48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
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/* channel.h - channel definitions */
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#include <stdio.h>
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#include "parco.h"
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typedef union channel {
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struct { /* Interprocess channel */
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char _type; /* Channel type, see note */
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char synch; /* State in channel synchronization */
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long val; /* Transmitted value */
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} c;
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struct { /* File channel */
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char _type; /* Dummy field, see note */
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char index; /* Index in the file array */
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char flgs; /* Status flags: in use & readahead */
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char preread; /* Possible preread character */
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} f;
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} chan;
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#define type c._type /* Channel type */
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/* Note: The channel type should not be part of each structure in chan. But
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* the C alignment rules would make chan about 50% bigger if we had done it
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* the right way. Note that the order of fields in a struct cannot be a problem
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* as long as struct c is the largest within the union.
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*/
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#define C_T_CHAN 0 /* Type of a interprocess channel */
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#define C_T_FILE 1 /* Type of a file channel */
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#define C_S_FREE 0 /* IP channel is free */
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#define C_S_ANY 1 /* IP channel contains data */
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#define C_S_ACK 2 /* IP channel data is removed */
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#define C_F_EOF (-1L) /* File channel returns EOF */
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#define C_F_TEXT (-2L) /* File channel becomes line oriented */
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#define C_F_RAW (-3L) /* File channel becomes character oriented */
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#define C_F_INUSE 0x01 /* File channel is connected to a UNIX file */
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#define C_F_READAHEAD 0x02 /* File channel has a preread character */
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extern chan file[_NFILE]; /* Array of file channels */
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extern FILE *unix_file[_NFILE]; /* Pointers to buffered UNIX files */
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void c_init();
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void chan_in(), cbyte_in(), c_wa_in(), c_ba_in();
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void chan_out(), c_wa_out(), c_ba_out();
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int chan_any();
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