1 /*-------------------------------------------------------------------------
2  *
3  * logtape.h
4  *	  Management of "logical tapes" within temporary files.
5  *
6  * See logtape.c for explanations.
7  *
8  * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
9  * Portions Copyright (c) 1994, Regents of the University of California
10  *
11  * src/include/utils/logtape.h
12  *
13  *-------------------------------------------------------------------------
14  */
15 
16 #ifndef LOGTAPE_H
17 #define LOGTAPE_H
18 
19 /* LogicalTapeSet is an opaque type whose details are not known outside logtape.c. */
20 
21 typedef struct LogicalTapeSet LogicalTapeSet;
22 
23 /*
24  * prototypes for functions in logtape.c
25  */
26 
27 extern LogicalTapeSet *LogicalTapeSetCreate(int ntapes);
28 extern void LogicalTapeSetClose(LogicalTapeSet *lts);
29 extern void LogicalTapeSetForgetFreeSpace(LogicalTapeSet *lts);
30 extern size_t LogicalTapeRead(LogicalTapeSet *lts, int tapenum,
31 				void *ptr, size_t size);
32 extern void LogicalTapeWrite(LogicalTapeSet *lts, int tapenum,
33 				 void *ptr, size_t size);
34 extern void LogicalTapeRewind(LogicalTapeSet *lts, int tapenum, bool forWrite);
35 extern void LogicalTapeFreeze(LogicalTapeSet *lts, int tapenum);
36 extern bool LogicalTapeBackspace(LogicalTapeSet *lts, int tapenum,
37 					 size_t size);
38 extern bool LogicalTapeSeek(LogicalTapeSet *lts, int tapenum,
39 				long blocknum, int offset);
40 extern void LogicalTapeTell(LogicalTapeSet *lts, int tapenum,
41 				long *blocknum, int *offset);
42 extern long LogicalTapeSetBlocks(LogicalTapeSet *lts);
43 
44 #endif   /* LOGTAPE_H */
45