50 lines
1.0 KiB
C
50 lines
1.0 KiB
C
/*
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* realloc.c
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "malloc.h"
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/* FIXME: This is cheesy, it should be fixed later */
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void *realloc(void *ptr, size_t size)
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{
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struct free_arena_header *ah;
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void *newptr;
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size_t oldsize;
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if ( !ptr )
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return malloc(size);
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if ( size == 0 ) {
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free(ptr);
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return NULL;
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}
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/* Add the obligatory arena header, and round up */
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size = (size+2*sizeof(struct arena_header)-1) & ARENA_SIZE_MASK;
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ah = (struct free_arena_header *)
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((struct arena_header *)ptr - 1);
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if ( ah->a.size >= size && size >= (ah->a.size >> 2) ) {
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/* This field is a good size already. */
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return ptr;
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} else {
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/* Make me a new block. This is kind of bogus; we should
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be checking the adjacent blocks to see if we can do an
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in-place adjustment... fix that later. */
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oldsize = ah->a.size - sizeof(struct arena_header);
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newptr = malloc(size);
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memcpy(newptr, ptr, (size < oldsize) ? size : oldsize);
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free(ptr);
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return newptr;
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}
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}
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