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emacs/mps/code/abq.c
Gareth Rees 1f517274f3 Cast all arguments to the writef function to make it easy to check that none of the necessary casts have been omitted.
New macro WriteFYesNo makes it easy to describe a Boolean.
Describe more structure elements for ABQ, Arena, Buffer, Format, MFS, Root, Seg.

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2014-09-27 12:49:30 +01:00

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8.5 KiB
C

/* abq.c: QUEUE IMPLEMENTATION
*
* $Id$
* Copyright (c) 2001-2014 Ravenbrook Limited. See end of file for license.
*
* .purpose: A fixed-length FIFO queue.
*
* .design: <design/abq/>
*/
#include "meter.h"
#include "abq.h"
#include "mpm.h"
SRCID(abq, "$Id$");
/* Private prototypes */
static Size ABQQueueSize(Count elements, Size elementSize);
static Index ABQNextIndex(ABQ abq, Index index);
static void *ABQElement(ABQ abq, Index index);
/* Methods */
/* ABQInit -- Initialize an ABQ
*
* elements is the number of elements the queue can hold
*/
Res ABQInit(Arena arena, ABQ abq, void *owner, Count elements, Size elementSize)
{
void *p;
Res res;
AVERT(Arena, arena);
AVER(abq != NULL);
AVER(elements > 0);
/* Allocate a dummy extra element in order to be able to distinguish
"empty" from "full" */
elements = elements + 1;
res = ControlAlloc(&p, arena, ABQQueueSize(elements, elementSize),
/* withReservoirPermit */ FALSE);
if (res != ResOK)
return res;
abq->elements = elements;
abq->elementSize = elementSize;
abq->in = 0;
abq->out = 0;
abq->queue = p;
METER_INIT(abq->push, "push", owner);
METER_INIT(abq->pop, "pop", owner);
METER_INIT(abq->peek, "peek", owner);
METER_INIT(abq->delete, "delete", owner);
abq->sig = ABQSig;
AVERT(ABQ, abq);
return ResOK;
}
/* ABQCheck -- validate an ABQ */
Bool ABQCheck(ABQ abq)
{
CHECKS(ABQ, abq);
CHECKL(abq->elements > 0);
CHECKL(abq->elementSize > 0);
CHECKL(abq->in < abq->elements);
CHECKL(abq->out < abq->elements);
CHECKL(abq->queue != NULL);
return TRUE;
}
/* ABQFinish -- finish an ABQ */
void ABQFinish(Arena arena, ABQ abq)
{
AVERT(Arena, arena);
AVERT(ABQ, abq);
METER_EMIT(&abq->push);
METER_EMIT(&abq->pop);
METER_EMIT(&abq->peek);
METER_EMIT(&abq->delete);
ControlFree(arena, abq->queue, ABQQueueSize(abq->elements, abq->elementSize));
abq->elements = 0;
abq->queue = NULL;
abq->sig = SigInvalid;
}
/* ABQPush -- push an element onto the tail of the ABQ */
Bool ABQPush(ABQ abq, void *element)
{
AVERT(ABQ, abq);
METER_ACC(abq->push, ABQDepth(abq));
if (ABQIsFull(abq))
return FALSE;
(void)mps_lib_memcpy(ABQElement(abq, abq->in), element, abq->elementSize);
abq->in = ABQNextIndex(abq, abq->in);
AVERT(ABQ, abq);
return TRUE;
}
/* ABQPop -- pop an element from the head of the ABQ */
Bool ABQPop(ABQ abq, void *elementReturn)
{
AVER(elementReturn != NULL);
AVERT(ABQ, abq);
METER_ACC(abq->pop, ABQDepth(abq));
if (ABQIsEmpty(abq))
return FALSE;
(void)mps_lib_memcpy(elementReturn, ABQElement(abq, abq->out), abq->elementSize);
abq->out = ABQNextIndex(abq, abq->out);
AVERT(ABQ, abq);
return TRUE;
}
/* ABQPeek -- peek at the head of the ABQ */
Bool ABQPeek(ABQ abq, void *elementReturn)
{
AVER(elementReturn != NULL);
AVERT(ABQ, abq);
METER_ACC(abq->peek, ABQDepth(abq));
if (ABQIsEmpty(abq))
return FALSE;
(void)mps_lib_memcpy(elementReturn, ABQElement(abq, abq->out), abq->elementSize);
/* Identical to pop, but don't increment out */
AVERT(ABQ, abq);
return TRUE;
}
/* ABQDescribe -- Describe an ABQ */
Res ABQDescribe(ABQ abq, ABQDescribeElement describeElement, mps_lib_FILE *stream, Count depth)
{
Res res;
Index index;
if (!TESTT(ABQ, abq)) return ResFAIL;
if (stream == NULL) return ResFAIL;
res = WriteF(stream, depth,
"ABQ $P {\n", (WriteFP)abq,
" elements $U\n", (WriteFU)abq->elements,
" elementSize $W\n", (WriteFW)abq->elementSize,
" in $U\n", (WriteFU)abq->in,
" out $U\n", (WriteFU)abq->out,
" queue:\n",
NULL);
if(res != ResOK)
return res;
for (index = abq->out; index != abq->in; ) {
res = (*describeElement)(ABQElement(abq, index), stream, depth + 2);
if(res != ResOK)
return res;
index = ABQNextIndex(abq, index);
}
METER_WRITE(abq->push, stream, depth + 2);
METER_WRITE(abq->pop, stream, depth + 2);
METER_WRITE(abq->peek, stream, depth + 2);
METER_WRITE(abq->delete, stream, depth + 2);
res = WriteF(stream, depth, "} ABQ $P\n", (WriteFP)abq, NULL);
if(res != ResOK)
return res;
return ResOK;
}
/* ABQIsEmpty -- Is an ABQ empty? */
Bool ABQIsEmpty(ABQ abq)
{
AVERT(ABQ, abq);
return abq->out == abq->in;
}
/* ABQIsFull -- Is an ABQ full? */
Bool ABQIsFull(ABQ abq)
{
AVERT(ABQ, abq);
return ABQNextIndex(abq, abq->in) == abq->out;
}
/* ABQDepth -- return the number of elements in an ABQ */
Count ABQDepth(ABQ abq)
{
Index out, in;
AVERT(ABQ, abq);
out = abq->out;
in = abq->in;
if (in >= out)
return in - out;
else
return in + abq->elements - out;
}
/* ABQIterate -- call 'iterate' for each element in an ABQ */
void ABQIterate(ABQ abq, ABQIterateMethod iterate, void *closureP, Size closureS)
{
Index copy, index, in;
AVERT(ABQ, abq);
AVER(FUNCHECK(iterate));
copy = abq->out;
index = abq->out;
in = abq->in;
while (index != in) {
void *element = ABQElement(abq, index);
Bool delete = FALSE;
Bool cont;
cont = (*iterate)(&delete, element, closureP, closureS);
AVERT(Bool, cont);
AVERT(Bool, delete);
if (!delete) {
if (copy != index)
(void)mps_lib_memcpy(ABQElement(abq, copy), element, abq->elementSize);
copy = ABQNextIndex(abq, copy);
}
index = ABQNextIndex(abq, index);
if (!cont)
break;
}
/* If any elements were deleted, need to copy remainder of queue. */
if (copy != index) {
while (index != in) {
(void)mps_lib_memcpy(ABQElement(abq, copy), ABQElement(abq, index),
abq->elementSize);
copy = ABQNextIndex(abq, copy);
index = ABQNextIndex(abq, index);
}
abq->in = copy;
}
AVERT(ABQ, abq);
}
/* ABQQueueSize -- calculate the storage required for the vector to
store the elements */
static Size ABQQueueSize(Count elements, Size elementSize)
{
return (Size)(elements * elementSize);
}
/* ABQNextIndex -- calculate the next index into the queue vector from
the current one */
static Index ABQNextIndex(ABQ abq, Index index)
{
Index next = index + 1;
if (next == abq->elements)
next = 0;
return next;
}
/* ABQElement -- return pointer to the index'th element in the queue
vector. */
static void *ABQElement(ABQ abq, Index index) {
return PointerAdd(abq->queue, index * abq->elementSize);
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
* All rights reserved. This is an open source license. Contact
* Ravenbrook for commercial licensing options.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Redistributions in any form must be accompanied by information on how
* to obtain complete source code for this software and any accompanying
* software that uses this software. The source code must either be
* included in the distribution or be available for no more than the cost
* of distribution plus a nominal fee, and must be freely redistributable
* under reasonable conditions. For an executable file, complete source
* code means the source code for all modules it contains. It does not
* include source code for modules or files that typically accompany the
* major components of the operating system on which the executable file
* runs.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
* PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/