1 files changed, 200 insertions, 0 deletions
diff --git a/src/liblzma/common/memory_limitter.c b/src/liblzma/common/memory_limitter.c
new file mode 100644
index 00000000..19cdefc2
--- /dev/null
+++ b/src/liblzma/common/memory_limitter.c
@@ -0,0 +1,200 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       memory_limitter.c
+/// \brief      Limitting memory usage
+//
+//  Copyright (C) 2007 Lasse Collin
+//
+//  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; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  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.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "common.h"
+
+
+/// Rounds an unsigned integer upwards to the next multiple.
+#define my_ceil(num, multiple) \
+	((num) + (((multiple) - ((num) % (multiple))) % (multiple)))
+
+
+/// Rounds upwards to the next multiple of 2 * sizeof(void*).
+/// malloc() tends to align allocations this way.
+#define malloc_ceil(num) my_ceil(num, 2 * sizeof(void *))
+
+
+typedef struct lzma_memlimit_list_s lzma_memlimit_list;
+struct lzma_memlimit_list_s {
+	lzma_memlimit_list *next;
+	void *ptr;
+	size_t size;
+};
+
+
+struct lzma_memlimit_s {
+	size_t used;
+	size_t limit;
+	lzma_memlimit_list *list;
+};
+
+
+extern LZMA_API lzma_memlimit *
+lzma_memlimit_create(size_t limit)
+{
+	if (limit < sizeof(lzma_memlimit))
+		return NULL;
+
+	lzma_memlimit *mem = malloc(sizeof(lzma_memlimit));
+
+	if (mem != NULL) {
+		mem->used = sizeof(lzma_memlimit);
+		mem->limit = limit;
+		mem->list = NULL;
+	}
+
+	return mem;
+}
+
+
+extern LZMA_API void
+lzma_memlimit_set(lzma_memlimit *mem, size_t limit)
+{
+	mem->limit = limit;
+	return;
+}
+
+
+extern LZMA_API size_t
+lzma_memlimit_get(const lzma_memlimit *mem)
+{
+	return mem->limit;
+}
+
+
+extern LZMA_API size_t
+lzma_memlimit_used(const lzma_memlimit *mem)
+{
+	return mem->used;
+}
+
+
+extern LZMA_API void
+lzma_memlimit_end(lzma_memlimit *mem, lzma_bool free_allocated)
+{
+	if (mem == NULL)
+		return;
+
+	lzma_memlimit_list *record = mem->list;
+	while (record != NULL) {
+		if (free_allocated)
+			free(record->ptr);
+
+		lzma_memlimit_list *tmp = record;
+		record = record->next;
+		free(tmp);
+	}
+
+	free(mem);
+
+	return;
+}
+
+
+extern LZMA_API void *
+lzma_memlimit_alloc(lzma_memlimit *mem, size_t nmemb, size_t size)
+{
+	// While liblzma always sets nmemb to one, do this multiplication
+	// to make these functions usable e.g. with zlib and libbzip2.
+	// Making sure that this doesn't overflow is up to the application.
+	size *= nmemb;
+
+	// Some malloc() implementations return NULL on malloc(0). We like
+	// to get a non-NULL value.
+	if (size == 0)
+		size = 1;
+
+	// Calculate how much memory we are going to allocate in reality.
+	// TODO: We should add some rough estimate how much malloc() needs
+	// for its internal structures.
+	const size_t total_size = malloc_ceil(size)
+			+ malloc_ceil(sizeof(lzma_memlimit_list));
+
+	// Integer overflow protection
+	if (SIZE_MAX - size <= total_size)
+		return NULL;
+
+	if (mem->limit < mem->used || mem->limit - mem->used < total_size)
+		return NULL;
+
+	lzma_memlimit_list *record = malloc(sizeof(lzma_memlimit_list));
+	void *ptr = malloc(size);
+
+	if (record == NULL || ptr == NULL) {
+		free(record);
+		free(ptr);
+		return NULL;
+	}
+
+	// Add the new entry to the beginning of the list. This should be
+	// more efficient when freeing memory, because usually it is
+	// "last allocated, first freed".
+	record->next = mem->list;
+	record->ptr = ptr;
+	record->size = total_size;
+
+	mem->list = record;
+	mem->used += total_size;
+
+	return ptr;
+}
+
+
+extern LZMA_API void
+lzma_memlimit_detach(lzma_memlimit *mem, void *ptr)
+{
+	if (ptr == NULL || mem->list == NULL)
+		return;
+
+	lzma_memlimit_list *record = mem->list;
+	lzma_memlimit_list *prev = NULL;
+
+	while (record->ptr != ptr) {
+		prev = record;
+		record = record->next;
+		if (record == NULL)
+			return;
+	}
+
+	if (prev != NULL)
+		prev->next = record->next;
+	else
+		mem->list = record->next;
+
+	assert(mem->used >= record->size);
+	mem->used -= record->size;
+
+	free(record);
+
+	return;
+}
+
+
+extern LZMA_API void
+lzma_memlimit_free(lzma_memlimit *mem, void *ptr)
+{
+	if (ptr == NULL)
+		return;
+
+	lzma_memlimit_detach(mem, ptr);
+
+	free(ptr);
+
+	return;
+}