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tommyarray.h

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+/*
+ * Copyright 2011 Andrea Mazzoleni. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY ANDREA MAZZOLENI AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL ANDREA MAZZOLENI OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * Dynamic array.
+ *
+ * This array is able to grow dynamically upon request.
+ *
+ * The resize involve an allocation of a new array segment, without reallocating
+ * the already allocated memory, and then not increasing the heap fragmentation.
+ *
+ * This means that the address of the allocated segments never change.
+ */
+
+#ifndef __TOMMYARRAY_H
+#define __TOMMYARRAY_H
+
+#include "tommytypes.h"
+
+#include <assert.h> /* for assert */
+
+/******************************************************************************/
+/* array */
+
+/**
+ * Initial and minimal size of the array expressed as a power of 2.
+ * The initial size is 2^TOMMY_ARRAY_BIT.
+ */
+#define TOMMY_ARRAY_BIT 6
+
+/** \internal
+ * Max number of elements as a power of 2.
+ */
+#define TOMMY_ARRAY_BIT_MAX 32
+
+/**
+ * Array.
+ */
+typedef struct tommy_array_struct {
+	void** bucket[TOMMY_ARRAY_BIT_MAX]; /**< Dynamic array of buckets. */
+	unsigned bucket_bit; /**< Bits used in the bit mask. */
+	unsigned bucket_max; /**< Number of buckets. */
+	unsigned bucket_mac; /**< Number of vectors allocated. */
+	unsigned size; /**< Currently allocated and initialized size. */
+} tommy_array;
+
+/**
+ * Initializes the array.
+ */
+void tommy_array_init(tommy_array* array);
+
+/**
+ * Deinitializes the array.
+ */
+void tommy_array_done(tommy_array* array);
+
+/**
+ * Grow the size up to the specified value.
+ * All the new elements in the array are initialized with the 0 value.
+ */
+void tommy_array_grow(tommy_array* array, unsigned size);
+
+/**
+ * Gets a reference of the element at the specified position.
+ * You must be sure that space for this position is already
+ * allocated calling tommy_array_grow().
+ */
+tommy_inline void** tommy_array_ref(tommy_array* array, unsigned pos)
+{
+	unsigned bsr;  
+
+	assert(pos < array->size);
+
+	/* special case for the first bucket */
+	if (pos < (1 << TOMMY_ARRAY_BIT)) {
+		return &array->bucket[0][pos];
+	}
+
+	/* get the highest bit set */
+	bsr = tommy_ilog2_u32(pos);
+
+	/* clear the highest bit */
+	pos -= 1 << bsr;
+
+	return &array->bucket[bsr - TOMMY_ARRAY_BIT + 1][pos];
+}
+
+/**
+ * Sets the element at the specified position.
+ * You must be sure that space for this position is already
+ * allocated calling tommy_array_grow().
+ */
+tommy_inline void tommy_array_set(tommy_array* array, unsigned pos, void* node)
+{
+	*tommy_array_ref(array, pos) = node;
+}
+
+/**
+ * Gets the element at the specified position.
+ * You must be sure that space for this position is already
+ * allocated calling tommy_array_grow().
+ */
+tommy_inline void* tommy_array_get(tommy_array* array, unsigned pos)
+{
+	return *tommy_array_ref(array, pos);
+}
+
+/**
+ * Grows and inserts a new element at the end of the array.
+ */
+tommy_inline void tommy_array_insert(tommy_array* array, void* node)
+{
+	unsigned pos = array->size;
+
+	tommy_array_grow(array, pos + 1);
+
+	tommy_array_set(array, pos, node);
+}
+
+/**
+ * Gets the initialized size of the array.
+ */
+tommy_inline unsigned tommy_array_size(tommy_array* array)
+{
+	return array->size;
+}
+
+/**
+ * Gets the size of allocated memory.
+ */
+tommy_size_t tommy_array_memory_usage(tommy_array* array);
+
+#endif
+