resample.c (rs_plain): Bug fixed about PRECALC_LOOPS counter.

Original form: i = (le - ofs) / incr + 1; (Original) Fixed form: i = (le - ofs + incr - 1) / incr; (Correct) [ from timidity++ v2.7.0-to-v2.8.0 diff, 1999-11-19 Masanao Izumo <mo@goice.co.jp> ]
libsdl-org · Oct 21, 2017 · 80f3924 · 80f3924
1 parent e141c9b
commit 80f3924
Showing 1 changed file with 11 additions and 9 deletions.
diff --git a/timidity/resample.c b/timidity/resample.c
@@ -27,6 +27,8 @@
 #include "tables.h"
 #include "resample.h"
 
+#define PRECALC_LOOP_COUNT(start, end, incr) (((end) - (start) + (incr) - 1) / (incr))
+
 /*************** resampling with fixed increment *****************/
 
 static sample_t *rs_plain(MidiSong *song, int v, Sint32 *countptr)
@@ -51,7 +53,7 @@ static sample_t *rs_plain(MidiSong *song, int v, Sint32 *countptr)
 
   /* Precalc how many times we should go through the loop.
      NOTE: Assumes that incr > 0 and that ofs <= le */
-  i = (le - ofs) / incr + 1;
+  i = PRECALC_LOOP_COUNT(ofs, le, incr);
 
   if (i > count)
     {
@@ -101,7 +103,7 @@ static sample_t *rs_loop(MidiSong *song, Voice *vp, Sint32 count)
       while (ofs >= le)
 	ofs -= ll;
       /* Precalc how many times we should go through the loop */
-      i = (le - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, le, incr);
       if (i > count) 
 	{
 	  i = count;
@@ -138,12 +140,12 @@ static sample_t *rs_bidir(MidiSong *song, Voice *vp, Sint32 count)
     i;
   /* Play normally until inside the loop region */
 
-  if (ofs <= ls) 
+  if (incr > 0 && ofs < ls)
     {
       /* NOTE: Assumes that incr > 0, which is NOT always the case
 	 when doing bidirectional looping.  I have yet to see a case
 	 where both ofs <= ls AND incr < 0, however. */
-      i = (ls - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, ls, incr);
       if (i > count) 
 	{
 	  i = count;
@@ -164,7 +166,7 @@ static sample_t *rs_bidir(MidiSong *song, Voice *vp, Sint32 count)
   while(count) 
     {
       /* Precalc how many times we should go through the loop */
-      i = ((incr > 0 ? le : ls) - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, incr > 0 ? le : ls, incr);
       if (i > count) 
 	{
 	  i = count;
@@ -349,7 +351,7 @@ static sample_t *rs_vib_loop(MidiSong *song, Voice *vp, Sint32 count)
 	ofs -= ll;
       /* Precalc how many times to go through the loop, taking
 	 the vibrato control ratio into account this time. */
-      i = (le - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, le, incr);
       if(i > count) i = count;
       if(i > cc)
 	{
@@ -400,9 +402,9 @@ static sample_t *rs_vib_bidir(MidiSong *song, Voice *vp, Sint32 count)
     vibflag = 0;
 
   /* Play normally until inside the loop region */
-  while (count && (ofs <= ls)) 
+  while (count && incr > 0 && ofs < ls)
     {
-      i = (ls - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, ls, incr);
       if (i > count) i = count;
       if (i > cc) 
 	{
@@ -431,7 +433,7 @@ static sample_t *rs_vib_bidir(MidiSong *song, Voice *vp, Sint32 count)
   while (count) 
     {
       /* Precalc how many times we should go through the loop */
-      i = ((incr > 0 ? le : ls) - ofs) / incr + 1;
+      i = PRECALC_LOOP_COUNT(ofs, incr > 0 ? le : ls, incr);
       if(i > count) i = count;
       if(i > cc) 
 	{