Vhex is a kernel which provide development and retro ingenierie platform for the Casio's OS
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#include <kernel/memory.h>
#include <kernel/util/atomic.h>
#include <kernel/devices/earlyterm.h>
#include <string.h>
// Internal function
extern void *pm_block_split(struct pm_heap_block *block, size_t size);
extern void pm_block_backmerge(struct pm_heap_block **block, struct pm_heap_block *parent);
extern void pm_block_frontmerge(struct pm_heap_block *block, void *brk);
static int pm_block_update(struct pm_heap_block *block, size_t size, void *brk)
{
struct pm_heap_block *block_front;
// Check front block validity
block_front = (void*)&block[1] + block->size;
if ((void*)block_front >= brk || block_front->status != 0)
return (-1);
// Check size
if (block_front->size + sizeof(struct pm_heap_block) + block->size < size)
return (-1);
// merge front block and try to split the block
block->size += block_front->size + sizeof(struct pm_heap_block);
pm_block_split(block, size);
return (0);
}
static void *pm_block_realloc(struct pm_heap_page **page, void *ptr, size_t size)
{
struct pm_heap_block *block_parent;
struct pm_heap_block *block;
struct pm_heap_block *new;
block_parent = NULL;
block = &(*page)->heap;
while ((void*)&block[1] < (*page)->brk)
{
// check block validity
if ((void*)&block[1] != ptr)
{
block_parent = block;
block = (void*)&block[1] + block->size;
continue;
}
// Check useless action
if (block->size >= size || pm_block_update(block, size, (*page)->brk) == 0)
return (&block[1]);
// Manually alloc new node
new = pm_heap_alloc(page, size);
if (new == NULL)
return (&block[1]);
// Copie old place
memcpy(new, &block[1], block->size);
// Try back-merge / front merge current block
pm_block_backmerge(&block, block_parent);
pm_block_frontmerge(block, (*page)->brk);
// Update block status
block->status = 0;
return (new);
}
return (NULL);
}
void *pm_heap_realloc(struct pm_heap_page **page, void *ptr, size_t size)
{
void *ret;
// Check error
if (ptr == NULL)
return (NULL);
// Force 4-align
size = (size + 3) >> 2 << 2;
// Start atomic operations
atomic_start();
// Try to find the page
while (*page != NULL)
{
// If is the page is found
if (ptr > (void*)*page && ptr < (*page)->brk)
{
// Check if the block is not found
ret = pm_block_realloc(page, ptr, size);
// Stop atomic operations and return area
atomic_stop();
return (ret);
}
// Get the next page
page = &(*page)->next;
}
// No block found, display error.
earlyterm_write(
"pm_free: Warning, you try to realloc an "
"unused or allocated memory (%p)\n", ptr
);
DBG_WAIT;
// Stop atomic operations
atomic_stop();
return (NULL);
}