167 lines
3.5 KiB
C
167 lines
3.5 KiB
C
/****************************************************************
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Copyright 1990, 1994 by AT&T Bell Laboratories and Bellcore.
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Permission to use, copy, modify, and distribute this software
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and its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the names of AT&T Bell Laboratories or
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Bellcore or any of their entities not be used in advertising or
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publicity pertaining to distribution of the software without
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specific, written prior permission.
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AT&T and Bellcore disclaim all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall AT&T or Bellcore be liable for
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any special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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****************************************************************/
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#ifndef CRAY
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#define STACKMIN 512
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#define MINBLK (2*sizeof(struct mem) + 16)
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#define F _malloc_free_
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#define SBGULP 8192
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#include "string.h" /* for memcpy */
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#ifdef KR_headers
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#define Char char
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#define Unsigned unsigned
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#define Int /*int*/
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#else
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#define Char void
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#define Unsigned size_t
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#define Int int
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#endif
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typedef struct mem {
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struct mem *next;
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Unsigned len;
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} mem;
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mem *F;
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Char *
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#ifdef KR_headers
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malloc(size)
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register Unsigned size;
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#else
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malloc(register Unsigned size)
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#endif
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{
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register mem *p, *q, *r, *s;
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unsigned register k, m;
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extern Char *sbrk(Int);
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char *top, *top1;
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size = (size+7) & ~7;
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r = (mem *) &F;
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for (p = F, q = 0; p; r = p, p = p->next) {
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if ((k = p->len) >= size && (!q || m > k)) {
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m = k;
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q = p;
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s = r;
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}
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}
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if (q) {
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if (q->len - size >= MINBLK) { /* split block */
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p = (mem *) (((char *) (q+1)) + size);
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p->next = q->next;
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p->len = q->len - size - sizeof(mem);
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s->next = p;
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q->len = size;
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}
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else
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s->next = q->next;
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}
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else {
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top = (Char *)(((long)sbrk(0) + 7) & ~7);
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if (F && (char *)(F+1) + F->len == top) {
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q = F;
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F = F->next;
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}
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else
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q = (mem *) top;
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top1 = (char *)(q+1) + size;
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if (sbrk((int)(top1-top+SBGULP)) == (Char *) -1)
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return 0;
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r = (mem *)top1;
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r->len = SBGULP - sizeof(mem);
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r->next = F;
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F = r;
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top1 += SBGULP;
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q->len = size;
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}
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return (Char *) (q+1);
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}
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void
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#ifdef KR_headers
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free(f)
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Char *f;
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#else
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free(Char *f)
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#endif
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{
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mem *p, *q, *r;
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char *pn, *qn;
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if (!f) return;
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q = (mem *) ((char *)f - sizeof(mem));
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qn = (char *)f + q->len;
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for (p = F, r = (mem *) &F; ; r = p, p = p->next) {
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if (qn == (Char *) p) {
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q->len += p->len + sizeof(mem);
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p = p->next;
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}
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pn = p ? ((char *) (p+1)) + p->len : 0;
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if (pn == (Char *) q) {
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p->len += sizeof(mem) + q->len;
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q->len = 0;
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q->next = p;
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r->next = p;
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break;
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}
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if (pn < (char *) q) {
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r->next = q;
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q->next = p;
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break;
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}
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}
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}
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Char *
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#ifdef KR_headers
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realloc(f, size)
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Char *f;
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Unsigned size;
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#else
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realloc(Char *f, Unsigned size)
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#endif
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{
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mem *p;
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Char *q, *f1;
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Unsigned s1;
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if (!f) return malloc(size);
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p = (mem *) ((char *)f - sizeof(mem));
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s1 = p->len;
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free(f);
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if (s1 > size)
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s1 = size + 7 & ~7;
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if (!p->len) {
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f1 = (Char *)(p->next + 1);
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memcpy(f1, f, s1);
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f = f1;
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}
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q = malloc(size);
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if (q && q != f)
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memcpy(q, f, s1);
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return q;
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}
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#endif
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