cpython/Modules/_decimal/libmpdec/mpalloc.c

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/*
* 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 = MPD_MINALLOC_MIN;
/* Custom allocation and free functions */
void *(* mpd_mallocfunc)(size_t size) = malloc;
void *(* mpd_reallocfunc)(void *ptr, size_t size) = realloc;
void *(* mpd_callocfunc)(size_t nmemb, size_t size) = calloc;
void (* mpd_free)(void *ptr) = free;
/* emulate calloc if it is not available */
void *
mpd_callocfunc_em(size_t nmemb, size_t size)
{
void *ptr;
size_t req;
mpd_size_t overflow;
#if MPD_SIZE_MAX < SIZE_MAX
/* full_coverage test only */
if (nmemb > MPD_SIZE_MAX || size > MPD_SIZE_MAX) {
return NULL;
}
#endif
req = mul_size_t_overflow((mpd_size_t)nmemb, (mpd_size_t)size,
&overflow);
if (overflow) {
return NULL;
}
ptr = mpd_mallocfunc(req);
if (ptr == NULL) {
return NULL;
}
/* used on uint32_t or uint64_t */
memset(ptr, 0, req);
return ptr;
}
/* malloc with overflow checking */
void *
mpd_alloc(mpd_size_t nmemb, mpd_size_t size)
{
mpd_size_t req, overflow;
req = mul_size_t_overflow(nmemb, size, &overflow);
if (overflow) {
return NULL;
}
return mpd_mallocfunc(req);
}
/* calloc with overflow checking */
void *
mpd_calloc(mpd_size_t nmemb, mpd_size_t size)
{
mpd_size_t overflow;
(void)mul_size_t_overflow(nmemb, size, &overflow);
if (overflow) {
return NULL;
}
return mpd_callocfunc(nmemb, size);
}
/* realloc with overflow checking */
void *
mpd_realloc(void *ptr, mpd_size_t nmemb, mpd_size_t size, uint8_t *err)
{
void *new;
mpd_size_t req, overflow;
req = mul_size_t_overflow(nmemb, size, &overflow);
if (overflow) {
*err = 1;
return ptr;
}
new = mpd_reallocfunc(ptr, req);
if (new == NULL) {
*err = 1;
return ptr;
}
return new;
}
/* struct hack malloc with overflow checking */
void *
mpd_sh_alloc(mpd_size_t struct_size, mpd_size_t nmemb, mpd_size_t size)
{
mpd_size_t req, overflow;
req = mul_size_t_overflow(nmemb, size, &overflow);
if (overflow) {
return NULL;
}
req = add_size_t_overflow(req, struct_size, &overflow);
if (overflow) {
return NULL;
}
return mpd_mallocfunc(req);
}
/* 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)
{
mpd_t *result;
nwords = (nwords < MPD_MINALLOC) ? MPD_MINALLOC : nwords;
result = mpd_alloc(1, sizeof *result);
if (result == NULL) {
return NULL;
}
result->data = mpd_alloc(nwords, sizeof *result->data);
if (result->data == NULL) {
mpd_free(result);
return NULL;
}
result->flags = 0;
result->exp = 0;
result->digits = 0;
result->len = 0;
result->alloc = nwords;
return result;
}
/* 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)
{
return mpd_qnew_size(MPD_MINALLOC);
}
/* Allocate new decimal. Caller can check for NULL or MPD_Malloc_error.
Raises on error. */
mpd_t *
mpd_new(mpd_context_t *ctx)
{
mpd_t *result;
result = mpd_qnew();
if (result == NULL) {
mpd_addstatus_raise(ctx, MPD_Malloc_error);
}
return result;
}
/*
* 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)
{
mpd_uint_t *p = result->data;
assert(nwords >= result->alloc);
result->data = mpd_alloc(nwords, sizeof *result->data);
if (result->data == NULL) {
result->data = p;
mpd_set_qnan(result);
mpd_set_positive(result);
result->exp = result->digits = result->len = 0;
*status |= MPD_Malloc_error;
return 0;
}
memcpy(result->data, p, result->alloc * (sizeof *result->data));
result->alloc = nwords;
mpd_set_dynamic_data(result);
return 1;
}
/*
* 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)
{
mpd_uint_t *p = result->data;
result->data = mpd_calloc(nwords, sizeof *result->data);
if (result->data == NULL) {
result->data = p;
mpd_set_qnan(result);
mpd_set_positive(result);
result->exp = result->digits = result->len = 0;
*status |= MPD_Malloc_error;
return 0;
}
result->alloc = nwords;
mpd_set_dynamic_data(result);
return 1;
}
/*
* 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)
{
uint8_t err = 0;
result->data = mpd_realloc(result->data, nwords, sizeof *result->data, &err);
if (!err) {
result->alloc = nwords;
}
else if (nwords > result->alloc) {
mpd_set_qnan(result);
mpd_set_positive(result);
result->exp = result->digits = result->len = 0;
*status |= MPD_Malloc_error;
return 0;
}
return 1;
}
/*
* 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)
{
assert(nwords >= result->alloc);
mpd_uint_t *data = mpd_alloc(nwords, sizeof *result->data);
if (data == NULL) {
return 0;
}
memcpy(data, result->data, result->alloc * (sizeof *result->data));
result->data = data;
result->alloc = nwords;
mpd_set_dynamic_data(result);
return 1;
}
/*
* 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)
{
uint8_t err = 0;
mpd_uint_t *p = mpd_realloc(result->data, nwords, sizeof *result->data, &err);
if (!err) {
result->data = p;
result->alloc = nwords;
}
else if (nwords > result->alloc) {
return 0;
}
return 1;
}