h" +#include "a52_internal.h" +#include "bitstream.h" + +#define BUFFER_SIZE 4096 + +void a52_bitstream_set_ptr (a52_state_t * state, uint8_t * buf) +{ + int align; + + align = (long)buf & 3; + state->buffer_start = (uint32_t *) (buf - align); + state->bits_left = 0; + state->current_word = 0; + bitstream_get (state, align * 8); + bitstream_get_2 (state, 0); /* pretend function is used - keep gcc happy */ +} + +static inline void bitstream_fill_current (a52_state_t * state) +{ + uint32_t tmp; + + tmp = *(state->buffer_start++); + state->current_word = swab32 (tmp); +} + +/* + * The fast paths for _get is in the + * bitstream.h header file so it can be inlined. + * + * The "bottom half" of this routine is suffixed _bh + * + * -ah + */ + +uint32_t a52_bitstream_get_bh (a52_state_t * state, uint32_t num_bits) +{ + uint32_t result; + + num_bits -= state->bits_left; + result = ((state->current_word << (32 - state->bits_left)) >> + (32 - state->bits_left)); + + bitstream_fill_current (state); + + if (num_bits != 0) + result = (result << num_bits) | (state->current_word >> (32 - num_bits)); + + state->bits_left = 32 - num_bits; + + return result; +} + +int32_t a52_bitstream_get_bh_2 (a52_state_t * state, uint32_t num_bits) +{ + int32_t result; + + num_bits -= state->bits_left; + result = ((((int32_t)state->current_word) << (32 - state->bits_left)) >> + (32 - state->bits_left)); + + bitstream_fill_current(state); + + if (num_bits != 0) + result = (result << num_bits) | (state->current_word >> (32 - num_bits)); + + state->bits_left = 32 - num_bits; + + return result; +} -- cgit v1.2.3