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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_300
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330_03
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tskwpip.c
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C/C++ Source or Header
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1990-10-12
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7KB
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283 lines
/*
--- Version 2.2 90-10-12 11:08 ---
TSKWPIP.C - CTask - Word Pipe handling routines.
Public Domain Software written by
Thomas Wagner
Ferrari electronic Gmbh
Beusselstrasse 27
D-1000 Berlin 21
Germany
*/
#include "tsk.h"
#include "tsklocal.h"
/*
create_wpipe - initialises wpipe.
*/
wpipeptr Globalfunc create_wpipe (wpipeptr pip, farptr buf, word bufsize
TN(byteptr name))
{
#if (TSK_DYNAMIC)
if (pip == LNULL)
{
if ((pip = tsk_palloc (sizeof (wpipe))) == LNULL)
return LNULL;
pip->flags = F_TEMP;
}
else
pip->flags = 0;
if (buf == LNULL)
{
if ((buf = tsk_palloc (bufsize)) == LNULL)
{
if (pip->flags & F_TEMP)
tsk_pfree (pip);
return LNULL;
}
pip->flags |= F_STTEMP;
}
#endif
tsk_init_qhead (&pip->wait_read, TYP_WPIPE);
tsk_init_qhead (&pip->wait_write, TYP_WPIPE);
tsk_init_qhead (&pip->wait_clear, TYP_WPIPE);
pip->outptr = pip->inptr = pip->filled = 0;
pip->bufsize = bufsize >> 1;
pip->wcontents = (wordptr)buf;
#if (TSK_NAMED)
tsk_add_name (&pip->name, name, TYP_WPIPE, pip);
#endif
return pip;
}
/*
delete_wpipe - kills all processes waiting for reading from or writing
to the wpipe.
*/
void Globalfunc delete_wpipe (wpipeptr pip)
{
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Delete Wpipe");
C_ENTER;
tsk_kill_queue (&(pip->wait_read));
tsk_kill_queue (&(pip->wait_write));
tsk_kill_queue (&(pip->wait_clear));
pip->outptr = pip->inptr = pip->filled = 0;
C_LEAVE;
#if (TSK_NAMED)
tsk_del_name (&pip->name);
#endif
#if (TSK_DYNAMIC)
if (pip->flags & F_STTEMP)
tsk_pfree (pip->wcontents);
if (pip->flags & F_TEMP)
tsk_pfree (pip);
#endif
}
/*
read_wpipe - Wait until a word is written to the wpipe. If there
is a word in the wpipe on entry, it is assigned to
the caller, and the task continues to run. If there are
tasks waiting to write, the first task is made eligible,
and the word is inserted into the wpipe.
*/
word Globalfunc read_wpipe (wpipeptr pip, dword timeout)
{
tcbptr curr;
word res;
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Read Wpipe");
C_ENTER;
if (pip->filled)
{
res = pip->wcontents [pip->outptr++];
if (pip->outptr >= pip->bufsize)
pip->outptr = 0;
pip->filled--;
if (!((curr = (tcbptr)pip->wait_write.first)->cqueue.kind & Q_HEAD))
{
pip->wcontents [pip->inptr++] = curr->retsize;
if (pip->inptr >= pip->bufsize)
pip->inptr = 0;
pip->filled++;
tsk_runable (curr);
curr->retptr = LNULL;
}
else if (!pip->filled)
tsk_runable_all (&pip->wait_clear);
C_LEAVE;
return res;
}
tsk_wait (&pip->wait_read, timeout);
return (int)((dword)GLOBDATA current_task->retptr);
}
/*
c_read_wpipe - If there is a word in the wpipe on entry,
read_wpipe is called, otherwise an error status is returned.
*/
word Globalfunc c_read_wpipe (wpipeptr pip)
{
CRITICAL, res;
CHECK_EVTPTR (pip, TYP_WPIPE, "Cond Read Wpipe");
C_ENTER;
res = (pip->filled) ? read_wpipe (pip, 0L) : (word)-1;
C_LEAVE;
return res;
}
/*
write_wpipe - Wait until space for the word to be written to the
wpipe is available. If there is enough space in the wpipe
on entry, the word is inserted into the wpipe, and
the task continues to run. If there are tasks waiting
to read, the first task is made eligible, and the word
is passed to the waiting task.
*/
int Globalfunc write_wpipe (wpipeptr pip, word ch, dword timeout)
{
tcbptr curr;
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Write Wpipe");
C_ENTER;
if (pip->filled < pip->bufsize)
{
if (!((curr = (tcbptr)pip->wait_read.first)->cqueue.kind & Q_HEAD))
{
tsk_runable (curr);
curr->retptr = (farptr)ch;
C_LEAVE;
return 0;
}
pip->wcontents [pip->inptr++] = ch;
if (pip->inptr >= pip->bufsize)
pip->inptr = 0;
pip->filled++;
C_LEAVE;
return 0;
}
GLOBDATA current_task->retsize = ch;
tsk_wait (&pip->wait_write, timeout);
return (int)((dword)GLOBDATA current_task->retptr);
}
/*
c_write_wpipe - If there is space for the word in the wpipe on entry,
write_wpipe is called, otherwise an error status is returned.
*/
int Globalfunc c_write_wpipe (wpipeptr pip, word ch)
{
int res;
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Cond Write Wpipe");
C_ENTER;
res = (pip->filled < pip->bufsize) ? write_wpipe (pip, ch, 0L) : -1;
C_LEAVE;
return res;
}
/*
wait_wpipe_empty - Wait until the pipe is empty. If the pipe is
empty on entry, the task continues to run.
*/
int Globalfunc wait_wpipe_empty (wpipeptr pip, dword timeout)
{
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Wait Wpipe Empty");
C_ENTER;
if (!pip->filled)
{
C_LEAVE;
return 0;
}
GLOBDATA current_task->retptr = LNULL;
tsk_wait (&pip->wait_clear, timeout);
return (int)((dword)GLOBDATA current_task->retptr);
}
/*
check_wpipe - returns -1 if there are no words in the wpipe, else
the first available word.
*/
word Globalfunc check_wpipe (wpipeptr pip)
{
CHECK_EVTPTR (pip, TYP_WPIPE, "Check Wpipe");
return (pip->filled) ? pip->wcontents [pip->outptr] : (word)-1;
}
/*
wpipe_free - returns the number of free words in the pipe.
*/
word Globalfunc wpipe_free (wpipeptr pip)
{
CHECK_EVTPTR (pip, TYP_WPIPE, "Wpipe Free");
return pip->bufsize - pip->filled;
}
/*
flush_wpipe - Empty the pipe buffer, activate tasks waiting for
pipe clear.
*/
void Globalfunc flush_wpipe (wpipeptr pip)
{
CRITICAL;
CHECK_EVTPTR (pip, TYP_WPIPE, "Flush Wpipe");
C_ENTER;
pip->inptr = pip->outptr = pip->filled = 0;
tsk_runable_all (&pip->wait_clear);
C_LEAVE;
}