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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
* Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
*
* This library is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation.
*
* This library 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "camel-mempool.h"
#include <string.h>
typedef struct _MemPoolNode {
struct _MemPoolNode *next;
gint free;
} MemPoolNode;
typedef struct _MemPoolThresholdNode {
struct _MemPoolThresholdNode *next;
} MemPoolThresholdNode;
#define ALIGNED_SIZEOF(t) ((sizeof (t) + G_MEM_ALIGN - 1) & -G_MEM_ALIGN)
struct _CamelMemPool {
gint blocksize;
gint threshold;
guint align;
struct _MemPoolNode *blocks;
struct _MemPoolThresholdNode *threshold_blocks;
};
/**
* camel_mempool_new:
* @blocksize: The base blocksize to use for all system alocations.
* @threshold: If the allocation exceeds the threshold, then it is
* allocated separately and stored in a separate list.
* @flags: Alignment options: CAMEL_MEMPOOL_ALIGN_STRUCT uses native
* struct alignment, CAMEL_MEMPOOL_ALIGN_WORD aligns to 16 bits (2 bytes),
* and CAMEL_MEMPOOL_ALIGN_BYTE aligns to the nearest byte. The default
* is to align to native structures.
*
* Create a new mempool header. Mempools can be used to efficiently
* allocate data which can then be freed as a whole.
*
* Mempools can also be used to efficiently allocate arbitrarily
* aligned data (such as strings) without incurring the space overhead
* of aligning each allocation (which is not required for strings).
*
* However, each allocation cannot be freed individually, only all
* or nothing.
*
* Returns:
*
* Since: 2.32
**/
CamelMemPool *
camel_mempool_new (gint blocksize,
gint threshold,
CamelMemPoolFlags flags)
{
CamelMemPool *pool;
pool = g_slice_new0 (CamelMemPool);
if (threshold >= blocksize)
threshold = blocksize * 2 / 3;
pool->blocksize = blocksize;
pool->threshold = threshold;
pool->blocks = NULL;
pool->threshold_blocks = NULL;
switch (flags & CAMEL_MEMPOOL_ALIGN_MASK) {
case CAMEL_MEMPOOL_ALIGN_STRUCT:
default:
pool->align = G_MEM_ALIGN - 1;
break;
case CAMEL_MEMPOOL_ALIGN_WORD:
pool->align = 2 - 1;
break;
case CAMEL_MEMPOOL_ALIGN_BYTE:
pool->align = 1 - 1;
}
return pool;
}
/**
* camel_mempool_alloc:
* @pool: a #CamelMemPool
* @size:
*
* Allocate a new data block in the mempool. Size will
* be rounded up to the mempool's alignment restrictions
* before being used.
*
* Since: 2.32
**/
gpointer
camel_mempool_alloc (CamelMemPool *pool,
register gint size)
{
size = (size + pool->align) & (~(pool->align));
if (size >= pool->threshold) {
MemPoolThresholdNode *n;
n = g_malloc (ALIGNED_SIZEOF (*n) + size);
n->next = pool->threshold_blocks;
pool->threshold_blocks = n;
return (gchar *) n + ALIGNED_SIZEOF (*n);
} else {
register MemPoolNode *n;
n = pool->blocks;
if (n && n->free >= size) {
n->free -= size;
return (gchar *) n + ALIGNED_SIZEOF (*n) + n->free;
}
/* maybe we could do some sort of the free blocks based on size, but
* it doubt its worth it at all */
n = g_malloc (ALIGNED_SIZEOF (*n) + pool->blocksize);
n->next = pool->blocks;
pool->blocks = n;
n->free = pool->blocksize - size;
return (gchar *) n + ALIGNED_SIZEOF (*n) + n->free;
}
}
/**
* camel_mempool_strdup:
* @pool: a #CamelMemPool
* @str:
*
* Since: 2.32
**/
gchar *
camel_mempool_strdup (CamelMemPool *pool,
const gchar *str)
{
gchar *out;
gsize out_len;
out_len = strlen (str) + 1;
out = camel_mempool_alloc (pool, out_len);
g_strlcpy (out, str, out_len);
return out;
}
/**
* camel_mempool_flush:
* @pool: a #CamelMemPool
* @freeall: free all system allocated blocks as well
*
* Flush used memory and mark allocated blocks as free.
*
* If @freeall is %TRUE, then all allocated blocks are free'd
* as well. Otherwise only blocks above the threshold are
* actually freed, and the others are simply marked as empty.
*
* Since: 2.32
**/
void
camel_mempool_flush (CamelMemPool *pool,
gint freeall)
{
MemPoolThresholdNode *tn, *tw;
MemPoolNode *pw, *pn;
tw = pool->threshold_blocks;
while (tw) {
tn = tw->next;
g_free (tw);
tw = tn;
}
pool->threshold_blocks = NULL;
if (freeall) {
pw = pool->blocks;
while (pw) {
pn = pw->next;
g_free (pw);
pw = pn;
}
pool->blocks = NULL;
} else {
pw = pool->blocks;
while (pw) {
pw->free = pool->blocksize;
pw = pw->next;
}
}
}
/**
* camel_mempool_destroy:
* @pool: a #CamelMemPool
*
* Free all memory associated with a mempool.
*
* Since: 2.32
**/
void
camel_mempool_destroy (CamelMemPool *pool)
{
if (pool) {
camel_mempool_flush (pool, 1);
g_slice_free (CamelMemPool, pool);
}
}
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