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/*
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* xfermem.h
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*
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* Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de>
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* Sat Mar 29 04:41:34 MET 1997
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*
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* This is a stand-alone module which implements a unidirectional,
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* fast pipe using mmap(). Its primary use is to transfer large
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* amounts of data from a parent process to its child process,
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* with a buffer in between which decouples blocking conditions
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* on both sides. Control information is transferred between the
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* processes through a socketpair. See xftest.c for an example on
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* how to use this module.
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*/
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#ifndef TRUE
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#define FALSE 0
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#define TRUE 1
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#endif
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typedef struct {
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int freeindex; /* [W] next free index */
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int readindex; /* [R] next index to read */
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int fd[2];
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int wakeme[2];
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byte *data;
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byte *metadata;
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int size;
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int metasize;
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int buf[3];
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} txfermem;
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/*
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* [W] -- May be written to by the writing process only!
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* [R] -- May be written to by the reading process only!
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* All other entries are initialized once.
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*/
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void xfermem_init (txfermem **xf, int bufsize, int msize,int skipbuf);
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void xfermem_init_writer (txfermem *xf);
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void xfermem_init_reader (txfermem *xf);
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int xfermem_write (txfermem *xf, byte *data, int count);
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int xfermem_read (txfermem *xf, byte *data, int count);
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int xfermem_get_freespace (txfermem *xf);
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int xfermem_get_usedspace (txfermem *xf);
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#define XF_CMD_WAKEUP_INFO 0x04
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#define XF_CMD_WAKEUP 0x02
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#define XF_CMD_TERMINATE 0x03
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#define XF_WRITER 0
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#define XF_READER 1
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int xfermem_getcmd (int fd, int block);
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int xfermem_putcmd (int fd, byte cmd);
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int xfermem_block (int fd, txfermem *xf);
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void xfermem_done (txfermem *xf);
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#define xfermem_done_writer xfermem_init_reader
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#define xfermem_done_reader xfermem_init_writer
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/* EOF */
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