1 files changed, 147 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/rangecoder.h b/ffmpeg1/libavcodec/rangecoder.h
new file mode 100644
index 0000000..88e555f
--- /dev/null
+++ b/ffmpeg1/libavcodec/rangecoder.h
@@ -0,0 +1,147 @@
+/*
+ * Range coder
+ * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Range coder.
+ */
+
+#ifndef AVCODEC_RANGECODER_H
+#define AVCODEC_RANGECODER_H
+
+#include <stdint.h>
+
+#include "libavutil/common.h"
+#include "libavutil/avassert.h"
+
+typedef struct RangeCoder {
+    int low;
+    int range;
+    int outstanding_count;
+    int outstanding_byte;
+    uint8_t zero_state[256];
+    uint8_t one_state[256];
+    uint8_t *bytestream_start;
+    uint8_t *bytestream;
+    uint8_t *bytestream_end;
+} RangeCoder;
+
+void ff_init_range_encoder(RangeCoder *c, uint8_t *buf, int buf_size);
+void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf, int buf_size);
+int ff_rac_terminate(RangeCoder *c);
+void ff_build_rac_states(RangeCoder *c, int factor, int max_p);
+
+static inline void renorm_encoder(RangeCoder *c)
+{
+    // FIXME: optimize
+    while (c->range < 0x100) {
+        if (c->outstanding_byte < 0) {
+            c->outstanding_byte = c->low >> 8;
+        } else if (c->low <= 0xFF00) {
+            *c->bytestream++ = c->outstanding_byte;
+            for (; c->outstanding_count; c->outstanding_count--)
+                *c->bytestream++ = 0xFF;
+            c->outstanding_byte = c->low >> 8;
+        } else if (c->low >= 0x10000) {
+            *c->bytestream++ = c->outstanding_byte + 1;
+            for (; c->outstanding_count; c->outstanding_count--)
+                *c->bytestream++ = 0x00;
+            c->outstanding_byte = (c->low >> 8) & 0xFF;
+        } else {
+            c->outstanding_count++;
+        }
+
+        c->low     = (c->low & 0xFF) << 8;
+        c->range <<= 8;
+    }
+}
+
+static inline int get_rac_count(RangeCoder *c)
+{
+    int x = c->bytestream - c->bytestream_start + c->outstanding_count;
+    if (c->outstanding_byte >= 0)
+        x++;
+    return 8 * x - av_log2(c->range);
+}
+
+static inline void put_rac(RangeCoder *c, uint8_t *const state, int bit)
+{
+    int range1 = (c->range * (*state)) >> 8;
+
+    av_assert2(*state);
+    av_assert2(range1 < c->range);
+    av_assert2(range1 > 0);
+    if (!bit) {
+        c->range -= range1;
+        *state    = c->zero_state[*state];
+    } else {
+        c->low  += c->range - range1;
+        c->range = range1;
+        *state   = c->one_state[*state];
+    }
+
+    renorm_encoder(c);
+}
+
+static inline void refill(RangeCoder *c)
+{
+    if (c->range < 0x100) {
+        c->range <<= 8;
+        c->low   <<= 8;
+        if (c->bytestream < c->bytestream_end)
+            c->low += c->bytestream[0];
+        c->bytestream++;
+    }
+}
+
+static inline int get_rac(RangeCoder *c, uint8_t *const state)
+{
+    int range1 = (c->range * (*state)) >> 8;
+    int av_unused one_mask;
+
+    c->range -= range1;
+#if 1
+    if (c->low < c->range) {
+        *state = c->zero_state[*state];
+        refill(c);
+        return 0;
+    } else {
+        c->low  -= c->range;
+        *state   = c->one_state[*state];
+        c->range = range1;
+        refill(c);
+        return 1;
+    }
+#else
+    one_mask = (c->range - c->low - 1) >> 31;
+
+    c->low   -= c->range & one_mask;
+    c->range += (range1 - c->range) & one_mask;
+
+    *state = c->zero_state[(*state) + (256 & one_mask)];
+
+    refill(c);
+
+    return one_mask & 1;
+#endif
+}
+
+#endif /* AVCODEC_RANGECODER_H */