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957146dcec
recycle storage within sort temp file on a block-by-block basis. This reduces peak disk usage to essentially just the volume of data being sorted, whereas it had been about 4x the data volume before.
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* logtape.h
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* Management of "logical tapes" within temporary files.
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*
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* See logtape.c for explanations.
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: logtape.h,v 1.1 1999/10/16 19:49:28 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LOGTAPE_H
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#define LOGTAPE_H
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/* LogicalTapeSet is an opaque type whose details are not known outside logtape.c. */
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typedef struct LogicalTapeSet LogicalTapeSet;
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/*
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* prototypes for functions in logtape.c
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*/
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extern LogicalTapeSet *LogicalTapeSetCreate(int ntapes);
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extern void LogicalTapeSetClose(LogicalTapeSet *lts);
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extern size_t LogicalTapeRead(LogicalTapeSet *lts, int tapenum,
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void *ptr, size_t size);
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extern void LogicalTapeWrite(LogicalTapeSet *lts, int tapenum,
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void *ptr, size_t size);
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extern void LogicalTapeRewind(LogicalTapeSet *lts, int tapenum, bool forWrite);
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extern void LogicalTapeFreeze(LogicalTapeSet *lts, int tapenum);
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extern bool LogicalTapeBackspace(LogicalTapeSet *lts, int tapenum,
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size_t size);
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extern bool LogicalTapeSeek(LogicalTapeSet *lts, int tapenum,
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long blocknum, int offset);
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extern void LogicalTapeTell(LogicalTapeSet *lts, int tapenum,
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long *blocknum, int *offset);
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#endif /* LOGTAPE_H */
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