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Diffstat (limited to 'include/scratch_buffer.h')
| -rw-r--r-- | include/scratch_buffer.h | 136 |
1 files changed, 0 insertions, 136 deletions
diff --git a/include/scratch_buffer.h b/include/scratch_buffer.h deleted file mode 100644 index dd17a4a7e1..0000000000 --- a/include/scratch_buffer.h +++ /dev/null @@ -1,136 +0,0 @@ -/* Variable-sized buffer with on-stack default allocation. - Copyright (C) 2015-2017 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 - <http://www.gnu.org/licenses/>. */ - -#ifndef _SCRATCH_BUFFER_H -#define _SCRATCH_BUFFER_H - -/* Scratch buffers with a default stack allocation and fallback to - heap allocation. It is expected that this function is used in this - way: - - struct scratch_buffer tmpbuf; - scratch_buffer_init (&tmpbuf); - - while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) - if (!scratch_buffer_grow (&tmpbuf)) - return -1; - - scratch_buffer_free (&tmpbuf); - return 0; - - The allocation functions (scratch_buffer_grow, - scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make - sure that the heap allocation, if any, is freed, so that the code - above does not have a memory leak. The buffer still remains in a - state that can be deallocated using scratch_buffer_free, so a loop - like this is valid as well: - - struct scratch_buffer tmpbuf; - scratch_buffer_init (&tmpbuf); - - while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) - if (!scratch_buffer_grow (&tmpbuf)) - break; - - scratch_buffer_free (&tmpbuf); - - scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed - to grow the buffer by at least 512 bytes. This means that when - using the scratch buffer as a backing store for a non-character - array whose element size, in bytes, is 512 or smaller, the scratch - buffer only has to grow once to make room for at least one more - element. -*/ - -#include <stdbool.h> -#include <stddef.h> -#include <stdlib.h> - -/* Scratch buffer. Must be initialized with scratch_buffer_init - before its use. */ -struct scratch_buffer { - void *data; /* Pointer to the beginning of the scratch area. */ - size_t length; /* Allocated space at the data pointer, in bytes. */ - char __space[1024] - __attribute__ ((aligned (__alignof__ (max_align_t)))); -}; - -/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space - and BUFFER->length reflects the available space. */ -static inline void -scratch_buffer_init (struct scratch_buffer *buffer) -{ - buffer->data = buffer->__space; - buffer->length = sizeof (buffer->__space); -} - -/* Deallocates *BUFFER (if it was heap-allocated). */ -static inline void -scratch_buffer_free (struct scratch_buffer *buffer) -{ - if (buffer->data != buffer->__space) - free (buffer->data); -} - -/* Grow *BUFFER by some arbitrary amount. The buffer contents is NOT - preserved. Return true on success, false on allocation failure (in - which case the old buffer is freed). On success, the new buffer is - larger than the previous size. On failure, *BUFFER is deallocated, - but remains in a free-able state, and errno is set. */ -bool __libc_scratch_buffer_grow (struct scratch_buffer *buffer); -libc_hidden_proto (__libc_scratch_buffer_grow) - -/* Alias for __libc_scratch_buffer_grow. */ -static __always_inline bool -scratch_buffer_grow (struct scratch_buffer *buffer) -{ - return __glibc_likely (__libc_scratch_buffer_grow (buffer)); -} - -/* Like __libc_scratch_buffer_grow, but preserve the old buffer - contents on success, as a prefix of the new buffer. */ -bool __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer); -libc_hidden_proto (__libc_scratch_buffer_grow_preserve) - -/* Alias for __libc_scratch_buffer_grow_preserve. */ -static __always_inline bool -scratch_buffer_grow_preserve (struct scratch_buffer *buffer) -{ - return __glibc_likely (__libc_scratch_buffer_grow_preserve (buffer)); -} - -/* Grow *BUFFER so that it can store at least NELEM elements of SIZE - bytes. The buffer contents are NOT preserved. Both NELEM and SIZE - can be zero. Return true on success, false on allocation failure - (in which case the old buffer is freed, but *BUFFER remains in a - free-able state, and errno is set). It is unspecified whether this - function can reduce the array size. */ -bool __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, - size_t nelem, size_t size); -libc_hidden_proto (__libc_scratch_buffer_set_array_size) - -/* Alias for __libc_scratch_set_array_size. */ -static __always_inline bool -scratch_buffer_set_array_size (struct scratch_buffer *buffer, - size_t nelem, size_t size) -{ - return __glibc_likely (__libc_scratch_buffer_set_array_size - (buffer, nelem, size)); -} - -#endif /* _SCRATCH_BUFFER_H */ |