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/**
* @file heap.c
* A basic memory manager
*
* Copyright (C) 2018 Clyne Sullivan
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <heap.h>
#define HEAP_ALIGN 4
static alloc_t *free_blocks;
static void *heap_end;
uint32_t heap_used;
void heap_init(void *buf)
{
heap_end = buf;
free_blocks = 0;
heap_used = 0;
}
void *malloc(uint32_t size)
{
size = (size + sizeof(alloc_t) + HEAP_ALIGN) & ~(HEAP_ALIGN - 1);
alloc_t *node = free_blocks;
alloc_t *prev = 0;
while (node != 0) {
if (node->size >= size) {
/*if (node->size > size + sizeof(alloc_t) + HEAP_ALIGN) {
alloc_t *rem = (alloc_t *)((uint8_t *)node +
sizeof(alloc_t) + size);
rem->size = node->size - size - sizeof(alloc_t);
rem->next = node->next;
if (prev != 0)
prev->next = rem;
else
free_blocks = rem;
node->size = size;
} else {*/
if (prev != 0)
prev->next = node->next;
else
free_blocks = node->next;
//}
node->next = 0;
heap_used += node->size;
return (void *)((uint8_t *)node + sizeof(alloc_t));
}
prev = node;
node = node->next;
}
node = (alloc_t *)heap_end;
node->size = size;
node->next = 0;
heap_end = (void *)((uint8_t *)heap_end + size);
heap_used += size;
return (void *)((uint8_t *)node + sizeof(alloc_t));
}
void *calloc(uint32_t count, uint32_t size)
{
uint8_t *buf = malloc(count * size);
for (uint32_t i = 0; i < count * size; i++)
buf[i] = 0;
return buf;
}
void free(void *buf)
{
if (buf == 0)
return;
alloc_t *alloc = (alloc_t *)((uint8_t *)buf - sizeof(alloc_t));
if (alloc->next != 0)
return;
heap_used -= alloc->size;
alloc->next = free_blocks;
free_blocks = alloc;
}
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