116 lines
2.5 KiB
C
116 lines
2.5 KiB
C
/*
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* Written by Julian Elischer (julian@tfs.com)
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* for TRW Financial Systems for use under the MACH(2.5) operating system.
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*
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* TRW Financial Systems, in accordance with their agreement with Carnegie
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* Mellon University, makes this software available to CMU to distribute
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* or use in any manner that they see fit as long as this message is kept with
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* the software. For this reason TFS also grants any other persons or
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* organisations permission to use or modify this software.
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*
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* TFS supplies this software to be publicly redistributed
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* on the understanding that TFS is not responsible for the correct
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* functioning of this software in any circumstances.
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*
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* $Id$
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*/
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/*
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* XXX XXX XXX XXX We should get DEVFS working so that we
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* don't have to do this, possibly sparse, array based junk.
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*/
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/*
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* Extensible arrays: Use a realloc like implementation to permit
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* the arrays to be extend.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <cam/cam_extend.h>
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struct extend_array
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{
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int nelem;
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void **ps;
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};
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static void *
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cam_extend_alloc(size_t s)
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{
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void *p = malloc(s, M_DEVBUF, M_NOWAIT);
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if (!p)
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panic("extend_alloc: malloc failed.");
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return p;
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}
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static void
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cam_extend_free(void *p)
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{
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free(p, M_DEVBUF);
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}
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/* EXTEND_CHUNK: Number of extend slots to allocate whenever we need a new
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* one.
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*/
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#ifndef EXTEND_CHUNK
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#define EXTEND_CHUNK 8
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#endif
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struct extend_array *
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cam_extend_new(void)
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{
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struct extend_array *p = cam_extend_alloc(sizeof(*p));
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if (p) {
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p->nelem = 0;
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p->ps = 0;
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}
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return p;
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}
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void *
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cam_extend_set(struct extend_array *ea, int index, void *value)
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{
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if (index >= ea->nelem) {
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void **space;
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space = cam_extend_alloc(sizeof(void *) * (index + EXTEND_CHUNK));
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bzero(space, sizeof(void *) * (index + EXTEND_CHUNK));
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/* Make sure we have something to copy before we copy it */
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if (ea->nelem) {
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bcopy(ea->ps, space, sizeof(void *) * ea->nelem);
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cam_extend_free(ea->ps);
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}
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ea->ps = space;
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ea->nelem = index + EXTEND_CHUNK;
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}
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if (ea->ps[index]) {
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printf("extend_set: entry %d already has storage.\n", index);
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return 0;
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}
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else
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ea->ps[index] = value;
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return value;
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}
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void *
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cam_extend_get(struct extend_array *ea,
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int index)
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{
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if (ea == NULL || index >= ea->nelem || index < 0)
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return NULL;
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return ea->ps[index];
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}
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void
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cam_extend_release(struct extend_array *ea, int index)
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{
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void *p = cam_extend_get(ea, index);
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if (p) {
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ea->ps[index] = 0;
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}
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}
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