XWasHere/lindows
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[lcrash/cckernel] FIX: Add support for fixed huffman compression

Browse Source
This commit is contained in:
xwashere 2024-04-17 13:15:34 -04:00
parent d81dd11837
commit fc7520c16f
Signed by: XWasHere
GPG Key ID: 042F8BFA1B0EF93B
1 changed files with 46 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

85
lcrash/setup/compressed/gzip.c
View File

@ -150,54 +150,59 @@ uptr GzipDecompress(c8* Input, uptr InputSize, c8* Output) {
case 0: { // NO COMPRESSION
break;
}
case 1: {
// FIXED HUFFMAN
break;
}
case 1: // FIXED HUFFMAN
case 2: { // DYNAMIC HUFFMAN
// Get huffman code counts
u64 OperationCount = GzipFetchBits(Stream, &BitLocation, 5) + 257;
u64 DistanceCount = GzipFetchBits(Stream, &BitLocation, 5) + 1;
u64 CodeCount = GzipFetchBits(Stream, &BitLocation, 4) + 4;
u64 OperationCount = (head & 2) ? 288 : GzipFetchBits(Stream, &BitLocation, 5) + 257;
u64 DistanceCount = (head & 2) ? 31 : GzipFetchBits(Stream, &BitLocation, 5) + 1;
u64 CodeCount = (head & 2) ? 0 : GzipFetchBits(Stream, &BitLocation, 4) + 4;
u8 Lengths[OperationCount + DistanceCount] = {};
const u8 CodeLengthLengthOffset[19] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
u8 CodeLengthLengthProto[19] = {};
for (int i = 0; i < CodeCount; i++) {
CodeLengthLengthProto[CodeLengthLengthOffset[i]] = GzipFetchBits(Stream, &BitLocation, 3);
}
if (head & 2) { // Build fixed huffman lengths
for (int i = 0; i <= 143; i++) Lengths[i] = 8;
for (int i = 143; i <= 255; i++) Lengths[i] = 9;
for (int i = 256; i <= 279; i++) Lengths[i] = 7;
for (int i = 280; i <= 287; i++) Lengths[i] = 8;
for (int i = 288; i <= 319; i++) Lengths[i] = 5;
} else { // Build dynamic huffman lengths
const u8 CodeLengthLengthOffset[19] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
u8 CodeLengthLengthProto[19] = {};
for (int i = 0; i < CodeCount; i++) {
CodeLengthLengthProto[CodeLengthLengthOffset[i]] = GzipFetchBits(Stream, &BitLocation, 3);
}
// Build our decoding tables
u8 CodeLengthLengths[0x80] = {};
u32 CodeLengthSymbols[0x80] = {};
GzipPopulateTable(CodeLengthLengthProto, 19, CodeLengthLengths, CodeLengthSymbols, 0x80, 7);
// Build our decoding tables
u8 CodeLengthLengths[0x80] = {};
u32 CodeLengthSymbols[0x80] = {};
GzipPopulateTable(CodeLengthLengthProto, 19, CodeLengthLengths, CodeLengthSymbols, 0x80, 7);
// Collect lengths
u8 Lengths[OperationCount + DistanceCount] = {};
uptr CurrentLen = 0;
while (CurrentLen < OperationCount + DistanceCount) {
// Fetch the next op
u64 Code = GzipFetchBits(Stream, &BitLocation, 7);
u64 Error = 7 - CodeLengthLengths[Code];
BitLocation -= Error;
Code = CodeLengthSymbols[Code];
// Collect lengths
uptr CurrentLen = 0;
while (CurrentLen < OperationCount + DistanceCount) {
// Fetch the next op
u64 Code = GzipFetchBits(Stream, &BitLocation, 7);
u64 Error = 7 - CodeLengthLengths[Code];
BitLocation -= Error;
Code = CodeLengthSymbols[Code];
if (Code < 16) { // Literal
Lengths[CurrentLen++] = Code;
} else { // Repeat
u64 RepeatCount = 0;
u64 RepeatedLen = 0;
if (Code < 16) { // Literal
Lengths[CurrentLen++] = Code;
} else { // Repeat
u64 RepeatCount = 0;
u64 RepeatedLen = 0;
if (Code == 16) {
RepeatCount = 3 + GzipFetchBits(Stream, &BitLocation, 2);
RepeatedLen = CurrentLen > 0 ? Lengths[CurrentLen - 1] : 0;
} else if (Code == 17) {
RepeatCount = 3 + GzipFetchBits(Stream, &BitLocation, 3);
} else if (Code == 18) {
RepeatCount =11 + GzipFetchBits(Stream, &BitLocation, 7);
} else {} // Should be unreachable
if (Code == 16) {
RepeatCount = 3 + GzipFetchBits(Stream, &BitLocation, 2);
RepeatedLen = CurrentLen > 0 ? Lengths[CurrentLen - 1] : 0;
} else if (Code == 17) {
RepeatCount = 3 + GzipFetchBits(Stream, &BitLocation, 3);
} else if (Code == 18) {
RepeatCount =11 + GzipFetchBits(Stream, &BitLocation, 7);
} else {} // Should be unreachable
for (int i = 0; i < RepeatCount; i++) {
Lengths[CurrentLen++] = RepeatedLen;
for (int i = 0; i < RepeatCount; i++) {
Lengths[CurrentLen++] = RepeatedLen;
}
}
}
}