mlp: Split common code from parser and decoder to be used by encoder.

Originally committed as revision 14733 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 120 insertions, 0 deletions

diff --git a/libavcodec/mlp.c b/libavcodec/mlp.c
new file mode 100644
index 0000000..f2a0276
--- /dev/null
+++ b/libavcodec/mlp.c
@@ -0,0 +1,120 @@
+/*
+ * MLP codec common code
+ * Copyright (c) 2007-2008 Ian Caulfield
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "libavutil/crc.h"
+#include "mlp.h"
+
+const uint8_t ff_mlp_huffman_tables[3][18][2] = {
+    {    /* Huffman table 0, -7 - +10 */
+        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
+        {0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
+        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
+    }, { /* Huffman table 1, -7 - +8 */
+        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
+        {0x02, 2}, {0x03, 2},
+        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
+    }, { /* Huffman table 2, -7 - +7 */
+        {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
+        {0x01, 1},
+        {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
+    }
+};
+
+static int crc_init = 0;
+static AVCRC crc_63[1024];
+static AVCRC crc_1D[1024];
+
+
+static int crc_init_2D = 0;
+static AVCRC crc_2D[1024];
+
+int av_cold ff_mlp_init_crc2D(AVCodecParserContext *s)
+{
+    if (!crc_init_2D) {
+        av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
+        crc_init_2D = 1;
+    }
+
+    return 0;
+}
+
+void av_cold ff_mlp_init_crc()
+{
+    if (!crc_init) {
+        av_crc_init(crc_63, 0,  8,   0x63, sizeof(crc_63));
+        av_crc_init(crc_1D, 0,  8,   0x1D, sizeof(crc_1D));
+        crc_init = 1;
+    }
+}
+
+uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
+{
+    uint16_t crc;
+
+    crc = av_crc(crc_2D, 0, buf, buf_size - 2);
+    crc ^= AV_RL16(buf + buf_size - 2);
+    return crc;
+}
+
+uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
+{
+    uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c
+    checksum ^= buf[buf_size-1];
+    return checksum;
+}
+
+uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
+{
+    int i;
+    int num_bytes = (bit_size + 2) / 8;
+
+    int crc = crc_1D[buf[0] & 0x3f];
+    crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2);
+    crc ^= buf[num_bytes - 1];
+
+    for (i = 0; i < ((bit_size + 2) & 7); i++) {
+        crc <<= 1;
+        if (crc & 0x100)
+            crc ^= 0x11D;
+        crc ^= (buf[num_bytes] >> (7 - i)) & 1;
+    }
+
+    return crc;
+}
+
+uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
+{
+    uint32_t scratch = 0;
+    const uint8_t *buf_end = buf + buf_size;
+
+    for (; buf < buf_end - 3; buf += 4)
+        scratch ^= *((const uint32_t*)buf);
+
+    scratch ^= scratch >> 16;
+    scratch ^= scratch >> 8;
+
+    for (; buf < buf_end; buf++)
+        scratch ^= *buf;
+
+    return scratch;
+}