mirror of
https://github.com/irmen/prog8.git
synced 2024-11-27 03:50:27 +00:00
5731b79554
In certain cases you will need to use string.copy() explicitly to overwrite strings with new strings.
410 lines
12 KiB
Lua
410 lines
12 KiB
Lua
; **experimental** data compression/decompression routines, API subject to change!!
|
|
|
|
compression {
|
|
|
|
%option no_symbol_prefixing, ignore_unused
|
|
|
|
sub encode_rle_outfunc(uword data, uword size, uword output_function, bool is_last_block) {
|
|
; -- Compress the given data block using ByteRun1 aka PackBits RLE encoding.
|
|
; output_function = address of a routine that gets a byte arg in A,
|
|
; this is the next RLE byte to write to the compressed output buffer or file.
|
|
; is_last_block = usually true, but you can set it to false if you want to concatenate multiple
|
|
; compressed blocks (for instance if the source data is >64Kb)
|
|
; Worst case result storage size needed = (size + (size+126) / 127) + 1
|
|
; This routine is not optimized for speed but for readability and ease of use.
|
|
uword idx = 0
|
|
uword literals_start_idx = 0
|
|
ubyte literals_length = 0
|
|
|
|
asmsub call_output_function(ubyte arg @A) {
|
|
%asm {{
|
|
jmp (p8v_output_function)
|
|
}}
|
|
}
|
|
|
|
sub next_same_span() {
|
|
; returns length in cx16.r1L, and the byte value in cx16.r1H
|
|
cx16.r1H = data[idx]
|
|
cx16.r1L = 0
|
|
while data[idx]==cx16.r1H and cx16.r1L<128 and idx<size {
|
|
idx++
|
|
cx16.r1L++
|
|
}
|
|
}
|
|
|
|
sub output_literals() {
|
|
call_output_function(literals_length-1)
|
|
uword dataptr = data + literals_start_idx
|
|
ubyte i
|
|
for i in 0 to literals_length-1 {
|
|
call_output_function(@(dataptr))
|
|
dataptr++
|
|
}
|
|
literals_length = 0
|
|
}
|
|
|
|
while idx<size {
|
|
next_same_span() ; count in r1L, value in r1H
|
|
if cx16.r1L>1 {
|
|
; a replicate run
|
|
if literals_length>0
|
|
output_literals()
|
|
call_output_function((cx16.r1L^255)+2) ; 257-cx16.r1L
|
|
call_output_function(cx16.r1H)
|
|
}
|
|
else {
|
|
; add more to the literals run
|
|
if literals_length==128
|
|
output_literals()
|
|
if literals_length==0
|
|
literals_start_idx = idx-1
|
|
literals_length++
|
|
}
|
|
}
|
|
|
|
if literals_length>0
|
|
output_literals()
|
|
|
|
if is_last_block
|
|
call_output_function(128)
|
|
}
|
|
|
|
sub encode_rle(uword data, uword size, uword target, bool is_last_block) -> uword {
|
|
; -- Compress the given data block using ByteRun1 aka PackBits RLE encoding.
|
|
; Returns the size of the compressed RLE data. Worst case result storage size needed = (size + (size+126) / 127) + 1.
|
|
; is_last_block = usually true, but you can set it to false if you want to concatenate multiple
|
|
; compressed blocks (for instance if the source data is >64Kb)
|
|
; This routine is not optimized for speed but for readability and ease of use.
|
|
uword idx = 0
|
|
uword literals_start_idx = 0
|
|
ubyte literals_length = 0
|
|
uword orig_target = target
|
|
|
|
sub next_same_span() {
|
|
; returns length in cx16.r1L, and the byte value in cx16.r1H
|
|
cx16.r1H = data[idx]
|
|
cx16.r1L = 0
|
|
while data[idx]==cx16.r1H and cx16.r1L<128 and idx<size {
|
|
idx++
|
|
cx16.r1L++
|
|
}
|
|
}
|
|
|
|
sub output_literals() {
|
|
@(target) = literals_length-1
|
|
target++
|
|
uword dataptr = data + literals_start_idx
|
|
ubyte i
|
|
for i in 0 to literals_length-1 {
|
|
@(target) = @(dataptr)
|
|
target++
|
|
dataptr++
|
|
}
|
|
literals_length = 0
|
|
}
|
|
|
|
while idx<size {
|
|
next_same_span() ; count in r1L, value in r1H
|
|
if cx16.r1L>1 {
|
|
; a replicate run
|
|
if literals_length>0
|
|
output_literals()
|
|
@(target) = (cx16.r1L^255)+2 ; 257-cx16.r1L
|
|
target++
|
|
@(target) = cx16.r1H
|
|
target++
|
|
}
|
|
else {
|
|
; add more to the literals run
|
|
if literals_length==128
|
|
output_literals()
|
|
if literals_length==0
|
|
literals_start_idx = idx-1
|
|
literals_length++
|
|
}
|
|
}
|
|
|
|
if literals_length>0
|
|
output_literals()
|
|
|
|
if is_last_block {
|
|
@(target) = 128
|
|
target ++
|
|
}
|
|
|
|
return target-orig_target
|
|
}
|
|
|
|
asmsub decode_rle_srcfunc(uword source_function @AY, uword target @R0, uword maxsize @R1) clobbers(X) -> uword @AY {
|
|
; -- decodes "ByteRun1" (aka PackBits) RLE compressed data. Control byte value 128 ends the decoding.
|
|
; instead of a source buffer, you provide a callback function that must return the next byte to compress in A.
|
|
; Stops decompressing when the maxsize has been reached.
|
|
%asm {{
|
|
sta _cb_mod1+1
|
|
sty _cb_mod1+2
|
|
sta _cb_mod2+1
|
|
sty _cb_mod2+2
|
|
sta _cb_mod3+1
|
|
sty _cb_mod3+2
|
|
lda cx16.r0L
|
|
ldy cx16.r0H
|
|
sta P8ZP_SCRATCH_W2 ; target ptr
|
|
sta _orig_target
|
|
sty P8ZP_SCRATCH_W2+1
|
|
sty _orig_target+1
|
|
lda cx16.r0L
|
|
clc
|
|
adc cx16.r1L
|
|
sta cx16.r1L
|
|
lda cx16.r0H
|
|
adc cx16.r1H
|
|
sta cx16.r1H ; decompression limit
|
|
|
|
_loop
|
|
; while target (W2) < limit (r1)
|
|
lda P8ZP_SCRATCH_W2
|
|
ldy P8ZP_SCRATCH_W2+1
|
|
cmp cx16.r1L
|
|
tya
|
|
sbc cx16.r1H
|
|
bcs _end
|
|
|
|
_cb_mod1 jsr $ffff ; modified
|
|
bpl _literals
|
|
cmp #128
|
|
beq _end
|
|
|
|
; replicate next byte -n+1 times
|
|
eor #255
|
|
clc
|
|
adc #2
|
|
sta P8ZP_SCRATCH_REG
|
|
_cb_mod2 jsr $ffff ; modified
|
|
ldx P8ZP_SCRATCH_REG
|
|
ldy #0
|
|
- sta (P8ZP_SCRATCH_W2),y
|
|
iny
|
|
dex
|
|
bne -
|
|
; add A to target
|
|
lda P8ZP_SCRATCH_REG
|
|
clc
|
|
adc P8ZP_SCRATCH_W2
|
|
sta P8ZP_SCRATCH_W2
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W2+1
|
|
sta P8ZP_SCRATCH_W2+1
|
|
jmp _loop
|
|
_literals
|
|
; copy the next n+1 bytes
|
|
pha
|
|
sta P8ZP_SCRATCH_B1
|
|
ldy #0
|
|
sty P8ZP_SCRATCH_REG
|
|
_cb_mod3 jsr $ffff ; modified
|
|
ldy P8ZP_SCRATCH_REG
|
|
sta (P8ZP_SCRATCH_W2),y
|
|
inc P8ZP_SCRATCH_REG
|
|
dec P8ZP_SCRATCH_B1
|
|
bpl _cb_mod3
|
|
; add N+1 to target
|
|
pla
|
|
sec
|
|
adc P8ZP_SCRATCH_W2
|
|
sta P8ZP_SCRATCH_W2
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W2+1
|
|
sta P8ZP_SCRATCH_W2+1
|
|
jmp _loop
|
|
|
|
_orig_target .word 0
|
|
_end
|
|
; return w2-orig_target, the size of the decompressed data
|
|
lda P8ZP_SCRATCH_W2
|
|
ldy P8ZP_SCRATCH_W2+1
|
|
sec
|
|
sbc _orig_target
|
|
tax
|
|
tya
|
|
sbc _orig_target+1
|
|
tay
|
|
txa
|
|
rts
|
|
}}
|
|
}
|
|
|
|
asmsub decode_rle(uword compressed @AY, uword target @R0, uword maxsize @R1) clobbers(X) -> uword @AY {
|
|
; -- decodes "ByteRun1" (aka PackBits) RLE compressed data. Control byte value 128 ends the decoding.
|
|
; Stops decompressing when the maxsize has been reached.
|
|
%asm {{
|
|
sta P8ZP_SCRATCH_W1 ; compressed data ptr
|
|
sty P8ZP_SCRATCH_W1+1
|
|
lda cx16.r0L
|
|
ldy cx16.r0H
|
|
sta P8ZP_SCRATCH_W2 ; target ptr
|
|
sta _orig_target
|
|
sty P8ZP_SCRATCH_W2+1
|
|
sty _orig_target+1
|
|
lda cx16.r0L
|
|
clc
|
|
adc cx16.r1L
|
|
sta cx16.r1L
|
|
lda cx16.r0H
|
|
adc cx16.r1H
|
|
sta cx16.r1H ; decompression limit
|
|
|
|
_loop ; while target (W2) < limit (r1)
|
|
lda P8ZP_SCRATCH_W2
|
|
ldy P8ZP_SCRATCH_W2+1
|
|
cmp cx16.r1L
|
|
tya
|
|
sbc cx16.r1H
|
|
bcs _end
|
|
|
|
ldy #0
|
|
lda (P8ZP_SCRATCH_W1),y
|
|
bpl _literals
|
|
cmp #128
|
|
beq _end
|
|
|
|
; replicate next byte -n+1 times
|
|
eor #255
|
|
clc
|
|
adc #2
|
|
pha
|
|
tax
|
|
iny
|
|
lda (P8ZP_SCRATCH_W1),y
|
|
ldy #0
|
|
- sta (P8ZP_SCRATCH_W2),y
|
|
iny
|
|
dex
|
|
bne -
|
|
; add A to target
|
|
pla
|
|
clc
|
|
adc P8ZP_SCRATCH_W2
|
|
sta P8ZP_SCRATCH_W2
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W2+1
|
|
sta P8ZP_SCRATCH_W2+1
|
|
; increase source by 2
|
|
clc
|
|
lda P8ZP_SCRATCH_W1
|
|
adc #2
|
|
sta P8ZP_SCRATCH_W1
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W1+1
|
|
sta P8ZP_SCRATCH_W1+1
|
|
jmp _loop
|
|
_literals
|
|
; copy the next n+1 bytes
|
|
pha
|
|
tax
|
|
inc P8ZP_SCRATCH_W1
|
|
bne +
|
|
inc P8ZP_SCRATCH_W1+1
|
|
+ ldy #0
|
|
- lda (P8ZP_SCRATCH_W1),y
|
|
sta (P8ZP_SCRATCH_W2),y
|
|
iny
|
|
dex
|
|
bpl -
|
|
; add N+1 to source
|
|
pla
|
|
tax
|
|
sec
|
|
adc P8ZP_SCRATCH_W1
|
|
sta P8ZP_SCRATCH_W1
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W1+1
|
|
sta P8ZP_SCRATCH_W1+1
|
|
; add N+1 to target as well
|
|
txa
|
|
sec
|
|
adc P8ZP_SCRATCH_W2
|
|
sta P8ZP_SCRATCH_W2
|
|
lda #0
|
|
adc P8ZP_SCRATCH_W2+1
|
|
sta P8ZP_SCRATCH_W2+1
|
|
jmp _loop
|
|
|
|
_orig_target .word 0
|
|
_end
|
|
; return w2-orig_target, the size of the decompressed data
|
|
lda P8ZP_SCRATCH_W2
|
|
ldy P8ZP_SCRATCH_W2+1
|
|
sec
|
|
sbc _orig_target
|
|
tax
|
|
tya
|
|
sbc _orig_target+1
|
|
tay
|
|
txa
|
|
rts
|
|
}}
|
|
}
|
|
|
|
|
|
/***
|
|
; prog8 source code for the asm routine above:
|
|
|
|
sub decode_rle_prog8(uword @zp compressed, uword @zp target, uword maxsize) -> uword {
|
|
cx16.r0 = target ; original target
|
|
cx16.r1 = target+maxsize ; decompression limit
|
|
|
|
while target<cx16.r1 {
|
|
cx16.r2L = @(compressed)
|
|
if_neg {
|
|
if cx16.r2L==128
|
|
break
|
|
; replicate the next byte -n+1 times
|
|
compressed++
|
|
cx16.r3L = @(compressed)
|
|
repeat 2+(cx16.r2L^255) {
|
|
@(target) = cx16.r3L
|
|
target++
|
|
}
|
|
compressed++
|
|
} else {
|
|
; copy the next n+1 bytes
|
|
compressed++
|
|
repeat cx16.r2L+1 {
|
|
@(target) = @(compressed)
|
|
compressed++
|
|
target++
|
|
}
|
|
}
|
|
}
|
|
return target-cx16.r0
|
|
}
|
|
|
|
sub decode_rle_callback_prog8(uword producer_callback, uword @zp target, uword maxsize) -> uword {
|
|
cx16.r0 = target ; original target
|
|
cx16.r1 = target+maxsize ; decompression limit
|
|
|
|
while target<cx16.r1 {
|
|
cx16.r2L = lsb(call(producer_callback))
|
|
if_neg {
|
|
if cx16.r2L==128
|
|
break
|
|
; replicate the next byte -n+1 times
|
|
cx16.r3L = lsb(call(producer_callback))
|
|
repeat 2+(cx16.r2L^255) {
|
|
@(target) = cx16.r3L
|
|
target++
|
|
}
|
|
} else {
|
|
; copy the next n+1 bytes
|
|
repeat cx16.r2L+1 {
|
|
@(target) = lsb(call(producer_callback))
|
|
target++
|
|
}
|
|
}
|
|
}
|
|
return target-cx16.r0
|
|
}
|
|
***/
|
|
|
|
}
|