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-rw-r--r--wsutil/wmem/wmem_allocator_block_fast.c258
1 files changed, 258 insertions, 0 deletions
diff --git a/wsutil/wmem/wmem_allocator_block_fast.c b/wsutil/wmem/wmem_allocator_block_fast.c
new file mode 100644
index 0000000000..bdb8c2f75d
--- /dev/null
+++ b/wsutil/wmem/wmem_allocator_block_fast.c
@@ -0,0 +1,258 @@
+/* wmem_allocator_block.c
+ * Wireshark Memory Manager Fast Large-Block Allocator
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <glib.h>
+
+#include "wmem_core.h"
+#include "wmem_allocator.h"
+#include "wmem_allocator_block_fast.h"
+
+/* https://mail.gnome.org/archives/gtk-devel-list/2004-December/msg00091.html
+ * The 2*sizeof(size_t) alignment here is borrowed from GNU libc, so it should
+ * be good most everywhere. It is more conservative than is needed on some
+ * 64-bit platforms, but ia64 does require a 16-byte alignment. The SIMD
+ * extensions for x86 and ppc32 would want a larger alignment than this, but
+ * we don't need to do better than malloc.
+ */
+#define WMEM_ALIGN_AMOUNT (2 * sizeof (gsize))
+#define WMEM_ALIGN_SIZE(SIZE) ((~(WMEM_ALIGN_AMOUNT-1)) & \
+ ((SIZE) + (WMEM_ALIGN_AMOUNT-1)))
+
+#define WMEM_CHUNK_TO_DATA(CHUNK) ((void*)((guint8*)(CHUNK) + WMEM_CHUNK_HEADER_SIZE))
+#define WMEM_DATA_TO_CHUNK(DATA) ((wmem_block_fast_chunk_t*)((guint8*)(DATA) - WMEM_CHUNK_HEADER_SIZE))
+
+#define WMEM_BLOCK_MAX_ALLOC_SIZE (WMEM_BLOCK_SIZE - (WMEM_BLOCK_HEADER_SIZE + WMEM_CHUNK_HEADER_SIZE))
+
+/* When required, allocate more memory from the OS in chunks of this size.
+ * 2MB is a pretty arbitrary value - it's big enough that it should last a while
+ * and small enough that a mostly-unused one doesn't waste *too* much. It's
+ * also a nice power of two, of course. */
+#define WMEM_BLOCK_SIZE (2 * 1024 * 1024)
+
+/* The header for an entire OS-level 'block' of memory */
+typedef struct _wmem_block_fast_hdr {
+ struct _wmem_block_fast_hdr *next;
+
+ gint32 pos;
+} wmem_block_fast_hdr_t;
+#define WMEM_BLOCK_HEADER_SIZE WMEM_ALIGN_SIZE(sizeof(wmem_block_fast_hdr_t))
+
+typedef struct {
+ guint32 len;
+} wmem_block_fast_chunk_t;
+#define WMEM_CHUNK_HEADER_SIZE WMEM_ALIGN_SIZE(sizeof(wmem_block_fast_chunk_t))
+
+#define JUMBO_MAGIC 0xFFFFFFFF
+typedef struct _wmem_block_fast_jumbo {
+ struct _wmem_block_fast_jumbo *prev, *next;
+} wmem_block_fast_jumbo_t;
+#define WMEM_JUMBO_HEADER_SIZE WMEM_ALIGN_SIZE(sizeof(wmem_block_fast_jumbo_t))
+
+typedef struct {
+ wmem_block_fast_hdr_t *block_list;
+ wmem_block_fast_jumbo_t *jumbo_list;
+} wmem_block_fast_allocator_t;
+
+/* Creates a new block, and initializes it. */
+static inline void
+wmem_block_fast_new_block(wmem_block_fast_allocator_t *allocator)
+{
+ wmem_block_fast_hdr_t *block;
+
+ /* allocate/initialize the new block and add it to the block list */
+ block = (wmem_block_fast_hdr_t *)wmem_alloc(NULL, WMEM_BLOCK_SIZE);
+
+ block->pos = WMEM_BLOCK_HEADER_SIZE;
+ block->next = allocator->block_list;
+
+ allocator->block_list = block;
+}
+
+/* API */
+
+static void *
+wmem_block_fast_alloc(void *private_data, const size_t size)
+{
+ wmem_block_fast_allocator_t *allocator = (wmem_block_fast_allocator_t*) private_data;
+ wmem_block_fast_chunk_t *chunk;
+ gint32 real_size;
+
+ if (size > WMEM_BLOCK_MAX_ALLOC_SIZE) {
+ wmem_block_fast_jumbo_t *block;
+
+ /* allocate/initialize a new block of the necessary size */
+ block = (wmem_block_fast_jumbo_t *)wmem_alloc(NULL,
+ size + WMEM_JUMBO_HEADER_SIZE + WMEM_CHUNK_HEADER_SIZE);
+
+ block->next = allocator->jumbo_list;
+ block->prev = NULL;
+ allocator->jumbo_list = block;
+
+ chunk = ((wmem_block_fast_chunk_t*)((guint8*)(block) + WMEM_JUMBO_HEADER_SIZE));
+ chunk->len = JUMBO_MAGIC;
+
+ return WMEM_CHUNK_TO_DATA(chunk);
+ }
+
+ real_size = (gint32)(WMEM_ALIGN_SIZE(size) + WMEM_CHUNK_HEADER_SIZE);
+
+ /* Allocate a new block if necessary. */
+ if (!allocator->block_list ||
+ (WMEM_BLOCK_SIZE - allocator->block_list->pos) < real_size) {
+ wmem_block_fast_new_block(allocator);
+ }
+
+ chunk = (wmem_block_fast_chunk_t *) ((guint8 *) allocator->block_list + allocator->block_list->pos);
+ /* safe to cast, size smaller than WMEM_BLOCK_MAX_ALLOC_SIZE */
+ chunk->len = (guint32) size;
+
+ allocator->block_list->pos += real_size;
+
+ /* and return the user's pointer */
+ return WMEM_CHUNK_TO_DATA(chunk);
+}
+
+static void
+wmem_block_fast_free(void *private_data _U_, void *ptr _U_)
+{
+ /* free is NOP */
+}
+
+static void *
+wmem_block_fast_realloc(void *private_data, void *ptr, const size_t size)
+{
+ wmem_block_fast_chunk_t *chunk;
+
+ chunk = WMEM_DATA_TO_CHUNK(ptr);
+
+ if (chunk->len == JUMBO_MAGIC) {
+ wmem_block_fast_jumbo_t *block;
+
+ block = ((wmem_block_fast_jumbo_t*)((guint8*)(chunk) - WMEM_JUMBO_HEADER_SIZE));
+ block = (wmem_block_fast_jumbo_t*)wmem_realloc(NULL, block,
+ size + WMEM_JUMBO_HEADER_SIZE + WMEM_CHUNK_HEADER_SIZE);
+ if (block->prev) {
+ block->prev->next = block;
+ }
+ else {
+ wmem_block_fast_allocator_t *allocator = (wmem_block_fast_allocator_t*) private_data;
+ allocator->jumbo_list = block;
+ }
+ if (block->next) {
+ block->next->prev = block;
+ }
+ return ((void*)((guint8*)(block) + WMEM_JUMBO_HEADER_SIZE + WMEM_CHUNK_HEADER_SIZE));
+ }
+ else if (chunk->len < size) {
+ /* grow */
+ void *newptr;
+
+ /* need to alloc and copy; free is no-op, so don't call it */
+ newptr = wmem_block_fast_alloc(private_data, size);
+ memcpy(newptr, ptr, chunk->len);
+
+ return newptr;
+ }
+
+ /* shrink or same space - great we can do nothing */
+ return ptr;
+}
+
+static void
+wmem_block_fast_free_all(void *private_data)
+{
+ wmem_block_fast_allocator_t *allocator = (wmem_block_fast_allocator_t*) private_data;
+ wmem_block_fast_hdr_t *cur, *nxt;
+ wmem_block_fast_jumbo_t *cur_jum, *nxt_jum;
+
+ /* iterate through the blocks, freeing all but the first and reinitializing
+ * that one */
+ cur = allocator->block_list;
+
+ if (cur) {
+ cur->pos = WMEM_BLOCK_HEADER_SIZE;
+ nxt = cur->next;
+ cur->next = NULL;
+ cur = nxt;
+ }
+
+ while (cur) {
+ nxt = cur->next;
+ wmem_free(NULL, cur);
+ cur = nxt;
+ }
+
+ /* now do the jumbo blocks, freeing all of them */
+ cur_jum = allocator->jumbo_list;
+ while (cur_jum) {
+ nxt_jum = cur_jum->next;
+ wmem_free(NULL, cur_jum);
+ cur_jum = nxt_jum;
+ }
+ allocator->jumbo_list = NULL;
+}
+
+static void
+wmem_block_fast_gc(void *private_data _U_)
+{
+ /* No-op */
+}
+
+static void
+wmem_block_fast_allocator_cleanup(void *private_data)
+{
+ wmem_block_fast_allocator_t *allocator = (wmem_block_fast_allocator_t*) private_data;
+
+ /* wmem guarantees that free_all() is called directly before this, so
+ * simply free the first block */
+ wmem_free(NULL, allocator->block_list);
+
+ /* then just free the allocator structs */
+ wmem_free(NULL, private_data);
+}
+
+void
+wmem_block_fast_allocator_init(wmem_allocator_t *allocator)
+{
+ wmem_block_fast_allocator_t *block_allocator;
+
+ block_allocator = wmem_new(NULL, wmem_block_fast_allocator_t);
+
+ allocator->walloc = &wmem_block_fast_alloc;
+ allocator->wrealloc = &wmem_block_fast_realloc;
+ allocator->wfree = &wmem_block_fast_free;
+
+ allocator->free_all = &wmem_block_fast_free_all;
+ allocator->gc = &wmem_block_fast_gc;
+ allocator->cleanup = &wmem_block_fast_allocator_cleanup;
+
+ allocator->private_data = (void*) block_allocator;
+
+ block_allocator->block_list = NULL;
+ block_allocator->jumbo_list = NULL;
+}
+
+/*
+ * Editor modelines - https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */
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