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Text File | 1990-02-12 | 12.0 KB | 521 lines

; lharc05.c ; ========================================================================== ; LHARC extraction/creation routines - Main Decode method ; ========================================================================== INSTXT "sfx.i" EXT InitGraph EXT UpdateGraph EXT text_buf EXT NewCRC ; New calculated CRC EXT InitCRC ; Initialize CRC routines EXT AdjCRC ; Merge .a into CRC EXT Prt EXT GetChar EXT StartHuff EXT InitCRC EXT AdjCRC EXT NewCRC EXT DecChar EXT DecPosition EXT Message EXT a2p EXT OutUnit EXT OutDrive EXT FirstTime EXT P_flag EXT AskDrives EXT CopyRight EXT open,close,setlfs,setnam,chkout,chrout,clrchn,getin RR EQU R0 C EQU R0+2 K EQU R1 J EQU R1+2 I EQU R2 TEXTPTR EQU R2+2 COUNT EQU R3 DELAY EQU 1 PAUSE EQU 0 ;──────────────────────────────────────────────────────────── ; void LzHead::Decode() ; { ; static int i, j, k, r, c; ; static long count; ; static word newcrc = 0; ; ; if (OriginalSize == 0) ; return; ; ; if (Put == obuf_putc) ; if(obuf_open(name)) { ; conout << obuf_Error() << "\n"; ; return; ; } ; ; StartHuff(); ; ; for (i = 0; i < N - F; i++) ; text_buf[i] = ' '; ; ; r = N - F; ; ; for (count = 0; count < OriginalSize; ) { ; ; c = DecChar(); ; ; if (c < 256) { ; newcrc = ArcCRC(c,newcrc); ; Put(c); ; text_buf[r++] = c; ; r &= (N - 1); ; count++; ; ; } else { ; ; i = (r - DecPosition() - 1) & (N - 1); ; j = c - 255 + THRESHOLD; ; ; for (k = 0; k < j; k++) { ; c = text_buf[(i + k) & (N - 1)]; ; newcrc = ArcCRC(c,newcrc); ; Put(c); ; text_buf[r++] = c; ; r &= (N - 1); ; count++; ; } ; } ; ; } ; ; if(newcrc != CRC) ; conout << "CRC error\n"; ; else ; conout << "CRC ok\n"; ; ; if(obuf_close()) ; conout << "Error Closing Output File : " << obuf_Error() << "\n"; ; ; conout << "\n"; ; } ;─────────────────────────────────────────────────────────────────────────── ; Error return codes: ; ; 0 = DecodeOK ; 1 = NullFile ; 2 = DiskError ; 3 = CRCError ; 4 = BadHeader PUBLIC ID PUBLIC CRC BSS Store,1 DSEG ID fcb 0,0,0,0,0 PackedSize fdb 0,0 OriginalSize fdb 0,0 Time fdb 0 Date fdb 0 Attr fdb 0 FilenameLen fcb 1 Filename fdb 0,0,0,0,0,0,0,0,0,0,0 CRC fdb 0 HeadEnd CSEG PUBLIC Decode PNT EQU T0 Decode jsr InitCRC lda #0 sta BITBUF sta P_flag jsr GetChar ; Get header size sta T0 cmp #0 beq EndOfArc cmp #HeadEnd-ID ; Make sure no lengthy filename bcs EndOfArc ; If so, we gotta quit jsr GetChar ; And checksum sta T0+1 lda #0 sta T1 tay GetHead jsr GetChar sta ID,y clc adc T1 sta T1 iny cpy T0 bne GetHead cmp T0+1 beq HeaderOK EndOfArc lda #BadHeader fcb $2c DecodeError lda #255 rts HeaderOK lda OriginalSize ; if(originalsize==0) return; ora OriginalSize+1 ora OriginalSize+2 ora OriginalSize+3 bne dec1 lda #1 rts dec1 ldy #0 Convert lda Filename,y jsr a2p sta Filename,y iny cpy FilenameLen bne Convert lda Filename,y sta CRC lda Filename+1,y sta CRC+1 lda #0 sta Filename,y ldy #0 sty P_flag lda FirstTime bne SkipTitle inc FirstTime CheckTitle lda Filename,y beq GotTitle cmp title,y bne SkipTitle iny bne CheckTitle ; Always GotTitle dec P_flag jsr clrchn lda #0 sta CopyRight ; Don't print copyright if title is there jmp dec2 SkipTitle jsr AskDrives ; Get output dev (maybe) ldx #<Filename ldy #>Filename jsr Message ldy FilenameLen Spaces lda #' ' jsr Prt iny cpy #20 bcc Spaces ldy FilenameLen ; Copy CRC lda Filename-2,y ; check for 0 type beq HasType lda #',' sta Filename,y iny lda #'P' sta Filename,y iny bne CommaW HasType lda #',' sta Filename-2,y lda Filename-1,y and #$7f sta Filename-1,y CommaW lda #',' sta Filename,y iny lda #'W' sta Filename,y iny iny iny lda #':' sta Filename-1 lda OutDrive ora #$30 sta Filename-2 tya ldx #<Filename-2 ldy #>Filename-2 jsr setnam lda #8 tay ldx OutUnit jsr setlfs jsr clrchn jsr open bit status bpl OpenOK lda #DiskError rts OpenOK ldx #8 jsr chkout bcc dec2 GoDiskErr lda #DiskError jmp ReturnA ;────────────────────────────────────────────────────────────────────────── ; Finished processsing header. Now test for stored file or compressed file ;────────────────────────────────────────────────────────────────────────── dec2 ldx #0 ; count = OriginalSize; dec6 lda OriginalSize,x sta COUNT,x inx cpx #4 bne dec6 bit P_flag bmi dec10 lda COUNT+1 ldx COUNT+2 ldy COUNT+3 jsr InitGraph dec10 lda #0 sta Store lda ID+3 cmp #'1' beq DeComp lda #$ff sta Store jmp for1 DeComp jsr StartHuff ; r = N-F; lda #<N-F ; for(i=0; i<N-F; i++) sta I ; text_buf[i] = ' '; sta RR lda #>N-F sta I+1 sta RR+1 lda #<text_buf sta PNT lda #>text_buf sta PNT+1 ldy #0 dec3 lda #' ' sta (PNT),y iny bne dec4 inc PNT+1 dec4 lda I bne dec5 dec I+1 dec5 dec I lda I ora I+1 bne dec3 for1 lda COUNT ; while(count) ora COUNT+1 ora COUNT+2 ora COUNT+3 bne f1a endfor jmp endfor1 f1a bit Store bpl f1aa jsr GetChar jsr put_c jmp for1 f1aa lda COUNT+3 ; Negative length means went past end bmi endfor jsr DecChar ; c = DecChar(); txa sta C tya ; if(c<256) sta C+1 bne else jsr do_put jmp for1 ; and continue with for loop else jsr DecPosition ; i = (r-DecPosition()-1) & (N-1); inx bne f1f iny f1f stx T0 sty T0+1 sec lda RR sbc T0 and #<N-1 sta I sta TEXTPTR lda RR+1 sbc T0+1 and #>N-1 sta I+1 sta TEXTPTR+1 sec ; j=c-255+THRESHOLD lda C sbc #255 sta J lda C+1 sbc #0 sta J+1 clc lda J adc #<THRESHOLD sta J lda J+1 adc #>THRESHOLD sta J+1 lda #0 ; for(k=0; sta K sta K+1 for2 lda K ; k<j; cmp J lda K+1 sbc J+1 bcc f2a jmp endfor2 f2a clc ; c=text_buf[(i+k)&(N-1)] lda TEXTPTR and #<N-1 adc #<text_buf sta T0 lda TEXTPTR+1 and #>N-1 adc #>text_buf sta T0+1 ldy #0 lda (T0),y sta C lda #0 sta C+1 jsr do_put ; Same code as above inc K ; k++ bne f2b inc K+1 f2b inc TEXTPTR bne f2c inc TEXTPTR+1 f2c jmp for2 endfor2 jmp for1 endfor1 lda CRC cmp NewCRC bne badcrc lda CRC+1 cmp NewCRC+1 bne badcrc lda #DecodeOK fcb $2c badcrc lda #CRCError ReturnA pha jsr clrchn lda #8 jsr close pla rts ;─────────────────────────── ; Common code from if..else ;─────────────────────────── do_put lda C put_c jsr AdjCRC bit P_flag bpl Printit cmp #PAUSE beq wait cmp #DELAY beq delay Printit jsr chrout bit P_flag bmi OutOK bit status bpl OutOK pla pla jmp GoDiskErr OutOK bit Store bmi Countpp clc ; text_buf[r++] = C; lda RR adc #<text_buf sta T0 lda RR+1 adc #>text_buf sta T0+1 ldy #0 lda C sta (T0),y inc RR bne f1b inc RR+1 f1b lda RR ; r &= N-1; and #<N-1 sta RR lda RR+1 and #>N-1 sta RR+1 Countpp lda COUNT ; count++ bne f1c lda COUNT+1 bne f1d lda COUNT+2 bne f1e dec COUNT+3 f1e dec COUNT+2 f1d dec COUNT+1 bit P_flag bmi f1c jsr UpdateGraph f1c dec COUNT rts title fcc "TITLE" fcb 0 wait jsr getin cmp #0 bne wait wait1 jsr getin cmp #0 beq wait1 lda #PAUSE jmp OutOK delay ldy #0 delay1 ldx #0 delay2 dex bne delay2 dey bne delay1 lda #DELAY jmp OutOK END