eccodes/src/grib_ieeefloat.c

533 lines
12 KiB
C

/*
* Copyright 2005-2017 ECMWF.
*
* This software is licensed under the terms of the Apache Licence Version 2.0
* which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
*
* In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
* virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
*/
/***************************************************************************
* Enrico Fucile - 06.01.2009 *
* *
***************************************************************************/
#include "grib_api_internal.h"
#if GRIB_PTHREADS
static pthread_once_t once = PTHREAD_ONCE_INIT;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
static void init() {
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr,PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&mutex,&attr);
pthread_mutexattr_destroy(&attr);
}
#elif GRIB_OMP_THREADS
static int once = 0;
static omp_nest_lock_t mutex;
static void init()
{
GRIB_OMP_CRITICAL(lock_grib_ieeefloat_c)
{
if (once == 0)
{
omp_init_nest_lock(&mutex);
once = 1;
}
}
}
#endif
#if 1
typedef struct ieee_table_t ieee_table_t;
struct ieee_table_t {
int inited;
double e[255];
double v[255];
double vmin;
double vmax;
};
static ieee_table_t ieee_table={ 0,{0,},{0,}, 0, 0 };
static void init_ieee_table()
{
if (!ieee_table.inited) {
unsigned long i;
unsigned long mmin=0x800000;
unsigned long mmax=0xffffff;
double e=1;
for (i=1; i<=104;i++) {
e*=2;
ieee_table.e[i+150]=e;
ieee_table.v[i+150]=e*mmin;
}
ieee_table.e[150]=1;
ieee_table.v[150]=mmin;
e=1;
for (i=1; i<150;i++) {
e/=2;
ieee_table.e[150-i]=e;
ieee_table.v[150-i]=e*mmin;
}
ieee_table.vmin=ieee_table.v[1];
ieee_table.vmax=ieee_table.e[254]*mmax;
ieee_table.inited=1;
/*for (i=0;i<128;i++) printf("++++ ieee_table.v[%d]=%g\n",i,ieee_table.v[i]);*/
}
}
static void init_table_if_needed()
{
GRIB_MUTEX_INIT_ONCE(&once,&init)
GRIB_MUTEX_LOCK(&mutex)
if (!ieee_table.inited) init_ieee_table();
GRIB_MUTEX_UNLOCK(&mutex)
}
static void binary_search(double xx[], const unsigned long n, double x, unsigned long *j)
{
/*These routine works only on ascending ordered arrays*/
unsigned long ju,jm,jl;
jl=0;
ju=n;
while (ju-jl > 1) {
jm=(ju+jl) >> 1;
/* printf("jl=%lu jm=%lu ju=%lu\n",jl,jm,ju); */
/* printf("xx[jl]=%.10e xx[jm]=%.10e xx[ju]=%.10e\n",xx[jl],xx[jm],xx[ju]); */
if (x >= xx[jm]) jl=jm;
else ju=jm;
}
*j=jl;
}
double grib_ieee_table_e(unsigned long e)
{
init_table_if_needed();
return ieee_table.e[e];
}
double grib_ieee_table_v(unsigned long e)
{
init_table_if_needed();
return ieee_table.v[e];
}
unsigned long grib_ieee_to_long(double x)
{
unsigned long s = 0;
unsigned long mmax = 0xffffff;
unsigned long mmin = 0x800000;
unsigned long m = mmax;
unsigned long e=0;
double rmmax=mmax+0.5;
init_table_if_needed();
/* printf("\ngrib_ieee_to_long: x=%.20e\n",x); */
if (x < 0) { s = 1; x = -x; }
/* Underflow */
if (x < ieee_table.vmin) {
/*printf("grib_ieee_to_long: (x < ieee_table.vmin) x=%.20e vmin=%.20e v=0x%lX\n",x,ieee_table.vmin,(s<<31));*/
return (s << 31);
}
/* Overflow */
if (x > ieee_table.vmax) {
fprintf(stderr, "grib_ieee_to_long: Number is too large: x=%.20e > xmax=%.20e\n", x, ieee_table.vmax);
Assert(0);
return 0;
}
binary_search(ieee_table.v, 254, x, &e);
/* printf("grib_ieee_to_long: e=%ld\n",e); */
x/=ieee_table.e[e];
/* printf("grib_ieee_to_long: x=%.20e\n",x); */
while(x < mmin ) { x *= 2; e--;
/* printf("grib_ieee_to_long (e--): x=%.20e e=%ld \n",x,e); */
}
while(x > rmmax ) { x /= 2; e++;
/* printf("grib_ieee_to_long (e++): x=%.20e e=%ld \n",x,e); */
}
m=x+0.5;
/* printf("grib_ieee_to_long: m=0x%lX (%lu) x=%.10e \n",m,m,x ); */
if ( m > mmax ) { e++; m=0x800000;
/* printf("grib_ieee_to_long: ( m > mmax ) m=0x%lX (%lu) x=%.10e \n",m,m,x ); */
}
/* printf("grib_ieee_to_long: s=%lu c=%lu (0x%lX) m=%lu (0x%lX)\n",s,e,e,m,m ); */
return (s << 31) | ( e << 23 ) | ( m & 0x7fffff );
}
double grib_ieeefloat_error(double x)
{
unsigned long e=0;
init_table_if_needed();
if (x < 0) x = -x;
/* Underflow */
if (x < ieee_table.vmin) return ieee_table.vmin;
/* Overflow */
if (x > ieee_table.vmax) {
fprintf(stderr, "grib_ieeefloat_error: Number is too large: x=%.20e > xmax=%.20e\n", x, ieee_table.vmax);
Assert(0);
return 0;
}
binary_search(ieee_table.v, 254, x, &e);
return ieee_table.e[e] ;
}
double grib_long_to_ieee(unsigned long x)
{
unsigned long s = x & 0x80000000;
unsigned long c = (x & 0x7f800000) >> 23;
unsigned long m = (x & 0x007fffff);
double val;
init_table_if_needed();
if (c == 0 && m==0) return 0;
if (c == 0) {
m |= 0x800000;
c=1;
} else m |= 0x800000;
val=m*ieee_table.e[c];
if(s) val = -val;
return val;
}
unsigned long grib_ieee_nearest_smaller_to_long(double x)
{
unsigned long l;
unsigned long e;
unsigned long m ;
unsigned long s;
unsigned long mmin = 0x800000;
double y,eps;
if(x == 0) return 0;
init_table_if_needed();
l=grib_ieee_to_long(x);
y=grib_long_to_ieee(l);
if ( x < y ) {
if ( x < 0 && -x < ieee_table.vmin ) {
l=0x80800000;
} else {
e = (l & 0x7f800000) >> 23;
m = (l & 0x007fffff) | 0x800000;
s = l & 0x80000000;
if ( m == mmin ) {
/* printf("grib_ieee_nearest_smaller_to_long: m == mmin (0x%lX) e=%lu\n",m,e); */
e = s ? e : e-1;
if (e<1) e=1;
if (e>254) e=254;
/* printf("grib_ieee_nearest_smaller_to_long: e=%lu \n",e); */
}
eps=ieee_table.e[e];
/* printf("grib_ieee_nearest_smaller_to_long: x<y\n"); */
l=grib_ieee_to_long(y-eps);
/* printf("grib_ieee_nearest_smaller_to_long: grib_ieee_to_long(y-eps)=0x%lX y=%.10e eps=%.10e x=%.10e\n",l,y,eps,x); */
}
} else return l;
if (x<grib_long_to_ieee(l)) {
printf("grib_ieee_nearest_smaller_to_long: x=%.20e grib_long_to_ieee(0x%lX)=%.20e\n",x,l,grib_long_to_ieee(l));
Assert(x >= grib_long_to_ieee(l));
}
return l;
}
int grib_nearest_smaller_ieee_float(double a,double* ret)
{
unsigned long l=0;
init_table_if_needed();
if (a>ieee_table.vmax) return GRIB_INTERNAL_ERROR;
l=grib_ieee_nearest_smaller_to_long(a);
*ret=grib_long_to_ieee(l);
return GRIB_SUCCESS;
}
#else
/* old code to be deleted */
double grib_ieeefloat_error(double x) {return 0;}
double grib_long_to_ieee(unsigned long x)
{
unsigned long s = x & 0x80000000;
unsigned long c = (x & 0x7f800000) >> 23;
unsigned long m;
double val;
long e;
if(x == 0) return 0;
Assert(c != 255);
if(c == 0) { m = x & 0x007fffff; e = -126 - 23; }
else { m = (x & 0x007fffff) | (1<<23); e = c - 127 - 23; }
val = m;
while(e < 0) { val /= 2.0; e++; }
while(e > 0) { val *= 2.0; e--; }
if(s) val = -val;
return val;
}
int grib_nearest_smaller_ieee_float(double a,double* x)
{
double e = grib_long_to_ieee(grib_ieee_to_long(a));
double b = a;
/* printf("----> a=%g e=%g e-a=%g\n",a,e,e-a); */
if( e > b )
{
unsigned long ub = grib_ieee_to_long(b);
unsigned long ue;
while(e>b)
{
/* printf("a=%g e=%g e-a=%g\n",a,e,e-a); */
a -= (e-a);
e = grib_long_to_ieee(grib_ieee_to_long(a));
}
ue = grib_ieee_to_long(e);
Assert((ue-ub) == 1);
}
Assert(b >= e);
*x=e;
return GRIB_SUCCESS;
}
unsigned long grib_ieee_to_long(double x)
{
/* double y = x; */
unsigned long s = 0;
unsigned long m;
long p = 0;
unsigned long e = 0;
if(x == 0) return 0;
if(x < 0) { s = 1; x = -x; }
while(x < 2) { x *= 2; p--; }
while(x >= 2) { x /= 2; p++; }
if(p > 127 ) {
/* Overflow */
e = 255;
m = 0;
}
else if(p < -126) {
/* int i; */
e = 0;
/* printf("p=%ld x=%g %ld\n",p,x,p+126+23); */
m = x * grib_power(p+126+23,2);
}
else {
e = p + 127;
m = x * ( 1 << 23);
m &= 0x007fffff;
}
m = (s << 31) | ( e << 23 ) | m;
return m;
}
#endif
#ifdef IEEE
unsigned long grib_ieee64_to_long(double x)
{
unsigned long lval = 0;
#if IEEE_LE
unsigned char s[8]={0,};
unsigned char* buf=(unsigned char*)&x;
int j=0;
for (j=7;j>=0;j--)
s[j]= *(buf++);
memcpy(&lval,s,8);
#elif IEEE_BE
memcpy(&lval,&x,8);
#endif
return lval;
}
double grib_long_to_ieee64(unsigned long x){
double dval = 0.0;
#if IEEE_LE
unsigned char s[8]={0,};
unsigned char* buf=(unsigned char*)&x;
int j=0;
for (j=7;j>=0;j--)
s[j]= *(buf++);
memcpy(&dval,s,8);
#elif IEEE_BE
memcpy(&dval,&x,8);
#else
Assert(!"Neither IEEE_LE nor IEEE_BE defined.");
#endif
return dval;
}
int grib_ieee_decode_array(grib_context* c,unsigned char* buf,size_t nvals,int bytes,double* val)
{
int err=0,i=0,j=0;
unsigned char s[8]={0,};
float fval;
double* pval=val;
switch (bytes) {
case 4:
for (i=0;i<nvals;i++) {
#if IEEE_LE
for (j=3;j>=0;j--)
s[j]=*(buf++);
memcpy(&fval,s,4);
val[i]=(double)fval;
#elif IEEE_BE
memcpy(&fval,buf,4);
val[i]=(double)fval;
buf+=4;
#endif
}
break;
case 8:
for (i=0;i<nvals;i++) {
#if IEEE_LE
for (j=7;j>=0;j--)
s[j]=*(buf++);
memcpy(pval++,s,8);
#elif IEEE_BE
memcpy(pval++,buf,8);
buf+=8;
#endif
}
break;
default:
grib_context_log(c,GRIB_LOG_ERROR,
"grib_ieee_decode_array: %d bits not implemented",bytes*8);
return GRIB_NOT_IMPLEMENTED;
}
return err;
}
#else
int grib_ieee_decode_array(grib_context* c,unsigned char* buf,size_t nvals,int bytes,double* val)
{
int err=0,i=0;
long bitr=0;
for(i=0;i< nvals;i++)
val[i] = grib_long_to_ieee(grib_decode_unsigned_long(buf,&bitr,bytes*8));
return err;
}
#endif
#ifdef IEEE
int grib_ieee_encode_array(grib_context* c,double* val,size_t nvals,int bytes,
unsigned char* buf) {
int err=0,i=0,j=0;
unsigned char s4[4];
unsigned char s8[8];
float fval=0;
double *pval=val;
switch (bytes) {
case 4:
for (i=0;i<nvals;i++) {
fval=(float)val[i];
#if IEEE_LE
memcpy(s4,&(fval),4);
for (j=3;j>=0;j--)
*(buf++)=s4[j];
#elif IEEE_BE
memcpy(buf,&(fval),4);
buf+=4;
#endif
}
break;
case 8:
for (i=0;i<nvals;i++) {
#if IEEE_LE
memcpy(s8,pval++,8);
for (j=7;j>=0;j--)
*(buf++)=s8[j];
#elif IEEE_BE
memcpy(buf,pval++,8);
buf+=8;
#endif
}
break;
default:
grib_context_log(c,GRIB_LOG_ERROR,
"grib_ieee_encode_array: %d bits not implemented",bytes*8);
return GRIB_NOT_IMPLEMENTED;
}
return err;
}
#else
int grib_ieee_encode_array(grib_context* c, double* val, size_t nvals, int bytes, unsigned char* buf)
{
int err=0,i=0;
long bitr=0;
for(i=0;i< nvals;i++)
grib_encode_unsigned_long(buf, grib_ieee_to_long(val[i]), &bitr, bytes*8);
return err;
}
#endif