ERXMacBinarySwissArmyKnife Class Reference

Collaboration diagram for ERXMacBinarySwissArmyKnife:

[legend]

List of all members.

Public Member Functions
int	calcCRC ()
int	calcCRC2 ()
int	checkFormat (boolean strictFormat)
	ERXMacBinarySwissArmyKnife (NSData fileData)
	ERXMacBinarySwissArmyKnife ()
final byte[]	getByteArray ()
byte	getByteAt (int offset)
int	getCRC ()
int	getDataForkLength ()
int	getIntAt (int offset)
long	getLongAt (int offset)
int	getResourceForkLength ()
short	getShortAt (int offset)
int	getUByteAt (int offset)
long	getUIntAt (int offset)
int	getUShortAt (int offset)
boolean	isMacBinary (NSData fileData)
boolean	isValidCRC ()
void	putByteAt (byte value, int offset)
void	putBytesAt (byte[] data, int offset, int count)
void	putBytesAt (byte[] data, int offset)
void	putIntAt (int value, int offset)
void	putLongAt (long value, int offset)
void	putShortAt (short value, int offset)
final void	setByteArray (byte[] bytes)
void	setCRC ()
NSData	unwrapMacBinary (NSData fileContents)
Static Public Member Functions
static int	calculateCRC (int seed, byte[] bytes, int offset, int count)
Static Public Attributes
static final int	_AT = 0
static final int	CRC_AT = 124
static final int	FILE_CREATOR_AT = 69
static final int	FILE_TYPE_AT = 65
static final int	FINDER_FLAGS1_AT = 73
static final int	FINDER_FLAGS2_AT = 101
static final int	FINDER_FLAGS3_AT = 107
static final int	FINDER_HORZ_AT = 77
static final int	FINDER_VERT_AT = 75
static final int	FINDER_WINDOW_AT = 79
static final int	FLAG_LOCKED_AT = 81
static final int	LEN_COMMENT_AT = 99
static final int	LEN_DATA_FORK_AT = 83
static final int	LEN_RES_FORK_AT = 87
static final int	LEN_SECONDARY_AT = 120
static final long	LIMIT_DATAFORK = Integer.MAX_VALUE
static final int	LIMIT_NAME = 31
static final int	LIMIT_RESFORK = (16 * 1024 * 1024) - 1
static final Logger	log = Logger.getLogger(ERXMacBinarySwissArmyKnife.class)
static final int	MACBINARY_HEADER_LEN = 128
static final int	MB1_VERSION = 128
static final int	MB2_VERSION = 129
static final int	MB3_SIGNATURE = 0x6D42494E
static final int	MB3_SIGNATURE_AT = 102
static final int	MB3_VERSION = 130
static final int	NAME_BYTES_AT = 2
static final int	NAME_LEN_AT = 1
static final int	NAME_SCRIPT_AT = 106
static final int	VERSION_MIN_AT = 123
static final int	VERSION_OBSOLETE_AT = 126
static final int	VERSION_TARGET_AT = 122
static final int	WHEN_CREATED_AT = 91
static final int	WHEN_MODIFIED_AT = 95
static final int	ZERO_1_AT = 0
static final int	ZERO_2_AT = 74
static final int	ZERO_3_AT = 82
Static Protected Attributes
static final int[]	levelMasks
static boolean	strict = false
Static Private Member Functions
static String	formatExplained (int format)
Private Attributes
byte[]	myBytes
Static Private Attributes
static final char[]	crcTable
static String[]	errorText
static final byte[]	noBytes = new byte[ 0 ]

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Detailed Description

Useful for extracting files from binhexed files, ie when a Mac user uploads a file.

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Constructor & Destructor Documentation

ERXMacBinarySwissArmyKnife

(

)

ERXMacBinarySwissArmyKnife

(

NSData

fileData

)

---

Member Function Documentation

int calcCRC

(

)

Calculate and return a CRC over the header. The CRC value is in the low 16-bits of the returned int.

int calcCRC2

(

)

Calculate and return an alternative header CRC. Where calcCRC() calculates over the first 124 bytes of the header, this calculates over the first 126 bytes of the header. I'm guessing that with a valid CRC-value in the header, the returned value is zero, but I don't know enough about CRC theory and practice to assert that confidently. This is more of a Greg's-hacky-toy than anything that might actually be useful.

static int calculateCRC	(	int	seed,
		byte[]	bytes,
		int	offset,
		int	count
	)			[static]

Calculate a MacBinary CRC using the given starting seed, and proceeding over the given range of bytes. The returned CRC value is a 16-bit result in an int, because it's unsigned.

int checkFormat

(

boolean

strictFormat

)

static String formatExplained

(

int

format

)

[static, private]

Return a brief text String explaining a format or result-code.

final byte [] getByteArray

(

)

Get the internal byte-array.

byte getByteAt

(

int

offset

)

Return the signed byte at the given offset.

int getCRC

(

)

Return the header CRC, as embedded in the header itself.

int getDataForkLength

(

)

Get the data-fork length from the header.

int getIntAt

(

int

offset

)

Return the signed int at the given offset.

long getLongAt

(

int

offset

)

Return the signed long at the given offset.

int getResourceForkLength

(

)

Get the resource-fork length from the header.

short getShortAt

(

int

offset

)

Return the signed short at the given offset.

int getUByteAt

(

int

offset

)

Return an int holding the unsigned byte at the given offset.

long getUIntAt

(

int

offset

)

Return a long holding the unsigned int at the given offset.

int getUShortAt

(

int

offset

)

Return an int holding the unsigned short at the given offset.

boolean isMacBinary

(

NSData

fileData

)

boolean isValidCRC

(

)

Calculate and check the header CRC.

void putByteAt	(	byte	value,
		int	offset
	)

Put the given byte at the supplied offset.

void putBytesAt	(	byte[]	data,
		int	offset,
		int	count
	)

Put the given bytes at the supplied offset.

void putBytesAt	(	byte[]	data,
		int	offset
	)

Put all the given bytes at the supplied offset.

void putIntAt	(	int	value,
		int	offset
	)

Put the given int at the supplied offset.

void putLongAt	(	long	value,
		int	offset
	)

Put the given long at the supplied offset.

void putShortAt	(	short	value,
		int	offset
	)

Put the given short at the supplied offset.

final void setByteArray

(

byte[]

bytes

)

Use the given array to hold bytes. Accepts null and/or zero-length arrays without error, though a subsequent get or put will throw an exception.

void setCRC

(

)

Calculate and set the CRC over the header bytes previously set, invoking calcCRC() to calculate the 16-bit value to store. You should only invoke this after setting every other field of interest, such as name and name-encoding, data-fork len, res-fork len, secondary-header len, etc. Since the CRC is calculated internally, there is no parameter to this method, even though it's a "setter" method.

In most cases, you will find finishHeader() more useful since it finishes all the assembly for a particular header-format you select.

NSData unwrapMacBinary

(

NSData

fileContents

)

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Member Data Documentation

final int _AT = 0 [static]

final int CRC_AT = 124 [static]

final char [] crcTable [static, private]

Conveniently, UniCode chars are unsigned 16-bit values. Equally convenient, it's very easy to create constant String objects, then retrieve individual chars from them later. In particular, the String-constant rendering of the code consumes vastly fewer byte-codes than an ordinary array initializer would. And we still get a char[] out of it.

String [] errorText [static, private]

Initial value:

    {
        "Zero-length name",
        "Invalid fork-lengths",
        "Non-zero byte at 74",
        "Non-zero bytes at 0 and/or 82"
    }

The array's index is the negative of the result-code. The result-code meanings are described at MacBinaryHeader.checkFormat().

See also:

MacBinaryHeader.checkFormat

final int FILE_CREATOR_AT = 69 [static]

final int FILE_TYPE_AT = 65 [static]

final int FINDER_FLAGS1_AT = 73 [static]

final int FINDER_FLAGS2_AT = 101 [static]

final int FINDER_FLAGS3_AT = 107 [static]

final int FINDER_HORZ_AT = 77 [static]

final int FINDER_VERT_AT = 75 [static]

final int FINDER_WINDOW_AT = 79 [static]

final int FLAG_LOCKED_AT = 81 [static]

final int LEN_COMMENT_AT = 99 [static]

final int LEN_DATA_FORK_AT = 83 [static]

final int LEN_RES_FORK_AT = 87 [static]

final int LEN_SECONDARY_AT = 120 [static]

final int [] levelMasks [static, protected]

Initial value:

    {
        0x00FFFE7F,
        0x0000FC00,             
        0x0000FC4E,             
        0x0000FC4E,             
    }

Bit-masks for different levels. The mask at 0 clears only the "do not restore" flags, but none of the "reserved" bits. "Reserved" bits are cleared to zero in the other masks -- you may not want

final long LIMIT_DATAFORK = Integer.MAX_VALUE [static]

Enforce this limit on data-fork length, due either to Mac OS API or field-width.

final int LIMIT_NAME = 31 [static]

Enforce this limit on name-length, regardless of available space in header.

final int LIMIT_RESFORK = (16 * 1024 * 1024) - 1 [static]

Enforce this limit on resource-fork length, due either to Mac OS API or field-width.

final Logger log = Logger.getLogger(ERXMacBinarySwissArmyKnife.class) [static]

final int MACBINARY_HEADER_LEN = 128 [static]

Length of a MacBinary header, always the first component of the file, and the only required element. A MacBinary file must be at least this length.

final int MB1_VERSION = 128 [static]

Possible values in VERSION_TARGET_AT and VERSION_MIN_AT byte-sized fields.

final int MB2_VERSION = 129 [static]

final int MB3_SIGNATURE = 0x6D42494E [static]

Distinctive int-sized value in MB3_SIGNATURE_AT field, only present for MB-3 format.

final int MB3_SIGNATURE_AT = 102 [static]

final int MB3_VERSION = 130 [static]

byte [] myBytes [private]

final int NAME_BYTES_AT = 2 [static]

final int NAME_LEN_AT = 1 [static]

final int NAME_SCRIPT_AT = 106 [static]

final byte [] noBytes = new byte[ 0 ] [static, private]

boolean strict = false [static, protected]

final int VERSION_MIN_AT = 123 [static]

final int VERSION_OBSOLETE_AT = 126 [static]

final int VERSION_TARGET_AT = 122 [static]

final int WHEN_CREATED_AT = 91 [static]

final int WHEN_MODIFIED_AT = 95 [static]

final int ZERO_1_AT = 0 [static]

Offsets in header where the fields are located.

final int ZERO_2_AT = 74 [static]

final int ZERO_3_AT = 82 [static]

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The documentation for this class was generated from the following file:

• /opt/source/Wonder/Frameworks/Core/ERExtensions/Sources/er/extensions/components/ERXMacBinarySwissArmyKnife.java