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Topic: unpacked bits (Read 1275 times) |
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rgovostes
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unpacked bits
« on: Oct 24th, 2004, 12:45am » |
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In my continuing search for some hidden images in the ROM of a Macintosh SE, I've written some code which functions identically to the UnpackBits, which is used in the compression of Macintosh PICT resources. It pulls out a chunk of data from a source file, attempts to decompress it, and then displays the output.
If I find them I'll be sure to share  You can run this on other Mac files (renamed "input.dat" and dropped in the sketch's data folder) and look for other hidden goodies.
I'm not positive it works; I tested the unpacking routine on a string I came up with and it output the expected data. I haven't tried it on images or anything else yet.
Code:int y, z;
byte[] b;
float offset;
boolean auto = false;
void setup() {
size(512, 342 + 8);
b = loadBytes("input.dat");
y = width * (height - 8) / 8;
z = width * (height - 8);
}
void loop() {
renderPICT();
if(auto) offset ++;
fill(0xffcccccc); stroke(0xffcccccc);
rect(0, height - 8, width - 1, 7);
fill(0xffffffff); stroke(0xff000000);
rect((offset / b.length) * (width - 8), (height - 8), 7, 7);
}
void renderPICT() {
int i, j, k, l = 0;
byte[] p = new byte[y + 1];
byte[] q = new byte[y];
System.arraycopy(b, (int)offset, p, 0, y + 1);
for(i = 0; i < p.length; i ++) {
if(p[i] < 0) {
k = p[i ++] + 0x80;
for(j = 0; j <= k; j ++) { q[l] = p[i]; l ++; if(l >= q.length) break; }
} else {
k = p[i];
for(j = 0; j <= k; j ++) { q[l] = p[i ++ + 1]; l ++; if(l >= q.length) break; }
}
if(l >= q.length) break;
}
for(i = 0; i < z; i ++)
pixels[i] = (~(q[i / 8] & 0xff) >> (7 - (i % 8)) & 1) * 0xffffffff;
}
void keyPressed() {
if (key == UP || key == RIGHT) {
offset = constrain(offset - 1, 0, b.length - 1);
} else if (key == DOWN || key == LEFT) {
offset = constrain(offset + 1, 0, b.length - 1);
} else if (key == ' ') {
auto = !auto;
}
}
void mouseReleased() {
println("Index: " + ((mouseY * width) + mouseX + (int)offset)/8);
} |
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| « Last Edit: Oct 24th, 2004, 2:04am by rgovostes » |
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