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Optimize opj_dwt_decode_partial_1() when cas == 0

This commit is contained in:
Even Rouault 2017-09-01 16:30:54 +02:00
parent 1644665a91
commit 82a43d8035
1 changed files with 44 additions and 1 deletions
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45
src/lib/openjp2/dwt.c
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@ -1584,12 +1584,55 @@ static void opj_dwt_decode_partial_1(OPJ_INT32 *a, OPJ_INT32 dn, OPJ_INT32 sn,
if (!cas) {
if ((dn > 0) || (sn > 1)) { /* NEW : CASE ONE ELEMENT */
for (i = win_l_x0; i < win_l_x1; i++) {
/* Naive version is :
for (i = win_l_x0; i < i_max; i++) {
OPJ_S(i) -= (OPJ_D_(i - 1) + OPJ_D_(i) + 2) >> 2;
}
for (i = win_h_x0; i < win_h_x1; i++) {
OPJ_D(i) += (OPJ_S_(i) + OPJ_S_(i + 1)) >> 1;
}
but the compiler doesn't manage to unroll it to avoid bound
checking in OPJ_S_ and OPJ_D_ macros
*/
i = win_l_x0;
if (i < win_l_x1) {
OPJ_INT32 i_max;
/* Left-most case */
OPJ_S(i) -= (OPJ_D_(i - 1) + OPJ_D_(i) + 2) >> 2;
i ++;
i_max = win_l_x1;
if (i_max > dn) {
i_max = dn;
}
for (; i < i_max; i++) {
/* No bound checking */
OPJ_S(i) -= (OPJ_D(i - 1) + OPJ_D(i) + 2) >> 2;
}
for (; i < win_l_x1; i++) {
/* Right-most case */
OPJ_S(i) -= (OPJ_D_(i - 1) + OPJ_D_(i) + 2) >> 2;
}
}
i = win_h_x0;
if (i < win_h_x1) {
OPJ_INT32 i_max = win_h_x1;
if (i_max >= sn) {
i_max = sn - 1;
}
for (; i < i_max; i++) {
/* No bound checking */
OPJ_D(i) += (OPJ_S(i) + OPJ_S(i + 1)) >> 1;
}
for (; i < win_h_x1; i++) {
/* Right-most case */
OPJ_D(i) += (OPJ_S_(i) + OPJ_S_(i + 1)) >> 1;
}
}
}
} else {
if (!sn && dn == 1) { /* NEW : CASE ONE ELEMENT */