Unit TLZHCOMP

Classes

TLZHCompressor -

Functions

Types

BufPtr
BufType
BWordRay
BWordRayPtr
FreqPtr
Freqtype
PntrPtr
PntrType
SonPtr
SonType
TBufPtr
TextBufType
WordRay
WordRayPtr

Constants

DefaultBufferSize
F
MAXIOBUFFER
MAX_FREQ
MINIOBUFFER
N
NUL
N_CHAR
R
T
THRESHOLD

Variables


Functions


Types


BufPtr = ^BufType
Convenient typecast.
BufType = Array[1..MAXIOBUFFER] OF BYTE;

BWordRay = Array[0..N+256] OF Integer;

BWordRayPtr = ^BWordRay

FreqPtr = ^freqtype

Freqtype = Array[0..T] OF WORD;

PntrPtr = ^pntrType

PntrType = Array[0..PRED(T+N_Char)] OF Integer;

SonPtr = ^SonType

SonType = Array[0..PRED(T)] OF Integer;

TBufPtr = ^TextBufType

TextBufType = Array[0..N+F-2] OF BYTE;

WordRay = Array[0..N] OF Integer;

WordRayPtr = ^WordRay

Constants

DefaultBufferSize = 1024

update when cumulative frequency } { reaches to this value

F = 60

Size of string buffer

MAXIOBUFFER = 32768

MAX_FREQ = $8000

root position

MINIOBUFFER = 16

N = 4096

LZSS Parameters

NUL = N

N_CHAR = (256 - THRESHOLD + F)

End of tree's node } { Huffman coding parameters

R = (T - 1)

Size of table

T = (N_CHAR * 2 - 1)

character code (:= 0..N_CHAR-1)

THRESHOLD = 2

Size of look-ahead buffer

Variables