cpython/Modules/_decimal/libmpdec/mpalloc.c

/*
 * Copyright (c) 2008-2020 Stefan Krah. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */


#include "mpdecimal.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mpalloc.h"
#include "typearith.h"


#if defined(_MSC_VER)
  #pragma warning(disable : 4232)
#endif


/* Guaranteed minimum allocation for a coefficient. May be changed once
   at program start using mpd_setminalloc(). */
mpd_ssize_t MPD_MINALLOC = …;

/* Custom allocation and free functions */
void *(* mpd_mallocfunc)(size_t size) = …;
void *(* mpd_reallocfunc)(void *ptr, size_t size) = …;
void *(* mpd_callocfunc)(size_t nmemb, size_t size) = …;
void (* mpd_free)(void *ptr) = …;


/* emulate calloc if it is not available */
void *
mpd_callocfunc_em(size_t nmemb, size_t size)
{ … }


/* malloc with overflow checking */
void *
mpd_alloc(mpd_size_t nmemb, mpd_size_t size)
{ … }

/* calloc with overflow checking */
void *
mpd_calloc(mpd_size_t nmemb, mpd_size_t size)
{ … }

/* realloc with overflow checking */
void *
mpd_realloc(void *ptr, mpd_size_t nmemb, mpd_size_t size, uint8_t *err)
{ … }

/* struct hack malloc with overflow checking */
void *
mpd_sh_alloc(mpd_size_t struct_size, mpd_size_t nmemb, mpd_size_t size)
{ … }


/* Allocate a new decimal with a coefficient of length 'nwords'. In case
   of an error the return value is NULL. */
mpd_t *
mpd_qnew_size(mpd_ssize_t nwords)
{ … }

/* Allocate a new decimal with a coefficient of length MPD_MINALLOC.
   In case of an error the return value is NULL. */
mpd_t *
mpd_qnew(void)
{ … }

/* Allocate new decimal. Caller can check for NULL or MPD_Malloc_error.
   Raises on error. */
mpd_t *
mpd_new(mpd_context_t *ctx)
{ … }

/*
 * Input: 'result' is a static mpd_t with a static coefficient.
 * Assumption: 'nwords' >= result->alloc.
 *
 * Resize the static coefficient to a larger dynamic one and copy the
 * existing data. If successful, the value of 'result' is unchanged.
 * Otherwise, set 'result' to NaN and update 'status' with MPD_Malloc_error.
 */
int
mpd_switch_to_dyn(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)
{ … }

/*
 * Input: 'result' is a static mpd_t with a static coefficient.
 *
 * Convert the coefficient to a dynamic one that is initialized to zero. If
 * malloc fails, set 'result' to NaN and update 'status' with MPD_Malloc_error.
 */
int
mpd_switch_to_dyn_zero(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)
{ … }

/*
 * Input: 'result' is a static or a dynamic mpd_t with a dynamic coefficient.
 * Resize the coefficient to length 'nwords':
 *   Case nwords > result->alloc:
 *     If realloc is successful:
 *       'result' has a larger coefficient but the same value. Return 1.
 *     Otherwise:
 *       Set 'result' to NaN, update status with MPD_Malloc_error and return 0.
 *   Case nwords < result->alloc:
 *     If realloc is successful:
 *       'result' has a smaller coefficient. result->len is undefined. Return 1.
 *     Otherwise (unlikely):
 *       'result' is unchanged. Reuse the now oversized coefficient. Return 1.
 */
int
mpd_realloc_dyn(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)
{ … }

/*
 * Input: 'result' is a static mpd_t with a static coefficient.
 * Assumption: 'nwords' >= result->alloc.
 *
 * Resize the static coefficient to a larger dynamic one and copy the
 * existing data.
 *
 * On failure the value of 'result' is unchanged.
 */
int
mpd_switch_to_dyn_cxx(mpd_t *result, mpd_ssize_t nwords)
{ … }

/*
 * Input: 'result' is a static or a dynamic mpd_t with a dynamic coefficient.
 * Resize the coefficient to length 'nwords':
 *   Case nwords > result->alloc:
 *     If realloc is successful:
 *       'result' has a larger coefficient but the same value. Return 1.
 *     Otherwise:
 *       'result' has a the same coefficient. Return 0.
 *   Case nwords < result->alloc:
 *     If realloc is successful:
 *       'result' has a smaller coefficient. result->len is undefined. Return 1.
 *     Otherwise (unlikely):
 *       'result' is unchanged. Reuse the now oversized coefficient. Return 1.
 */
int
mpd_realloc_dyn_cxx(mpd_t *result, mpd_ssize_t nwords)
{ … }