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- /*
- * The authors of this software are Rob Pike and Ken Thompson.
- * Copyright (c) 2002 by Lucent Technologies.
- * Permission to use, copy, modify, and distribute this software for any
- * purpose without fee is hereby granted, provided that this entire notice
- * is included in all copies of any software which is or includes a copy
- * or modification of this software and in all copies of the supporting
- * documentation for such software.
- * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
- * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
- * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
- * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
- */
- #include <stdarg.h>
- #include <string.h>
- #include "utf.h"
- #include "fmt.h"
- #include "fmtdef.h"
- /*
- * Reads a floating-point number by interpreting successive characters
- * returned by (*f)(vp). The last call it makes to f terminates the
- * scan, so is not a character in the number. It may therefore be
- * necessary to back up the input stream up one byte after calling charstod.
- */
- double
- fmtcharstod(int(*f)(void*), void *vp)
- {
- double num, dem;
- int neg, eneg, dig, exp, c;
- num = 0;
- neg = 0;
- dig = 0;
- exp = 0;
- eneg = 0;
- c = (*f)(vp);
- while(c == ' ' || c == '\t')
- c = (*f)(vp);
- if(c == '-' || c == '+'){
- if(c == '-')
- neg = 1;
- c = (*f)(vp);
- }
- while(c >= '0' && c <= '9'){
- num = num*10 + c-'0';
- c = (*f)(vp);
- }
- if(c == '.')
- c = (*f)(vp);
- while(c >= '0' && c <= '9'){
- num = num*10 + c-'0';
- dig++;
- c = (*f)(vp);
- }
- if(c == 'e' || c == 'E'){
- c = (*f)(vp);
- if(c == '-' || c == '+'){
- if(c == '-'){
- dig = -dig;
- eneg = 1;
- }
- c = (*f)(vp);
- }
- while(c >= '0' && c <= '9'){
- exp = exp*10 + c-'0';
- c = (*f)(vp);
- }
- }
- exp -= dig;
- if(exp < 0){
- exp = -exp;
- eneg = !eneg;
- }
- dem = __fmtpow10(exp);
- if(eneg)
- num /= dem;
- else
- num *= dem;
- if(neg)
- return -num;
- return num;
- }
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