cpython/Modules/_decimal/libmpdec/context.c

287 lines
5.9 KiB
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 <signal.h>
#include <stdio.h>
#include <string.h>
void
mpd_dflt_traphandler(mpd_context_t *ctx)
{
(void)ctx;
raise(SIGFPE);
}
void (* mpd_traphandler)(mpd_context_t *) = mpd_dflt_traphandler;
/* Set guaranteed minimum number of coefficient words. The function may
be used once at program start. Setting MPD_MINALLOC to out-of-bounds
values is a catastrophic error, so in that case the function exits rather
than relying on the user to check a return value. */
void
mpd_setminalloc(mpd_ssize_t n)
{
static int minalloc_is_set = 0;
if (minalloc_is_set) {
mpd_err_warn("mpd_setminalloc: ignoring request to set "
"MPD_MINALLOC a second time\n");
return;
}
if (n < MPD_MINALLOC_MIN || n > MPD_MINALLOC_MAX) {
mpd_err_fatal("illegal value for MPD_MINALLOC"); /* GCOV_NOT_REACHED */
}
MPD_MINALLOC = n;
minalloc_is_set = 1;
}
void
mpd_init(mpd_context_t *ctx, mpd_ssize_t prec)
{
mpd_ssize_t ideal_minalloc;
mpd_defaultcontext(ctx);
if (!mpd_qsetprec(ctx, prec)) {
mpd_addstatus_raise(ctx, MPD_Invalid_context);
return;
}
ideal_minalloc = 2 * ((prec+MPD_RDIGITS-1) / MPD_RDIGITS);
if (ideal_minalloc < MPD_MINALLOC_MIN) ideal_minalloc = MPD_MINALLOC_MIN;
if (ideal_minalloc > MPD_MINALLOC_MAX) ideal_minalloc = MPD_MINALLOC_MAX;
mpd_setminalloc(ideal_minalloc);
}
void
mpd_maxcontext(mpd_context_t *ctx)
{
ctx->prec=MPD_MAX_PREC;
ctx->emax=MPD_MAX_EMAX;
ctx->emin=MPD_MIN_EMIN;
ctx->round=MPD_ROUND_HALF_EVEN;
ctx->traps=MPD_Traps;
ctx->status=0;
ctx->newtrap=0;
ctx->clamp=0;
ctx->allcr=1;
}
void
mpd_defaultcontext(mpd_context_t *ctx)
{
ctx->prec=2*MPD_RDIGITS;
ctx->emax=MPD_MAX_EMAX;
ctx->emin=MPD_MIN_EMIN;
ctx->round=MPD_ROUND_HALF_UP;
ctx->traps=MPD_Traps;
ctx->status=0;
ctx->newtrap=0;
ctx->clamp=0;
ctx->allcr=1;
}
void
mpd_basiccontext(mpd_context_t *ctx)
{
ctx->prec=9;
ctx->emax=MPD_MAX_EMAX;
ctx->emin=MPD_MIN_EMIN;
ctx->round=MPD_ROUND_HALF_UP;
ctx->traps=MPD_Traps|MPD_Clamped;
ctx->status=0;
ctx->newtrap=0;
ctx->clamp=0;
ctx->allcr=1;
}
int
mpd_ieee_context(mpd_context_t *ctx, int bits)
{
if (bits <= 0 || bits > MPD_IEEE_CONTEXT_MAX_BITS || bits % 32) {
return -1;
}
ctx->prec = 9 * (bits/32) - 2;
ctx->emax = 3 * ((mpd_ssize_t)1<<(bits/16+3));
ctx->emin = 1 - ctx->emax;
ctx->round=MPD_ROUND_HALF_EVEN;
ctx->traps=0;
ctx->status=0;
ctx->newtrap=0;
ctx->clamp=1;
ctx->allcr=1;
return 0;
}
mpd_ssize_t
mpd_getprec(const mpd_context_t *ctx)
{
return ctx->prec;
}
mpd_ssize_t
mpd_getemax(const mpd_context_t *ctx)
{
return ctx->emax;
}
mpd_ssize_t
mpd_getemin(const mpd_context_t *ctx)
{
return ctx->emin;
}
int
mpd_getround(const mpd_context_t *ctx)
{
return ctx->round;
}
uint32_t
mpd_gettraps(const mpd_context_t *ctx)
{
return ctx->traps;
}
uint32_t
mpd_getstatus(const mpd_context_t *ctx)
{
return ctx->status;
}
int
mpd_getclamp(const mpd_context_t *ctx)
{
return ctx->clamp;
}
int
mpd_getcr(const mpd_context_t *ctx)
{
return ctx->allcr;
}
int
mpd_qsetprec(mpd_context_t *ctx, mpd_ssize_t prec)
{
if (prec <= 0 || prec > MPD_MAX_PREC) {
return 0;
}
ctx->prec = prec;
return 1;
}
int
mpd_qsetemax(mpd_context_t *ctx, mpd_ssize_t emax)
{
if (emax < 0 || emax > MPD_MAX_EMAX) {
return 0;
}
ctx->emax = emax;
return 1;
}
int
mpd_qsetemin(mpd_context_t *ctx, mpd_ssize_t emin)
{
if (emin > 0 || emin < MPD_MIN_EMIN) {
return 0;
}
ctx->emin = emin;
return 1;
}
int
mpd_qsetround(mpd_context_t *ctx, int round)
{
if (!(0 <= round && round < MPD_ROUND_GUARD)) {
return 0;
}
ctx->round = round;
return 1;
}
int
mpd_qsettraps(mpd_context_t *ctx, uint32_t traps)
{
if (traps > MPD_Max_status) {
return 0;
}
ctx->traps = traps;
return 1;
}
int
mpd_qsetstatus(mpd_context_t *ctx, uint32_t flags)
{
if (flags > MPD_Max_status) {
return 0;
}
ctx->status = flags;
return 1;
}
int
mpd_qsetclamp(mpd_context_t *ctx, int c)
{
if (c != 0 && c != 1) {
return 0;
}
ctx->clamp = c;
return 1;
}
int
mpd_qsetcr(mpd_context_t *ctx, int c)
{
if (c != 0 && c != 1) {
return 0;
}
ctx->allcr = c;
return 1;
}
void
mpd_addstatus_raise(mpd_context_t *ctx, uint32_t flags)
{
ctx->status |= flags;
if (flags&ctx->traps) {
ctx->newtrap = (flags&ctx->traps);
mpd_traphandler(ctx);
}
}