Add support for ARC Trim method

XADARCParser.h

@@ -22,12 +22,14 @@
 
 @interface XADARCParser:XADArchiveParser
 {
+	BOOL isARC7;
 }
 
 +(int)requiredHeaderSize;
 +(BOOL)recognizeFileWithHandle:(CSHandle *)handle firstBytes:(NSData *)data
 name:(NSString *)name;
 
+-(id)init;
 -(void)parse;
 -(CSHandle *)handleForEntryWithDictionary:(NSDictionary *)dict wantChecksum:(BOOL)checksum;
 -(NSString *)formatName;

XADARCParser.m

@@ -22,6 +22,7 @@
 #import "XADARCCrunchHandle.h"
 #import "XADARCCrushHandle.h"
 #import "XADARCDistillHandle.h"
+#import "XADLZHDynamicHandle.h"
 #import "XADRLE90Handle.h"
 #import "XADSqueezeHandle.h"
 #import "XADCompressHandle.h"
@@ -93,6 +94,28 @@ static BOOL IsARCHeader(const uint8_t *bytes,int length,BOOL acceptloader)
 	}
 }
 
+static BOOL IsARC7Header(const uint8_t *bytes,int length)
+{
+	if(length<0x1d) return NO;
+
+	// Check ID.
+	if(bytes[0x00]!=0x1a) return NO;
+
+	// Method == 20
+	if(bytes[0x01]!=0x14) return NO;
+
+	// Name is an empty string
+	if(bytes[0x02]!=0) return NO;
+
+	// Uncompressed size == 0
+	if(bytes[25]!=0) return NO;
+	if(bytes[26]!=0) return NO;
+	if(bytes[27]!=0) return NO;
+	if(bytes[28]!=0) return NO;
+
+	return YES;
+}
+
 @implementation XADARCParser
 
 +(int)requiredHeaderSize { return 0x1d; }
@@ -103,7 +126,16 @@ +(BOOL)recognizeFileWithHandle:(CSHandle *)handle firstBytes:(NSData *)data
 	const uint8_t *bytes=[data bytes];
 	int length=[data length];
 
-	return IsARCHeader(bytes,length,NO);
+	return IsARC7Header(bytes,length) || IsARCHeader(bytes,length,NO);
+}
+
+-(id)init
+{
+	if((self=[super init]))
+	{
+		isARC7 = NO;
+	}
+	return self;
 }
 
 -(void)parse
@@ -177,6 +209,18 @@ -(void)parse
 
 			parent=path;
 		}
+		else if (method==0x14)
+		{
+			// Generated by SEA ARC 7; method 10 is Trim
+			if (namebuf[0]==0 && uncompsize==0)
+				isARC7 = YES;
+			[fh seekToFileOffset:dataoffset+compsize];
+		}
+		else if (method==0x15)
+		{
+			// SEA ARC file comment
+			[fh seekToFileOffset:dataoffset+compsize];
+		}
 		else
 		{
 			NSMutableDictionary *dict=[NSMutableDictionary dictionaryWithObjectsAndKeys:
@@ -202,7 +246,12 @@ -(void)parse
 				case 0x07: methodname=@"Crunched (fast)"; break;
 				case 0x08: methodname=@"Crunched (LZW)"; break;
 				case 0x09: methodname=@"Squashed"; break;
-				case 0x0a: methodname=@"Crushed"; break;
+				case 0x0a:
+					if (isARC7)
+						methodname=@"Trimmed";
+					else
+						methodname=@"Crushed";
+					break;
 				case 0x0b: methodname=@"Distilled"; break;
 				case 0x7f: methodname=@"Compressed"; break;
 			}
@@ -298,9 +347,17 @@ -(CSHandle *)handleForEntryWithDictionary:(NSDictionary *)dict wantChecksum:(BOO
 			length:length flags:0x8d] autorelease];
 		break;
 
-		case 0x0a: // Crushed
-			handle=[[[XADARCCrushHandle alloc] initWithHandle:handle] autorelease];
-
+		case 0x0a:
+			if (isARC7) // Trimmed
+				// Pass 0xffffffff as the length because some files get
+				// truncated if we pass the actual length. We need to rely on
+				// the stop code in the compressed data.
+				handle=[[[XADLZHDynamicHandle alloc] initWithHandle:handle length:0xffffffff
+				hasStopCode:YES] autorelease];
+			else // Crushed
+				handle=[[[XADARCCrushHandle alloc] initWithHandle:handle] autorelease];
+
+			// Both Trim and Crush use RLE90 on output
 			handle=[[[XADRLE90Handle alloc] initWithHandle:handle
 			length:length] autorelease];
 		break;
@@ -381,7 +438,7 @@ +(BOOL)recognizeFileWithHandle:(CSHandle *)handle firstBytes:(NSData *)data
 	{
 		for(int i=2;i<=length-0x1d /*&& i<0x10000-0x1d*/;i++)
 		{
-			if(IsARCHeader(&bytes[i],length-i,NO))
+			if(IsARC7Header(&bytes[i],length-i) || IsARCHeader(&bytes[i],length-i,NO))
 			{
 				[props setObject:[NSNumber numberWithInt:i] forKey:@"ARCSFXOffset"];
 				return YES;

XADLZHDynamicHandle.h

@@ -33,9 +33,11 @@ struct XADLZHDynamicNode
 {
 	XADPrefixCode *distancecode;
 	XADLZHDynamicNode *nodes[314*2-1],nodestorage[314*2-1];
+	BOOL hasstopcode;
 }
 
 -(id)initWithHandle:(CSHandle *)handle length:(off_t)length;
+-(id)initWithHandle:(CSHandle *)handle length:(off_t)length hasStopCode:(BOOL)hasStopCode;
 -(void)dealloc;
 
 -(void)resetLZSSHandle;

XADLZHDynamicHandle.m

@@ -24,6 +24,11 @@
 @implementation XADLZHDynamicHandle
 
 -(id)initWithHandle:(CSHandle *)handle length:(off_t)length
+{
+	return [self initWithHandle:handle length:length hasStopCode:NO];
+}
+
+-(id)initWithHandle:(CSHandle *)handle length:(off_t)length hasStopCode:(BOOL)hasStopCode
 {
 	if((self=[super initWithInputBufferForHandle:handle length:length windowSize:4096]))
 	{
@@ -37,6 +42,7 @@ -(id)initWithHandle:(CSHandle *)handle length:(off_t)length
 
 		distancecode=[[XADPrefixCode alloc] initWithLengths:lengths numberOfSymbols:64
 		maximumLength:8 shortestCodeIsZeros:YES];
+		hasstopcode=hasStopCode;
 	}
 	return self;
 }
@@ -96,9 +102,13 @@ -(int)nextLiteralOrOffset:(int *)offset andLength:(int *)length atPosition:(off_
 	int lit=node->value;
 
 	if(lit<0x100) return lit;
+	else if (lit==0x100 && hasstopcode)
+		return XADLZSSEnd;
 	else
 	{
 		*length=lit-0x100+3;
+		if (hasstopcode)
+			--(*length);
 
 		int highbits=CSInputNextSymbolUsingCode(input,distancecode);
 		int lowbits=CSInputNextBitString(input,6);