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 PKWARE Data Compression Library v1.02  PKWARE Inc. 29.03.1995

Библиотека сжатия/распаковки данных от фирмы PKWare. Приведены объектные модули .Obj/.Lib и примеры использования на C/ASM/Pascal/Clipper/Basic


- New Basic interface example code for Microsoft QuickBasic 4.5 and Professional Basic 7.1. - Updated Clipper interface example that no longer requires the EXTOR module and includes compiled INTERFCE.OBJ module. - Minor anomalies when running on older 8088 CPU's have been corrected. - Problems when running as a DLL under Windows or OS/2 have been fixed, i.e. it is no longer assumed that DS == SS. Additional notes: The segments used/declared in the PKWARE Data Compression Library are: DGROUP GROUP _DATA ASSUME DS: DGROUP _DATA SEGMENT use16 WORD PUBLIC 'DATA' PK_TEXT SEGMENT use16 DWORD 'CODE' ASSUME CS: PK_TEXT When used under Windows or OS/2, the _DATA segment used by the library should be declared 'non shareable' in the .DEF file. When used with a 32-bit application using a DOS extender, these segments must be declared to be 16-bit segments. CRC-32 routine: This routine calculates a running CRC-32 value on the buffer passed to it. You should use proper CRC pre and post-conditioning, meaning an initial start value of ~0 (all ones) and the final value be one's complemented. Below is an example pseudo-code code using the CRC 32 routine: unsigned long far pascal crc32( unsigned char far *buffer, unsigned short int far *size, unsigned long far *old_crc); unsigned long crc_cal = ~0; unsigned short int size; extern char far buffer[]; /* some buffer containing data */ /* data to be CRC'd */ while (data is being put in buffer) { size = amount of data in buffer; crc_val=crc32(buffer,&size,&crc_val); } crc_val=~crc_val; printf("Final CRC residual value is: %lu\n",crc_val); ------------------------------- When using Turbo Pascal 5.0 use the { $F+ } meta-command instead of using the 'far' keyword in the example program.