mirror of https://github.com/hsoft/collapseos.git
177 lines
3.6 KiB
NASM
177 lines
3.6 KiB
NASM
; ed - line editor
|
|
;
|
|
; A text editor modeled after UNIX's ed, but simpler. The goal is to stay tight
|
|
; on resources and to avoid having to implement screen management code (that is,
|
|
; develop the machinery to have ncurses-like apps in Collapse OS).
|
|
;
|
|
; ed has a mechanism to avoid having to move a lot of memory around at each
|
|
; edit. Each line is an element in an doubly-linked list and each element point
|
|
; to an offset in the "scratchpad". The scratchpad starts with the file
|
|
; contents and every time we change or add a line, that line goes to the end of
|
|
; the scratch pad and linked lists are reorganized whenever lines are changed.
|
|
; Contents itself is always appended to the scratchpad.
|
|
;
|
|
; That's on a resourceful UNIX system.
|
|
;
|
|
; That doubly linked list on the z80 would use 7 bytes per line (prev, next,
|
|
; offset, len), which is a bit much.
|
|
;
|
|
; We sacrifice speed for memory usage by making that linked list into a simple
|
|
; array of pointers to line contents in scratchpad. This means that we
|
|
; don't have an easy access to line length and we have to move a lot of memory
|
|
; around whenever we add or delete lines. Hopefully, "LDIR" will be our friend
|
|
; here...
|
|
;
|
|
; *** Variables ***
|
|
;
|
|
.equ ED_CURLINE ED_RAMSTART
|
|
.equ ED_RAMEND @+2
|
|
|
|
edMain:
|
|
; because ed only takes a single string arg, we can use HL directly
|
|
call ioInit
|
|
ret nz
|
|
; diverge from UNIX: start at first line
|
|
ld hl, 0
|
|
ld (ED_CURLINE), hl
|
|
|
|
call bufInit
|
|
|
|
.mainLoop:
|
|
ld a, ':'
|
|
call stdioPutC
|
|
call stdioReadLine ; --> HL
|
|
; Now, process line.
|
|
call printcrlf
|
|
call cmdParse
|
|
jp nz, .error
|
|
ld a, (CMD_TYPE)
|
|
cp 'q'
|
|
jr z, .doQ
|
|
cp 'w'
|
|
jr z, .doW
|
|
; The rest of the commands need an address
|
|
call edReadAddrs
|
|
jr nz, .error
|
|
ld a, (CMD_TYPE)
|
|
cp 'i'
|
|
jr z, .doI
|
|
; The rest of the commands don't allow addr == cnt
|
|
push hl ; --> lvl 1
|
|
ld hl, (BUF_LINECNT)
|
|
call cpHLDE
|
|
pop hl ; <-- lvl 1
|
|
jr z, .error
|
|
ld a, (CMD_TYPE)
|
|
cp 'd'
|
|
jr z, .doD
|
|
cp 'a'
|
|
jr z, .doA
|
|
jr .doP
|
|
|
|
.doQ:
|
|
xor a
|
|
ret
|
|
|
|
.doW:
|
|
ld a, 3 ; seek beginning
|
|
call ioSeek
|
|
ld de, 0 ; cur line
|
|
.wLoop:
|
|
push de \ pop hl
|
|
call bufGetLine ; --> buffer in (HL)
|
|
jr nz, .wEnd
|
|
call ioPutLine
|
|
jr nz, .error
|
|
inc de
|
|
jr .wLoop
|
|
.wEnd:
|
|
; Set new file size
|
|
call ioTell
|
|
call ioSetSize
|
|
; for now, writing implies quitting
|
|
; TODO: reload buffer
|
|
xor a
|
|
ret
|
|
.doD:
|
|
ld (ED_CURLINE), de
|
|
; bufDelLines expects an exclusive upper bound, which is why we inc DE.
|
|
inc de
|
|
call bufDelLines
|
|
jr .mainLoop
|
|
.doA:
|
|
inc de
|
|
.doI:
|
|
call stdioReadLine ; --> HL
|
|
call bufScratchpadAdd ; --> HL
|
|
; insert index in DE, line offset in HL. We want the opposite.
|
|
ex de, hl
|
|
ld (ED_CURLINE), hl
|
|
call bufInsertLine
|
|
call printcrlf
|
|
jr .mainLoop
|
|
|
|
.doP:
|
|
push hl
|
|
call bufGetLine
|
|
jr nz, .error
|
|
call printstr
|
|
call printcrlf
|
|
pop hl
|
|
call cpHLDE
|
|
jr z, .doPEnd
|
|
inc hl
|
|
jr .doP
|
|
.doPEnd:
|
|
ld (ED_CURLINE), hl
|
|
jp .mainLoop
|
|
.error:
|
|
ld a, '?'
|
|
call stdioPutC
|
|
call printcrlf
|
|
jp .mainLoop
|
|
|
|
|
|
; Transform an address "cmd" in IX into an absolute address in HL.
|
|
edResolveAddr:
|
|
ld a, (ix)
|
|
cp RELATIVE
|
|
jr z, .relative
|
|
cp EOF
|
|
jr z, .eof
|
|
; absolute
|
|
ld l, (ix+1)
|
|
ld h, (ix+2)
|
|
ret
|
|
.relative:
|
|
ld hl, (ED_CURLINE)
|
|
push de
|
|
ld e, (ix+1)
|
|
ld d, (ix+2)
|
|
add hl, de
|
|
pop de
|
|
ret
|
|
.eof:
|
|
ld hl, (BUF_LINECNT)
|
|
dec hl
|
|
ret
|
|
|
|
; Read absolute addr1 in HL and addr2 in DE. Also, check bounds and set Z if
|
|
; both addresses are within bounds, unset if not.
|
|
edReadAddrs:
|
|
ld ix, CMD_ADDR2
|
|
call edResolveAddr
|
|
ld de, (BUF_LINECNT)
|
|
ex de, hl ; HL: cnt DE: addr2
|
|
call cpHLDE
|
|
jp c, unsetZ ; HL (cnt) < DE (addr2). no good
|
|
ld ix, CMD_ADDR1
|
|
call edResolveAddr
|
|
ex de, hl ; HL: addr2, DE: addr1
|
|
call cpHLDE
|
|
jp c, unsetZ ; HL (addr2) < DE (addr1). no good
|
|
ex de, hl ; HL: addr1, DE: addr2
|
|
cp a ; ensure Z
|
|
ret
|
|
|