/*
* Copyright (c) 2011 Apple Inc. All rights reserved.
*
* @APPLE_APACHE_LICENSE_HEADER_START@
*
* Licensed under the Apache License, Version 2.0 (the "License") ;
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @APPLE_APACHE_LICENSE_HEADER_END@
*/
/*
File: dp_enc.c
Contains: Dynamic Predictor encode routines
Copyright: (c) 2001-2011 Apple, Inc.
*/
#include <string.h>
#include "dplib.h"
#include "shift.h"
#if __GNUC__
#define ALWAYS_INLINE __attribute__ ((always_inline))
#else
#define ALWAYS_INLINE
#endif
#define LOOP_ALIGN
void
init_coefs (int16_t * coefs, uint32_t denshift, int32_t numPairs)
{
int32_t k ;
int32_t den = 1 << denshift ;
coefs [0] = (AINIT * den) >> 4 ;
coefs [1] = (BINIT * den) >> 4 ;
coefs [2] = (CINIT * den) >> 4 ;
for (k = 3 ; k < numPairs ; k++)
coefs [k] = 0 ;
}
void
copy_coefs (const int16_t * srcCoefs, int16_t * dstCoefs, int32_t numPairs)
{
int32_t k ;
for (k = 0 ; k < numPairs ; k++)
dstCoefs [k] = srcCoefs [k] ;
}
static inline int32_t ALWAYS_INLINE sign_of_int (int32_t i)
{
int32_t negishift ;
negishift = ((uint32_t) - i) >> 31 ;
return negishift | (i >> 31) ;
}
void
pc_block (int32_t * in, int32_t * pc1, int32_t num, int16_t * coefs, int32_t numactive, uint32_t chanbits, uint32_t denshift)
{
register int16_t a0, a1, a2, a3 ;
register int32_t b0, b1, b2, b3 ;
int32_t j, k, lim ;
int32_t * pin ;
int32_t sum1, dd ;
int32_t sg, sgn ;
int32_t top ;
int32_t del, del0 ;
uint32_t chanshift = 32 - chanbits ;
int32_t denhalf = 1 << (denshift - 1) ;
pc1 [0] = in [0] ;
if (numactive == 0)
{
// just copy if numactive == 0 (but don't bother if in/out pointers the same)
if ((num > 1) && (in != pc1))
memcpy (&pc1 [1], &in [1], (num - 1) * sizeof (int32_t)) ;
return ;
}
if (numactive == 31)
{
// short-circuit if numactive == 31
for (j = 1 ; j < num ; j++)
{
del = in [j] - in [j-1] ;
pc1 [j] = (del << chanshift) >> chanshift ;
}
return ;
}
for (j = 1 ; j <= numactive ; j++)
{
del = in [j] - in [j-1] ;
pc1 [j] = arith_shift_left (del, chanshift) >> chanshift ;
}
lim = numactive + 1 ;
if (numactive == 4)
{
// optimization for numactive == 4
a0 = coefs [0] ;
a1 = coefs [1] ;
a2 = coefs [2] ;
a3 = coefs [3] ;
for (j = lim ; j < num ; j++)
{
LOOP_ALIGN
top = in [j - lim] ;
pin = in + j - 1 ;
b0 = top - pin [0] ;
b1 = top - pin [-1] ;
b2 = top - pin [-2] ;
b3 = top - pin [-3] ;
sum1 = (denhalf - a0 * b0 - a1 * b1 - a2 * b2 - a3 * b3) >> denshift ;
del = in [j] - top - sum1 ;
del = arith_shift_left (del, chanshift) >> chanshift ;
pc1 [j] = del ;
del0 = del ;
sg = sign_of_int (del) ;
if (sg > 0)
{
sgn = sign_of_int (b3) ;
a3 -= sgn ;
del0 -= (4 - 3) * ((sgn * b3) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b2) ;
a2 -= sgn ;
del0 -= (4 - 2) * ((sgn * b2) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b1) ;
a1 -= sgn ;
del0 -= (4 - 1) * ((sgn * b1) >> denshift) ;
if (del0 <= 0)
continue ;
a0 -= sign_of_int (b0) ;
}
else if (sg < 0)
{
// note: to avoid unnecessary negations, we flip the value of "sgn"
sgn = -sign_of_int (b3) ;
a3 -= sgn ;
del0 -= (4 - 3) * ((sgn * b3) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b2) ;
a2 -= sgn ;
del0 -= (4 - 2) * ((sgn * b2) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b1) ;
a1 -= sgn ;
del0 -= (4 - 1) * ((sgn * b1) >> denshift) ;
if (del0 >= 0)
continue ;
a0 += sign_of_int (b0) ;
}
}
coefs [0] = a0 ;
coefs [1] = a1 ;
coefs [2] = a2 ;
coefs [3] = a3 ;
}
else if (numactive == 8)
{
// optimization for numactive == 8
register int16_t a4, a5, a6, a7 ;
register int32_t b4, b5, b6, b7 ;
a0 = coefs [0] ;
a1 = coefs [1] ;
a2 = coefs [2] ;
a3 = coefs [3] ;
a4 = coefs [4] ;
a5 = coefs [5] ;
a6 = coefs [6] ;
a7 = coefs [7] ;
for (j = lim ; j < num ; j++)
{
LOOP_ALIGN
top = in [j - lim] ;
pin = in + j - 1 ;
b0 = top - (*pin--) ;
b1 = top - (*pin--) ;
b2 = top - (*pin--) ;
b3 = top - (*pin--) ;
b4 = top - (*pin--) ;
b5 = top - (*pin--) ;
b6 = top - (*pin--) ;
b7 = top - (*pin) ;
pin += 8 ;
sum1 = (denhalf - a0 * b0 - a1 * b1 - a2 * b2 - a3 * b3
- a4 * b4 - a5 * b5 - a6 * b6 - a7 * b7) >> denshift ;
del = in [j] - top - sum1 ;
del = arith_shift_left (del, chanshift) >> chanshift ;
pc1 [j] = del ;
del0 = del ;
sg = sign_of_int (del) ;
if (sg > 0)
{
sgn = sign_of_int (b7) ;
a7 -= sgn ;
del0 -= 1 * ((sgn * b7) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b6) ;
a6 -= sgn ;
del0 -= 2 * ((sgn * b6) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b5) ;
a5 -= sgn ;
del0 -= 3 * ((sgn * b5) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b4) ;
a4 -= sgn ;
del0 -= 4 * ((sgn * b4) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b3) ;
a3 -= sgn ;
del0 -= 5 * ((sgn * b3) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b2) ;
a2 -= sgn ;
del0 -= 6 * ((sgn * b2) >> denshift) ;
if (del0 <= 0)
continue ;
sgn = sign_of_int (b1) ;
a1 -= sgn ;
del0 -= 7 * ((sgn * b1) >> denshift) ;
if (del0 <= 0)
continue ;
a0 -= sign_of_int (b0) ;
}
else if (sg < 0)
{
// note: to avoid unnecessary negations, we flip the value of "sgn"
sgn = -sign_of_int (b7) ;
a7 -= sgn ;
del0 -= 1 * ((sgn * b7) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b6) ;
a6 -= sgn ;
del0 -= 2 * ((sgn * b6) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b5) ;
a5 -= sgn ;
del0 -= 3 * ((sgn * b5) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b4) ;
a4 -= sgn ;
del0 -= 4 * ((sgn * b4) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b3) ;
a3 -= sgn ;
del0 -= 5 * ((sgn * b3) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b2) ;
a2 -= sgn ;
del0 -= 6 * ((sgn * b2) >> denshift) ;
if (del0 >= 0)
continue ;
sgn = -sign_of_int (b1) ;
a1 -= sgn ;
del0 -= 7 * ((sgn * b1) >> denshift) ;
if (del0 >= 0)
continue ;
a0 += sign_of_int (b0) ;
}
}
coefs [0] = a0 ;
coefs [1] = a1 ;
coefs [2] = a2 ;
coefs [3] = a3 ;
coefs [4] = a4 ;
coefs [5] = a5 ;
coefs [6] = a6 ;
coefs [7] = a7 ;
}
else
{
//pc_block_general:
// general case
for (j = lim ; j < num ; j++)
{
LOOP_ALIGN
top = in [j - lim] ;
pin = in + j - 1 ;
sum1 = 0 ;
for (k = 0 ; k < numactive ; k++)
sum1 -= coefs [k] * (top - pin [-k]) ;
del = in [j] - top - ((sum1 + denhalf) >> denshift) ;
del = (del << chanshift) >> chanshift ;
pc1 [j] = del ;
del0 = del ;
sg = sign_of_int (del) ;
if (sg > 0)
{
for (k = (numactive - 1) ; k >= 0 ; k--)
{
dd = top - pin [-k] ;
sgn = sign_of_int (dd) ;
coefs [k] -= sgn ;
del0 -= (numactive - k) * ((sgn * dd) >> denshift) ;
if (del0 <= 0)
break ;
}
}
else if (sg < 0)
{
for (k = (numactive - 1) ; k >= 0 ; k--)
{
dd = top - pin [-k] ;
sgn = sign_of_int (dd) ;
coefs [k] += sgn ;
del0 -= (numactive - k) * ((-sgn * dd) >> denshift) ;
if (del0 >= 0)
break ;
}
}
}
}
}