68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
/* Variable-sized buffer with on-stack default allocation.
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Copyright (C) 2015-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _LIBC
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# include <libc-config.h>
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#endif
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#include <scratch_buffer.h>
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#include <errno.h>
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#include <string.h>
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bool
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__libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer)
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{
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size_t new_length = 2 * buffer->length;
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void *new_ptr;
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if (buffer->data == buffer->__space.__c)
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{
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/* Move buffer to the heap. No overflow is possible because
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buffer->length describes a small buffer on the stack. */
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new_ptr = malloc (new_length);
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if (new_ptr == NULL)
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return false;
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memcpy (new_ptr, buffer->__space.__c, buffer->length);
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}
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else
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{
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/* Buffer was already on the heap. Check for overflow. */
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if (__glibc_likely (new_length >= buffer->length))
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new_ptr = realloc (buffer->data, new_length);
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else
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{
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__set_errno (ENOMEM);
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new_ptr = NULL;
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}
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if (__glibc_unlikely (new_ptr == NULL))
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{
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/* Deallocate, but buffer must remain valid to free. */
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free (buffer->data);
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scratch_buffer_init (buffer);
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return false;
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}
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}
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/* Install new heap-based buffer. */
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buffer->data = new_ptr;
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buffer->length = new_length;
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return true;
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}
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libc_hidden_def (__libc_scratch_buffer_grow_preserve)
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