diff options
| -rw-r--r-- | Makefile.am | 3 | ||||
| -rw-r--r-- | src/dsd2pcm/dsd2pcm.c | 12 | ||||
| -rw-r--r-- | src/util/bit_reverse.c | 31 | ||||
| -rw-r--r-- | src/util/bit_reverse.h | 35 |
4 files changed, 73 insertions, 8 deletions
diff --git a/Makefile.am b/Makefile.am index c7b110354..d7f7f2314 100644 --- a/Makefile.am +++ b/Makefile.am @@ -227,6 +227,7 @@ src_mpd_SOURCES = \ $(MIXER_API_SRC) \ src/util/list.h \ src/util/list_sort.c src/util/list_sort.h \ + src/util/bit_reverse.c src/util/bit_reverse.h \ src/glib_socket.h \ src/notify.c \ src/audio_config.c src/audio_config.h \ @@ -1174,6 +1175,7 @@ test_run_normalize_LDADD = \ $(GLIB_LIBS) test_run_convert_SOURCES = test/run_convert.c \ + src/util/bit_reverse.c \ src/dsd2pcm/dsd2pcm.c \ src/fifo_buffer.c \ src/audio_format.c \ @@ -1272,6 +1274,7 @@ if HAVE_CXX noinst_PROGRAMS += src/dsd2pcm/dsd2pcm src_dsd2pcm_dsd2pcm_SOURCES = \ + src/util/bit_reverse.c \ src/dsd2pcm/dsd2pcm.c src/dsd2pcm/dsd2pcm.h \ src/dsd2pcm/noiseshape.c src/dsd2pcm/noiseshape.h \ src/dsd2pcm/main.cpp diff --git a/src/dsd2pcm/dsd2pcm.c b/src/dsd2pcm/dsd2pcm.c index 315820f60..4c7640853 100644 --- a/src/dsd2pcm/dsd2pcm.c +++ b/src/dsd2pcm/dsd2pcm.c @@ -1,3 +1,5 @@ +#include "util/bit_reverse.h" + #include <stdlib.h> #include <string.h> @@ -84,7 +86,6 @@ static const double htaps[HTAPS] = { }; static float ctables[CTABLES][256]; -static unsigned char bitreverse[256]; static int precalculated = 0; static void precalc(void) @@ -92,11 +93,6 @@ static void precalc(void) int t, e, m, k; double acc; if (precalculated) return; - for (t=0, e=0; t<256; ++t) { - bitreverse[t] = e; - for (m=128; m && !((e^=m)&m); m>>=1) - ; - } for (t=0; t<CTABLES; ++t) { k = HTAPS - t*8; if (k>8) k=8; @@ -170,10 +166,10 @@ extern void dsd2pcm_translate( lsbf = lsbf ? 1 : 0; while (samples-- > 0) { bite1 = *src & 0xFFu; - if (lsbf) bite1 = bitreverse[bite1]; + if (lsbf) bite1 = bit_reverse(bite1); ptr->fifo[ffp] = bite1; src += src_stride; p = ptr->fifo + ((ffp-CTABLES) & FIFOMASK); - *p = bitreverse[*p & 0xFF]; + *p = bit_reverse(*p); acc = 0; for (i=0; i<CTABLES; ++i) { bite1 = ptr->fifo[(ffp -i) & FIFOMASK] & 0xFF; diff --git a/src/util/bit_reverse.c b/src/util/bit_reverse.c new file mode 100644 index 000000000..ba8a23ef1 --- /dev/null +++ b/src/util/bit_reverse.c @@ -0,0 +1,31 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program 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. + * + * This program 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "bit_reverse.h" + +/** + * @see http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable + */ +const uint8_t bit_reverse_table[256] = +{ +#define R2(n) n, n + 2*64, n + 1*64, n + 3*64 +#define R4(n) R2(n), R2(n + 2*16), R2(n + 1*16), R2(n + 3*16) +#define R6(n) R4(n), R4(n + 2*4 ), R4(n + 1*4 ), R4(n + 3*4 ) + R6(0), R6(2), R6(1), R6(3) +}; diff --git a/src/util/bit_reverse.h b/src/util/bit_reverse.h new file mode 100644 index 000000000..e44693b1d --- /dev/null +++ b/src/util/bit_reverse.h @@ -0,0 +1,35 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program 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. + * + * This program 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef MPD_BIT_REVERSE_H +#define MPD_BIT_REVERSE_H + +#include <glib.h> +#include <stdint.h> + +extern const uint8_t bit_reverse_table[256]; + +G_GNUC_CONST +static inline uint8_t +bit_reverse(uint8_t x) +{ + return bit_reverse_table[x]; +} + +#endif |