934df19c52
Some libc calls like memcpy() expect the pointer to be valid even when the size is zero and there is nothing to do. Instead of checking the size before all such calls, modify ARR_GetElements() to return a pointer to the array instance itself if data was not allocated yet.
135 lines
3 KiB
C
135 lines
3 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2014
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* 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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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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Functions implementing an array with automatic memory allocation.
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*/
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#include "config.h"
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#include "sysincl.h"
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#include "array.h"
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#include "memory.h"
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struct ARR_Instance_Record {
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void *data;
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unsigned int elem_size;
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unsigned int used;
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unsigned int allocated;
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};
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ARR_Instance
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ARR_CreateInstance(unsigned int elem_size)
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{
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ARR_Instance array;
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assert(elem_size > 0);
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array = MallocNew(struct ARR_Instance_Record);
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array->data = NULL;
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array->elem_size = elem_size;
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array->used = 0;
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array->allocated = 0;
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return array;
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}
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void
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ARR_DestroyInstance(ARR_Instance array)
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{
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Free(array->data);
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Free(array);
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}
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static void
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realloc_array(ARR_Instance array, unsigned int min_size)
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{
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size_t data_size;
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assert(min_size <= 2 * min_size);
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if (array->allocated >= min_size && array->allocated <= 2 * min_size)
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return;
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if (array->allocated < min_size) {
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while (array->allocated < min_size)
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array->allocated = array->allocated ? 2 * array->allocated : 1;
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} else {
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array->allocated = min_size;
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}
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data_size = (size_t)array->elem_size * array->allocated;
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assert(data_size / array->elem_size == array->allocated);
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array->data = Realloc(array->data, data_size);
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}
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void *
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ARR_GetNewElement(ARR_Instance array)
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{
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array->used++;
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realloc_array(array, array->used);
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return ARR_GetElement(array, array->used - 1);
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}
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void *
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ARR_GetElement(ARR_Instance array, unsigned int index)
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{
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assert(index < array->used);
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return (void *)((char *)array->data + (size_t)index * array->elem_size);
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}
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void *
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ARR_GetElements(ARR_Instance array)
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{
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/* Return a non-NULL pointer when the array has zero size */
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if (!array->data) {
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assert(!array->used);
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return array;
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}
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return array->data;
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}
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void
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ARR_AppendElement(ARR_Instance array, void *element)
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{
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void *e;
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e = ARR_GetNewElement(array);
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memcpy(e, element, array->elem_size);
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}
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void
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ARR_SetSize(ARR_Instance array, unsigned int size)
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{
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realloc_array(array, size);
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array->used = size;
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}
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unsigned int
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ARR_GetSize(ARR_Instance array)
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{
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return array->used;
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}
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