97 lines
4.0 KiB
C
97 lines
4.0 KiB
C
/***********************************************************************/
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/* */
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/* Objective Caml */
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/* */
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/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
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/* */
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/* Copyright 1996 Institut National de Recherche en Informatique et */
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/* en Automatique. All rights reserved. This file is distributed */
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/* under the terms of the GNU Library General Public License, with */
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/* the special exception on linking described in file ../LICENSE. */
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/* */
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/***********************************************************************/
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/* $Id$ */
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/* Buffered input/output */
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#ifndef _io_
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#define _io_
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#include "misc.h"
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#include "mlvalues.h"
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#ifndef IO_BUFFER_SIZE
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#define IO_BUFFER_SIZE 4096
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#endif
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struct channel {
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int fd; /* Unix file descriptor */
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long offset; /* Absolute position of fd in the file */
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char * end; /* Physical end of the buffer */
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char * curr; /* Current position in the buffer */
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char * max; /* Logical end of the buffer (for input) */
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void * mutex; /* Placeholder for mutex (for systhreads) */
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struct channel * next; /* Linear chaining of channels (flush_all) */
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int revealed; /* For Cash only */
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int old_revealed; /* For Cash only */
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int refcount; /* For flush_all and for Cash */
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char buff[IO_BUFFER_SIZE]; /* The buffer itself */
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};
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/* For an output channel:
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[offset] is the absolute position of the beginning of the buffer [buff].
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For an input channel:
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[offset] is the absolute position of the logical end of the buffer, [max].
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*/
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/* Functions and macros that can be called from C. Take arguments of
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type struct channel *. No locking is performed. */
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#define putch(channel, ch) do{ \
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if ((channel)->curr >= (channel)->end) flush_partial(channel); \
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*((channel)->curr)++ = (ch); \
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}while(0)
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#define getch(channel) \
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((channel)->curr >= (channel)->max \
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? refill(channel) \
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: (unsigned char) *((channel))->curr++)
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CAMLextern struct channel * open_descriptor_in (int);
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CAMLextern struct channel * open_descriptor_out (int);
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CAMLextern void close_channel (struct channel *);
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CAMLextern int channel_binary_mode (struct channel *);
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CAMLextern int flush_partial (struct channel *);
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CAMLextern void flush (struct channel *);
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CAMLextern void putword (struct channel *, uint32);
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CAMLextern int putblock (struct channel *, char *, long);
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CAMLextern void really_putblock (struct channel *, char *, long);
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CAMLextern unsigned char refill (struct channel *);
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CAMLextern uint32 getword (struct channel *);
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CAMLextern int getblock (struct channel *, char *, long);
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CAMLextern int really_getblock (struct channel *, char *, long);
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/* Extract a struct channel * from the heap object representing it */
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#define Channel(v) (*((struct channel **) (Data_custom_val(v))))
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/* The locking machinery */
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CAMLextern void (*channel_mutex_free) (struct channel *);
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CAMLextern void (*channel_mutex_lock) (struct channel *);
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CAMLextern void (*channel_mutex_unlock) (struct channel *);
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CAMLextern void (*channel_mutex_unlock_exn) (void);
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#define Lock(channel) \
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if (channel_mutex_lock != NULL) (*channel_mutex_lock)(channel)
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#define Unlock(channel) \
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if (channel_mutex_unlock != NULL) (*channel_mutex_unlock)(channel)
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#define Unlock_exn() \
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if (channel_mutex_unlock_exn != NULL) (*channel_mutex_unlock_exn)()
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#endif /* _io_ */
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