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