37 lines
1.6 KiB
C
37 lines
1.6 KiB
C
// SPDX-License-Identifier: LGPL-2.1+
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#ifndef __NM_STD_UTILS_H__
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#define __NM_STD_UTILS_H__
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#include <stdbool.h>
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#include "nm-std-aux.h"
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/*****************************************************************************/
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/* nm_utils_get_next_realloc_size() is used to grow buffers exponentially, when
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* the final size is unknown. As such, it has borders for which it allocates
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* certain buffer sizes.
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*
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* The use of these defines is to get favorable allocation sequences.
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* For example, nm_str_buf_init() asks for an initial allocation size. Note that
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* it reserves the exactly requested amount, under the assumption that the
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* user may know how many bytes will be required. However, often the caller
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* doesn't know in advance, and NMStrBuf grows exponentially by calling
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* nm_utils_get_next_realloc_size().
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* Imagine you call nm_str_buf_init() with an initial buffer size 100, and you
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* add one character at a time. Then the first reallocation will increase the
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* buffer size only from 100 to 104.
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* If you however start with an initial buffer size of 104, then the next reallocation
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* via nm_utils_get_next_realloc_size() gives you 232, and so on. By using
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* these sizes, it results in one less allocation, if you anyway don't know the
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* exact size in advance. */
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#define NM_UTILS_GET_NEXT_REALLOC_SIZE_32 ((size_t) 32)
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#define NM_UTILS_GET_NEXT_REALLOC_SIZE_40 ((size_t) 40)
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#define NM_UTILS_GET_NEXT_REALLOC_SIZE_104 ((size_t) 104)
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#define NM_UTILS_GET_NEXT_REALLOC_SIZE_1000 ((size_t) 1000)
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size_t nm_utils_get_next_realloc_size (bool true_realloc, size_t requested);
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#endif /* __NM_STD_UTILS_H__ */
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