2004-08-24 Steven G. Johnson <stevenj@alum.mit.edu>

	* mingwex/mingw-aligned-malloc.c: New file.
	* mingwex/tst-aligned-malloc.c: New file.

2 files changed, 210 insertions, 0 deletions

diff --git a/winsup/mingw/mingwex/mingw-aligned-malloc.c b/winsup/mingw/mingwex/mingw-aligned-malloc.c
new file mode 100755
index 000000000..a6d4ac934
--- /dev/null
+++ b/winsup/mingw/mingwex/mingw-aligned-malloc.c
@@ -0,0 +1,120 @@
+/*
+  __mingw_aligned_malloc and friends, implemented using Microsoft's public
+  interfaces and with the help of the algorithm description provided
+  by Wu Yongwei: http://sourceforge.net/mailarchive/message.php?msg_id=3847075
+
+  I hereby place this implementation in the public domain.
+               -- Steven G. Johnson (stevenj@alum.mit.edu)
+*/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <stddef.h>		/* ptrdiff_t */
+#include <string.h>		/* memmove */
+
+#ifdef HAVE_STDINT_H
+#  include <stdint.h>		/* uintptr_t */
+#else
+#  define uintptr_t size_t
+#endif
+
+#define NOT_POWER_OF_TWO(n) (((n) & ((n) - 1)))
+#define UI(p) ((uintptr_t) (p))
+#define CP(p) ((char *) p)
+
+#define PTR_ALIGN(p0, alignment, offset)				\
+            ((void *) (((UI(p0) + (alignment + sizeof(void*)) + offset)	\
+			& (~UI(alignment - 1)))				\
+		       - offset))
+
+/* Pointer must sometimes be aligned; assume sizeof(void*) is a power of two. */
+#define ORIG_PTR(p) (*(((void **) (UI(p) & (~UI(sizeof(void*) - 1)))) - 1))
+
+void *
+__mingw_aligned_offset_malloc (size_t size, size_t alignment, size_t offset)
+{
+  void *p0, *p;
+
+  if (NOT_POWER_OF_TWO (alignment))
+    {
+      errno = EINVAL;
+      return ((void *) 0);
+    }
+  if (size == 0)
+    return ((void *) 0);
+  if (alignment < sizeof (void *))
+    alignment = sizeof (void *);
+
+  /* Including the extra sizeof(void*) is overkill on a 32-bit
+     machine, since malloc is already 8-byte aligned, as long
+     as we enforce alignment >= 8 ...but oh well.  */
+
+  p0 = malloc (size + (alignment + sizeof (void *)));
+  if (!p0)
+    return ((void *) 0);
+  p = PTR_ALIGN (p0, alignment, offset);
+  ORIG_PTR (p) = p0;
+  return p;
+}
+
+void *
+__mingw_aligned_malloc (size_t size, size_t alignment)
+{
+  return __mingw_aligned_offset_malloc (size, alignment, 0);
+}
+
+void
+__mingw_aligned_free (void *memblock)
+{
+  if (memblock)
+    free (ORIG_PTR (memblock));
+}
+
+void *
+__mingw_aligned_offset_realloc (void *memblock, size_t size,
+				size_t alignment, size_t offset)
+{
+  void *p0, *p;
+  ptrdiff_t shift;
+
+  if (!memblock)
+    return __mingw_aligned_offset_malloc (size, alignment, offset);
+  if (NOT_POWER_OF_TWO (alignment))
+    goto bad;
+  if (size == 0)
+    {
+      __mingw_aligned_free (memblock);
+      return ((void *) 0);
+    }
+  if (alignment < sizeof (void *))
+    alignment = sizeof (void *);
+
+  p0 = ORIG_PTR (memblock);
+  /* It is an error for the alignment to change. */
+  if (memblock != PTR_ALIGN (p0, alignment, offset))
+    goto bad;
+  shift = CP (memblock) - CP (p0);
+
+  p0 = realloc (p0, size + (alignment + sizeof (void *)));
+  if (!p0)
+    return ((void *) 0);
+  p = PTR_ALIGN (p0, alignment, offset);
+
+  /* Relative shift of actual data may be different from before, ugh.  */
+  if (shift != CP (p) - CP (p0))
+    /* ugh, moves more than necessary if size is increased.  */
+    memmove (CP (p), CP (p0) + shift, size);
+
+  ORIG_PTR (p) = p0;
+  return p;
+
+bad:
+  errno = EINVAL;
+  return ((void *) 0);
+}
+
+void *
+__mingw_aligned_realloc (void *memblock, size_t size, size_t alignment)
+{
+  return __mingw_aligned_offset_realloc (memblock, size, alignment, 0);
+}
diff --git a/winsup/mingw/mingwex/tst-aligned-malloc.c b/winsup/mingw/mingwex/tst-aligned-malloc.c
new file mode 100755
index 000000000..43ee734bc
--- /dev/null
+++ b/winsup/mingw/mingwex/tst-aligned-malloc.c
@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <errno.h>
+#include <malloc.h>
+
+#ifdef HAVE_STDINT_H
+#  include <stdint.h>		/* uintptr_t */
+#else
+#  define uintptr_t size_t
+#endif
+
+#define NELEM(a) (sizeof(a) / sizeof(a[0]))
+
+static int
+is_aligned (void *p, size_t alignment, size_t offset)
+{
+  return !((((uintptr_t) p) + offset) & (alignment - 1));
+}
+
+#define MAX_SIZE (1 << sizeof(unsigned char))
+#define NP 1000
+#define NTST 100000U
+
+#define ERRMSG fprintf(stderr, "Iteration %u, align = %u, offset = %u, size = %u (oldsize = %u), errno = %d (%s)\n", i, align[j % NELEM(align)], offset[j % NELEM(offset)], size[j], oldsize, errno, strerror(errno))
+
+int
+main (void)
+{
+  unsigned char *p[NP];
+  size_t size[NP];
+  size_t align[] = { 2, 4, 8, 16, 32, 64 };
+  size_t offset[20];
+  unsigned i;
+
+  srand (time (NULL));
+
+  for (i = 0; i < NELEM (p); ++i)
+    {
+      p[i] = 0;
+      size[i] = 0;
+    }
+
+  for (i = 0; i < NELEM (offset); ++i)
+    offset[i] = rand () % 512;
+
+  for (i = 0; i < NTST; ++i)
+    {
+      size_t oldsize;
+      unsigned j, k;
+      j = rand () % NELEM (p);
+      oldsize = size[j];
+      p[j] = __mingw_aligned_offset_realloc (p[j],
+					     size[j] = rand () % MAX_SIZE,
+					     align[j % NELEM (align)],
+					     offset[j % NELEM (offset)]);
+
+      if (size[j] && !p[j])
+	{
+	  fprintf (stderr, "Returned NULL!\n");
+	  ERRMSG;
+	  return EXIT_FAILURE;
+	}
+      if (size[j] && !is_aligned (p[j],
+				  align[j % NELEM (align)],
+				  offset[j % NELEM (offset)]))
+	{
+	  fprintf (stderr, "Misaligned block!\n");
+	  ERRMSG;
+	  return EXIT_FAILURE;
+	}
+      if (oldsize > size[j])
+	oldsize = size[j];
+      for (k = 0; k < oldsize; ++k)
+	if (p[j][k] != k)
+	  {
+	    fprintf (stderr, "Miscopied block!\n");
+	    ERRMSG;
+	    return EXIT_FAILURE;
+	  }
+      for (k = 0; k < size[j]; ++k)
+	p[j][k] = k;
+    }
+
+  for (i = 0; i < NELEM (p); ++i)
+    __mingw_aligned_free (p[i]);
+
+  return EXIT_SUCCESS;
+}