64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
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/* This file is part of the sample code and exercises
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* used by the class "Advanced Programming in the UNIX
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* Environment" taught by Jan Schaumann
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* <jschauma@netmeister.org> at Stevens Institute of
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* Technology.
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*
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* This file is in the public domain.
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*
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* You don't have to, but if you feel like
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* acknowledging where you got this code, you may
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* reference me by name, email address, or point
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* people to the course website:
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* https://stevens.netmeister.org/631/
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*/
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#include <err.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#define MALLOC_SIZE 1024 * 1024
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void
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printMalloc(void *p, int s) {
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(void)printf("malloc/realloc %d\n", s);
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(void)printf("begins at 0x%12lX\n", (unsigned long)p);
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(void)printf("ends at 0x%12lX\n", (unsigned long)p+s);
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(void)printf("\n");
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}
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int
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main() {
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void *ptr;
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if ((ptr = malloc(BUFSIZ)) == NULL) {
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err(EXIT_FAILURE, "malloc");
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/* NOTREACHED */
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}
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printMalloc(ptr, BUFSIZ);
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/* shrink */
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if ((ptr = realloc(ptr, BUFSIZ / 2)) == NULL) {
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err(EXIT_FAILURE, "realloc");
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/* NOTREACHED */
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}
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printMalloc(ptr, BUFSIZ / 2);
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/* grow */
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if ((ptr = realloc(ptr, MALLOC_SIZE)) == NULL) {
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err(EXIT_FAILURE, "realloc");
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/* NOTREACHED */
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}
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printMalloc(ptr, MALLOC_SIZE);
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/* shrink, but larger than initial allocation */
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if ((ptr = realloc(ptr, BUFSIZ * 2)) == NULL) {
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err(EXIT_FAILURE, "realloc");
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/* NOTREACHED */
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}
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printMalloc(ptr, BUFSIZ * 4);
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return EXIT_SUCCESS;
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}
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