*
**************************************************************************/
-/**
- * This file is based uppon slice_xvmc.c and vlc.h from the xine project,
- * which in turn is based on mpeg2dec. The following is the original copyright:
- *
- * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
- * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
- *
- * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
- * See http://libmpeg2.sourceforge.net/ for updates.
- *
- * mpeg2dec 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.
- *
- * mpeg2dec 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+/*
+ * Functions for fast bitwise access to multiple probably unaligned input buffers
*/
#ifndef vl_vlc_h
#define vl_vlc_h
+#include "pipe/p_compiler.h"
+
+#include "util/u_math.h"
+#include "util/u_pointer.h"
+#include "util/u_debug.h"
+
struct vl_vlc
{
- uint32_t buf; /* current 32 bit working set of buffer */
- int bits; /* used bits in working set */
- const uint8_t *ptr; /* buffer with stream data */
- const uint8_t *max; /* ptr+len of buffer */
+ uint64_t buffer;
+ signed invalid_bits;
+ const uint8_t *data;
+ const uint8_t *end;
+
+ unsigned num_inputs;
+ const void *const *inputs;
+ const unsigned *sizes;
+ unsigned bytes_left;
};
-static inline void
-vl_vlc_restart(struct vl_vlc *vlc)
+struct vl_vlc_entry
{
- vlc->buf = (vlc->ptr[0] << 24) | (vlc->ptr[1] << 16) | (vlc->ptr[2] << 8) | vlc->ptr[3];
- vlc->bits = -16;
- vlc->ptr += 4;
-}
+ int8_t length;
+ int8_t value;
+};
-static inline void
-vl_vlc_init(struct vl_vlc *vlc, const uint8_t *data, unsigned len)
+struct vl_vlc_compressed
{
- vlc->ptr = data;
- vlc->max = data + len;
- vl_vlc_restart(vlc);
-}
+ uint16_t bitcode;
+ struct vl_vlc_entry entry;
+};
-static inline bool
-vl_vlc_getbyte(struct vl_vlc *vlc)
+/**
+ * initalize and decompress a lookup table
+ */
+static INLINE void
+vl_vlc_init_table(struct vl_vlc_entry *dst, unsigned dst_size, const struct vl_vlc_compressed *src, unsigned src_size)
{
- vlc->buf <<= 8;
- vlc->buf |= vlc->ptr[0];
- vlc->ptr++;
- return vlc->ptr < vlc->max;
+ unsigned i, bits = util_logbase2(dst_size);
+
+ assert(dst && dst_size);
+ assert(src && src_size);
+
+ for (i=0;i<dst_size;++i) {
+ dst[i].length = 0;
+ dst[i].value = 0;
+ }
+
+ for(; src_size > 0; --src_size, ++src) {
+ for(i=0; i<(1 << (bits - src->entry.length)); ++i)
+ dst[src->bitcode >> (16 - bits) | i] = src->entry;
+ }
}
-#define vl_vlc_getword(vlc, shift) \
-do { \
- (vlc)->buf |= (((vlc)->ptr[0] << 8) | (vlc)->ptr[1]) << (shift); \
- (vlc)->ptr += 2; \
-} while (0)
-
-/* make sure that there are at least 16 valid bits in bit_buf */
-#define vl_vlc_needbits(vlc) \
-do { \
- if ((vlc)->bits >= 0) { \
- vl_vlc_getword(vlc, (vlc)->bits); \
- (vlc)->bits -= 16; \
- } \
-} while (0)
-
-/* make sure that the full 32 bit of the buffer are valid */
-static inline void
-vl_vlc_need32bits(struct vl_vlc *vlc)
+/**
+ * switch over to next input buffer
+ */
+static INLINE void
+vl_vlc_next_input(struct vl_vlc *vlc)
{
- vl_vlc_needbits(vlc);
- if (vlc->bits > -8) {
- unsigned n = -vlc->bits;
- vlc->buf <<= n;
- vlc->buf |= *vlc->ptr << 8;
- vlc->bits = -8;
- vlc->ptr++;
+ const uint8_t* data = vlc->inputs[0];
+ unsigned len = vlc->sizes[0];
+
+ assert(vlc);
+ assert(vlc->num_inputs);
+
+ vlc->bytes_left -= len;
+
+ /* align the data pointer */
+ while (len && pointer_to_uintptr(data) & 3) {
+ vlc->buffer |= (uint64_t)*data << (24 + vlc->invalid_bits);
+ ++data;
+ --len;
+ vlc->invalid_bits -= 8;
}
- if (vlc->bits > -16) {
- unsigned n = -vlc->bits - 8;
- vlc->buf <<= n;
- vlc->buf |= *vlc->ptr;
- vlc->bits = -16;
- vlc->ptr++;
+ vlc->data = data;
+ vlc->end = data + len;
+
+ --vlc->num_inputs;
+ ++vlc->inputs;
+ ++vlc->sizes;
+}
+
+/**
+ * fill the bit buffer, so that at least 32 bits are valid
+ */
+static INLINE void
+vl_vlc_fillbits(struct vl_vlc *vlc)
+{
+ assert(vlc);
+
+ /* as long as the buffer needs to be filled */
+ while (vlc->invalid_bits > 0) {
+ unsigned bytes_left = vlc->end - vlc->data;
+
+ /* if this input is depleted */
+ if (bytes_left == 0) {
+
+ if (vlc->num_inputs)
+ /* go on to next input */
+ vl_vlc_next_input(vlc);
+ else
+ /* or give up since we don't have anymore inputs */
+ return;
+
+ } else if (bytes_left >= 4) {
+
+ /* enough bytes in buffer, read in a whole dword */
+ uint64_t value = *(const uint32_t*)vlc->data;
+
+#ifndef PIPE_ARCH_BIG_ENDIAN
+ value = util_bswap32(value);
+#endif
+
+ vlc->buffer |= value << vlc->invalid_bits;
+ vlc->data += 4;
+ vlc->invalid_bits -= 32;
+
+ /* buffer is now definitely filled up avoid the loop test */
+ break;
+
+ } else while (vlc->data < vlc->end) {
+
+ /* not enough bytes left in buffer, read single bytes */
+ vlc->buffer |= (uint64_t)*vlc->data << (24 + vlc->invalid_bits);
+ ++vlc->data;
+ vlc->invalid_bits -= 8;
+ }
}
}
-/* remove num valid bits from bit_buf */
-#define vl_vlc_dumpbits(vlc, num) \
-do { \
- (vlc)->buf <<= (num); \
- (vlc)->bits += (num); \
-} while (0)
+/**
+ * initialize vlc structure and start reading from first input buffer
+ */
+static INLINE void
+vl_vlc_init(struct vl_vlc *vlc, unsigned num_inputs,
+ const void *const *inputs, const unsigned *sizes)
+{
+ unsigned i;
+
+ assert(vlc);
+ assert(num_inputs);
-/* take num bits from the high part of bit_buf and zero extend them */
-#define vl_vlc_ubits(vlc, num) (((uint32_t)((vlc)->buf)) >> (32 - (num)))
+ vlc->buffer = 0;
+ vlc->invalid_bits = 32;
+ vlc->num_inputs = num_inputs;
+ vlc->inputs = inputs;
+ vlc->sizes = sizes;
+ vlc->bytes_left = 0;
-/* take num bits from the high part of bit_buf and sign extend them */
-#define vl_vlc_sbits(vlc, num) (((int32_t)((vlc)->buf)) >> (32 - (num)))
+ for (i = 0; i < num_inputs; ++i)
+ vlc->bytes_left += sizes[i];
+
+ vl_vlc_next_input(vlc);
+ vl_vlc_fillbits(vlc);
+ vl_vlc_fillbits(vlc);
+}
+
+/**
+ * number of bits still valid in bit buffer
+ */
+static INLINE unsigned
+vl_vlc_valid_bits(struct vl_vlc *vlc)
+{
+ return 32 - vlc->invalid_bits;
+}
+
+/**
+ * number of bits left over all inbut buffers
+ */
+static INLINE unsigned
+vl_vlc_bits_left(struct vl_vlc *vlc)
+{
+ signed bytes_left = vlc->end - vlc->data;
+ bytes_left += vlc->bytes_left;
+ return bytes_left * 8 + vl_vlc_valid_bits(vlc);
+}
+
+/**
+ * get num_bits from bit buffer without removing them
+ */
+static INLINE unsigned
+vl_vlc_peekbits(struct vl_vlc *vlc, unsigned num_bits)
+{
+ assert(vl_vlc_valid_bits(vlc) >= num_bits || vlc->data >= vlc->end);
+ return vlc->buffer >> (64 - num_bits);
+}
+
+/**
+ * remove num_bits from bit buffer
+ */
+static INLINE void
+vl_vlc_eatbits(struct vl_vlc *vlc, unsigned num_bits)
+{
+ assert(vl_vlc_valid_bits(vlc) >= num_bits);
+
+ vlc->buffer <<= num_bits;
+ vlc->invalid_bits += num_bits;
+}
+
+/**
+ * get num_bits from bit buffer with removing them
+ */
+static INLINE unsigned
+vl_vlc_get_uimsbf(struct vl_vlc *vlc, unsigned num_bits)
+{
+ unsigned value;
+
+ assert(vl_vlc_valid_bits(vlc) >= num_bits);
+
+ value = vlc->buffer >> (64 - num_bits);
+ vl_vlc_eatbits(vlc, num_bits);
+
+ return value;
+}
+
+/**
+ * treat num_bits as signed value and remove them from bit buffer
+ */
+static INLINE signed
+vl_vlc_get_simsbf(struct vl_vlc *vlc, unsigned num_bits)
+{
+ signed value;
+
+ assert(vl_vlc_valid_bits(vlc) >= num_bits);
+
+ value = ((int64_t)vlc->buffer) >> (64 - num_bits);
+ vl_vlc_eatbits(vlc, num_bits);
+
+ return value;
+}
+
+/**
+ * lookup a value and length in a decompressed table
+ */
+static INLINE int8_t
+vl_vlc_get_vlclbf(struct vl_vlc *vlc, const struct vl_vlc_entry *tbl, unsigned num_bits)
+{
+ tbl += vl_vlc_peekbits(vlc, num_bits);
+ vl_vlc_eatbits(vlc, tbl->length);
+ return tbl->value;
+}
#endif /* vl_vlc_h */
projects / mesa.git / blobdiff