Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 928 insertions, 0 deletions

diff --git a/src/VBox/Runtime/common/alloc/heapoffset.cpp b/src/VBox/Runtime/common/alloc/heapoffset.cpp
new file mode 100644
index 00000000..78cc4b9c
--- /dev/null
+++ b/src/VBox/Runtime/common/alloc/heapoffset.cpp
@@ -0,0 +1,928 @@
+/* $Id: heapoffset.cpp $ */
+/** @file
+ * IPRT - An Offset Based Heap.
+ */
+
+/*
+ * Copyright (C) 2006-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/heap.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/asm.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+
+#include "internal/magics.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Pointer to the heap anchor block. */
+typedef struct RTHEAPOFFSETINTERNAL *PRTHEAPOFFSETINTERNAL;
+/** Pointer to a heap block. */
+typedef struct RTHEAPOFFSETBLOCK *PRTHEAPOFFSETBLOCK;
+/** Pointer to a free heap block. */
+typedef struct RTHEAPOFFSETFREE *PRTHEAPOFFSETFREE;
+
+/**
+ * Structure describing a block in an offset based heap.
+ *
+ * If this block is allocated, it is followed by the user data.
+ * If this block is free, see RTHEAPOFFSETFREE.
+ */
+typedef struct RTHEAPOFFSETBLOCK
+{
+    /** The next block in the global block list. */
+    uint32_t /*PRTHEAPOFFSETBLOCK*/     offNext;
+    /** The previous block in the global block list. */
+    uint32_t /*PRTHEAPOFFSETBLOCK*/     offPrev;
+    /** Offset into the heap of this block. Used to locate the anchor block. */
+    uint32_t /*PRTHEAPOFFSETINTERNAL*/  offSelf;
+    /** Flags + magic. */
+    uint32_t                            fFlags;
+} RTHEAPOFFSETBLOCK;
+AssertCompileSize(RTHEAPOFFSETBLOCK, 16);
+
+/** The block is free if this flag is set. When cleared it's allocated. */
+#define RTHEAPOFFSETBLOCK_FLAGS_FREE        (RT_BIT_32(0))
+/** The magic value. */
+#define RTHEAPOFFSETBLOCK_FLAGS_MAGIC       (UINT32_C(0xabcdef00))
+/** The mask that needs to be applied to RTHEAPOFFSETBLOCK::fFlags to obtain the magic value. */
+#define RTHEAPOFFSETBLOCK_FLAGS_MAGIC_MASK  (~RT_BIT_32(0))
+
+/**
+ * Checks if the specified block is valid or not.
+ * @returns boolean answer.
+ * @param   pBlock      Pointer to a RTHEAPOFFSETBLOCK structure.
+ */
+#define RTHEAPOFFSETBLOCK_IS_VALID(pBlock)  \
+    ( ((pBlock)->fFlags & RTHEAPOFFSETBLOCK_FLAGS_MAGIC_MASK) == RTHEAPOFFSETBLOCK_FLAGS_MAGIC )
+
+/**
+ * Checks if the specified block is valid and in use.
+ * @returns boolean answer.
+ * @param   pBlock      Pointer to a RTHEAPOFFSETBLOCK structure.
+ */
+#define RTHEAPOFFSETBLOCK_IS_VALID_USED(pBlock)  \
+    ( ((pBlock)->fFlags & (RTHEAPOFFSETBLOCK_FLAGS_MAGIC_MASK | RTHEAPOFFSETBLOCK_FLAGS_FREE)) \
+       == RTHEAPOFFSETBLOCK_FLAGS_MAGIC )
+
+/**
+ * Checks if the specified block is valid and free.
+ * @returns boolean answer.
+ * @param   pBlock      Pointer to a RTHEAPOFFSETBLOCK structure.
+ */
+#define RTHEAPOFFSETBLOCK_IS_VALID_FREE(pBlock)  \
+    ( ((pBlock)->fFlags & (RTHEAPOFFSETBLOCK_FLAGS_MAGIC_MASK | RTHEAPOFFSETBLOCK_FLAGS_FREE)) \
+       == (RTHEAPOFFSETBLOCK_FLAGS_MAGIC | RTHEAPOFFSETBLOCK_FLAGS_FREE) )
+
+/**
+ * Checks if the specified block is free or not.
+ * @returns boolean answer.
+ * @param   pBlock      Pointer to a valid RTHEAPOFFSETBLOCK structure.
+ */
+#define RTHEAPOFFSETBLOCK_IS_FREE(pBlock)   (!!((pBlock)->fFlags & RTHEAPOFFSETBLOCK_FLAGS_FREE))
+
+/**
+ * A free heap block.
+ * This is an extended version of RTHEAPOFFSETBLOCK that takes the unused
+ * user data to store free list pointers and a cached size value.
+ */
+typedef struct RTHEAPOFFSETFREE
+{
+    /** Core stuff. */
+    RTHEAPOFFSETBLOCK               Core;
+    /** Pointer to the next free block. */
+    uint32_t /*PRTHEAPOFFSETFREE*/  offNext;
+    /** Pointer to the previous free block. */
+    uint32_t /*PRTHEAPOFFSETFREE*/  offPrev;
+    /** The size of the block (excluding the RTHEAPOFFSETBLOCK part). */
+    uint32_t                        cb;
+    /** An alignment filler to make it a multiple of 16 bytes. */
+    uint32_t                        Alignment;
+} RTHEAPOFFSETFREE;
+AssertCompileSize(RTHEAPOFFSETFREE, 16+16);
+
+
+/**
+ * The heap anchor block.
+ * This structure is placed at the head of the memory block specified to RTHeapOffsetInit(),
+ * which means that the first RTHEAPOFFSETBLOCK appears immediately after this structure.
+ */
+typedef struct RTHEAPOFFSETINTERNAL
+{
+    /** The typical magic (RTHEAPOFFSET_MAGIC). */
+    uint32_t                        u32Magic;
+    /** The heap size. (This structure is included!) */
+    uint32_t                        cbHeap;
+    /** The amount of free memory in the heap. */
+    uint32_t                        cbFree;
+    /** Free head pointer. */
+    uint32_t /*PRTHEAPOFFSETFREE*/  offFreeHead;
+    /** Free tail pointer. */
+    uint32_t /*PRTHEAPOFFSETFREE*/  offFreeTail;
+    /** Make the size of this structure 32 bytes. */
+    uint32_t                        au32Alignment[3];
+} RTHEAPOFFSETINTERNAL;
+AssertCompileSize(RTHEAPOFFSETINTERNAL, 32);
+
+
+/** The minimum allocation size. */
+#define RTHEAPOFFSET_MIN_BLOCK  (sizeof(RTHEAPOFFSETBLOCK))
+AssertCompile(RTHEAPOFFSET_MIN_BLOCK >= sizeof(RTHEAPOFFSETBLOCK));
+AssertCompile(RTHEAPOFFSET_MIN_BLOCK >= sizeof(RTHEAPOFFSETFREE) - sizeof(RTHEAPOFFSETBLOCK));
+
+/** The minimum and default alignment.  */
+#define RTHEAPOFFSET_ALIGNMENT  (sizeof(RTHEAPOFFSETBLOCK))
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RT_STRICT
+# define RTHEAPOFFSET_STRICT 1
+#endif
+
+/**
+ * Converts RTHEAPOFFSETBLOCK::offSelf into a heap anchor block pointer.
+ *
+ * @returns Pointer of given type.
+ * @param   pBlock          The block to find the heap anchor block for.
+ */
+#define RTHEAPOFF_GET_ANCHOR(pBlock)    ( (PRTHEAPOFFSETINTERNAL)((uint8_t *)(pBlock) - (pBlock)->offSelf ) )
+
+
+/**
+ * Converts an offset to a pointer.
+ *
+ * All offsets are relative to the heap to make life simple.
+ *
+ * @returns Pointer of given type.
+ * @param   pHeapInt        Pointer to the heap anchor block.
+ * @param   off             The offset to convert.
+ * @param   type            The desired type.
+ */
+#ifdef RTHEAPOFFSET_STRICT
+# define RTHEAPOFF_TO_PTR_N(pHeapInt, off, type)   ( (type)rtHeapOffCheckedOffToPtr(pHeapInt, off, true /*fNull*/) )
+#else
+# define RTHEAPOFF_TO_PTR_N(pHeapInt, off, type)   ( (type)((off) ? (uint8_t *)(pHeapInt) + (off) : NULL) )
+#endif
+
+/**
+ * Converts an offset to a pointer.
+ *
+ * All offsets are relative to the heap to make life simple.
+ *
+ * @returns Pointer of given type.
+ * @param   pHeapInt        Pointer to the heap anchor block.
+ * @param   off             The offset to convert.
+ * @param   type            The desired type.
+ */
+#ifdef RTHEAPOFFSET_STRICT
+# define RTHEAPOFF_TO_PTR(pHeapInt, off, type)   ( (type)rtHeapOffCheckedOffToPtr(pHeapInt, off, false /*fNull*/) )
+#else
+# define RTHEAPOFF_TO_PTR(pHeapInt, off, type)   ( (type)((uint8_t *)(pHeapInt) + (off)) )
+#endif
+
+/**
+ * Converts a pointer to an offset.
+ *
+ * All offsets are relative to the heap to make life simple.
+ *
+ * @returns Offset into the heap.
+ * @param   pHeapInt        Pointer to the heap anchor block.
+ * @param   ptr             The pointer to convert.
+ */
+#ifdef RTHEAPOFFSET_STRICT
+# define RTHEAPOFF_TO_OFF(pHeapInt, ptr)    rtHeapOffCheckedPtrToOff(pHeapInt, ptr)
+#else
+# define RTHEAPOFF_TO_OFF(pHeapInt, ptr)    ( (uint32_t)((ptr) ? (uintptr_t)(ptr) - (uintptr_t)(pHeapInt) : UINT32_C(0)) )
+#endif
+
+#define ASSERT_L(a, b)    AssertMsg((a) <  (b), ("a=%08x b=%08x\n", (a), (b)))
+#define ASSERT_LE(a, b)   AssertMsg((a) <= (b), ("a=%08x b=%08x\n", (a), (b)))
+#define ASSERT_G(a, b)    AssertMsg((a) >  (b), ("a=%08x b=%08x\n", (a), (b)))
+#define ASSERT_GE(a, b)   AssertMsg((a) >= (b), ("a=%08x b=%08x\n", (a), (b)))
+#define ASSERT_ALIGN(a)   AssertMsg(!((uintptr_t)(a) & (RTHEAPOFFSET_ALIGNMENT - 1)), ("a=%p\n", (uintptr_t)(a)))
+
+#define ASSERT_PREV(pHeapInt, pBlock)  \
+    do { ASSERT_ALIGN((pBlock)->offPrev); \
+         if ((pBlock)->offPrev) \
+         { \
+             ASSERT_L((pBlock)->offPrev, RTHEAPOFF_TO_OFF(pHeapInt, pBlock)); \
+             ASSERT_GE((pBlock)->offPrev, sizeof(RTHEAPOFFSETINTERNAL)); \
+         } \
+         else \
+             Assert((pBlock) == (PRTHEAPOFFSETBLOCK)((pHeapInt) + 1)); \
+    } while (0)
+
+#define ASSERT_NEXT(pHeap, pBlock) \
+    do { ASSERT_ALIGN((pBlock)->offNext); \
+         if ((pBlock)->offNext) \
+         { \
+             ASSERT_L((pBlock)->offNext, (pHeapInt)->cbHeap); \
+             ASSERT_G((pBlock)->offNext, RTHEAPOFF_TO_OFF(pHeapInt, pBlock)); \
+         } \
+    } while (0)
+
+#define ASSERT_BLOCK(pHeapInt, pBlock) \
+    do { AssertMsg(RTHEAPOFFSETBLOCK_IS_VALID(pBlock), ("%#x\n", (pBlock)->fFlags)); \
+         AssertMsg(RTHEAPOFF_GET_ANCHOR(pBlock) == (pHeapInt), ("%p != %p\n", RTHEAPOFF_GET_ANCHOR(pBlock), (pHeapInt))); \
+         ASSERT_GE(RTHEAPOFF_TO_OFF(pHeapInt, pBlock), sizeof(RTHEAPOFFSETINTERNAL)); \
+         ASSERT_L( RTHEAPOFF_TO_OFF(pHeapInt, pBlock), (pHeapInt)->cbHeap); \
+         ASSERT_NEXT(pHeapInt, pBlock); \
+         ASSERT_PREV(pHeapInt, pBlock); \
+    } while (0)
+
+#define ASSERT_BLOCK_USED(pHeapInt, pBlock) \
+    do { AssertMsg(RTHEAPOFFSETBLOCK_IS_VALID_USED((pBlock)), ("%#x\n", (pBlock)->fFlags)); \
+         AssertMsg(RTHEAPOFF_GET_ANCHOR(pBlock) == (pHeapInt), ("%p != %p\n", RTHEAPOFF_GET_ANCHOR(pBlock), (pHeapInt))); \
+         ASSERT_GE(RTHEAPOFF_TO_OFF(pHeapInt, pBlock), sizeof(RTHEAPOFFSETINTERNAL)); \
+         ASSERT_L( RTHEAPOFF_TO_OFF(pHeapInt, pBlock), (pHeapInt)->cbHeap); \
+         ASSERT_NEXT(pHeapInt, pBlock); \
+         ASSERT_PREV(pHeapInt, pBlock); \
+    } while (0)
+
+#define ASSERT_FREE_PREV(pHeapInt, pBlock) \
+    do { ASSERT_ALIGN((pBlock)->offPrev); \
+         if ((pBlock)->offPrev) \
+         { \
+             ASSERT_GE((pBlock)->offPrev, (pHeapInt)->offFreeHead); \
+             ASSERT_L((pBlock)->offPrev, RTHEAPOFF_TO_OFF(pHeapInt, pBlock)); \
+             ASSERT_LE((pBlock)->offPrev, (pBlock)->Core.offPrev); \
+         } \
+         else \
+             Assert((pBlock) == RTHEAPOFF_TO_PTR(pHeapInt, (pHeapInt)->offFreeHead, PRTHEAPOFFSETFREE) ); \
+    } while (0)
+
+#define ASSERT_FREE_NEXT(pHeapInt, pBlock) \
+    do { ASSERT_ALIGN((pBlock)->offNext); \
+         if ((pBlock)->offNext) \
+         { \
+             ASSERT_LE((pBlock)->offNext, (pHeapInt)->offFreeTail); \
+             ASSERT_G((pBlock)->offNext, RTHEAPOFF_TO_OFF(pHeapInt, pBlock)); \
+             ASSERT_GE((pBlock)->offNext, (pBlock)->Core.offNext); \
+         } \
+         else \
+             Assert((pBlock) == RTHEAPOFF_TO_PTR(pHeapInt, (pHeapInt)->offFreeTail, PRTHEAPOFFSETFREE)); \
+    } while (0)
+
+#ifdef RTHEAPOFFSET_STRICT
+# define ASSERT_FREE_CB(pHeapInt, pBlock) \
+    do { size_t cbCalc = ((pBlock)->Core.offNext ? (pBlock)->Core.offNext : (pHeapInt)->cbHeap) \
+                       - RTHEAPOFF_TO_OFF((pHeapInt), (pBlock)) - sizeof(RTHEAPOFFSETBLOCK); \
+         AssertMsg((pBlock)->cb == cbCalc, ("cb=%#zx cbCalc=%#zx\n", (pBlock)->cb, cbCalc)); \
+    } while (0)
+#else
+# define ASSERT_FREE_CB(pHeapInt, pBlock) do {} while (0)
+#endif
+
+/** Asserts that a free block is valid. */
+#define ASSERT_BLOCK_FREE(pHeapInt, pBlock) \
+    do { ASSERT_BLOCK(pHeapInt, &(pBlock)->Core); \
+         Assert(RTHEAPOFFSETBLOCK_IS_VALID_FREE(&(pBlock)->Core)); \
+         ASSERT_GE(RTHEAPOFF_TO_OFF(pHeapInt, pBlock), (pHeapInt)->offFreeHead); \
+         ASSERT_LE(RTHEAPOFF_TO_OFF(pHeapInt, pBlock), (pHeapInt)->offFreeTail); \
+         ASSERT_FREE_NEXT(pHeapInt, pBlock); \
+         ASSERT_FREE_PREV(pHeapInt, pBlock); \
+         ASSERT_FREE_CB(pHeapInt, pBlock); \
+    } while (0)
+
+/** Asserts that the heap anchor block is ok. */
+#define ASSERT_ANCHOR(pHeapInt) \
+    do { AssertPtr(pHeapInt);\
+         Assert((pHeapInt)->u32Magic == RTHEAPOFFSET_MAGIC); \
+    } while (0)
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+#ifdef RTHEAPOFFSET_STRICT
+static void rtHeapOffsetAssertAll(PRTHEAPOFFSETINTERNAL pHeapInt);
+#endif
+static PRTHEAPOFFSETBLOCK rtHeapOffsetAllocBlock(PRTHEAPOFFSETINTERNAL pHeapInt, size_t cb, size_t uAlignment);
+static void rtHeapOffsetFreeBlock(PRTHEAPOFFSETINTERNAL pHeapInt, PRTHEAPOFFSETBLOCK pBlock);
+
+#ifdef RTHEAPOFFSET_STRICT
+
+/** Checked version of RTHEAPOFF_TO_PTR and RTHEAPOFF_TO_PTR_N. */
+static void *rtHeapOffCheckedOffToPtr(PRTHEAPOFFSETINTERNAL pHeapInt, uint32_t off, bool fNull)
+{
+    Assert(off || fNull);
+    if (!off)
+        return NULL;
+    AssertMsg(off < pHeapInt->cbHeap,   ("%#x %#x\n", off, pHeapInt->cbHeap));
+    AssertMsg(off >= sizeof(*pHeapInt), ("%#x %#x\n", off, sizeof(*pHeapInt)));
+    return (uint8_t *)pHeapInt + off;
+}
+
+/** Checked version of RTHEAPOFF_TO_OFF. */
+static uint32_t rtHeapOffCheckedPtrToOff(PRTHEAPOFFSETINTERNAL pHeapInt, void *pv)
+{
+    if (!pv)
+        return 0;
+    uintptr_t off = (uintptr_t)pv - (uintptr_t)pHeapInt;
+    AssertMsg(off < pHeapInt->cbHeap,   ("%#x %#x\n", off, pHeapInt->cbHeap));
+    AssertMsg(off >= sizeof(*pHeapInt), ("%#x %#x\n", off, sizeof(*pHeapInt)));
+    return (uint32_t)off;
+}
+
+#endif /* RTHEAPOFFSET_STRICT */
+
+
+
+RTDECL(int) RTHeapOffsetInit(PRTHEAPOFFSET phHeap, void *pvMemory, size_t cbMemory)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt;
+    PRTHEAPOFFSETFREE pFree;
+    unsigned i;
+
+    /*
+     * Validate input. The imposed minimum heap size is just a convenient value.
+     */
+    AssertReturn(cbMemory >= PAGE_SIZE, VERR_INVALID_PARAMETER);
+    AssertReturn(cbMemory < UINT32_MAX, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pvMemory, VERR_INVALID_POINTER);
+    AssertReturn((uintptr_t)pvMemory + (cbMemory - 1) > (uintptr_t)cbMemory, VERR_INVALID_PARAMETER);
+
+    /*
+     * Place the heap anchor block at the start of the heap memory,
+     * enforce 32 byte alignment of it. Also align the heap size correctly.
+     */
+    pHeapInt = (PRTHEAPOFFSETINTERNAL)pvMemory;
+    if ((uintptr_t)pvMemory & 31)
+    {
+        const uintptr_t off = 32 - ((uintptr_t)pvMemory & 31);
+        cbMemory -= off;
+        pHeapInt = (PRTHEAPOFFSETINTERNAL)((uintptr_t)pvMemory + off);
+    }
+    cbMemory &= ~(RTHEAPOFFSET_ALIGNMENT - 1);
+
+
+    /* Init the heap anchor block. */
+    pHeapInt->u32Magic = RTHEAPOFFSET_MAGIC;
+    pHeapInt->cbHeap = (uint32_t)cbMemory;
+    pHeapInt->cbFree = (uint32_t)cbMemory
+                     - sizeof(RTHEAPOFFSETBLOCK)
+                     - sizeof(RTHEAPOFFSETINTERNAL);
+    pHeapInt->offFreeTail = pHeapInt->offFreeHead = sizeof(*pHeapInt);
+    for (i = 0; i < RT_ELEMENTS(pHeapInt->au32Alignment); i++)
+        pHeapInt->au32Alignment[i] = UINT32_MAX;
+
+    /* Init the single free block. */
+    pFree = RTHEAPOFF_TO_PTR(pHeapInt, pHeapInt->offFreeHead, PRTHEAPOFFSETFREE);
+    pFree->Core.offNext = 0;
+    pFree->Core.offPrev = 0;
+    pFree->Core.offSelf = pHeapInt->offFreeHead;
+    pFree->Core.fFlags = RTHEAPOFFSETBLOCK_FLAGS_MAGIC | RTHEAPOFFSETBLOCK_FLAGS_FREE;
+    pFree->offNext = 0;
+    pFree->offPrev = 0;
+    pFree->cb = pHeapInt->cbFree;
+
+    *phHeap = pHeapInt;
+
+#ifdef RTHEAPOFFSET_STRICT
+    rtHeapOffsetAssertAll(pHeapInt);
+#endif
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetInit);
+
+
+RTDECL(void *) RTHeapOffsetAlloc(RTHEAPOFFSET hHeap, size_t cb, size_t cbAlignment)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt = hHeap;
+    PRTHEAPOFFSETBLOCK pBlock;
+
+    /*
+     * Validate and adjust the input.
+     */
+    AssertPtrReturn(pHeapInt, NULL);
+    if (cb < RTHEAPOFFSET_MIN_BLOCK)
+        cb = RTHEAPOFFSET_MIN_BLOCK;
+    else
+        cb = RT_ALIGN_Z(cb, RTHEAPOFFSET_ALIGNMENT);
+    if (!cbAlignment)
+        cbAlignment = RTHEAPOFFSET_ALIGNMENT;
+    else
+    {
+        Assert(!(cbAlignment & (cbAlignment - 1)));
+        Assert((cbAlignment & ~(cbAlignment - 1)) == cbAlignment);
+        if (cbAlignment < RTHEAPOFFSET_ALIGNMENT)
+            cbAlignment = RTHEAPOFFSET_ALIGNMENT;
+    }
+
+    /*
+     * Do the allocation.
+     */
+    pBlock = rtHeapOffsetAllocBlock(pHeapInt, cb, cbAlignment);
+    if (RT_LIKELY(pBlock))
+    {
+        void *pv = pBlock + 1;
+        return pv;
+    }
+    return NULL;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetAlloc);
+
+
+RTDECL(void *) RTHeapOffsetAllocZ(RTHEAPOFFSET hHeap, size_t cb, size_t cbAlignment)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt = hHeap;
+    PRTHEAPOFFSETBLOCK pBlock;
+
+    /*
+     * Validate and adjust the input.
+     */
+    AssertPtrReturn(pHeapInt, NULL);
+    if (cb < RTHEAPOFFSET_MIN_BLOCK)
+        cb = RTHEAPOFFSET_MIN_BLOCK;
+    else
+        cb = RT_ALIGN_Z(cb, RTHEAPOFFSET_ALIGNMENT);
+    if (!cbAlignment)
+        cbAlignment = RTHEAPOFFSET_ALIGNMENT;
+    else
+    {
+        Assert(!(cbAlignment & (cbAlignment - 1)));
+        Assert((cbAlignment & ~(cbAlignment - 1)) == cbAlignment);
+        if (cbAlignment < RTHEAPOFFSET_ALIGNMENT)
+            cbAlignment = RTHEAPOFFSET_ALIGNMENT;
+    }
+
+    /*
+     * Do the allocation.
+     */
+    pBlock = rtHeapOffsetAllocBlock(pHeapInt, cb, cbAlignment);
+    if (RT_LIKELY(pBlock))
+    {
+        void *pv = pBlock + 1;
+        memset(pv, 0, cb);
+        return pv;
+    }
+    return NULL;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetAllocZ);
+
+
+/**
+ * Allocates a block of memory from the specified heap.
+ *
+ * No parameter validation or adjustment is performed.
+ *
+ * @returns Pointer to the allocated block.
+ * @returns NULL on failure.
+ *
+ * @param   pHeapInt    The heap.
+ * @param   cb          Size of the memory block to allocate.
+ * @param   uAlignment  The alignment specifications for the allocated block.
+ */
+static PRTHEAPOFFSETBLOCK rtHeapOffsetAllocBlock(PRTHEAPOFFSETINTERNAL pHeapInt, size_t cb, size_t uAlignment)
+{
+    PRTHEAPOFFSETBLOCK  pRet = NULL;
+    PRTHEAPOFFSETFREE   pFree;
+
+    AssertReturn((pHeapInt)->u32Magic == RTHEAPOFFSET_MAGIC, NULL);
+#ifdef RTHEAPOFFSET_STRICT
+    rtHeapOffsetAssertAll(pHeapInt);
+#endif
+
+    /*
+     * Search for a fitting block from the lower end of the heap.
+     */
+    for (pFree = RTHEAPOFF_TO_PTR_N(pHeapInt, pHeapInt->offFreeHead, PRTHEAPOFFSETFREE);
+         pFree;
+         pFree = RTHEAPOFF_TO_PTR_N(pHeapInt, pFree->offNext, PRTHEAPOFFSETFREE))
+    {
+        uintptr_t offAlign;
+        ASSERT_BLOCK_FREE(pHeapInt, pFree);
+
+        /*
+         * Match for size and alignment.
+         */
+        if (pFree->cb < cb)
+            continue;
+        offAlign = (uintptr_t)(&pFree->Core + 1) & (uAlignment - 1);
+        if (offAlign)
+        {
+            PRTHEAPOFFSETFREE pPrev;
+
+            offAlign = (uintptr_t)(&pFree[1].Core + 1) & (uAlignment - 1);
+            offAlign = uAlignment - offAlign;
+            if (pFree->cb < cb + offAlign + sizeof(RTHEAPOFFSETFREE))
+                continue;
+
+            /*
+             * Split up the free block into two, so that the 2nd is aligned as
+             * per specification.
+             */
+            pPrev = pFree;
+            pFree = (PRTHEAPOFFSETFREE)((uintptr_t)(pFree + 1) + offAlign);
+            pFree->Core.offPrev = pPrev->Core.offSelf;
+            pFree->Core.offNext = pPrev->Core.offNext;
+            pFree->Core.offSelf = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+            pFree->Core.fFlags  = RTHEAPOFFSETBLOCK_FLAGS_MAGIC | RTHEAPOFFSETBLOCK_FLAGS_FREE;
+            pFree->offPrev      = pPrev->Core.offSelf;
+            pFree->offNext      = pPrev->offNext;
+            pFree->cb           = (pFree->Core.offNext ? pFree->Core.offNext : pHeapInt->cbHeap)
+                                - pFree->Core.offSelf - sizeof(RTHEAPOFFSETBLOCK);
+
+            pPrev->Core.offNext = pFree->Core.offSelf;
+            pPrev->offNext      = pFree->Core.offSelf;
+            pPrev->cb           = pFree->Core.offSelf - pPrev->Core.offSelf - sizeof(RTHEAPOFFSETBLOCK);
+
+            if (pFree->Core.offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->Core.offNext, PRTHEAPOFFSETBLOCK)->offPrev = pFree->Core.offSelf;
+            if (pFree->offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->Core.offNext, PRTHEAPOFFSETFREE)->offPrev = pFree->Core.offSelf;
+            else
+                pHeapInt->offFreeTail = pFree->Core.offSelf;
+
+            pHeapInt->cbFree -= sizeof(RTHEAPOFFSETBLOCK);
+            ASSERT_BLOCK_FREE(pHeapInt, pPrev);
+            ASSERT_BLOCK_FREE(pHeapInt, pFree);
+        }
+
+        /*
+         * Split off a new FREE block?
+         */
+        if (pFree->cb >= cb + RT_ALIGN_Z(sizeof(RTHEAPOFFSETFREE), RTHEAPOFFSET_ALIGNMENT))
+        {
+            /*
+             * Create a new FREE block at then end of this one.
+             */
+            PRTHEAPOFFSETFREE   pNew = (PRTHEAPOFFSETFREE)((uintptr_t)&pFree->Core + cb + sizeof(RTHEAPOFFSETBLOCK));
+
+            pNew->Core.offSelf = RTHEAPOFF_TO_OFF(pHeapInt, pNew);
+            pNew->Core.offNext = pFree->Core.offNext;
+            if (pFree->Core.offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->Core.offNext, PRTHEAPOFFSETBLOCK)->offPrev = pNew->Core.offSelf;
+            pNew->Core.offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+            pNew->Core.fFlags = RTHEAPOFFSETBLOCK_FLAGS_MAGIC | RTHEAPOFFSETBLOCK_FLAGS_FREE;
+
+            pNew->offNext = pFree->offNext;
+            if (pNew->offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pNew->offNext, PRTHEAPOFFSETFREE)->offPrev = pNew->Core.offSelf;
+            else
+                pHeapInt->offFreeTail = pNew->Core.offSelf;
+            pNew->offPrev = pFree->offPrev;
+            if (pNew->offPrev)
+                RTHEAPOFF_TO_PTR(pHeapInt, pNew->offPrev, PRTHEAPOFFSETFREE)->offNext = pNew->Core.offSelf;
+            else
+                pHeapInt->offFreeHead = pNew->Core.offSelf;
+            pNew->cb    = (pNew->Core.offNext ? pNew->Core.offNext : pHeapInt->cbHeap) \
+                        - pNew->Core.offSelf - sizeof(RTHEAPOFFSETBLOCK);
+            ASSERT_BLOCK_FREE(pHeapInt, pNew);
+
+            /*
+             * Adjust and convert the old FREE node into a USED node.
+             */
+            pFree->Core.fFlags &= ~RTHEAPOFFSETBLOCK_FLAGS_FREE;
+            pFree->Core.offNext = pNew->Core.offSelf;
+            pHeapInt->cbFree -= pFree->cb;
+            pHeapInt->cbFree += pNew->cb;
+            pRet = &pFree->Core;
+            ASSERT_BLOCK_USED(pHeapInt, pRet);
+        }
+        else
+        {
+            /*
+             * Link it out of the free list.
+             */
+            if (pFree->offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->offNext, PRTHEAPOFFSETFREE)->offPrev = pFree->offPrev;
+            else
+                pHeapInt->offFreeTail = pFree->offPrev;
+            if (pFree->offPrev)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->offPrev, PRTHEAPOFFSETFREE)->offNext = pFree->offNext;
+            else
+                pHeapInt->offFreeHead = pFree->offNext;
+
+            /*
+             * Convert it to a used block.
+             */
+            pHeapInt->cbFree -= pFree->cb;
+            pFree->Core.fFlags &= ~RTHEAPOFFSETBLOCK_FLAGS_FREE;
+            pRet = &pFree->Core;
+            ASSERT_BLOCK_USED(pHeapInt, pRet);
+        }
+        break;
+    }
+
+#ifdef RTHEAPOFFSET_STRICT
+    rtHeapOffsetAssertAll(pHeapInt);
+#endif
+    return pRet;
+}
+
+
+RTDECL(void) RTHeapOffsetFree(RTHEAPOFFSET hHeap, void *pv)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt;
+    PRTHEAPOFFSETBLOCK pBlock;
+
+    /*
+     * Validate input.
+     */
+    if (!pv)
+        return;
+    AssertPtr(pv);
+    Assert(RT_ALIGN_P(pv, RTHEAPOFFSET_ALIGNMENT) == pv);
+
+    /*
+     * Get the block and heap. If in strict mode, validate these.
+     */
+    pBlock = (PRTHEAPOFFSETBLOCK)pv - 1;
+    pHeapInt = RTHEAPOFF_GET_ANCHOR(pBlock);
+    ASSERT_BLOCK_USED(pHeapInt, pBlock);
+    ASSERT_ANCHOR(pHeapInt);
+    Assert(pHeapInt == (PRTHEAPOFFSETINTERNAL)hHeap || !hHeap); RT_NOREF_PV(hHeap);
+
+#ifdef RTHEAPOFFSET_FREE_POISON
+    /*
+     * Poison the block.
+     */
+    const size_t cbBlock = (pBlock->pNext ? (uintptr_t)pBlock->pNext : (uintptr_t)pHeapInt->pvEnd)
+                         - (uintptr_t)pBlock - sizeof(RTHEAPOFFSETBLOCK);
+    memset(pBlock + 1, RTHEAPOFFSET_FREE_POISON, cbBlock);
+#endif
+
+    /*
+     * Call worker which does the actual job.
+     */
+    rtHeapOffsetFreeBlock(pHeapInt, pBlock);
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetFree);
+
+
+/**
+ * Free a memory block.
+ *
+ * @param   pHeapInt       The heap.
+ * @param   pBlock         The memory block to free.
+ */
+static void rtHeapOffsetFreeBlock(PRTHEAPOFFSETINTERNAL pHeapInt, PRTHEAPOFFSETBLOCK pBlock)
+{
+    PRTHEAPOFFSETFREE   pFree = (PRTHEAPOFFSETFREE)pBlock;
+    PRTHEAPOFFSETFREE   pLeft;
+    PRTHEAPOFFSETFREE   pRight;
+
+#ifdef RTHEAPOFFSET_STRICT
+    rtHeapOffsetAssertAll(pHeapInt);
+#endif
+
+    /*
+     * Look for the closest free list blocks by walking the blocks right
+     * of us (both lists are sorted by address).
+     */
+    pLeft = NULL;
+    pRight = NULL;
+    if (pHeapInt->offFreeTail)
+    {
+        pRight = RTHEAPOFF_TO_PTR_N(pHeapInt, pFree->Core.offNext, PRTHEAPOFFSETFREE);
+        while (pRight && !RTHEAPOFFSETBLOCK_IS_FREE(&pRight->Core))
+        {
+            ASSERT_BLOCK(pHeapInt, &pRight->Core);
+            pRight = RTHEAPOFF_TO_PTR_N(pHeapInt, pRight->Core.offNext, PRTHEAPOFFSETFREE);
+        }
+        if (!pRight)
+            pLeft = RTHEAPOFF_TO_PTR_N(pHeapInt, pHeapInt->offFreeTail, PRTHEAPOFFSETFREE);
+        else
+        {
+            ASSERT_BLOCK_FREE(pHeapInt, pRight);
+            pLeft = RTHEAPOFF_TO_PTR_N(pHeapInt, pRight->offPrev, PRTHEAPOFFSETFREE);
+        }
+        if (pLeft)
+            ASSERT_BLOCK_FREE(pHeapInt, pLeft);
+    }
+    AssertMsgReturnVoid(pLeft != pFree, ("Freed twice! pv=%p (pBlock=%p)\n", pBlock + 1, pBlock));
+    ASSERT_L(RTHEAPOFF_TO_OFF(pHeapInt, pLeft), RTHEAPOFF_TO_OFF(pHeapInt, pFree));
+    Assert(!pRight || (uintptr_t)pRight > (uintptr_t)pFree);
+    Assert(!pLeft || RTHEAPOFF_TO_PTR_N(pHeapInt, pLeft->offNext, PRTHEAPOFFSETFREE) == pRight);
+
+    /*
+     * Insert at the head of the free block list?
+     */
+    if (!pLeft)
+    {
+        Assert(pRight == RTHEAPOFF_TO_PTR_N(pHeapInt, pHeapInt->offFreeHead, PRTHEAPOFFSETFREE));
+        pFree->Core.fFlags |= RTHEAPOFFSETBLOCK_FLAGS_FREE;
+        pFree->offPrev = 0;
+        pFree->offNext = RTHEAPOFF_TO_OFF(pHeapInt, pRight);
+        if (pRight)
+            pRight->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+        else
+            pHeapInt->offFreeTail = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+        pHeapInt->offFreeHead = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+    }
+    else
+    {
+        /*
+         * Can we merge with left hand free block?
+         */
+        if (pLeft->Core.offNext == RTHEAPOFF_TO_OFF(pHeapInt, pFree))
+        {
+            pLeft->Core.offNext = pFree->Core.offNext;
+            if (pFree->Core.offNext)
+                RTHEAPOFF_TO_PTR(pHeapInt, pFree->Core.offNext, PRTHEAPOFFSETBLOCK)->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pLeft);
+            pHeapInt->cbFree -= pLeft->cb;
+            pFree = pLeft;
+        }
+        /*
+         * No, just link it into the free list then.
+         */
+        else
+        {
+            pFree->Core.fFlags |= RTHEAPOFFSETBLOCK_FLAGS_FREE;
+            pFree->offNext = RTHEAPOFF_TO_OFF(pHeapInt, pRight);
+            pFree->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pLeft);
+            pLeft->offNext = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+            if (pRight)
+                pRight->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+            else
+                pHeapInt->offFreeTail = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+        }
+    }
+
+    /*
+     * Can we merge with right hand free block?
+     */
+    if (    pRight
+        &&  pRight->Core.offPrev == RTHEAPOFF_TO_OFF(pHeapInt, pFree))
+    {
+        /* core */
+        pFree->Core.offNext = pRight->Core.offNext;
+        if (pRight->Core.offNext)
+            RTHEAPOFF_TO_PTR(pHeapInt, pRight->Core.offNext, PRTHEAPOFFSETBLOCK)->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+
+        /* free */
+        pFree->offNext = pRight->offNext;
+        if (pRight->offNext)
+            RTHEAPOFF_TO_PTR(pHeapInt, pRight->offNext, PRTHEAPOFFSETFREE)->offPrev = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+        else
+            pHeapInt->offFreeTail = RTHEAPOFF_TO_OFF(pHeapInt, pFree);
+        pHeapInt->cbFree -= pRight->cb;
+    }
+
+    /*
+     * Calculate the size and update free stats.
+     */
+    pFree->cb = (pFree->Core.offNext ? pFree->Core.offNext : pHeapInt->cbHeap)
+              - RTHEAPOFF_TO_OFF(pHeapInt, pFree) - sizeof(RTHEAPOFFSETBLOCK);
+    pHeapInt->cbFree += pFree->cb;
+    ASSERT_BLOCK_FREE(pHeapInt, pFree);
+
+#ifdef RTHEAPOFFSET_STRICT
+    rtHeapOffsetAssertAll(pHeapInt);
+#endif
+}
+
+
+#ifdef RTHEAPOFFSET_STRICT
+/**
+ * Internal consistency check (relying on assertions).
+ * @param   pHeapInt
+ */
+static void rtHeapOffsetAssertAll(PRTHEAPOFFSETINTERNAL pHeapInt)
+{
+    PRTHEAPOFFSETFREE pPrev = NULL;
+    PRTHEAPOFFSETFREE pPrevFree = NULL;
+    PRTHEAPOFFSETFREE pBlock;
+    for (pBlock = (PRTHEAPOFFSETFREE)(pHeapInt + 1);
+         pBlock;
+         pBlock = RTHEAPOFF_TO_PTR_N(pHeapInt, pBlock->Core.offNext, PRTHEAPOFFSETFREE))
+    {
+        if (RTHEAPOFFSETBLOCK_IS_FREE(&pBlock->Core))
+        {
+            ASSERT_BLOCK_FREE(pHeapInt, pBlock);
+            Assert(pBlock->offPrev == RTHEAPOFF_TO_OFF(pHeapInt, pPrevFree));
+            Assert(pPrevFree || pHeapInt->offFreeHead == RTHEAPOFF_TO_OFF(pHeapInt, pBlock));
+            pPrevFree = pBlock;
+        }
+        else
+            ASSERT_BLOCK_USED(pHeapInt, &pBlock->Core);
+        Assert(!pPrev || RTHEAPOFF_TO_OFF(pHeapInt, pPrev) == pBlock->Core.offPrev);
+        pPrev = pBlock;
+    }
+    Assert(pHeapInt->offFreeTail == RTHEAPOFF_TO_OFF(pHeapInt, pPrevFree));
+}
+#endif
+
+
+RTDECL(size_t) RTHeapOffsetSize(RTHEAPOFFSET hHeap, void *pv)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt;
+    PRTHEAPOFFSETBLOCK pBlock;
+    size_t cbBlock;
+
+    /*
+     * Validate input.
+     */
+    if (!pv)
+        return 0;
+    AssertPtrReturn(pv, 0);
+    AssertReturn(RT_ALIGN_P(pv, RTHEAPOFFSET_ALIGNMENT) == pv, 0);
+
+    /*
+     * Get the block and heap. If in strict mode, validate these.
+     */
+    pBlock = (PRTHEAPOFFSETBLOCK)pv - 1;
+    pHeapInt = RTHEAPOFF_GET_ANCHOR(pBlock);
+    ASSERT_BLOCK_USED(pHeapInt, pBlock);
+    ASSERT_ANCHOR(pHeapInt);
+    Assert(pHeapInt == (PRTHEAPOFFSETINTERNAL)hHeap || !hHeap); RT_NOREF_PV(hHeap);
+
+    /*
+     * Calculate the block size.
+     */
+    cbBlock = (pBlock->offNext ? pBlock->offNext : pHeapInt->cbHeap)
+            - RTHEAPOFF_TO_OFF(pHeapInt, pBlock) - sizeof(RTHEAPOFFSETBLOCK);
+    return cbBlock;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetSize);
+
+
+RTDECL(size_t) RTHeapOffsetGetHeapSize(RTHEAPOFFSET hHeap)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt;
+
+    if (hHeap == NIL_RTHEAPOFFSET)
+        return 0;
+
+    pHeapInt = hHeap;
+    AssertPtrReturn(pHeapInt, 0);
+    ASSERT_ANCHOR(pHeapInt);
+    return pHeapInt->cbHeap;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetGetHeapSize);
+
+
+RTDECL(size_t) RTHeapOffsetGetFreeSize(RTHEAPOFFSET hHeap)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt;
+
+    if (hHeap == NIL_RTHEAPOFFSET)
+        return 0;
+
+    pHeapInt = hHeap;
+    AssertPtrReturn(pHeapInt, 0);
+    ASSERT_ANCHOR(pHeapInt);
+    return pHeapInt->cbFree;
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetGetFreeSize);
+
+
+RTDECL(void) RTHeapOffsetDump(RTHEAPOFFSET hHeap, PFNRTHEAPOFFSETPRINTF pfnPrintf)
+{
+    PRTHEAPOFFSETINTERNAL pHeapInt = (PRTHEAPOFFSETINTERNAL)hHeap;
+    PRTHEAPOFFSETFREE pBlock;
+
+    pfnPrintf("**** Dumping Heap %p - cbHeap=%x cbFree=%x ****\n",
+              hHeap, pHeapInt->cbHeap, pHeapInt->cbFree);
+
+    for (pBlock = (PRTHEAPOFFSETFREE)(pHeapInt + 1);
+         pBlock;
+         pBlock = RTHEAPOFF_TO_PTR_N(pHeapInt, pBlock->Core.offNext, PRTHEAPOFFSETFREE))
+    {
+        size_t cb = (pBlock->offNext ? pBlock->Core.offNext : pHeapInt->cbHeap)
+                  - RTHEAPOFF_TO_OFF(pHeapInt, pBlock) - sizeof(RTHEAPOFFSETBLOCK);
+        if (RTHEAPOFFSETBLOCK_IS_FREE(&pBlock->Core))
+            pfnPrintf("%p  %06x FREE offNext=%06x offPrev=%06x fFlags=%#x cb=%#06x : cb=%#06x offNext=%06x offPrev=%06x\n",
+                      pBlock, pBlock->Core.offSelf, pBlock->Core.offNext, pBlock->Core.offPrev, pBlock->Core.fFlags, cb,
+                      pBlock->cb, pBlock->offNext, pBlock->offPrev);
+        else
+            pfnPrintf("%p  %06x USED offNext=%06x offPrev=%06x fFlags=%#x cb=%#06x\n",
+                      pBlock, pBlock->Core.offSelf, pBlock->Core.offNext, pBlock->Core.offPrev, pBlock->Core.fFlags, cb);
+    }
+    pfnPrintf("**** Done dumping Heap %p ****\n", hHeap);
+}
+RT_EXPORT_SYMBOL(RTHeapOffsetDump);
+