dts decoder using libdca

1 files changed, 115 insertions, 0 deletions

diff --git a/plugins/dca/bitstream.c b/plugins/dca/bitstream.c
new file mode 100644
index 00000000..f77cbc70
--- /dev/null
+++ b/plugins/dca/bitstream.c
@@ -0,0 +1,115 @@
+/*
+ * bitstream.c
+ * Copyright (C) 2004 Gildas Bazin <gbazin@videolan.org>
+ * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
+ * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
+ *
+ * This file is part of libdca, a free DTS Coherent Acoustics stream decoder.
+ * See http://www.videolan.org/developers/libdca.html for updates.
+ *
+ * libdca 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.
+ *
+ * libdca 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 "config.h"
+
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "dca.h"
+#include "dca_internal.h"
+#include "bitstream.h"
+
+#define BUFFER_SIZE 4096
+
+void dca_bitstream_init (dca_state_t * state, uint8_t * buf, int word_mode,
+                         int bigendian_mode)
+{
+    intptr_t align;
+
+    align = (uintptr_t)buf & 3;
+    state->buffer_start = (uint32_t *) ((uintptr_t)buf - align);
+    state->bits_left = 0;
+    state->current_word = 0;
+    state->word_mode = word_mode;
+    state->bigendian_mode = bigendian_mode;
+    bitstream_get (state, align * 8);
+}
+
+static inline void bitstream_fill_current (dca_state_t * state)
+{
+    uint32_t tmp;
+
+    tmp = *(state->buffer_start++);
+
+    if (state->bigendian_mode)
+        state->current_word = swab32 (tmp);
+    else
+        state->current_word = swable32 (tmp);
+
+    if (!state->word_mode)
+    {
+        state->current_word = (state->current_word & 0x00003FFF) |
+            ((state->current_word & 0x3FFF0000 ) >> 2);
+    }
+}
+
+/*
+ * 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 dca_bitstream_get_bh (dca_state_t * state, uint32_t num_bits)
+{
+    uint32_t result = 0;
+
+    if (state->bits_left)
+    {
+	num_bits -= state->bits_left;
+        result = ((state->current_word << (32 - state->bits_left)) >>
+		  (32 - state->bits_left));
+    }
+
+    if ( !state->word_mode && num_bits > 28 ) {
+        bitstream_fill_current (state);
+	result = (result << 28) | state->current_word;
+	num_bits -= 28;
+    }
+
+    bitstream_fill_current (state);
+
+    if ( state->word_mode )
+    {
+        if (num_bits != 0)
+	    result = (result << num_bits) |
+	             (state->current_word >> (32 - num_bits));
+
+	state->bits_left = 32 - num_bits;
+    }
+    else
+    {
+        if (num_bits != 0)
+	    result = (result << num_bits) |
+	             (state->current_word >> (28 - num_bits));
+
+	state->bits_left = 28 - num_bits;
+    }
+
+    return result;
+}