diff options
| author | Even Rouault <even.rouault@spatialys.com> | 2017-09-01 16:30:54 +0200 |
|---|---|---|
| committer | Even Rouault <even.rouault@spatialys.com> | 2017-09-01 16:30:54 +0200 |
| commit | 82a43d8035ca5f43e198e15faef6c9ac44b39541 (patch) | |
| tree | 724a233b6bd7aab83733ecbdf13f4b113ea1369e /src/lib | |
| parent | 1644665a9105e2d761e8b29f43af602560e6bcf9 (diff) | |
Optimize opj_dwt_decode_partial_1() when cas == 0
Diffstat (limited to 'src/lib')
| -rw-r--r-- | src/lib/openjp2/dwt.c | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/src/lib/openjp2/dwt.c b/src/lib/openjp2/dwt.c index d0cd3b4e..153bfa40 100644 --- a/src/lib/openjp2/dwt.c +++ b/src/lib/openjp2/dwt.c @@ -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 */ |