vl/rbsp: add H.264 RBSP implementation

Signed-off-by: Christian König <christian.koenig@amd.com>

src/gallium/auxiliary/vl/vl_rbsp.h

@@ -0,0 +1,164 @@
+/**************************************************************************
+ *
+ * Copyright 2013 Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/*
+ * Authors:
+ *      Christian König <christian.koenig@amd.com>
+ *
+ */
+
+/*
+ * Functions for reading the raw byte sequence payload of H.264
+ */
+
+#ifndef vl_rbsp_h
+#define vl_rbsp_h
+
+#include "vl/vl_vlc.h"
+
+struct vl_rbsp {
+   struct vl_vlc nal;
+   unsigned escaped;
+};
+
+/**
+ * Initialize the RBSP object
+ */
+static INLINE void vl_rbsp_init(struct vl_rbsp *rbsp, struct vl_vlc *nal, unsigned num_bits)
+{
+   unsigned bits_left = vl_vlc_bits_left(nal);
+
+   /* copy the position */
+   rbsp->nal = *nal;
+
+   rbsp->escaped = 0;
+
+   /* search for the end of the NAL unit */
+   while (vl_vlc_search_byte(nal, num_bits, 0x00)) {
+      if (vl_vlc_peekbits(nal, 24) == 0x000001 ||
+          vl_vlc_peekbits(nal, 32) == 0x00000001) {
+         vl_vlc_limit(&rbsp->nal, bits_left - vl_vlc_bits_left(nal));
+         return;
+      }
+      vl_vlc_eatbits(nal, 8);
+   }
+}
+
+/**
+ * Make at least 16 more bits available
+ */
+static INLINE void vl_rbsp_fillbits(struct vl_rbsp *rbsp)
+{
+   unsigned valid = vl_vlc_valid_bits(&rbsp->nal);
+   unsigned i, bits;
+
+   /* abort if we still have enough bits */
+   if (valid >= 32)
+      return;
+
+   vl_vlc_fillbits(&rbsp->nal);
+
+   /* abort if we have less than 24 bits left in this nal */
+   if (vl_vlc_bits_left(&rbsp->nal) < 24)
+      return;
+
+   /* check that we have enough bits left from the last fillbits */
+   assert(valid >= rbsp->escaped);
+
+   /* handle the already escaped bits */
+   valid -= rbsp->escaped;
+
+   /* search for the emulation prevention three byte */
+   rbsp->escaped = 16;
+   bits = vl_vlc_valid_bits(&rbsp->nal);
+   for (i = valid + 24; i <= bits; i += 8) {
+      if ((vl_vlc_peekbits(&rbsp->nal, i) & 0xffffff) == 0x3) {
+         vl_vlc_removebits(&rbsp->nal, i - 8, 8);
+         rbsp->escaped = bits - i;
+         bits -= 8;
+         i += 8;
+      }
+   }
+}
+
+/**
+ * Return an unsigned integer from the first n bits
+ */
+static INLINE unsigned vl_rbsp_u(struct vl_rbsp *rbsp, unsigned n)
+{
+   if (n == 0)
+      return 0;
+
+   vl_rbsp_fillbits(rbsp);
+   return vl_vlc_get_uimsbf(&rbsp->nal, n);
+}
+
+/**
+ * Return an unsigned exponential Golomb encoded integer
+ */
+static INLINE unsigned vl_rbsp_ue(struct vl_rbsp *rbsp)
+{
+   unsigned bits = 0;
+
+   vl_rbsp_fillbits(rbsp);
+   while (!vl_vlc_get_uimsbf(&rbsp->nal, 1))
+      ++bits;
+
+   return (1 << bits) - 1 + vl_rbsp_u(rbsp, bits);
+}
+
+/**
+ * Return an signed exponential Golomb encoded integer
+ */
+static INLINE signed vl_rbsp_se(struct vl_rbsp *rbsp)
+{
+   signed codeNum = vl_rbsp_ue(rbsp);
+   if (codeNum & 1)
+      return (codeNum + 1) >> 1;
+   else
+      return -(codeNum >> 1);
+}
+
+/**
+ * Are more data available in the RBSP ?
+ */
+static INLINE bool vl_rbsp_more_data(struct vl_rbsp *rbsp)
+{
+   unsigned bits, value;
+
+   if (vl_vlc_bits_left(&rbsp->nal) > 8)
+      return TRUE;
+
+   bits = vl_vlc_valid_bits(&rbsp->nal);
+   value = vl_vlc_peekbits(&rbsp->nal, bits);
+   if (value == 0 || value == (1 << (bits - 1)))
+      return FALSE;
+
+   return TRUE;
+}
+
+#endif /* vl_rbsp_h */