[OMPT-svn-commit] SF.net SVN: modplug:[4312] trunk/OpenMPT

[<sag...@us...>]

Revision: 4312
          http://sourceforge.net/p/modplug/code/4312
Author:   saga-games
Date:     2014-09-27 15:49:35 +0000 (Sat, 27 Sep 2014)
Log Message:
-----------
[Imp] Song length estimation: Slightly improve calculation of nested pattern loops (http://bugs.openmpt.org/view.php?id=591)

Modified Paths:
--------------
    trunk/OpenMPT/common/misc_util.h
    trunk/OpenMPT/soundlib/Snd_fx.cpp

Modified: trunk/OpenMPT/common/misc_util.h
===================================================================
--- trunk/OpenMPT/common/misc_util.h	2014-09-26 09:06:17 UTC (rev 4311)
+++ trunk/OpenMPT/common/misc_util.h	2014-09-27 15:49:35 UTC (rev 4312)
@@ -296,27 +296,6 @@
 }
 
 
-// Greatest Common Divisor.
-template <class T>
-T gcd(T a, T b)
-//-------------
-{
-	if(a < 0)
-		a = -a;
-	if(b < 0)
-		b = -b;
-	do
-	{
-		if(a == 0)
-			return b;
-		b %= a;
-		if(b == 0)
-			return a;
-		a %= b;
-	} while(true);
-}
-
-
 // Returns sign of a number (-1 for negative numbers, 1 for positive numbers, 0 for 0)
 template <class T>
 int sgn(T value)
@@ -467,6 +446,38 @@
 		return (a >= 0) ? mpt::saturate_cast<int32>(a / c) : mpt::saturate_cast<int32>((a - (c - 1)) / c);
 	}
 
+	// Greatest Common Divisor. Always returns non-negative number.
+	template <class T>
+	T gcd(T a, T b)
+	{
+		if(a < 0)
+			a = -a;
+		if(b < 0)
+			b = -b;
+		do
+		{
+			if(a == 0)
+				return b;
+			b %= a;
+			if(b == 0)
+				return a;
+			a %= b;
+		} while(true);
+	}
+
+	// Least Common Multiple. Always returns non-negative number.
+	template <class T>
+	int lcm(T a, T b)
+	{
+		if(a < 0)
+			a = -a;
+		if(b < 0)
+			b = -b;
+		if((a | b) == 0)
+			return 0;
+		return a / gcd<T>(a, b) * b;
+	}
+
 	template<typename T, std::size_t n>
 	class fixed_size_queue
 	{

Modified: trunk/OpenMPT/soundlib/Snd_fx.cpp
===================================================================
--- trunk/OpenMPT/soundlib/Snd_fx.cpp	2014-09-26 09:06:17 UTC (rev 4311)
+++ trunk/OpenMPT/soundlib/Snd_fx.cpp	2014-09-27 15:49:35 UTC (rev 4312)
@@ -775,14 +775,24 @@
 		if(patternLoopEndedOnThisRow)
 		{
 			p = Patterns[nPattern].GetRow(nRow);
+			std::map<double, int> startTimes;
+			// This is really just a simple estimation for nested pattern loops. It should handle cases correctly where all parallel loops start and end on the same row.
+			// If one of them starts or ends "in between", it will most likely calculate a wrong duration.
+			// For S3M files, it's also way off.
 			for(CHANNELINDEX nChn = 0; nChn < GetNumChannels(); p++, nChn++)
 			{
 				if((p->command == CMD_S3MCMDEX && p->param >= 0xB1 && p->param <= 0xBF)
 					|| (p->command == CMD_MODCMDEX && p->param >= 0x61 && p->param <= 0x6F))
 				{
-					memory.elapsedTime += (memory.elapsedTime - memory.chnSettings[nChn].patLoop) * (double)(p->param & 0x0F);
+					const double start = memory.chnSettings[nChn].patLoop;
+					if(!startTimes[start]) startTimes[start] = 1;
+					startTimes[start] = Util::lcm<int>(startTimes[start], 1 + (p->param & 0x0F));
 				}
 			}
+			for(std::map<double, int>::iterator i = startTimes.begin(); i != startTimes.end(); i++)
+			{
+				memory.elapsedTime += (memory.elapsedTime - i->first) * (double)(i->second - 1);
+			}
 			if(GetType() == MOD_TYPE_IT)
 			{
 				// IT pattern loop start row update - at the end of a pattern loop, set pattern loop start to next row (for upcoming pattern loops with missing SB0)

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