dynarray: new module

* config/srclist.txt: Mention the new files.
* lib/cdefs.h (__attribute_maybe_unused__): New macro,
like Gnulib’s _GL_ATTRIBUTE_MAYBE_UNUSED but with glibc
naming conventions.
* lib/libc-config.h: Use it instead of __glibc_likely.
* lib/dynarray.h, modules/dynarray: New files.
* lib/malloc/dynarray-skeleton.c, lib/malloc/dynarray.h:
* lib/malloc/dynarray_at_failure.c:
* lib/malloc/dynarray_emplace_enlarge.c:
* lib/malloc/dynarray_finalize.c, lib/malloc/dynarray_resize.c:
* lib/malloc/dynarray_resize_clear.c, modules/dynarray:
New files, from glibc with the following changes needed for
portability to compilers that are not recent-enough GCC.
* lib/malloc/dynarray_at_failure.c: Include stdlib.h, for abort.
(__libc_dynarray_at_failure) [!_LIBC]: Simply abort.
* lib/malloc/dynarray_emplace_enlarge.c:
* lib/malloc/dynarray_resize.c:
Include intprops.h, and use INT_MULTIPLY_WRAPV instead
of __builtin_mul_overflow.
* lib/malloc/dynarray.h (__libc_dynarray_at_failure):
Use _Noreturn instead of __attribute__ ((noreturn)).
* lib/malloc/dynarray_resize_clear.c: Do not include stdlib.h;
it’s not needed.
(__libc_dynarray_resize_clear): Do not do arithmetic on void *.
* lib/malloc/dynarray-skeleton.c (struct DYNARRAY_STRUCT):
Do not use anonymous unions, as they are not in C99. All uses changed.
Use __nonnull (X) instead of __attribute__ ((nonnull X)),
and __attribute_maybe_unused__ instead of __attribute__ ((unused)).

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/malloc/dynarray_finalize.c b/lib/malloc/dynarray_finalize.c
new file mode 100644
index 0000000000..8ec6ad2bcc
--- /dev/null
+++ b/lib/malloc/dynarray_finalize.c
@@ -0,0 +1,62 @@
+/* Copy the dynamically-allocated area to an explicitly-sized heap allocation.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C 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.
+
+   The GNU C 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.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool
+__libc_dynarray_finalize (struct dynarray_header *list,
+                          void *scratch, size_t element_size,
+                          struct dynarray_finalize_result *result)
+{
+  if (__dynarray_error (list))
+    /* The caller will reported the deferred error.  */
+    return false;
+
+  size_t used = list->used;
+
+  /* Empty list.  */
+  if (used == 0)
+    {
+      /* An empty list could still be backed by a heap-allocated
+         array.  Free it if necessary.  */
+      if (list->array != scratch)
+        free (list->array);
+      *result = (struct dynarray_finalize_result) { NULL, 0 };
+      return true;
+    }
+
+  size_t allocation_size = used * element_size;
+  void *heap_array = malloc (allocation_size);
+  if (heap_array != NULL)
+    {
+      /* The new array takes ownership of the strings.  */
+      if (list->array != NULL)
+        memcpy (heap_array, list->array, allocation_size);
+      if (list->array != scratch)
+        free (list->array);
+      *result = (struct dynarray_finalize_result)
+        { .array = heap_array, .length = used };
+      return true;
+    }
+  else
+    /* The caller will perform the freeing operation.  */
+    return false;
+}
+libc_hidden_def (__libc_dynarray_finalize)