431 lines
8.9 KiB
C
431 lines
8.9 KiB
C
static char RCSId[] = "$Id: heap.c,v 1.3 1993/07/04 04:04:21 root Exp root $";
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static char Copyright[] = "Copyright Robert J. Amstadt, 1993";
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#include <stdio.h>
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#include <stdlib.h>
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#include "prototypes.h"
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#include "segmem.h"
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#include "heap.h"
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MDESC *LOCAL_FreeList;
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/**********************************************************************
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* HEAP_Init
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*/
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void
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HEAP_Init(MDESC **free_list, void *start, int length)
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{
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*free_list = (MDESC *) start;
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(*free_list)->prev = NULL;
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(*free_list)->next = NULL;
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(*free_list)->length = length - sizeof(MDESC);
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}
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/**********************************************************************
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* HEAP_Alloc
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*/
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void *
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HEAP_Alloc(MDESC **free_list, int flags, int bytes)
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{
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MDESC *m, *m_new;
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#ifdef DEBUG_HEAP
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printf("HeapAlloc: free_list %08x, flags %x, bytes %d\n",
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free_list, flags, bytes);
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#endif
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/*
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* Find free block big enough.
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*/
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for (m = *free_list; m != NULL; m = m->next)
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{
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if (m->length >= bytes && m->length < bytes + 4 * sizeof(MDESC))
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{
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break;
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}
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else if (m->length > bytes)
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{
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m_new = m + (bytes / sizeof(MDESC)) + 2;
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if (m->prev == NULL)
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*free_list = m_new;
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else
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m->prev->next = m_new;
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if (m->next != NULL)
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m->next->prev = m_new;
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m_new->next = m->next;
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m_new->prev = m->prev;
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m_new->length = m->length - ((int) m_new - (int) m);
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m->length -= (m_new->length + sizeof(MDESC));
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m->prev = m;
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m->next = m;
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m->lock = 0;
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m->flags = 0;
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if (flags & GLOBAL_FLAGS_ZEROINIT)
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memset(m + 1, 0, bytes);
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#ifdef DEBUG_HEAP
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printf("HeapAlloc: returning %08x\n", (m + 1));
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#endif
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return (void *) (m + 1);
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}
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}
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if (m != NULL)
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{
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if (m->prev == NULL)
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*free_list = m->next;
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else
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m->prev->next = m->next;
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if (m->next != NULL)
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m->next->prev = m->prev;
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m->prev = m;
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m->next = m;
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m->lock = 0;
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m->flags = 0;
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if (flags & GLOBAL_FLAGS_ZEROINIT)
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memset(m + 1, 0, bytes);
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#ifdef DEBUG_HEAP
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printf("HeapAlloc: returning %08x\n", (m + 1));
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#endif
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return (void *) (m + 1);
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}
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#ifdef DEBUG_HEAP
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printf("HeapAlloc: returning %08x\n", 0);
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#endif
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return 0;
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}
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/**********************************************************************
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* HEAP_ReAlloc
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*/
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void *
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HEAP_ReAlloc(MDESC **free_list, void *old_block,
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int new_size, unsigned int flags)
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{
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MDESC *m_free;
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MDESC *m;
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/*
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* Check validity of block
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*/
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m = (MDESC *) old_block - 1;
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if (m->prev != m || m->next != m ||
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((int) m & 0xffff0000) != ((int) *free_list & 0xffff0000))
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{
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#ifdef DEBUG_HEAP
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printf("Attempt to resize bad pointer, m = %08x, *free_list = %08x\n",
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m, free_list);
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#endif
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return NULL;
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}
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/*
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* Check for grow block
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*/
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if (new_size > m->length)
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{
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m_free = m + 1 + m->length / sizeof(MDESC);
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if (m_free->next != m_free ||
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m_free->prev != m_free ||
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m_free->length + sizeof(MDESC) < new_size)
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{
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void *new_p = HEAP_Alloc(free_list, flags, new_size);
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if (new_p ==NULL)
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return NULL;
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memcpy(new_p, old_block, m->length);
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HEAP_Free(free_list, old_block);
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return new_p;
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}
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if (m_free->prev == NULL)
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*free_list = m_free->next;
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else
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m_free->prev->next = m_free->next;
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if (m_free->next != NULL)
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m_free->next->prev = m_free->prev;
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m->length += sizeof(MDESC) + m_free->length;
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if (flags & GLOBAL_FLAGS_ZEROINIT)
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memset(m_free, '\0', sizeof(MDESC) + m_free->length);
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}
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/*
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* Check for shrink block.
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*/
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if (new_size < m->length - 4 * sizeof(MDESC))
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{
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m_free = m + new_size / sizeof(MDESC) + 2;
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m_free->next = m_free;
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m_free->prev = m_free;
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m_free->length = m->length - (int) m_free - (int) m;
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m->length = (int) m_free - (int) (m + 1);
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HEAP_Free(free_list, m_free + 1);
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}
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return old_block;
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}
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/**********************************************************************
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* HEAP_Free
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*/
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int
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HEAP_Free(MDESC **free_list, void *block)
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{
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MDESC *m_free;
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MDESC *m;
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MDESC *m_prev;
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/*
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* Validate pointer.
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*/
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m_free = (MDESC *) block - 1;
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if (m_free->prev != m_free || m_free->next != m_free ||
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((int) m_free & 0xffff0000) != ((int) *free_list & 0xffff0000))
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{
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#ifdef DEBUG_HEAP
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printf("Attempt to free bad pointer,"
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"m_free = %08x, *free_list = %08x\n",
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m_free, free_list);
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#endif
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return -1;
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}
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/*
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* Find location in free list.
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*/
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m_prev = NULL;
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for (m = *free_list; m != NULL && m < m_free; m = m->next)
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m_prev = m;
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if (m_prev != NULL && (int) m_prev + m_prev->length > (int) m_free)
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{
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#ifdef DEBUG_HEAP
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printf("Attempt to free bad pointer,"
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"m_free = %08x, m_prev = %08x (length %x)\n",
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m_free, m_prev, m_prev->length);
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#endif
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return -1;
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}
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if ((m != NULL && (int) m_free + m_free->length > (int) m) ||
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(int) m_free + m_free->length > ((int) m_free | 0xffff))
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{
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#ifdef DEBUG_HEAP
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printf("Attempt to free bad pointer,"
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"m_free = %08x (length %x), m = %08x\n",
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m_free, m_free->length, m);
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#endif
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return -1;
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}
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/*
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* Put block back in free list.
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* Does it merge with the previos block?
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*/
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if (m_prev != NULL)
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{
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if ((int) m_prev + m_prev->length == (int) m_free)
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{
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m_prev->length += sizeof(MDESC) + m_free->length;
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m_free = m_prev;
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}
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else
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{
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m_prev->next = m_free;
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m_free->prev = m_prev;
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}
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}
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else
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{
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*free_list = m_free;
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m_free->prev = NULL;
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}
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/*
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* Does it merge with the next block?
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*/
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if (m != NULL)
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{
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if ((int) m_free + m_free->length == (int) m)
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{
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m_free->length += sizeof(MDESC) + m->length;
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m_free->next = m->next;
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}
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else
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{
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m->prev = m_free;
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m_free->next = m;
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}
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}
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else
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{
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m_free->next = NULL;
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}
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return 0;
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}
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/**********************************************************************
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* HEAP_LocalInit
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*/
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void
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HEAP_LocalInit(void *start, int length)
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{
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HEAP_Init(&LOCAL_FreeList, start, length);
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}
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/**********************************************************************
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* LocalAlloc
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*/
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void *
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LocalAlloc(int flags, int bytes)
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{
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void *m;
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#ifdef DEBUG_HEAP
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printf("LocalAlloc: flags %x, bytes %d\n", flags, bytes);
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#endif
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m = HEAP_Alloc(&LOCAL_FreeList, flags, bytes);
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#ifdef DEBUG_HEAP
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printf("LocalAlloc: returning %x\n", (int) m);
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#endif
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return m;
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}
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/**********************************************************************
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* LocalCompact
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*/
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int
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LocalCompact(int min_free)
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{
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MDESC *m;
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int max_block;
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max_block = 0;
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for (m = LOCAL_FreeList; m != NULL; m = m->next)
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if (m->length > max_block)
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max_block = m->length;
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return max_block;
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}
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/**********************************************************************
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* LocalFlags
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*/
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unsigned int
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LocalFlags(unsigned int handle)
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{
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MDESC *m;
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m = (MDESC *) (((int) LOCAL_FreeList & 0xffff0000) |
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(handle & 0xffff)) - 1;
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if (m->next != m || m->prev != m)
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return 0;
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return m->lock;
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}
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/**********************************************************************
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* LocalFree
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*/
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unsigned int
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LocalFree(unsigned int handle)
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{
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unsigned int addr;
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addr = ((int) LOCAL_FreeList & 0xffff0000) | (handle & 0xffff);
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if (HEAP_Free(&LOCAL_FreeList, (void *) addr) < 0)
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return handle;
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else
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return 0;
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}
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/**********************************************************************
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* LocalInit
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*/
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unsigned int
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LocalInit(unsigned int segment, unsigned int start, unsigned int end)
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{
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HEAP_Init(&LOCAL_FreeList,
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(void *) ((segment << 16) | start), end - start + 1);
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return segment;
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}
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/**********************************************************************
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* LocalLock
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*/
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void *
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LocalLock(unsigned int handle)
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{
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MDESC *m;
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m = (MDESC *) (((int) LOCAL_FreeList & 0xffff0000) |
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(handle & 0xffff)) - 1;
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if (m->next != m || m->prev != m)
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return 0;
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m->lock++;
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return (void *) (m + 1);
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}
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/**********************************************************************
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* LocalReAlloc
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*/
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void *
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LocalReAlloc(unsigned int handle, int flags, int bytes)
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{
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void *m;
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m = HEAP_ReAlloc(&LOCAL_FreeList, (void *)
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(((int) LOCAL_FreeList & 0xffff0000) | (handle & 0xffff)),
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bytes, flags);
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return m;
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}
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/**********************************************************************
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* LocalSize
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*/
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unsigned int
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LocalSize(unsigned int handle)
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{
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MDESC *m;
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m = (MDESC *) (((int) LOCAL_FreeList & 0xffff0000) |
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(handle & 0xffff)) - 1;
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if (m->next != m || m->prev != m)
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return 0;
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return m->length;
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}
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/**********************************************************************
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* LocalUnlock
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*/
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unsigned int
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LocalUnlock(unsigned int handle)
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{
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MDESC *m;
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m = (MDESC *) (((int) LOCAL_FreeList & 0xffff0000) |
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(handle & 0xffff)) - 1;
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if (m->next != m || m->prev != m)
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return 1;
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if (m->lock > 0)
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m->lock--;
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return 0;
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}
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