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A little Delphine unpacker documentation addition and variable renaming.

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svn-id: r32660
This commit is contained in:
Kari Salminen 2008-06-10 22:37:55 +00:00
parent 235504e600
commit efc4fd7ae0
2 changed files with 22 additions and 16 deletions
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28
engines/cine/unpack.cpp
View File

@ -36,23 +36,23 @@ uint32 CineUnpacker::readSource() {
return value;
}
int CineUnpacker::rcr(int CF) {
int rCF = (_chk & 1);
_chk >>= 1;
if (CF) {
_chk |= 0x80000000;
int CineUnpacker::rcr(int inputCarry) {
int outputCarry = (_chunk32b & 1);
_chunk32b >>= 1;
if (inputCarry) {
_chunk32b |= 0x80000000;
}
return rCF;
return outputCarry;
}
int CineUnpacker::nextBit() {
int CF = rcr(0);
if (_chk == 0) {
_chk = readSource();
_crc ^= _chk;
CF = rcr(1);
int carry = rcr(0);
if (_chunk32b == 0) {
_chunk32b = readSource();
_crc ^= _chunk32b;
carry = rcr(1);
}
return CF;
return carry;
}
uint16 CineUnpacker::getBits(byte numBits) {
@ -85,8 +85,8 @@ bool CineUnpacker::unpack(byte *dst, const byte *src, int srcLen) {
_datasize = readSource();
_dst = dst + _datasize - 1;
_crc = readSource();
_chk = readSource();
_crc ^= _chk;
_chunk32b = readSource();
_crc ^= _chunk32b;
do {
if (!nextBit()) {
if (!nextBit()) {

10
engines/cine/unpack.h
View File

@ -38,7 +38,13 @@ public:
private:
/** Reads a single big endian 32-bit integer from the source and goes backwards 4 bytes. */
uint32 readSource();
int rcr(int CF);
/**
* Shifts the current internal 32-bit chunk to the right by one.
* Puts input carry into internal chunk's topmost (i.e. leftmost) bit.
* Returns the least significant bit that was shifted out.
*/
int rcr(int inputCarry);
int nextBit();
uint16 getBits(byte numBits);
void unpackBytes(uint16 numBytes);
@ -46,7 +52,7 @@ private:
private:
int _datasize;
uint32 _crc;
uint32 _chk;
uint32 _chunk32b; //!< The current internal 32-bit chunk
byte *_dst;
const byte *_src;
};