-cvar_t registered = {0, "registered","0", "indicates if this is running registered quake (whether gfx/pop.lmp was found)"};
-cvar_t cmdline = {0, "cmdline","0", "contains commandline the engine was launched with"};
-
-char com_token[MAX_INPUTLINE];
-int com_argc;
-const char **com_argv;
-
-gamemode_t gamemode;
-const char *gamename;
-const char *gamedirname1;
-const char *gamedirname2;
-const char *gamescreenshotname;
-const char *gameuserdirname;
-char com_modname[MAX_OSPATH] = "";
-
-
-/*
-============================================================================
-
- BYTE ORDER FUNCTIONS
-
-============================================================================
-*/
-
-short ShortSwap (short l)
-{
- unsigned char b1,b2;
-
- b1 = l&255;
- b2 = (l>>8)&255;
-
- return (b1<<8) + b2;
-}
-
-int LongSwap (int l)
-{
- unsigned char b1,b2,b3,b4;
-
- b1 = l&255;
- b2 = (l>>8)&255;
- b3 = (l>>16)&255;
- b4 = (l>>24)&255;
-
- return ((int)b1<<24) + ((int)b2<<16) + ((int)b3<<8) + b4;
-}
-
-float FloatSwap (float f)
-{
- union
- {
- float f;
- unsigned char b[4];
- } dat1, dat2;
-
-
- dat1.f = f;
- dat2.b[0] = dat1.b[3];
- dat2.b[1] = dat1.b[2];
- dat2.b[2] = dat1.b[1];
- dat2.b[3] = dat1.b[0];
- return dat2.f;
-}
-
-
-// Extract integers from buffers
-
-unsigned int BuffBigLong (const unsigned char *buffer)
-{
- return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
-}
-
-unsigned short BuffBigShort (const unsigned char *buffer)
-{
- return (buffer[0] << 8) | buffer[1];
-}
-
-unsigned int BuffLittleLong (const unsigned char *buffer)
-{
- return (buffer[3] << 24) | (buffer[2] << 16) | (buffer[1] << 8) | buffer[0];
-}
-
-unsigned short BuffLittleShort (const unsigned char *buffer)
-{
- return (buffer[1] << 8) | buffer[0];
-}
-
-
-/*
-============================================================================
-
- CRC FUNCTIONS
-
-============================================================================
-*/
-
-// this is a 16 bit, non-reflected CRC using the polynomial 0x1021
-// and the initial and final xor values shown below... in other words, the
-// CCITT standard CRC used by XMODEM
-
-#define CRC_INIT_VALUE 0xffff
-#define CRC_XOR_VALUE 0x0000
-
-static unsigned short crctable[256] =
-{
- 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
- 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
- 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
- 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
- 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
- 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
- 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
- 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
- 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
- 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
- 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
- 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
- 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
- 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
- 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
- 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
- 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
- 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
- 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
- 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
- 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
- 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
- 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
- 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
- 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
- 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
- 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
- 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
- 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
- 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
- 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
- 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
-};
-
-unsigned short CRC_Block(const unsigned char *data, size_t size)
-{
- unsigned short crc = CRC_INIT_VALUE;
- while (size--)
- crc = (crc << 8) ^ crctable[(crc >> 8) ^ (*data++)];
- return crc ^ CRC_XOR_VALUE;
-}
-
-unsigned short CRC_Block_CaseInsensitive(const unsigned char *data, size_t size)
-{
- unsigned short crc = CRC_INIT_VALUE;
- while (size--)
- crc = (crc << 8) ^ crctable[(crc >> 8) ^ (tolower(*data++))];
- return crc ^ CRC_XOR_VALUE;
-}
-
-// QuakeWorld
-static unsigned char chktbl[1024 + 4] =
-{
- 0x78,0xd2,0x94,0xe3,0x41,0xec,0xd6,0xd5,0xcb,0xfc,0xdb,0x8a,0x4b,0xcc,0x85,0x01,
- 0x23,0xd2,0xe5,0xf2,0x29,0xa7,0x45,0x94,0x4a,0x62,0xe3,0xa5,0x6f,0x3f,0xe1,0x7a,
- 0x64,0xed,0x5c,0x99,0x29,0x87,0xa8,0x78,0x59,0x0d,0xaa,0x0f,0x25,0x0a,0x5c,0x58,
- 0xfb,0x00,0xa7,0xa8,0x8a,0x1d,0x86,0x80,0xc5,0x1f,0xd2,0x28,0x69,0x71,0x58,0xc3,
- 0x51,0x90,0xe1,0xf8,0x6a,0xf3,0x8f,0xb0,0x68,0xdf,0x95,0x40,0x5c,0xe4,0x24,0x6b,
- 0x29,0x19,0x71,0x3f,0x42,0x63,0x6c,0x48,0xe7,0xad,0xa8,0x4b,0x91,0x8f,0x42,0x36,
- 0x34,0xe7,0x32,0x55,0x59,0x2d,0x36,0x38,0x38,0x59,0x9b,0x08,0x16,0x4d,0x8d,0xf8,
- 0x0a,0xa4,0x52,0x01,0xbb,0x52,0xa9,0xfd,0x40,0x18,0x97,0x37,0xff,0xc9,0x82,0x27,
- 0xb2,0x64,0x60,0xce,0x00,0xd9,0x04,0xf0,0x9e,0x99,0xbd,0xce,0x8f,0x90,0x4a,0xdd,
- 0xe1,0xec,0x19,0x14,0xb1,0xfb,0xca,0x1e,0x98,0x0f,0xd4,0xcb,0x80,0xd6,0x05,0x63,
- 0xfd,0xa0,0x74,0xa6,0x86,0xf6,0x19,0x98,0x76,0x27,0x68,0xf7,0xe9,0x09,0x9a,0xf2,
- 0x2e,0x42,0xe1,0xbe,0x64,0x48,0x2a,0x74,0x30,0xbb,0x07,0xcc,0x1f,0xd4,0x91,0x9d,
- 0xac,0x55,0x53,0x25,0xb9,0x64,0xf7,0x58,0x4c,0x34,0x16,0xbc,0xf6,0x12,0x2b,0x65,
- 0x68,0x25,0x2e,0x29,0x1f,0xbb,0xb9,0xee,0x6d,0x0c,0x8e,0xbb,0xd2,0x5f,0x1d,0x8f,
- 0xc1,0x39,0xf9,0x8d,0xc0,0x39,0x75,0xcf,0x25,0x17,0xbe,0x96,0xaf,0x98,0x9f,0x5f,
- 0x65,0x15,0xc4,0x62,0xf8,0x55,0xfc,0xab,0x54,0xcf,0xdc,0x14,0x06,0xc8,0xfc,0x42,
- 0xd3,0xf0,0xad,0x10,0x08,0xcd,0xd4,0x11,0xbb,0xca,0x67,0xc6,0x48,0x5f,0x9d,0x59,
- 0xe3,0xe8,0x53,0x67,0x27,0x2d,0x34,0x9e,0x9e,0x24,0x29,0xdb,0x69,0x99,0x86,0xf9,
- 0x20,0xb5,0xbb,0x5b,0xb0,0xf9,0xc3,0x67,0xad,0x1c,0x9c,0xf7,0xcc,0xef,0xce,0x69,
- 0xe0,0x26,0x8f,0x79,0xbd,0xca,0x10,0x17,0xda,0xa9,0x88,0x57,0x9b,0x15,0x24,0xba,
- 0x84,0xd0,0xeb,0x4d,0x14,0xf5,0xfc,0xe6,0x51,0x6c,0x6f,0x64,0x6b,0x73,0xec,0x85,
- 0xf1,0x6f,0xe1,0x67,0x25,0x10,0x77,0x32,0x9e,0x85,0x6e,0x69,0xb1,0x83,0x00,0xe4,
- 0x13,0xa4,0x45,0x34,0x3b,0x40,0xff,0x41,0x82,0x89,0x79,0x57,0xfd,0xd2,0x8e,0xe8,
- 0xfc,0x1d,0x19,0x21,0x12,0x00,0xd7,0x66,0xe5,0xc7,0x10,0x1d,0xcb,0x75,0xe8,0xfa,
- 0xb6,0xee,0x7b,0x2f,0x1a,0x25,0x24,0xb9,0x9f,0x1d,0x78,0xfb,0x84,0xd0,0x17,0x05,
- 0x71,0xb3,0xc8,0x18,0xff,0x62,0xee,0xed,0x53,0xab,0x78,0xd3,0x65,0x2d,0xbb,0xc7,
- 0xc1,0xe7,0x70,0xa2,0x43,0x2c,0x7c,0xc7,0x16,0x04,0xd2,0x45,0xd5,0x6b,0x6c,0x7a,
- 0x5e,0xa1,0x50,0x2e,0x31,0x5b,0xcc,0xe8,0x65,0x8b,0x16,0x85,0xbf,0x82,0x83,0xfb,
- 0xde,0x9f,0x36,0x48,0x32,0x79,0xd6,0x9b,0xfb,0x52,0x45,0xbf,0x43,0xf7,0x0b,0x0b,
- 0x19,0x19,0x31,0xc3,0x85,0xec,0x1d,0x8c,0x20,0xf0,0x3a,0xfa,0x80,0x4d,0x2c,0x7d,
- 0xac,0x60,0x09,0xc0,0x40,0xee,0xb9,0xeb,0x13,0x5b,0xe8,0x2b,0xb1,0x20,0xf0,0xce,
- 0x4c,0xbd,0xc6,0x04,0x86,0x70,0xc6,0x33,0xc3,0x15,0x0f,0x65,0x19,0xfd,0xc2,0xd3,
-
- // map checksum goes here
- 0x00,0x00,0x00,0x00
-};
-
-// QuakeWorld
-unsigned char COM_BlockSequenceCRCByteQW(unsigned char *base, int length, int sequence)
-{
- unsigned char *p;
- unsigned char chkb[60 + 4];
-
- p = chktbl + (sequence % (sizeof(chktbl) - 8));
-
- if (length > 60)
- length = 60;
- memcpy(chkb, base, length);
-
- chkb[length] = (sequence & 0xff) ^ p[0];
- chkb[length+1] = p[1];
- chkb[length+2] = ((sequence>>8) & 0xff) ^ p[2];
- chkb[length+3] = p[3];
-
- return CRC_Block(chkb, length + 4) & 0xff;
-}
-
-/*
-==============================================================================
-
- MESSAGE IO FUNCTIONS
-
-Handles byte ordering and avoids alignment errors
-==============================================================================
-*/
-
-//
-// writing functions
-//
-
-void MSG_WriteChar (sizebuf_t *sb, int c)
-{
- unsigned char *buf;
-
- buf = SZ_GetSpace (sb, 1);
- buf[0] = c;
-}
-
-void MSG_WriteByte (sizebuf_t *sb, int c)
-{
- unsigned char *buf;
-
- buf = SZ_GetSpace (sb, 1);
- buf[0] = c;
-}
-
-void MSG_WriteShort (sizebuf_t *sb, int c)
-{
- unsigned char *buf;
-
- buf = SZ_GetSpace (sb, 2);
- buf[0] = c&0xff;
- buf[1] = c>>8;
-}
-
-void MSG_WriteLong (sizebuf_t *sb, int c)
-{
- unsigned char *buf;
-
- buf = SZ_GetSpace (sb, 4);
- buf[0] = c&0xff;
- buf[1] = (c>>8)&0xff;
- buf[2] = (c>>16)&0xff;
- buf[3] = c>>24;
-}
-
-void MSG_WriteFloat (sizebuf_t *sb, float f)
-{
- union
- {
- float f;
- int l;
- } dat;
-
-
- dat.f = f;
- dat.l = LittleLong (dat.l);
-
- SZ_Write (sb, (unsigned char *)&dat.l, 4);
-}
-
-void MSG_WriteString (sizebuf_t *sb, const char *s)
-{
- if (!s || !*s)
- MSG_WriteChar (sb, 0);
- else
- SZ_Write (sb, (unsigned char *)s, (int)strlen(s)+1);
-}
-
-void MSG_WriteUnterminatedString (sizebuf_t *sb, const char *s)
-{
- if (s && *s)
- SZ_Write (sb, (unsigned char *)s, (int)strlen(s));
-}
-
-void MSG_WriteCoord13i (sizebuf_t *sb, float f)
-{
- if (f >= 0)
- MSG_WriteShort (sb, (int)(f * 8.0 + 0.5));
- else
- MSG_WriteShort (sb, (int)(f * 8.0 - 0.5));
-}
-
-void MSG_WriteCoord16i (sizebuf_t *sb, float f)
-{
- if (f >= 0)
- MSG_WriteShort (sb, (int)(f + 0.5));
- else
- MSG_WriteShort (sb, (int)(f - 0.5));
-}
-
-void MSG_WriteCoord32f (sizebuf_t *sb, float f)
-{
- MSG_WriteFloat (sb, f);
-}
-
-void MSG_WriteCoord (sizebuf_t *sb, float f, protocolversion_t protocol)
-{
- if (protocol == PROTOCOL_QUAKE || protocol == PROTOCOL_QUAKEDP || protocol == PROTOCOL_NEHAHRAMOVIE || protocol == PROTOCOL_NEHAHRABJP || protocol == PROTOCOL_NEHAHRABJP2 || protocol == PROTOCOL_NEHAHRABJP3 || protocol == PROTOCOL_QUAKEWORLD)
- MSG_WriteCoord13i (sb, f);
- else if (protocol == PROTOCOL_DARKPLACES1)
- MSG_WriteCoord32f (sb, f);
- else if (protocol == PROTOCOL_DARKPLACES2 || protocol == PROTOCOL_DARKPLACES3 || protocol == PROTOCOL_DARKPLACES4)
- MSG_WriteCoord16i (sb, f);
- else
- MSG_WriteCoord32f (sb, f);
-}
-
-void MSG_WriteVector (sizebuf_t *sb, float *v, protocolversion_t protocol)
-{
- MSG_WriteCoord (sb, v[0], protocol);
- MSG_WriteCoord (sb, v[1], protocol);
- MSG_WriteCoord (sb, v[2], protocol);
-}
-
-// LordHavoc: round to nearest value, rather than rounding toward zero, fixes crosshair problem
-void MSG_WriteAngle8i (sizebuf_t *sb, float f)
-{
- if (f >= 0)
- MSG_WriteByte (sb, (int)(f*(256.0/360.0) + 0.5) & 255);
- else
- MSG_WriteByte (sb, (int)(f*(256.0/360.0) - 0.5) & 255);
-}
-
-void MSG_WriteAngle16i (sizebuf_t *sb, float f)
-{
- if (f >= 0)
- MSG_WriteShort (sb, (int)(f*(65536.0/360.0) + 0.5) & 65535);
- else
- MSG_WriteShort (sb, (int)(f*(65536.0/360.0) - 0.5) & 65535);
-}
-
-void MSG_WriteAngle32f (sizebuf_t *sb, float f)
-{
- MSG_WriteFloat (sb, f);
-}
-
-void MSG_WriteAngle (sizebuf_t *sb, float f, protocolversion_t protocol)
-{
- if (protocol == PROTOCOL_QUAKE || protocol == PROTOCOL_QUAKEDP || protocol == PROTOCOL_NEHAHRAMOVIE || protocol == PROTOCOL_NEHAHRABJP || protocol == PROTOCOL_NEHAHRABJP2 || protocol == PROTOCOL_NEHAHRABJP3 || protocol == PROTOCOL_DARKPLACES1 || protocol == PROTOCOL_DARKPLACES2 || protocol == PROTOCOL_DARKPLACES3 || protocol == PROTOCOL_DARKPLACES4 || protocol == PROTOCOL_QUAKEWORLD)
- MSG_WriteAngle8i (sb, f);
- else
- MSG_WriteAngle16i (sb, f);
-}
-
-//
-// reading functions
-//
-int msg_readcount;
-qboolean msg_badread;
-
-void MSG_BeginReading (void)
-{
- msg_readcount = 0;
- msg_badread = false;
-}
-
-int MSG_ReadLittleShort (void)
-{
- if (msg_readcount+2 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 2;
- return (short)(net_message.data[msg_readcount-2] | (net_message.data[msg_readcount-1]<<8));
-}
-
-int MSG_ReadBigShort (void)
-{
- if (msg_readcount+2 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 2;
- return (short)((net_message.data[msg_readcount-2]<<8) + net_message.data[msg_readcount-1]);
-}
-
-int MSG_ReadLittleLong (void)
-{
- if (msg_readcount+4 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 4;
- return net_message.data[msg_readcount-4] | (net_message.data[msg_readcount-3]<<8) | (net_message.data[msg_readcount-2]<<16) | (net_message.data[msg_readcount-1]<<24);
-}
-
-int MSG_ReadBigLong (void)
-{
- if (msg_readcount+4 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 4;
- return (net_message.data[msg_readcount-4]<<24) + (net_message.data[msg_readcount-3]<<16) + (net_message.data[msg_readcount-2]<<8) + net_message.data[msg_readcount-1];
-}
-
-float MSG_ReadLittleFloat (void)
-{
- union
- {
- float f;
- int l;
- } dat;
- if (msg_readcount+4 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 4;
- dat.l = net_message.data[msg_readcount-4] | (net_message.data[msg_readcount-3]<<8) | (net_message.data[msg_readcount-2]<<16) | (net_message.data[msg_readcount-1]<<24);
- return dat.f;
-}
-
-float MSG_ReadBigFloat (void)
-{
- union
- {
- float f;
- int l;
- } dat;
- if (msg_readcount+4 > net_message.cursize)
- {
- msg_badread = true;
- return -1;
- }
- msg_readcount += 4;
- dat.l = (net_message.data[msg_readcount-4]<<24) | (net_message.data[msg_readcount-3]<<16) | (net_message.data[msg_readcount-2]<<8) | net_message.data[msg_readcount-1];
- return dat.f;
-}
-
-char *MSG_ReadString (void)
-{
- static char string[MAX_INPUTLINE];
- int l,c;
- for (l = 0;l < (int) sizeof(string) - 1 && (c = MSG_ReadByte()) != -1 && c != 0;l++)
- string[l] = c;
- string[l] = 0;
- return string;
-}
-
-int MSG_ReadBytes (int numbytes, unsigned char *out)
-{
- int l, c;
- for (l = 0;l < numbytes && (c = MSG_ReadByte()) != -1;l++)
- out[l] = c;
- return l;
-}
-
-float MSG_ReadCoord13i (void)
-{
- return MSG_ReadLittleShort() * (1.0/8.0);
-}
-
-float MSG_ReadCoord16i (void)
-{
- return (signed short) MSG_ReadLittleShort();
-}
-
-float MSG_ReadCoord32f (void)
-{
- return MSG_ReadLittleFloat();
-}
-
-float MSG_ReadCoord (protocolversion_t protocol)
-{
- if (protocol == PROTOCOL_QUAKE || protocol == PROTOCOL_QUAKEDP || protocol == PROTOCOL_NEHAHRAMOVIE || protocol == PROTOCOL_NEHAHRABJP || protocol == PROTOCOL_NEHAHRABJP2 || protocol == PROTOCOL_NEHAHRABJP3 || protocol == PROTOCOL_QUAKEWORLD)
- return MSG_ReadCoord13i();
- else if (protocol == PROTOCOL_DARKPLACES1)
- return MSG_ReadCoord32f();
- else if (protocol == PROTOCOL_DARKPLACES2 || protocol == PROTOCOL_DARKPLACES3 || protocol == PROTOCOL_DARKPLACES4)
- return MSG_ReadCoord16i();
- else
- return MSG_ReadCoord32f();
-}
-
-void MSG_ReadVector (float *v, protocolversion_t protocol)
-{
- v[0] = MSG_ReadCoord(protocol);
- v[1] = MSG_ReadCoord(protocol);
- v[2] = MSG_ReadCoord(protocol);
-}
-
-// LordHavoc: round to nearest value, rather than rounding toward zero, fixes crosshair problem
-float MSG_ReadAngle8i (void)
-{
- return (signed char) MSG_ReadByte () * (360.0/256.0);
-}
-
-float MSG_ReadAngle16i (void)
-{
- return (signed short)MSG_ReadShort () * (360.0/65536.0);
-}
projects / xonotic / darkplaces.git / blobdiff