mirror of https://github.com/PCSX2/pcsx2.git
cdvd:iso: Use Volume Descriptor to find layer break
The DVD layer 0 sector count is stored in the Volume Space Size field of the Primary Volume Descriptor on DVD layer 0. This value is the same as the total sector count for a single layer DVD and the first layer 1 LSN of a dual layer DVD. Let's use that to determine the layer 1 start LSN instead of using the brute force approach. Since this approach is much faster than the previous approach, the layer break is no longer cached.
This commit is contained in:
Jonathan Li
parent
6649f43069
commit
5d303c793b
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@ -22,14 +22,12 @@
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#include "PrecompiledHeader.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include "CDVDisoReader.h"
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#include "AsyncFileReader.h"
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#include <cstring>
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#include <array>
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static InputIsoFile iso;
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static int pmode, cdtype;
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@ -130,122 +128,54 @@ s32 CALLBACK ISOgetTD(u8 Track, cdvdTD *Buffer)
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return 0;
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}
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#include "gui/App.h"
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#include "Utilities/HashMap.h"
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static bool testForPartitionInfo( const u8 (&tempbuffer)[CD_FRAMESIZE_RAW] )
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static bool testForPrimaryVolumeDescriptor(const std::array<u8, CD_FRAMESIZE_RAW>& buffer)
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{
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const int off = iso.GetBlockOffset();
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const std::array<u8, 6> identifier = {1, 'C', 'D', '0', '0', '1'};
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// test for: CD001
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return (
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(tempbuffer[off+1] == 0x43) &&
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(tempbuffer[off+2] == 0x44) &&
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(tempbuffer[off+3] == 0x30) &&
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(tempbuffer[off+4] == 0x30) &&
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(tempbuffer[off+5] == 0x31)
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);
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return std::equal(identifier.begin(), identifier.end(), buffer.begin() + iso.GetBlockOffset());
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}
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static void FindLayer1Start()
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{
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if (iso.GetBlockCount() < 0x230540) return;
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if (layer1start != -1) return;
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if (layer1searched) return;
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if (layer1searched)
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return;
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Console.WriteLn("isoFile: searching for layer1...");
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layer1searched = true;
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int blockresult = -1;
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std::array<u8, CD_FRAMESIZE_RAW> buffer;
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// Check the ini file cache first:
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// Cache is stored in LayerBreakCache.ini, and is associated by hex-encoded hash key of the
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// complete filename/path of the iso file. :)
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wxString layerCacheFile( Path::Combine(GetSettingsFolder().ToString(), L"LayerBreakCache.ini") );
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wxFileConfig layerCacheIni( wxEmptyString, wxEmptyString, layerCacheFile, wxEmptyString, wxCONFIG_USE_RELATIVE_PATH );
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FastFormatUnicode cacheKey;
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cacheKey.Write( L"%X", HashTools::Hash( (s8*)iso.GetFilename().wx_str(), iso.GetFilename().Length() * sizeof(wxChar) ) );
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blockresult = layerCacheIni.Read( cacheKey, -1 );
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if( blockresult != -1 )
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// The ISO9660 primary volume descriptor for layer 0 is located at sector 16
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iso.ReadSync(buffer.data(), 16);
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if (!testForPrimaryVolumeDescriptor(buffer))
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{
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u8 tempbuffer[CD_FRAMESIZE_RAW];
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iso.ReadSync(tempbuffer, blockresult);
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if( testForPartitionInfo( tempbuffer ) )
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{
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Console.WriteLn( "isoFile: loaded second layer from settings cache, sector=0x%08x", blockresult );
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layer1start = blockresult;
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}
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else
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{
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Console.Warning( "isoFile: second layer info in the settings cache appears to be obsolete or invalid. Ignoring..." );
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}
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}
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else
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{
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DevCon.WriteLn( "isoFile: no cached info for second layer found." );
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Console.Error("isoFile: Invalid layer0 Primary Volume Descriptor");
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return;
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}
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if( layer1start == -1 )
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// The volume space size (sector count) is located at bytes 80-87 - 80-83
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// is the little endian size, 84-87 is the big endian size.
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const int offset = iso.GetBlockOffset();
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uint blockresult = buffer[offset + 80]
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+ (buffer[offset + 81] << 8)
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+ (buffer[offset + 82] << 16)
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+ (buffer[offset + 83] << 24);
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// If the ISO sector count is larger than the volume size, then we should
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// have a dual layer DVD. Layer 1 is on a different volume.
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if (blockresult < iso.GetBlockCount())
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{
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// The layer 1 start LSN contains the primary volume descriptor for layer 1.
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// The check might be a bit unnecessary though.
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if (iso.ReadSync(buffer.data(), blockresult) == -1)
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return;
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// Layer sizes are arbitrary, and either layer could be the smaller (GoW and Rogue Galaxy
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// both have Layer1 larger than Layer0 for example), so we have to brute-force the search
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// from some arbitrary start position.
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//
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// Method: Inside->out. We start at the middle of the image and work our way out toward
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// both the beginning and end of the image at the same time. Most images have the layer
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// break quite close to the middle of the image, so this should be pretty fast in most cases.
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// [TODO] Layer searching can be slow, especially for compressed disc images, so it would
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// be quite courteous to pop up a status dialog bar that lets the user know that it's
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// thinking. Since we're not on the GUI thread, we'll need to establish some messages
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// to create the window and pass progress increments back to it.
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uint midsector = (iso.GetBlockCount() / 2) & ~0xf;
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uint deviation = 0;
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while( (layer1start == -1) && (deviation < midsector-16) )
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if (!testForPrimaryVolumeDescriptor(buffer))
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{
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u8 tempbuffer[CD_FRAMESIZE_RAW];
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iso.ReadSync(tempbuffer, midsector-deviation);
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if(testForPartitionInfo( tempbuffer ))
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layer1start = midsector-deviation;
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else
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{
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iso.ReadSync(tempbuffer, midsector+deviation);
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if( testForPartitionInfo( tempbuffer ) )
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layer1start = midsector+deviation;
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}
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if( layer1start != -1 )
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{
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const int blockofs = iso.GetBlockOffset();
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if( !pxAssertDev( tempbuffer[blockofs] == 0x01, "Layer1-Detect: CD001 tag found, but the partition type is invalid." ) )
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{
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Console.Error( "isoFile: Invalid partition type on layer 1!? (type=0x%x)", tempbuffer[blockofs] );
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}
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}
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deviation += 16;
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}
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if( layer1start == -1 )
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{
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Console.Error("isoFile: Couldn't find layer1... iso image is probably corrupt or incomplete.");
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}
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else
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{
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Console.WriteLn( Color_Blue, "isoFile: second layer found at sector 0x%08x", layer1start);
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// Save layer information to configuration:
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layerCacheIni.Write( cacheKey, layer1start );
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Console.Error("isoFile: Invalid layer1 Primary Volume Descriptor");
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return;
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}
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layer1start = blockresult;
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Console.WriteLn(Color_Blue, "isoFile: second layer found at sector 0x%08x", layer1start);
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}
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}
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