mirror of https://github.com/tongzx/nt5src
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
104 lines
2.1 KiB
104 lines
2.1 KiB
/***
|
|
* istrgdbl.cpp - definitions for istream class core double routine
|
|
*
|
|
* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
|
|
*
|
|
*Purpose:
|
|
* Definitions of member function for istream getdouble().
|
|
* [AT&T C++]
|
|
*
|
|
*Revision History:
|
|
* 09-26-91 KRS Created. Split off from istream.cxx for granularity.
|
|
* 06-14-95 CFW Comment cleanup.
|
|
*
|
|
*******************************************************************************/
|
|
|
|
#include <cruntime.h>
|
|
#include <internal.h>
|
|
#include <ctype.h>
|
|
#include <iostream.h>
|
|
#pragma hdrstop
|
|
|
|
/***
|
|
*int istream::getdouble(char * buffer, int buflen) - get a double
|
|
*
|
|
*Purpose:
|
|
* Get a double from stream.
|
|
*
|
|
*Entry:
|
|
* char * buffer = area for number to be copied.
|
|
* int buflen = max. length of buffer
|
|
*
|
|
*Exit:
|
|
* Returns 0 if fatal error
|
|
* Otherwise, returns length of buffer filled.
|
|
* Sets ios::failbit on error forming number.
|
|
* If successful, buffer[] contains the number, followed by \0.
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
int istream::getdouble(char * buffer, int buflen) // returns length
|
|
{
|
|
int c;
|
|
int i = 0;
|
|
int fDigit = 0; // true if legal digit encountered
|
|
int fDecimal=0; // true if '.' encountered or no longer valid
|
|
int fExp=0; // true if 'E' or 'e' encounted
|
|
|
|
if (ipfx(0))
|
|
{
|
|
c=bp->sgetc();
|
|
for (; i<buflen; buffer[i] = (char)c,c=bp->snextc(),i++)
|
|
{
|
|
if (c==EOF)
|
|
{
|
|
state |= ios::eofbit;
|
|
break;
|
|
}
|
|
if ((!i) || (fExp==1))
|
|
{
|
|
if ((c=='-') || (c=='+'))
|
|
{
|
|
continue;
|
|
}
|
|
}
|
|
if ((c=='.') && (!fExp) && (!fDecimal))
|
|
{
|
|
fDecimal++;
|
|
continue;
|
|
}
|
|
if (((c=='E') || (c=='e')) && (!fExp))
|
|
{
|
|
fDecimal++; // can't allow decimal now
|
|
fExp++;
|
|
continue;
|
|
}
|
|
if (!isdigit(c))
|
|
break;
|
|
if (fExp)
|
|
fExp++;
|
|
else
|
|
fDigit++;
|
|
}
|
|
if (fExp==1) // E or e with no number after it
|
|
{
|
|
if (bp->sputbackc(buffer[i])!=EOF)
|
|
{
|
|
i--;
|
|
state &= ~(ios::eofbit);
|
|
}
|
|
else
|
|
{
|
|
state |= ios::failbit;
|
|
}
|
|
}
|
|
if ((!fDigit) || (i==buflen))
|
|
state |= ios::failbit;
|
|
|
|
// buffer contains a valid number or '\0'
|
|
buffer[i] = '\0';
|
|
isfx();
|
|
}
|
|
return i;
|
|
}
|