ucx/ucx/allocator.h

changeset 157
0b33b9396851
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/ucx/allocator.h	Mon Feb 04 17:49:50 2019 +0100
@@ -0,0 +1,206 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2017 Mike Becker, Olaf Wintermann 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 THE COPYRIGHT HOLDERS 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 THE COPYRIGHT HOLDER 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.
+ */
+/**
+ * Allocator for custom memory management.
+ * 
+ * A UCX allocator consists of a pointer to the memory area / pool and four
+ * function pointers to memory management functions operating on this memory
+ * area / pool. These functions shall behave equivalent to the standard libc
+ * functions <code>malloc(), calloc(), realloc()</code> and <code>free()</code>.
+ * 
+ * The signature of the memory management functions is based on the signature
+ * of the respective libc function but each of them takes the pointer to the
+ * memory area / pool as first argument.
+ * 
+ * As the pointer to the memory area / pool can be arbitrarily chosen, any data
+ * can be provided to the memory management functions. A UcxMempool is just
+ * one example.
+ * 
+ * @see mempool.h
+ * @see UcxMap
+ * 
+ * @file   allocator.h
+ * @author Mike Becker
+ * @author Olaf Wintermann
+ */
+
+#ifndef UCX_ALLOCATOR_H
+#define	UCX_ALLOCATOR_H
+
+#include "ucx.h"
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/**
+ * A function pointer to the allocators <code>malloc()</code> function.
+ * @see UcxAllocator
+ */
+typedef void*(*ucx_allocator_malloc)(void *pool, size_t n);
+
+/**
+ * A function pointer to the allocators <code>calloc()</code> function.
+ * @see UcxAllocator
+ */
+typedef void*(*ucx_allocator_calloc)(void *pool, size_t n, size_t size);
+
+/**
+ * A function pointer to the allocators <code>realloc()</code> function.
+ * @see UcxAllocator
+ */
+typedef void*(*ucx_allocator_realloc)(void *pool, void *data, size_t n);
+
+/**
+ * A function pointer to the allocators <code>free()</code> function.
+ * @see UcxAllocator
+ */
+typedef void(*ucx_allocator_free)(void *pool, void *data);
+
+/**
+ * UCX allocator data structure containing memory management functions.
+ */
+typedef struct {
+    /** Pointer to an area of memory or a complex memory pool.
+     * This pointer will be passed to any memory management function as first
+     * argument.
+     */
+    void *pool;
+    /**
+     * The <code>malloc()</code> function for this allocator.
+     */
+    ucx_allocator_malloc  malloc;
+    /**
+     * The <code>calloc()</code> function for this allocator.
+     */
+    ucx_allocator_calloc  calloc;
+    /**
+     * The <code>realloc()</code> function for this allocator.
+     */
+    ucx_allocator_realloc realloc;
+    /**
+     * The <code>free()</code> function for this allocator.
+     */
+    ucx_allocator_free    free;
+} UcxAllocator;
+
+/**
+ * Returns a pointer to the default allocator.
+ * 
+ * The default allocator contains wrappers to the standard libc memory
+ * management functions. Use this function to get a pointer to a globally
+ * available allocator. You may also define an own UcxAllocator by assigning
+ * #UCX_ALLOCATOR_DEFAULT to a variable and pass the address of this variable
+ * to any function that takes a UcxAllocator as argument. Note that using
+ * this function is the recommended way of passing a default allocator, thus
+ * it never runs out of scope.
+ * 
+ * @return a pointer to the default allocator
+ * 
+ * @see UCX_ALLOCATOR_DEFAULT
+ */
+UcxAllocator *ucx_default_allocator();
+
+/**
+ * A wrapper for the standard libc <code>malloc()</code> function.
+ * @param ignore ignored (may be used by allocators for pooled memory)
+ * @param n argument passed to <code>malloc()</code>
+ * @return return value of <code>malloc()</code>
+ */
+void *ucx_default_malloc(void *ignore, size_t n);
+/**
+ * A wrapper for the standard libc <code>calloc()</code> function.
+ * @param ignore ignored (may be used by allocators for pooled memory)
+ * @param n argument passed to <code>calloc()</code>
+ * @param size  argument passed to <code>calloc()</code>
+ * @return return value of <code>calloc()</code>
+ */
+void *ucx_default_calloc(void *ignore, size_t n, size_t size);
+/**
+ * A wrapper for the standard libc <code>realloc()</code> function.
+ * @param ignore ignored (may be used by allocators for pooled memory)
+ * @param data argumend passed to <code>realloc()</code>
+ * @param n argument passed to <code>realloc()</code>
+ * @return return value of <code>realloc()</code>
+ */
+void *ucx_default_realloc(void *ignore, void *data, size_t n);
+/**
+ * A wrapper for the standard libc <code>free()</code> function.
+ * @param ignore ignored (may be used by allocators for pooled memory)
+ * @param data argument passed to <code>free()</code>
+ */
+void ucx_default_free(void *ignore, void *data);
+
+/**
+ * Shorthand for calling an allocators malloc function.
+ * @param allocator the allocator to use
+ * @param n size of space to allocate
+ * @return a pointer to the allocated memory area
+ */
+#define almalloc(allocator, n) ((allocator)->malloc((allocator)->pool, n))
+
+/**
+ * Shorthand for calling an allocators calloc function.
+ * @param allocator the allocator to use
+ * @param n the count of elements the space should be allocated for
+ * @param size the size of each element
+ * @return a pointer to the allocated memory area
+ */
+#define alcalloc(allocator, n, size) \
+        ((allocator)->calloc((allocator)->pool, n, size))
+
+/**
+ * Shorthand for calling an allocators realloc function.
+ * @param allocator the allocator to use
+ * @param ptr the pointer to the memory area that shall be reallocated
+ * @param n the new size of the allocated memory area
+ * @return a pointer to the reallocated memory area
+ */
+#define alrealloc(allocator, ptr, n) \
+        ((allocator)->realloc((allocator)->pool, ptr, n))
+
+/**
+ * Shorthand for calling an allocators free function.
+ * @param allocator the allocator to use
+ * @param ptr the pointer to the memory area that shall be freed
+ */
+#define alfree(allocator, ptr) ((allocator)->free((allocator)->pool, ptr))
+
+/**
+ * Convenient macro for a default allocator <code>struct</code> definition.
+ */
+#define UCX_ALLOCATOR_DEFAULT {NULL, \
+        ucx_default_malloc, ucx_default_calloc, ucx_default_realloc, \
+        ucx_default_free }
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* UCX_ALLOCATOR_H */
+

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