Improve code generation in opj_t1_dec_clnpass()

Add a opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit() method that
does the job of opj_t1_dec_clnpass_step_only() assuming the conditions
are met. And use it in opj_t1_dec_clnpass(). The compiler generates
more efficient code.

diff --git a/src/lib/openjp2/t1.c b/src/lib/openjp2/t1.c
index 37fc4fc1c77698e1feb5742ac4079d0d2646aeaa..124d68ea20eeabc58a38cca8f621fa68c7f12cb2 100644 (file)
--- a/src/lib/openjp2/t1.c
+++ b/src/lib/openjp2/t1.c
@@ -906,6 +906,32 @@ static void opj_t1_dec_clnpass_step(
        *flagsp &= ~T1_VISIT;
 }                              /* VSC and  BYPASS by Antonin */
 
+static void opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit(
+        opj_t1_t *t1,
+        opj_flag_t *flagsp,
+        OPJ_INT32 *datap,
+        OPJ_INT32 orient,
+        OPJ_INT32 oneplushalf)
+{
+    OPJ_INT32 v;
+    OPJ_INT32 flag;
+
+    opj_mqc_t *mqc = t1->mqc;   /* MQC component */
+
+    flag = *flagsp;
+    /*if (!(flag & (T1_SIG | T1_VISIT)))*/
+    {
+        opj_mqc_setcurctx(mqc, opj_t1_getctxno_zc((OPJ_UINT32)flag, (OPJ_UINT32)orient));
+        if (opj_mqc_decode(mqc)) {
+            opj_mqc_setcurctx(mqc, opj_t1_getctxno_sc((OPJ_UINT32)flag));
+            v = opj_mqc_decode(mqc) ^ opj_t1_getspb((OPJ_UINT32)flag);
+            *datap = v ? -oneplushalf : oneplushalf;
+            opj_t1_updateflags(flagsp, v, t1->flags_stride);
+        }
+    }
+    /*flagsp &= ~T1_VISIT;*/
+}
+
 static void opj_t1_dec_clnpass_step_vsc(
                opj_t1_t *t1,
                opj_flag_t *flagsp,
@@ -1084,17 +1110,30 @@ static void opj_t1_dec_clnpass(
                                                data2 += t1->w;
                                        }
                                } else {
+                                       opj_flag_t flag;
                                        flags2 += t1->flags_stride;
-                                       opj_t1_dec_clnpass_step(t1, flags2, data2, orient, oneplushalf);
+                                       flag = *flags2;
+                                       if (!(flag & (T1_SIG | T1_VISIT)))
+                                               opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit(t1, flags2, data2, orient, oneplushalf);
+                                       *flags2 &= ~T1_VISIT;
                                        data2 += t1->w;
                                        flags2 += t1->flags_stride;
-                                       opj_t1_dec_clnpass_step(t1, flags2, data2, orient, oneplushalf);
+                                       flag = *flags2;
+                                       if (!(flag & (T1_SIG | T1_VISIT)))
+                                               opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit(t1, flags2, data2, orient, oneplushalf);
+                                       *flags2 &= ~T1_VISIT;
                                        data2 += t1->w;
                                        flags2 += t1->flags_stride;
-                                       opj_t1_dec_clnpass_step(t1, flags2, data2, orient, oneplushalf);
+                                       flag = *flags2;
+                                       if (!(flag & (T1_SIG | T1_VISIT)))
+                                               opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit(t1, flags2, data2, orient, oneplushalf);
+                                       *flags2 &= ~T1_VISIT;
                                        data2 += t1->w;
                                        flags2 += t1->flags_stride;
-                                       opj_t1_dec_clnpass_step(t1, flags2, data2, orient, oneplushalf);
+                                       flag = *flags2;
+                                       if (!(flag & (T1_SIG | T1_VISIT)))
+                                               opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit(t1, flags2, data2, orient, oneplushalf);
+                                       *flags2 &= ~T1_VISIT;
                                        data2 += t1->w;
                                }
                        }