Author: sagamusix
Date: Sat Apr 20 18:15:57 2024
New Revision: 20622
URL: https://source.openmpt.org/browse/openmpt/?op=revision&rev=20622
Log:
[Imp] IT: Reduce number of FileReader calls during initial pattern scan.
Modified:
trunk/OpenMPT/soundlib/Load_it.cpp
Modified: trunk/OpenMPT/soundlib/Load_it.cpp
==============================================================================
--- trunk/OpenMPT/soundlib/Load_it.cpp Sat Apr 20 18:12:47 2024 (r20621)
+++ trunk/OpenMPT/soundlib/Load_it.cpp Sat Apr 20 18:15:57 2024 (r20622)
@@ -927,31 +927,22 @@
chnMask.resize(ch + 1, 0);
}
- if(b & IT_bitmask_patternChanEnabled_c) // 0x80 check if the upper bit is enabled.
+ if(b & IT_bitmask_patternChanEnabled_c) // 0x80 check if the upper bit is enabled.
{
- chnMask[ch] = patternData.ReadUint8(); // set the channel mask for this channel.
+ chnMask[ch] = patternData.ReadUint8(); // set the channel mask for this channel.
}
// Channel used
- if(chnMask[ch] & 0x0F) // if this channel is used set m_nChannels
+ if(chnMask[ch] & 0x0F) // if this channel is used set m_nChannels
{
if(ch >= GetNumChannels() && ch < MAX_BASECHANNELS)
{
m_nChannels = ch + 1;
}
+
+ // Skip a number of bytes depending on note, instrument, volume, effect being present.
+ static constexpr uint8 maskToSkips[] = {0, 1, 1, 2, 1, 2, 2, 3, 2, 3, 3, 4, 3, 4, 4, 5};
+ patternData.Skip(maskToSkips[chnMask[ch] & 0x0F]);
}
- // Now we actually update the pattern-row entry the note,instrument etc.
- // Note
- if(chnMask[ch] & 1)
- patternData.Skip(1);
- // Instrument
- if(chnMask[ch] & 2)
- patternData.Skip(1);
- // Volume
- if(chnMask[ch] & 4)
- patternData.Skip(1);
- // Effect
- if(chnMask[ch] & 8)
- patternData.Skip(2);
}
lastSampleOffset = std::max(lastSampleOffset, file.GetPosition());
}
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