HPAVC/HPAVC CD-ROM.iso/MCASM.RAR/MC_ASM.EXE/WROX_ASM/CH10/PROGRAMS/RLE.ASM

Assembly Source File | 1994-05-30 | 4KB | 216 lines

; RLE coding
; Written by Malakhov K.A.
; Compile with TASM 3.0 or latter
;         TASM RLE.ASM /MX /ZX /O
; CALL:    rle_encode(char *buffinput,unsigned int inputlength,
;            char *buffoutput);
; CALL:    rle_decode(char *buffinput,unsigned int inputlength,
;            char *buffoutput);

model large

PUBLIC    _rle_encode
PUBLIC    _rle_decode

.code

_rle_encode    PROC    C FAR
        ARG    buffi:dword,leng:word,buffo:dword
        USES    bx,cx,dx,di,si,ds,es
; Initialization
        mov    ax,leng
        mov    cs:lng,ax

        mov    ax,word ptr buffi+2
        mov    ds,ax
        mov    ax,word ptr buffo+2
        mov    es,ax
        mov    si,word ptr buffi
        mov    di,word ptr buffo

        mov    cs:count1,di
        mov    cs:count2,0
        mov    cs:begflg,1
        inc    di
        cld
; Loop
ARH_01:        mov    cl,3fh
        mov    cs:count3,0
ARH_02:        lodsb
        mov    bx,leng
        dec    bx
        mov    leng,bx
        cmp    bx,3
        ja    ARH_03
        jmp    ARH_kon
; Compare with next byte
ARH_03:        cmp    al,byte ptr ds:[si]
        je    ARH_04
; Not equal.
ARH_031:    mov    cs:begflg,0
        stosb
        inc    word ptr cs:count2
        mov    ax,word ptr cs:count2
        cmp    ax,64000
        jbe    ARH_0311
        jmp    ARH_09
ARH_0311:    inc    byte ptr cs:count3
        dec    cl
        jnz    ARH_02
; Set controll code for not compressed block
        mov    dl,cs:count3
        or    dl,10000000b
        mov    bx,cs:count1
        mov    es:[bx],dl
        inc    word ptr cs:count2
        mov    cs:count1,di
        inc    di
        mov    cs:begflg,1
        jmp    ARH_01

ARH_032:    dec    di
        jmp    short    ARH_041
; Compare with third byte
ARH_04:        cmp    al,byte ptr ds:[si+1]
        jne    ARH_031
        dec    si
        inc    word ptr leng
        cmp    cs:begflg,1
        je    ARH_032
; Set not compressed block
        mov    dl,cs:count3
        or    dl,10000000b
        mov    bx,cs:count1
        mov    es:[bx],dl
        inc    word ptr cs:count2
; Begin compressed block
ARH_041:    mov    cl,3fh
        mov    cs:count3,0
ARH_05:        lodsb
        mov    bx,leng
        dec    bx
        mov    leng,bx
        cmp    bx,1
        jbe    ARH_06
        cmp    al,byte ptr ds:[si]
        jne    ARH_06
        inc    byte ptr cs:count3
        dec    cl
        jnz    ARH_05
        mov    dl,cs:count3
        mov    es:[di],dl
        inc    di
        inc    word ptr cs:count2
        mov    es:[di],al
        inc    word ptr cs:count2
        inc    di
        mov    cs:count1,di
        jmp    ARH_041
ARH_06:        mov    dl,cs:count3
        inc    dl
        mov    es:[di],dl
        inc    di
        inc    word ptr cs:count2
        mov    es:[di],al
        inc    word ptr cs:count2
        inc    di
        mov    cs:count1,di
        inc    di
        mov    cs:begflg,1
        jmp    ARH_01
ARH_kon:    stosb
        inc    word ptr cs:count2
        mov    cx,cs:count2
        cmp    cx,64000
        ja    ARH_09
; Save the rest of bytes
        inc    byte ptr cs:count3
        mov    cx,leng
ARH_07:        cmp    cx,1
        jb    ARH_08
ARH_071:    movsb
        inc    word ptr cs:count2
        mov    ax,cs:count2
        cmp    ax,cs:lng
        ja    ARH_09

        inc    byte ptr cs:count3
        dec    cx
        jnz    ARH_071
ARH_08:
        mov    al,cs:count3
        or    al,10000000b
        mov    bx,cs:count1
        mov    es:[bx],al
        inc    word ptr cs:count2

        mov    ax,cs:cs:count2
        ret

ARH_09:        xor    ax,ax
        ret

count1        dw    ?    ; Ptr for controll code
count2        dw    ?    ; Total bytes counter
count3        db    ?    ; Bytes counter in block
begflg        db    ?
lng        dw    ?

_rle_encode    ENDP

; Decompression
_rle_decode    PROC    C FAR
        ARG    buffi:dword,leng:word,buffo:dword
        USES    bx,cx,dx,di,si,ds,es
; Init
        mov    ax,word ptr buffi+2
        mov    ds,ax
        mov    ax,word ptr buffo+2
        mov    es,ax
        mov    si,word ptr buffi
        mov    di,word ptr buffo

        mov    cs:count1,di
        cld
; Load byte
DARH_01:    lodsb
        mov    bx,leng
        dec    bx
        mov    leng,bx
        cmp    bx,0
        je    DARH_kon
; Check block
        test    al,10000000b
        jz    DARH_02
; Do not compressed
        and    al,01111111b
        mov    cl,al
        xor    ch,ch
DARH_011:    movsb
        mov    bx,leng
        dec    bx
        mov    leng,bx
        cmp    bx,0
        je    DARH_kon
        dec    cx
        jnz    DARH_011
        jmp    short    DARH_01
; Compressed
DARH_02:    mov    cl,al
        xor    ch,ch
        lodsb
        mov    bx,leng
        dec    bx
        mov    leng,bx
        cmp    bx,0
        je    DARH_kon
    rep    stosb
        jmp    short    DARH_01
DARH_kon:    mov    ax,di
        sub    ax,cs:count1
        ret

_rle_decode    ENDP

        END