/* Microsoft Mosaic Copyright 1995 Microsoft, Inc. All Rights Reserved Create 1/27/95 Chris Franklin CMF */ #include "all.h" #include "safestrm.h" #include "stdio.h" #ifdef FEATURE_IMG_THREADS #define MIN_BLOCK 0x1000 #define DAT_SIZE 4 typedef struct _DATABLOCK { struct _DATABLOCK *pnext; unsigned long cbAlloc; unsigned char udata[DAT_SIZE]; } DATABLOCK,*PDATABLOCK; #define HYSTERESIS_SIZE 0x800 static const long crc_32_tab[] = { 0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL, 0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L, 0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L, 0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L, 0x90BF1D91L, 0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL, 0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L, 0x136C9856L, 0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL, 0x14015C4FL, 0x63066CD9L, 0xFA0F3D63L, 0x8D080DF5L, 0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L, 0xA2677172L, 0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL, 0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L, 0x32D86CE3L, 0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L, 0x26D930ACL, 0x51DE003AL, 0xC8D75180L, 0xBFD06116L, 0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L, 0xB8BDA50FL, 0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L, 0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL, 0x76DC4190L, 0x01DB7106L, 0x98D220BCL, 0xEFD5102AL, 0x71B18589L, 0x06B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L, 0x7807C9A2L, 0x0F00F934L, 0x9609A88EL, 0xE10E9818L, 0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L, 0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL, 0x6C0695EDL, 0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L, 0x65B0D9C6L, 0x12B7E950L, 0x8BBEB8EAL, 0xFCB9887CL, 0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L, 0xFBD44C65L, 0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L, 0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL, 0x4369E96AL, 0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L, 0x44042D73L, 0x33031DE5L, 0xAA0A4C5FL, 0xDD0D7CC9L, 0x5005713CL, 0x270241AAL, 0xBE0B1010L, 0xC90C2086L, 0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL, 0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L, 0x59B33D17L, 0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL, 0xEDB88320L, 0x9ABFB3B6L, 0x03B6E20CL, 0x74B1D29AL, 0xEAD54739L, 0x9DD277AFL, 0x04DB2615L, 0x73DC1683L, 0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L, 0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L, 0xF00F9344L, 0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL, 0xF762575DL, 0x806567CBL, 0x196C3671L, 0x6E6B06E7L, 0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL, 0x67DD4ACCL, 0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L, 0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L, 0xD1BB67F1L, 0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL, 0xD80D2BDAL, 0xAF0A1B4CL, 0x36034AF6L, 0x41047A60L, 0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL, 0x4669BE79L, 0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L, 0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL, 0xC5BA3BBEL, 0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L, 0xC2D7FFA7L, 0xB5D0CF31L, 0x2CD99E8BL, 0x5BDEAE1DL, 0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL, 0x026D930AL, 0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L, 0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L, 0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L, 0x86D3D2D4L, 0xF1D4E242L, 0x68DDB3F8L, 0x1FDA836EL, 0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L, 0x18B74777L, 0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL, 0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L, 0xA00AE278L, 0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L, 0xA7672661L, 0xD06016F7L, 0x4969474DL, 0x3E6E77DBL, 0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L, 0x37D83BF0L, 0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L, 0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L, 0xBAD03605L, 0xCDD70693L, 0x54DE5729L, 0x23D967BFL, 0xB3667A2EL, 0xC4614AB8L, 0x5D681B02L, 0x2A6F2B94L, 0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL, 0x2D02EF8DL }; /* update running CRC calculation with contents of a buffer */ unsigned long CRC32Compute(unsigned char *pb,unsigned long cb,unsigned long crc32) { //** Put CRC in form loop want it crc32 = (-1L - crc32); while (cb--) { crc32 = crc_32_tab[(BYTE)crc32 ^ *pb++] ^ ((crc32 >> 8) & 0x00FFFFFFL); } //** Put CRC in form client wants it return (-1L - crc32); } // initializes a SAFESTREAM. doesn't allocate it, assumes SAFESTREAM is either // allocated statically or as member of another struct. Call SS_New the first // time and SS_Reset to reinit contents each time. // Returns: TRUE on error. boolean bSS_New(PSAFESTREAM self) { memset(self,0,sizeof(SAFESTREAM)); self->evDataRead = CreateEvent(NULL, // no security FALSE, // automatic reset FALSE, // initially false NULL); // unnamed if (self->evDataRead == NULL) return TRUE; return FALSE; } // reinitializes a SAFESTREAM that has already been init'ed by bSS_New void SS_Reset(PSAFESTREAM self) { HANDLE evDataRead = self->evDataRead; PDATABLOCK pblock = self->pfirst; PDATABLOCK pnext; memset(self,0,sizeof(SAFESTREAM)); self->cbCheckSum = CRC32_INITIAL_VALUE; self->evDataRead = evDataRead; while (pblock) { pnext = pblock->pnext; GTR_FREE(pblock); pblock = pnext; } } // frees a SAFESTREAM that has been init'ed by bSS_New void SS_Free(PSAFESTREAM self) { SS_Reset(self); CloseHandle(self->evDataRead); self->evDataRead = NULL; } // writes cbCount bytes of data in pdata to end of self. frees unneeded blocks // (ie those that have been already read) // Returns: TRUE on success, FALSE on failure. On error sets errorCode and // bEOF boolean bSS_Write(PSAFESTREAM self,unsigned char *pudata,unsigned long cbCount) { PDATABLOCK pwrite = self->pwrite; PDATABLOCK pnext; PDATABLOCK pblock; unsigned long cbWrite = self->cbWrite; unsigned long cbOldWrite = cbWrite; unsigned long cbWriteBase = self->cbWriteBase; unsigned long cbAlloc; unsigned long cbPrevAlloc = 0; unsigned long cbXfer = 0; unsigned long cbOffset; enum GuitError errorCode = errNoError; #define HEADER_SIZE (sizeof(DATABLOCK)- DAT_SIZE) if (pwrite) { cbOffset = cbWrite - cbWriteBase; cbXfer = cbCount; cbPrevAlloc = pwrite->cbAlloc; if(cbOffset+cbCount > cbPrevAlloc) cbXfer = cbPrevAlloc - cbOffset; if (cbXfer) memcpy(&pwrite->udata[cbOffset],pudata,cbXfer); cbWrite += cbXfer; } // If can't fit data in current block, alloc one big enough for remainder, // but round total size of DATABLOCK structure to MIN_BLOCK. if (cbCount > cbXfer) { // At this point we can free blocks that have been read. // NOTE: if pfirst == NULL, then so are pwrite and pread // NOTE: due to concurrency, pblock may be != to self->pread at loop end pblock = self->pfirst; while (pblock != self->pread) { pnext = pblock->pnext; GTR_FREE(pblock); pblock = pnext; } self->pfirst = pblock; pudata += cbXfer; cbXfer = cbCount - cbXfer; cbAlloc = ((cbXfer + HEADER_SIZE + MIN_BLOCK-1) / MIN_BLOCK ) * MIN_BLOCK; pblock = GTR_MALLOC(cbAlloc); if (pblock == NULL) { errorCode = errOUTOFMEM; goto exitPoint; } if (self->pfirst == NULL) { self->pread = self->pfirst = pblock; } else pwrite->pnext = pblock; pwrite = pblock; cbAlloc -= HEADER_SIZE; pwrite->pnext = NULL; pwrite->cbAlloc = cbAlloc; cbWriteBase += cbPrevAlloc; self->cbTotal += cbAlloc; memcpy(&pwrite->udata[0],pudata,cbXfer); cbWrite += cbXfer; } exitPoint: self->cbWrite = cbWrite; self->cbWriteBase = cbWriteBase; self->pwrite = pwrite; if (cbWrite >= self->cbNeed && self->cbNeed > self->cbSignalWrite && (cbOldWrite == 0 || (cbWrite-self->cbRead) > HYSTERESIS_SIZE)) { if (!SetEvent(self->evDataRead)) errorCode = errInternalError; else self->cbSignalWrite = cbWrite; } if (errorCode != errNoError) SS_EOF(self,errorCode); return errorCode == errNoError ? TRUE:FALSE; } // reads cbCount bytes into pudata, unless EOF occurs in which case less // are read. // Returns: the actual number of bytes read unsigned long cbSS_Read(PSAFESTREAM self,unsigned char *pudata,unsigned long cbCount) { unsigned long cbRead = self->cbRead; unsigned long cbReadBase = self->cbReadBase; unsigned long cbToXfer; unsigned long cbXfer; unsigned long cbOffset; PDATABLOCK pread; unsigned char *puread = pudata; self->cbNeed = cbRead + cbCount; while ((!self->bEOF) && self->cbNeed > self->cbWrite) { WaitForSingleObject(self->evDataRead,INFINITE); } // after EOF self->cbWrite cannot change if (self->cbNeed > self->cbWrite) cbCount = self->cbWrite-cbRead; pread = self->pread; cbToXfer = cbCount; cbOffset = cbRead-cbReadBase; while (cbToXfer) { cbXfer = pread->cbAlloc - cbOffset; if (cbXfer > cbToXfer) cbXfer = cbToXfer; // NOTE: we never follow the pwrite->pnext link before we know that there // is data beyond this block. this implies that we may have already // read all the data in pwrite. if (cbXfer) { memcpy(puread,&pread->udata[cbOffset],cbXfer); puread += cbXfer; cbToXfer -= cbXfer; cbRead += cbXfer; } if (cbToXfer) { #ifdef XX_DEBUG if (pread->pnext == NULL) { XX_Assert((0), ("bad links found in cbSS_Read\n")); } #endif cbOffset = 0; cbReadBase += pread->cbAlloc; pread = pread->pnext; } } self->pread = pread; self->cbReadBase = cbReadBase; self->cbRead = cbRead; self->cbCheckSum = CRC32Compute(pudata,cbCount,self->cbCheckSum); return cbCount; } // writer calls SS_EOF when it has no more data to write and also indicates // why the stream has finished. reader detects EOF when cbSS_Read returns // fewer bytes than requested. void SS_EOF(PSAFESTREAM self,enum GuitErr errorCode) { if (self->errorCode == errNoError) self->errorCode = errorCode; self->bEOF = TRUE; if (!SetEvent(self->evDataRead)) self->errorCode = errInternalError; } // reader calls cbSS_ErrorCode to interrogate the reason for EOF. this is // only valid for reader after EOF has been detected - ie reader detects EOF. // the writer may interogate/set it at any time. enum GuitErr cbSS_ErrorCode(PSAFESTREAM self) { return self->errorCode; } // returns checksum of all bytes read at point of call extern unsigned long cbSS_CheckSum(PSAFESTREAM self) { return self->cbCheckSum; } // returns number of bytes read at point of call extern unsigned long cbSS_BytesRead(PSAFESTREAM self) { return self->cbRead; } #endif