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xfermem: unidirectional fast pipe
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copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
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see COPYING and AUTHORS files in distribution or http://mpg123.de
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initially written by Oliver Fromme
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old timestamp: Sat Mar 29 04:41:34 MET 1997
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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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note: xftest not there anymore
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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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* [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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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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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
added
removed
src/xfermem.h
