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/*
** An alternative implemtation of "strtod()" that is both
** simplier, and thread-safe.
*/
#include <pthread.h>
#include <ctype.h>
#include <math.h>
#ifdef TEST
# define strtod NewStrtod
#include <stdio.h>
#endif
static double scaler10[] = {
1.0, 1e10, 1e20, 1e30, 1e40, 1e50, 1e60, 1e70, 1e80, 1e90
};
static double scaler1[] = {
1.0, 10.0, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9
};
static double pastpoint[] = {
1e-1, 1e-2, 1e-3, 1e-4, 1e-5, 1e-6, 1e-7, 1e-8, 1e-9,
1e-10, 1e-11, 1e-12, 1e-13, 1e-14, 1e-15, 1e-16, 1e-17, 1e-18, 1e-19,
1e-20, 1e-21, 1e-22, 1e-23, 1e-24, 1e-25, 1e-26, 1e-27, 1e-28, 1e-29,
1e-30, 1e-31, 1e-32, 1e-33, 1e-34, 1e-35, 1e-36, 1e-37, 1e-38, 1e-39,
1e-40, 1e-41, 1e-42, 1e-43, 1e-44, 1e-45, 1e-46, 1e-47, 1e-48, 1e-49,
1e-50, 1e-51, 1e-52, 1e-53, 1e-54, 1e-55, 1e-56, 1e-57, 1e-58, 1e-59,
};
#ifndef DBL_MAX
#define DBL_MAX 1.7976931348623157e+308
#endif
double strtod(const char *zNum, char **pzEnd){
double rResult = 0.0;
int isNegative = 0;
while( isspace(*zNum) ){
zNum++;
}
if( *zNum=='-' ){
zNum++;
isNegative = 1;
}else if( *zNum=='+' ){
zNum++;
}
while( isdigit(*zNum) ){
rResult = rResult*10.0 + (*zNum - '0');
zNum++;
}
if( *zNum=='.' ){
int n = 0;
zNum++;
while( isdigit(*zNum) ){
if( n<sizeof(pastpoint)/sizeof(pastpoint[0]) ){
rResult += pastpoint[n] * (*zNum - '0');
n++;
}
zNum++;
}
}
if( *zNum=='e' || *zNum=='E' ){
int expVal = 0;
int isNegExp = 0;
const char *zExpStart = zNum;
zNum++;
if( *zNum=='-' ){
isNegExp = 1;
zNum++;
}else if( *zNum=='+' ){
zNum++;
}
if( !isdigit(*zNum) ){
zNum = zExpStart;
}else{
double scaler = 1.0;
while( isdigit(*zNum) ){
expVal = expVal*10 + *zNum - '0';
zNum++;
}
if( expVal >= 1000 ){
if( isNegExp ){
rResult = 0.0;
}else{
rResult = DBL_MAX;
}
goto done;
}
while( expVal >= 100 ){
scaler *= 1.0e100;
expVal -= 100;
}
scaler *= scaler10[expVal/10]*scaler1[expVal%10];
if( isNegExp ){
scaler = 1.0/scaler;
}
rResult *= scaler;
}
}
done:
if( pzEnd ){
*pzEnd = (char *)zNum;
}
if( isNegative && rResult!=0.0 ){
rResult = -rResult;
}
return rResult;
}
double atof(const char *nptr)
{
return (strtod(nptr, 0));
}
#ifdef TEST
#undef strtod
double strtod(const char*,char**);
double NewStrtod(const char*,char**);
int main(int argc, char **argv){
int nTest = 0;
int nFail = 0;
int nBigFail = 0;
char zBuf[1000];
while( fgets(zBuf,sizeof(zBuf),stdin) ){
double old, new;
char *zTailOld, *zTailNew;
int i;
for(i=0; zBuf[i] && zBuf[i]!='\n'; i++){}
zBuf[i] = 0;
#if TEST==1
printf("Input line: [%s]\n",zBuf);
old = strtod(zBuf,&zTailOld);
printf("value=%g\n",old);
printf("Old: 0x%08x%08x tail=[%s]\n",
((int*)&old)[1], ((int*)&old)[0], zTailOld);
new = NewStrtod(zBuf,&zTailNew);
printf("value=%g\n",new);
printf("New: 0x%08x%08x tail=[%s]\n\n",
((int*)&new)[1], ((int*)&new)[0], zTailNew);
#else
old = strtod(zBuf,&zTailOld);
new = NewStrtod(zBuf,&zTailNew);
nTest++;
if( strcmp(zTailOld,zTailNew)
|| ((int*)&old)[0]!=((int*)&new)[0]
|| ((int*)&old)[1]!=((int*)&new)[1]
){
int olda, oldb, newa, newb;
nFail++;
olda = ((int*)&old)[1];
oldb = ((int*)&old)[0];
newa = ((int*)&new)[1];
newb = ((int*)&new)[0];
if( olda!=newa || abs(oldb-newb)>2 ){
nBigFail++;
printf("******* Big failure \n");
}
printf("Input = [%s]\n",zBuf);
printf("old: val=%g 0x%08x%08x tail=[%s]\n",
old, olda, oldb, zTailOld);
printf("new: val=%g 0x%08x%08x tail=[%s]\n\n",
new, newa, newb, zTailNew);
}
#endif
}
printf("Out of %d tests, %d failures and %d big failurs\n",
nTest,nFail, nBigFail);
}
#endif
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