Protocol format for PackedEncode and PackedDecode classes. More...

Variables
static const uint1	HEADER_MASK = 0xc0
	Bits encoding the record type.

static const uint1	ELEMENT_START = 0x40
	Header for an element start record.

static const uint1	ELEMENT_END = 0x80
	Header for an element end record.

static const uint1	ATTRIBUTE = 0xc0
	Header for an attribute record.

static const uint1	HEADEREXTEND_MASK = 0x20
	Bit indicating the id extends into the next byte.

static const uint1	ELEMENTID_MASK = 0x1f
	Bits encoding (part of) the id in the record header.

static const uint1	RAWDATA_MASK = 0x7f
	Bits of raw data in follow-on bytes.

static const int4	RAWDATA_BITSPERBYTE = 7
	Number of bits used in a follow-on byte.

static const uint1	RAWDATA_MARKER = 0x80
	The unused bit in follow-on bytes. (Always set to 1)

static const int4	TYPECODE_SHIFT = 4
	Bit position of the type code in the type byte.

static const uint1	LENGTHCODE_MASK = 0xf
	Bits in the type byte forming the length code.

static const uint1	TYPECODE_BOOLEAN = 1
	Type code for the boolean type.

static const uint1	TYPECODE_SIGNEDINT_POSITIVE = 2
	Type code for the signed positive integer type.

static const uint1	TYPECODE_SIGNEDINT_NEGATIVE = 3
	Type code for the signed negative integer type.

static const uint1	TYPECODE_UNSIGNEDINT = 4
	Type code for the unsigned integer type.

static const uint1	TYPECODE_ADDRESSSPACE = 5
	Type code for the address space type.

static const uint1	TYPECODE_SPECIALSPACE = 6
	Type code for the special address space type.

static const uint1	TYPECODE_STRING = 7
	Type code for the string type.

static const uint4	SPECIALSPACE_STACK = 0
	Special code for the stack space.

static const uint4	SPECIALSPACE_JOIN = 1
	Special code for the join space.

static const uint4	SPECIALSPACE_FSPEC = 2
	Special code for the fspec space.

static const uint4	SPECIALSPACE_IOP = 3
	Special code for the iop space.

static const uint4	SPECIALSPACE_SPACEBASE = 4
	Special code for a spacebase space.

Detailed Description

Protocol format for PackedEncode and PackedDecode classes.

All bytes in the encoding are expected to be non-zero. Element encoding looks like

01xiiiii is an element start
10xiiiii is an element end
11xiiiii is an attribute start

Where iiiii is the (first) 5 bits of the element/attribute id. If x=0, the id is complete. If x=1, the next byte contains 7 more bits of the id: 1iiiiiii

After an attribute start, there follows a type byte: ttttllll, where the first 4 bits indicate the type of attribute and final 4 bits are a length code. The types are:

1 = boolean (lengthcode=0 for false, lengthcode=1 for true)
2 = positive signed integer
3 = negative signed integer (stored in negated form)
4 = unsigned integer
5 = basic address space (encoded as the integer index of the space)
6 = special address space (lengthcode 0=>stack 1=>join 2=>fspec 3=>iop)
7 = string

All attribute types except boolean and special, have an encoded integer after the type byte. The length code, indicates the number bytes used to encode the integer, 7-bits of info per byte, 1iiiiiii. A length code of zero is used to encode an integer value of 0, with no following bytes.

For strings, the integer encoded after the type byte, is the actual length of the string. The string data itself is stored immediately after the length integer using UTF8 format.

Variables

Detailed Description