mirror of
https://github.com/badvision/lawless-legends.git
synced 2025-02-28 12:29:59 +00:00
Made decompression slightly faster.
This commit is contained in:
Martin Haye
parent
8dc84239e4
commit
6e8089d3a3
@ -14,7 +14,7 @@ public class Lx47Algorithm
|
||||
static final int MAX_OFFSET = 16384; /* range 1..65536 */
|
||||
static final int MAX_LEN = 255; /* range 2..65536 */
|
||||
static final int OFFSET_EXP_BITS = 6;
|
||||
|
||||
|
||||
LinkedList<String> debugs;
|
||||
|
||||
void addDebug(String format, Object... arguments) {
|
||||
@ -48,7 +48,7 @@ public class Lx47Algorithm
|
||||
}
|
||||
return bits;
|
||||
}
|
||||
|
||||
|
||||
int countCodePair(int prevLits, int matchLen, int offset) {
|
||||
assert offset >= 1;
|
||||
int nBits = (prevLits>0 ? 0 : 1)
|
||||
@ -57,7 +57,7 @@ public class Lx47Algorithm
|
||||
+ (matchLen>2 ? countGammaBits(matchLen-2) : 0);
|
||||
return nBits;
|
||||
}
|
||||
|
||||
|
||||
int countLitBits(int lits) {
|
||||
if (lits == 0)
|
||||
return 0;
|
||||
@ -69,7 +69,7 @@ public class Lx47Algorithm
|
||||
}
|
||||
return bits;
|
||||
}
|
||||
|
||||
|
||||
Optimal[] optimize(byte[] input_data) {
|
||||
int[] min = new int[MAX_OFFSET+1];
|
||||
int[] max = new int[MAX_OFFSET+1];
|
||||
@ -83,7 +83,7 @@ public class Lx47Algorithm
|
||||
int best_len;
|
||||
int bits;
|
||||
int i;
|
||||
|
||||
|
||||
for (i=0; i<256*256; i++)
|
||||
matches[i] = new Match();
|
||||
for (i=0; i<input_data.length; i++) {
|
||||
@ -104,7 +104,7 @@ public class Lx47Algorithm
|
||||
optimal[i].bits = optimal[i-1].bits
|
||||
- countLitBits(optimal[i-1].lits)
|
||||
+ countLitBits(optimal[i].lits);
|
||||
|
||||
|
||||
// Now search for a match that's better than just using a literal.
|
||||
match_index = (input_data[i-1] & 0xFF) << 8 | (input_data[i] & 0xFF);
|
||||
best_len = 1;
|
||||
@ -182,27 +182,27 @@ public class Lx47Algorithm
|
||||
mask >>= 1;
|
||||
bitPos++;
|
||||
}
|
||||
|
||||
|
||||
void writeGamma(int value) {
|
||||
assert value >= 1 && value <= 255;
|
||||
|
||||
|
||||
int i;
|
||||
|
||||
|
||||
// Find highest set bit
|
||||
for (i = 128; (i&value) == 0; i >>= 1)
|
||||
;
|
||||
|
||||
|
||||
// Write out extra bits with markers
|
||||
while (i > 1) {
|
||||
i >>= 1;
|
||||
writeBit(0);
|
||||
writeBit(value & i);
|
||||
}
|
||||
|
||||
|
||||
// And finish
|
||||
writeBit(1);
|
||||
}
|
||||
|
||||
|
||||
void writeLiteralLen(int value) {
|
||||
if (value == 0)
|
||||
writeBit(0);
|
||||
@ -224,7 +224,7 @@ public class Lx47Algorithm
|
||||
data |= 128;
|
||||
|
||||
writeByte(data);
|
||||
|
||||
|
||||
if (offset >= 64)
|
||||
writeGamma(offset>>6);
|
||||
if (matchLen > 2)
|
||||
@ -237,7 +237,7 @@ public class Lx47Algorithm
|
||||
int input_index;
|
||||
int input_prev;
|
||||
int i;
|
||||
|
||||
|
||||
//for (i=0; i<optimal.length; i++)
|
||||
// System.out.format("opt[%d]: bits=%d off=%d len=%d lits=%d\n", i,
|
||||
// optimal[i].bits, optimal[i].offset, optimal[i].len, optimal[i].lits);
|
||||
@ -293,15 +293,15 @@ public class Lx47Algorithm
|
||||
// Sequence. If two in a row, insert a zero-length lit str
|
||||
if (!prevIsLit) {
|
||||
addDebug("lits l=$00");
|
||||
w.writeBit(0);
|
||||
w.writeLiteralLen(0);
|
||||
}
|
||||
|
||||
|
||||
// Now write sequence info
|
||||
addDebug("seq l=$%02x o=$%04x", optimal[input_index].len, optimal[input_index].offset);
|
||||
w.writeCodePair(optimal[input_index].len, optimal[input_index].offset);
|
||||
prevIsLit = false;
|
||||
}
|
||||
|
||||
|
||||
assert optimal[input_index].bits == w.bitPos :
|
||||
String.format("pos miscalc: calc'd %d, got %d", optimal[input_index].bits, w.bitPos);
|
||||
}
|
||||
@ -309,16 +309,16 @@ public class Lx47Algorithm
|
||||
// EOF marker
|
||||
if (!prevIsLit) {
|
||||
addDebug("lits l=$00");
|
||||
w.writeBit(0);
|
||||
w.writeLiteralLen(0);
|
||||
}
|
||||
addDebug("EOF");
|
||||
|
||||
assert w.outPos == output_size : String.format("size miscalc: got %d, want %d", w.outPos, output_size);
|
||||
System.arraycopy(w.buf, 0, output_data, 0, w.outPos);
|
||||
|
||||
|
||||
return output_data;
|
||||
}
|
||||
|
||||
|
||||
public class Lx47Reader
|
||||
{
|
||||
public byte[] buf;
|
||||
@ -352,7 +352,7 @@ public class Lx47Algorithm
|
||||
out = (out << 1) | readBit();
|
||||
return out;
|
||||
}
|
||||
|
||||
|
||||
int readLiteralLen() {
|
||||
if (readBit() == 0)
|
||||
return 0;
|
||||
@ -373,7 +373,7 @@ public class Lx47Algorithm
|
||||
return matchLen | (offset<<16); // pack both vals into a single int
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
int debugPos = 0;
|
||||
void chkDebug(String format, Object... arguments) {
|
||||
String toCheck = String.format(format, arguments);
|
||||
@ -388,7 +388,7 @@ public class Lx47Algorithm
|
||||
int len;
|
||||
Lx47Reader r = new Lx47Reader(input_data, inStart);
|
||||
int outPos = outStart;
|
||||
|
||||
|
||||
// Now decompress until done.
|
||||
chkDebug("start");
|
||||
while (true)
|
||||
@ -404,11 +404,11 @@ public class Lx47Algorithm
|
||||
if (len != 255)
|
||||
break;
|
||||
}
|
||||
|
||||
|
||||
// Check for EOF at the end of each literal string
|
||||
if (outPos == outStart+outLen)
|
||||
break;
|
||||
|
||||
|
||||
// Not a literal, so it's a sequence. Get len, offset, and copy.
|
||||
int codePair = r.readCodePair();
|
||||
len = codePair & 0xFFFF;
|
||||
@ -419,7 +419,7 @@ public class Lx47Algorithm
|
||||
++outPos;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
chkDebug("EOF");
|
||||
}
|
||||
|
||||
|
||||
@ -38,7 +38,6 @@ DEBUG = 0
|
||||
decomp !zone {
|
||||
ldy #0 ; In lit loop Y must be zero
|
||||
beq .lits2 ; always taken
|
||||
|
||||
.lits asl bits ; get bit that tells us whether there's a literal string
|
||||
bne + ; ran out of bits in bit buffer?
|
||||
.lits2 jsr .getbts ; get more bits
|
||||
@ -46,18 +45,26 @@ decomp !zone {
|
||||
jsr .gamma ; Yes we have literals. Get the count.
|
||||
!if DEBUG { jsr .dbg1 }
|
||||
tax
|
||||
cpx #255 ; special case: long literal marked by len=255; chk and save to carry
|
||||
- lda (pSrc),y
|
||||
sta (pDst),y
|
||||
inc pSrc
|
||||
bne +
|
||||
inc pSrc+1
|
||||
+ inc pDst
|
||||
bne +
|
||||
inc pDst+1
|
||||
+ dex
|
||||
iny
|
||||
dex
|
||||
bne -
|
||||
bcs .lits ; (see special case above)
|
||||
tya
|
||||
clc
|
||||
adc pSrc
|
||||
sta pSrc
|
||||
bcc +
|
||||
inc pSrc+1
|
||||
+ tya
|
||||
clc
|
||||
adc pDst
|
||||
sta pDst
|
||||
bcc +
|
||||
inc pDst+1
|
||||
+ iny ; special case: long literal marked by len=255
|
||||
beq .lits
|
||||
ldy #0
|
||||
.endchk lda pDst ; check for done at end of each literal string
|
||||
cmp pEnd
|
||||
lda pDst+1
|
||||
@ -109,9 +116,9 @@ decomp !zone {
|
||||
adc pDst
|
||||
sta pDst
|
||||
ldy #0 ; back to 0 as expected by lits section
|
||||
bcc .lits
|
||||
bcc +
|
||||
inc pDst+1
|
||||
jmp .lits
|
||||
+ jmp .lits
|
||||
|
||||
; Read an Elias Gamma value into A. Destroys X. Sets carry.
|
||||
.gamma lda #1
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user