avcodec/jpeg2000dec: iterate in tile sample space for CPRL & RPCL

Thats what the spec says should be done
aka iterate in the wrong space and use special cases to patch that up.
It sometimes can result in different order
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/jpeg2000dec.c

@@ -1012,9 +1012,6 @@ static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile
             Jpeg2000Component *comp     = tile->comp + compno;
             Jpeg2000CodingStyle *codsty = tile->codsty + compno;
             Jpeg2000QuantStyle *qntsty  = tile->qntsty + compno;
-            int maxlogstep_x = 0;
-            int maxlogstep_y = 0;
-            int start_x, start_y;
             step_x = 32;
             step_y = 32;
 
@@ -1023,30 +1020,28 @@ static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile
                 Jpeg2000ResLevel *rlevel = comp->reslevel + reslevelno;
                 step_x = FFMIN(step_x, rlevel->log2_prec_width  + reducedresno);
                 step_y = FFMIN(step_y, rlevel->log2_prec_height + reducedresno);
-                maxlogstep_x = FFMAX(maxlogstep_x, rlevel->log2_prec_width  + reducedresno);
-                maxlogstep_y = FFMAX(maxlogstep_y, rlevel->log2_prec_height + reducedresno);
             }
             step_x = 1<<step_x;
             step_y = 1<<step_y;
 
-            start_y = comp->coord_o[1][0] >> maxlogstep_y << maxlogstep_y;
-            start_x = comp->coord_o[0][0] >> maxlogstep_x << maxlogstep_x;
-            for (y = start_y; y < comp->coord_o[1][1]; y += step_y) {
-                for (x = start_x; x < comp->coord_o[0][1]; x += step_x) {
+            for (y = tile->coord[1][0]; y < tile->coord[1][1]; y = (y/step_y + 1)*step_y) {
+                for (x = tile->coord[0][0]; x < tile->coord[0][1]; x = (x/step_x + 1)*step_x) {
                     for (reslevelno = 0; reslevelno < codsty->nreslevels; reslevelno++) {
                         unsigned prcx, prcy;
                         uint8_t reducedresno = codsty->nreslevels - 1 -reslevelno; //  ==> N_L - r
                         Jpeg2000ResLevel *rlevel = comp->reslevel + reslevelno;
+                        int xc = x / s->cdx[compno];
+                        int yc = y / s->cdy[compno];
 
-                        if (y % (1 << (rlevel->log2_prec_height + reducedresno)))
+                        if (yc % (1 << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
                             continue;
 
-                        if (x % (1 << (rlevel->log2_prec_width + reducedresno)))
+                        if (xc % (1 << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
                             continue;
 
                         // check if a precinct exists
-                        prcx   = ff_jpeg2000_ceildivpow2(x, reducedresno) >> rlevel->log2_prec_width;
-                        prcy   = ff_jpeg2000_ceildivpow2(y, reducedresno) >> rlevel->log2_prec_height;
+                        prcx   = ff_jpeg2000_ceildivpow2(xc, reducedresno) >> rlevel->log2_prec_width;
+                        prcy   = ff_jpeg2000_ceildivpow2(yc, reducedresno) >> rlevel->log2_prec_height;
                         prcx  -= ff_jpeg2000_ceildivpow2(comp->coord_o[0][0], reducedresno) >> rlevel->log2_prec_width;
                         prcy  -= ff_jpeg2000_ceildivpow2(comp->coord_o[1][0], reducedresno) >> rlevel->log2_prec_height;
 
@@ -1092,9 +1087,8 @@ static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile
             step_x = 1<<step_x;
             step_y = 1<<step_y;
 
-            //FIXME we could iterate over less than the whole image
-            for (y = 0; y < s->height; y += step_y) {
-                for (x = 0; x < s->width; x += step_x) {
+            for (y = tile->coord[1][0]; y < tile->coord[1][1]; y = (y/step_y + 1)*step_y) {
+                for (x = tile->coord[0][0]; x < tile->coord[0][1]; x = (x/step_x + 1)*step_x) {
                     for (compno = 0; compno < s->ncomponents; compno++) {
                         Jpeg2000Component *comp     = tile->comp + compno;
                         Jpeg2000CodingStyle *codsty = tile->codsty + compno;
@@ -1109,10 +1103,10 @@ static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile
                         if (reslevelno >= codsty->nreslevels)
                             continue;
 
-                        if (yc % (1 << (rlevel->log2_prec_height + reducedresno)))
+                        if (yc % (1 << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
                             continue;
 
-                        if (xc % (1 << (rlevel->log2_prec_width + reducedresno)))
+                        if (xc % (1 << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
                             continue;
 
                         // check if a precinct exists