61 lines
1.9 KiB
C
61 lines
1.9 KiB
C
/* Variable-sized buffer with on-stack default allocation.
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Copyright (C) 2015-2016 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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<http://www.gnu.org/licenses/>. */
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#include <scratch_buffer.h>
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#include <errno.h>
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#include <limits.h>
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bool
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__libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer,
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size_t nelem, size_t size)
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{
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size_t new_length = nelem * size;
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/* Avoid overflow check if both values are small. */
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if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0
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&& nelem != 0 && size != new_length / nelem)
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{
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/* Overflow. Discard the old buffer, but it must remain valid
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to free. */
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scratch_buffer_free (buffer);
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scratch_buffer_init (buffer);
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__set_errno (ENOMEM);
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return false;
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}
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if (new_length <= buffer->length)
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return true;
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/* Discard old buffer. */
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scratch_buffer_free (buffer);
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char *new_ptr = malloc (new_length);
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if (new_ptr == NULL)
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{
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/* Buffer must remain valid to free. */
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scratch_buffer_init (buffer);
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return false;
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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_set_array_size);
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