/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2.0, as published by the Free Software Foundation. This program is also distributed with certain software (including but not limited to OpenSSL) that is licensed under separate terms, as designated in a particular file or component or in included license documentation. The authors of MySQL hereby grant you an additional permission to link the program and your derivative works with the separately licensed software that they have included with MySQL. Without limiting anything contained in the foregoing, this file, which is part of C Driver for MySQL (Connector/C), is also subject to the Universal FOSS Exception, version 1.0, a copy of which can be found at http://oss.oracle.com/licenses/universal-foss-exception. This program 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 General Public License, version 2.0, for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /** @file mysys/array.cc Handling of arrays that can grow dynamically. */ #include #include #include "my_alloc.h" #include "my_dbug.h" #include "my_inttypes.h" #include "my_macros.h" #include "my_sys.h" #include "mysql/psi/psi_memory.h" #include "mysql/service_mysql_alloc.h" /* Initiate dynamic array SYNOPSIS my_init_dynamic_array() array Pointer to an array element_size Size of element init_buffer Initial buffer pointer init_alloc Number of initial elements alloc_increment Increment for adding new elements DESCRIPTION init_dynamic_array() initiates array and allocate space for init_alloc eilements. Array is usable even if space allocation failed, hence, the function never returns true. Static buffers must begin immediately after the array structure. RETURN VALUE false Ok */ bool my_init_dynamic_array(DYNAMIC_ARRAY *array, PSI_memory_key psi_key, uint element_size, void *init_buffer, uint init_alloc, uint alloc_increment) { DBUG_TRACE; if (!alloc_increment) { alloc_increment = MY_MAX((8192 - MALLOC_OVERHEAD) / element_size, 16); if (init_alloc > 8 && alloc_increment > init_alloc * 2) alloc_increment = init_alloc * 2; } if (!init_alloc) { init_alloc = alloc_increment; init_buffer = 0; } array->elements = 0; array->max_element = init_alloc; array->alloc_increment = alloc_increment; array->size_of_element = element_size; array->m_psi_key = psi_key; if ((array->buffer = static_cast(init_buffer))) return false; /* Since the dynamic array is usable even if allocation fails here malloc should not throw an error */ if (!(array->buffer = (uchar *)my_malloc(psi_key, element_size * init_alloc, MYF(0)))) array->max_element = 0; return false; } /* Insert element at the end of array. Allocate memory if needed. SYNOPSIS insert_dynamic() array element RETURN VALUE true Insert failed false Ok */ bool insert_dynamic(DYNAMIC_ARRAY *array, const void *element) { uchar *buffer; if (array->elements == array->max_element) { /* Call only when nessesary */ if (!(buffer = static_cast(alloc_dynamic(array)))) return true; } else { buffer = array->buffer + (array->elements * array->size_of_element); array->elements++; } memcpy(buffer, element, (size_t)array->size_of_element); return false; } /* Alloc space for next element(s) SYNOPSIS alloc_dynamic() array DESCRIPTION alloc_dynamic() checks if there is empty space for at least one element if not tries to allocate space for alloc_increment elements at the end of array. RETURN VALUE pointer Pointer to empty space for element 0 Error */ void *alloc_dynamic(DYNAMIC_ARRAY *array) { if (array->elements == array->max_element) { char *new_ptr; if (array->buffer == (uchar *)(array + 1)) { /* In this senerio, the buffer is statically preallocated, so we have to create an all-new malloc since we overflowed */ if (!(new_ptr = (char *)my_malloc( array->m_psi_key, (array->max_element + array->alloc_increment) * array->size_of_element, MYF(MY_WME)))) return 0; memcpy(new_ptr, array->buffer, array->elements * array->size_of_element); } else if (!(new_ptr = (char *)my_realloc( array->m_psi_key, array->buffer, (array->max_element + array->alloc_increment) * array->size_of_element, MYF(MY_WME | MY_ALLOW_ZERO_PTR)))) return 0; array->buffer = (uchar *)new_ptr; array->max_element += array->alloc_increment; } return array->buffer + (array->elements++ * array->size_of_element); } /* Pop last element from array. SYNOPSIS pop_dynamic() array RETURN VALUE pointer Ok 0 Array is empty */ void *pop_dynamic(DYNAMIC_ARRAY *array) { if (array->elements) return array->buffer + (--array->elements * array->size_of_element); return 0; } void claim_dynamic(DYNAMIC_ARRAY *array) { /* Check for a static buffer */ if (array->buffer == (uchar *)(array + 1)) return; my_claim(array->buffer); } /* Empty array by freeing all memory SYNOPSIS delete_dynamic() array Array to be deleted */ void delete_dynamic(DYNAMIC_ARRAY *array) { /* Just mark as empty if we are using a static buffer */ if (array->buffer == (uchar *)(array + 1)) array->elements = 0; else if (array->buffer) { my_free(array->buffer); array->buffer = 0; array->elements = array->max_element = 0; } } /* Free unused memory SYNOPSIS freeze_size() array Array to be freed */ void freeze_size(DYNAMIC_ARRAY *array) { uint elements = MY_MAX(array->elements, 1); /* Do nothing if we are using a static buffer */ if (array->buffer == (uchar *)(array + 1)) return; if (array->buffer && array->max_element != elements) { array->buffer = (uchar *)my_realloc(array->m_psi_key, array->buffer, elements * array->size_of_element, MYF(MY_WME)); array->max_element = elements; } }