jpeg2000: Refactor decode_packets

Move the packet-specific parsers in separate functions.

libavcodec/jpeg2000dec.c

@@ -732,85 +732,103 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s,
     return 0;
 }
 
-static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
+static int decode_pgod_lrcp(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
 {
-    int ret = 0;
     int layno, reslevelno, compno, precno, ok_reslevel;
-    int x, y;
-
-    s->bit_index = 8;
-    switch (tile->codsty[0].prog_order) {
-    case JPEG2000_PGOD_LRCP:
-        for (layno = 0; layno < tile->codsty[0].nlayers; layno++) {
-            ok_reslevel = 1;
-            for (reslevelno = 0; ok_reslevel; reslevelno++) {
-                ok_reslevel = 0;
-                for (compno = 0; compno < s->ncomponents; compno++) {
-                    Jpeg2000CodingStyle *codsty = tile->codsty + compno;
-                    Jpeg2000QuantStyle *qntsty  = tile->qntsty + compno;
-                    if (reslevelno < codsty->nreslevels) {
-                        Jpeg2000ResLevel *rlevel = tile->comp[compno].reslevel +
-                                                   reslevelno;
-                        ok_reslevel = 1;
-                        for (precno = 0; precno < rlevel->num_precincts_x * rlevel->num_precincts_y; precno++)
-                            if ((ret = jpeg2000_decode_packet(s,
-                                                              codsty, rlevel,
-                                                              precno, layno,
-                                                              qntsty->expn + (reslevelno ? 3 * (reslevelno - 1) + 1 : 0),
-                                                              qntsty->nguardbits)) < 0)
-                                return ret;
-                    }
+    int ret;
+
+    for (layno = 0; layno < tile->codsty[0].nlayers; layno++) {
+        ok_reslevel = 1;
+        for (reslevelno = 0; ok_reslevel; reslevelno++) {
+            ok_reslevel = 0;
+            for (compno = 0; compno < s->ncomponents; compno++) {
+                Jpeg2000CodingStyle *codsty = tile->codsty + compno;
+                Jpeg2000QuantStyle *qntsty  = tile->qntsty + compno;
+                if (reslevelno < codsty->nreslevels) {
+                    Jpeg2000ResLevel *rlevel = tile->comp[compno].reslevel +
+                                               reslevelno;
+                    ok_reslevel = 1;
+                    for (precno = 0; precno < rlevel->num_precincts_x * rlevel->num_precincts_y; precno++)
+                        if ((ret = jpeg2000_decode_packet(s,
+                                                          codsty, rlevel,
+                                                          precno, layno,
+                                                          qntsty->expn + (reslevelno ? 3 * (reslevelno - 1) + 1 : 0),
+                                                          qntsty->nguardbits)) < 0)
+                            return ret;
                 }
             }
         }
-        break;
+    }
 
-    case JPEG2000_PGOD_CPRL:
-        for (compno = 0; compno < s->ncomponents; compno++) {
-            Jpeg2000CodingStyle *codsty = tile->codsty + compno;
-            Jpeg2000QuantStyle *qntsty  = tile->qntsty + compno;
+    return 0;
+}
 
-            /* Set bit stream buffer address according to tile-part.
-             * For DCinema one tile-part per component, so can be
-             * indexed by component. */
-            s->g = tile->tile_part[compno].tpg;
+static int decode_pgod_cprl(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
+{
+    int layno, reslevelno, compno, precno;
+    int ret, x, y;
+
+    for (compno = 0; compno < s->ncomponents; compno++) {
+        Jpeg2000CodingStyle *codsty = tile->codsty + compno;
+        Jpeg2000QuantStyle *qntsty  = tile->qntsty + compno;
 
+        /* Set bit stream buffer address according to tile-part.
+         * For DCinema one tile-part per component, so can be
+         * indexed by component. */
+        s->g = tile->tile_part[compno].tpg;
+
+        /* Position loop (y axis)
+         * TODO: Automate computing of step 256.
+         * Fixed here, but to be computed before entering here. */
+        for (y = 0; y < s->height; y += 256) {
             /* Position loop (y axis)
-             * TODO: Automate computing of step 256.
+             * TODO: automate computing of step 256.
              * Fixed here, but to be computed before entering here. */
-            for (y = 0; y < s->height; y += 256) {
-                /* Position loop (y axis)
-                 * TODO: automate computing of step 256.
-                 * Fixed here, but to be computed before entering here. */
-                for (x = 0; x < s->width; x += 256) {
-                    for (reslevelno = 0; reslevelno < codsty->nreslevels; reslevelno++) {
-                        uint16_t prcx, prcy;
-                        uint8_t reducedresno = codsty->nreslevels - 1 -reslevelno; //  ==> N_L - r
-                        Jpeg2000ResLevel *rlevel = tile->comp[compno].reslevel + reslevelno;
-
-                        if (!((y % (1 << (rlevel->log2_prec_height + reducedresno)) == 0) ||
-                              (y == 0))) // TODO: 2nd condition simplified as try0 always =0 for dcinema
-                            continue;
-
-                        if (!((x % (1 << (rlevel->log2_prec_width + reducedresno)) == 0) ||
-                              (x == 0))) // TODO: 2nd condition simplified as try0 always =0 for dcinema
-                            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;
-                        precno = prcx + rlevel->num_precincts_x * prcy;
-                        for (layno = 0; layno < tile->codsty[0].nlayers; layno++) {
-                            if ((ret = jpeg2000_decode_packet(s, codsty, rlevel,
-                                                              precno, layno,
-                                                              qntsty->expn + (reslevelno ? 3 * (reslevelno - 1) + 1 : 0),
-                                                              qntsty->nguardbits)) < 0)
-                                return ret;
-                        }
+            for (x = 0; x < s->width; x += 256) {
+                for (reslevelno = 0; reslevelno < codsty->nreslevels; reslevelno++) {
+                    uint16_t prcx, prcy;
+                    uint8_t reducedresno = codsty->nreslevels - 1 -reslevelno; //  ==> N_L - r
+                    Jpeg2000ResLevel *rlevel = tile->comp[compno].reslevel + reslevelno;
+
+                    if (!((y % (1 << (rlevel->log2_prec_height + reducedresno)) == 0) ||
+                          (y == 0))) // TODO: 2nd condition simplified as try0 always =0 for dcinema
+                        continue;
+
+                    if (!((x % (1 << (rlevel->log2_prec_width + reducedresno)) == 0) ||
+                          (x == 0))) // TODO: 2nd condition simplified as try0 always =0 for dcinema
+                        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;
+                    precno = prcx + rlevel->num_precincts_x * prcy;
+                    for (layno = 0; layno < tile->codsty[0].nlayers; layno++) {
+                        if ((ret = jpeg2000_decode_packet(s, codsty, rlevel,
+                                                          precno, layno,
+                                                          qntsty->expn + (reslevelno ? 3 * (reslevelno - 1) + 1 : 0),
+                                                          qntsty->nguardbits)) < 0)
+                            return ret;
                     }
                 }
             }
         }
+    }
+
+    return 0;
+}
+
+static int jpeg2000_decode_packets(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
+{
+    int ret = 0;
+
+    s->bit_index = 8;
+    switch (tile->codsty[0].prog_order) {
+    case JPEG2000_PGOD_LRCP:
+        ret = decode_pgod_lrcp(s, tile);
+        break;
+
+    case JPEG2000_PGOD_CPRL:
+        ret = decode_pgod_cprl(s, tile);
         break;
 
     case JPEG2000_PGOD_RLCP: