rockbox/firmware/include/chunk_alloc.h
William Wilgus 7faf6be35f chunk_alloc
chunk_alloc allows arrays (or any data) to be allocated in smaller chunks

you have to save the indices..
 variable data will have variable indices you need to
 store these as [chunk_alloc] doesn't keep track
 if you have a fixed size for each
 alloc you can do indice / sizeof(data)
 or index * sizeof(data) to convert

Lots of debug stuff still in and it needs optimization

User provides chunk_size and max_chunks
max_chunks * struct chunk will be allocated at start
with (1) chunk_size allocation initially

alloc_chunk() with size = 0 shrinks the last allocation to the size of the data used

add OOM checks on buflib_alloc -- oops

move bytes available to the header -- less memory per chunk & better alignment
keep track of the current in use chunk index -- should speed things up a bit

Now allows:
realloc chunk header
larger allocations than chunk size

reallocs smaller than existing will shrink the current array
rather than alloc a new and copy data

Comments welcome :)

Change-Id: I8ed170eef73da95da19430a80b32e5debf0c8276
2023-01-10 23:59:19 -05:00

64 lines
2.3 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2023 William Wilgus
*
* 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 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef _CHUNKALLOC_H_
#define _CHUNKALLOC_H_
#include <stdbool.h>
#include <string.h>
#include "config.h"
#include "buflib.h"
#define CHUNK_ALLOC_INVALID ((size_t)-1)
struct chunk_alloc_header
{
size_t chunk_bytes_total; /* total bytes in current chunk */
size_t chunk_bytes_free; /* free bytes in current chunk */
size_t chunk_size; /* default chunk size */
size_t count; /* total chunks possible */
size_t current; /* current chunk in use */
struct buflib_context *context; /* buflib context for all allocations */
int chunk_handle; /* data handle of buflib allocated array of struct chunk */
};
void chunk_alloc_free(struct chunk_alloc_header *hdr);
bool chunk_alloc_init(struct chunk_alloc_header *hdr,
struct buflib_context *ctx,
size_t chunk_size, size_t max_chunks);
bool chunk_realloc(struct chunk_alloc_header *hdr,
size_t chunk_size, size_t max_chunks);
void chunk_alloc_finalize(struct chunk_alloc_header *hdr);
size_t chunk_alloc(struct chunk_alloc_header *hdr, size_t size); /* Returns offset */
void* chunk_get_data(struct chunk_alloc_header *hdr, size_t offset); /* Returns data */
void chunk_put_data(struct chunk_alloc_header *hdr, size_t offset);
static inline bool chunk_alloc_is_initialized(struct chunk_alloc_header *hdr)
{
return (hdr->chunk_handle > 0);
}
#endif