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engine: common: add GoldSrc bitbuf operations, add support for GoldSrc signed integers

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This commit is contained in:
Alibek Omarov 2024-10-07 19:34:19 +03:00
parent 61342547ce
commit d128997d40
2 changed files with 71 additions and 12 deletions
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60
engine/common/net_buffer.c
View file

@ -213,17 +213,25 @@ void MSG_WriteSBitLong( sizebuf_t *sb, int data, int numbits )
// do we have a valid # of bits to encode with?
Assert( numbits >= 1 && numbits <= 32 );
// NOTE: it does this wierdness here so it's bit-compatible with regular integer data in the buffer.
// (Some old code writes direct integers right into the buffer).
if( data < 0 )
{
if( sb->iAlternateSign )
MSG_WriteOneBit( sb, 1 );
MSG_WriteUBitLong( sb, (uint)( 0x80000000 + data ), numbits - 1 );
MSG_WriteOneBit( sb, 1 );
if( !sb->iAlternateSign )
MSG_WriteOneBit( sb, 1 );
}
else
{
if( sb->iAlternateSign )
MSG_WriteOneBit( sb, 0 );
MSG_WriteUBitLong( sb, (uint)data, numbits - 1 );
MSG_WriteOneBit( sb, 0 );
if( !sb->iAlternateSign )
MSG_WriteOneBit( sb, 0 );
}
}
@ -533,12 +541,22 @@ int MSG_ReadSBitLong( sizebuf_t *sb, int numbits )
{
int r, sign;
r = MSG_ReadUBitLong( sb, numbits - 1 );
if( sb->iAlternateSign )
{
sign = MSG_ReadOneBit( sb );
r = MSG_ReadUBitLong( sb, numbits - 1 );
// NOTE: it does this wierdness here so it's bit-compatible with regular integer data in the buffer.
// (Some old code writes direct integers right into the buffer).
sign = MSG_ReadOneBit( sb );
if( sign ) r = -( BIT( numbits - 1 ) - r );
if( sign )
r = -r;
}
else
{
r = MSG_ReadUBitLong( sb, numbits - 1 );
sign = MSG_ReadOneBit( sb );
if( sign )
r = -( BIT( numbits - 1 ) - r );
}
return r;
}
@ -569,7 +587,13 @@ int MSG_ReadCmd( sizebuf_t *sb, netsrc_t type )
int MSG_ReadChar( sizebuf_t *sb )
{
return MSG_ReadSBitLong( sb, sizeof( int8_t ) << 3 );
int alt = sb->iAlternateSign, ret;
sb->iAlternateSign = 0;
ret = MSG_ReadSBitLong( sb, sizeof( int8_t ) << 3 );
sb->iAlternateSign = alt;
return ret;
}
int MSG_ReadByte( sizebuf_t *sb )
@ -579,7 +603,13 @@ int MSG_ReadByte( sizebuf_t *sb )
int MSG_ReadShort( sizebuf_t *sb )
{
return MSG_ReadSBitLong( sb, sizeof( int16_t ) << 3 );
int alt = sb->iAlternateSign, ret;
sb->iAlternateSign = 0;
ret = MSG_ReadSBitLong( sb, sizeof( int16_t ) << 3 );
sb->iAlternateSign = alt;
return ret;
}
int MSG_ReadWord( sizebuf_t *sb )
@ -611,7 +641,13 @@ void MSG_ReadVec3Angles( sizebuf_t *sb, vec3_t fa )
int MSG_ReadLong( sizebuf_t *sb )
{
return MSG_ReadSBitLong( sb, sizeof( int32_t ) << 3 );
int alt = sb->iAlternateSign, ret;
sb->iAlternateSign = 0;
ret = MSG_ReadSBitLong( sb, sizeof( int32_t ) << 3 );
sb->iAlternateSign = alt;
return ret;
}
uint MSG_ReadDword( sizebuf_t *sb )

23
engine/common/net_buffer.h
View file

@ -42,6 +42,9 @@ struct sizebuf_s
int iCurBit;
int nDataBits;
const char *pDebugName; // buffer name (pointer to const name)
// to support GoldSrc broken signed integers
int iAlternateSign;
};
#define MSG_StartReading MSG_StartWriting
@ -71,6 +74,7 @@ static inline void MSG_InitExt( sizebuf_t *sb, const char *pDebugName, void *pDa
sb->nDataBits = nBits;
sb->pDebugName = pDebugName;
sb->iAlternateSign = 0;
}
static inline void MSG_StartWriting( sizebuf_t *sb, void *pData, int nBytes, int iStartBit, int nBits )
@ -169,6 +173,25 @@ static inline qboolean MSG_Overflow( sizebuf_t *sb, int nBits )
return sb->bOverflow;
}
static inline void MSG_EndBitWriting( sizebuf_t *sb )
{
sb->iAlternateSign--;
if( sb->iAlternateSign < 0 )
{
Con_Printf( "%s: non-even MSG_Start/EndBitWriting\n", __func__ );
sb->iAlternateSign = 0;
}
// we have native bit ops here, just pad to closest byte
MSG_SeekToBit( sb, MSG_GetNumBytesWritten( sb ) << 3, SEEK_SET );
}
static inline void MSG_StartBitWriting( sizebuf_t *sb )
{
sb->iAlternateSign++;
}
void MSG_InitMasks( void ); // called once at startup engine
void MSG_ExciseBits( sizebuf_t *sb, int startbit, int bitstoremove );