diff options
Diffstat (limited to 'compat/strtod.c')
| -rw-r--r-- | compat/strtod.c | 252 |
1 files changed, 0 insertions, 252 deletions
diff --git a/compat/strtod.c b/compat/strtod.c deleted file mode 100644 index 9643c09..0000000 --- a/compat/strtod.c +++ /dev/null @@ -1,252 +0,0 @@ -/* - * strtod.c -- - * - * Source code for the "strtod" library procedure. - * - * Copyright (c) 1988-1993 The Regents of the University of California. - * Copyright (c) 1994 Sun Microsystems, Inc. - * - * See the file "license.terms" for information on usage and redistribution - * of this file, and for a DISCLAIMER OF ALL WARRANTIES. - */ - -#include "tclInt.h" - -#ifndef TRUE -#define TRUE 1 -#define FALSE 0 -#endif -#ifndef NULL -#define NULL 0 -#endif - -static const int maxExponent = 511; /* Largest possible base 10 exponent. Any - * exponent larger than this will already - * produce underflow or overflow, so there's - * no need to worry about additional digits. - */ -static const double powersOf10[] = { /* Table giving binary powers of 10. Entry */ - 10., /* is 10^2^i. Used to convert decimal */ - 100., /* exponents into floating-point numbers. */ - 1.0e4, - 1.0e8, - 1.0e16, - 1.0e32, - 1.0e64, - 1.0e128, - 1.0e256 -}; - -/* - *---------------------------------------------------------------------- - * - * strtod -- - * - * This procedure converts a floating-point number from an ASCII - * decimal representation to internal double-precision format. - * - * Results: - * The return value is the double-precision floating-point - * representation of the characters in string. If endPtr isn't - * NULL, then *endPtr is filled in with the address of the - * next character after the last one that was part of the - * floating-point number. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -double -strtod( - const char *string, /* A decimal ASCII floating-point number, - * optionally preceded by white space. Must - * have form "-I.FE-X", where I is the integer - * part of the mantissa, F is the fractional - * part of the mantissa, and X is the - * exponent. Either of the signs may be "+", - * "-", or omitted. Either I or F may be - * omitted, or both. The decimal point isn't - * necessary unless F is present. The "E" may - * actually be an "e". E and X may both be - * omitted (but not just one). */ - char **endPtr) /* If non-NULL, store terminating character's - * address here. */ -{ - int sign, expSign = FALSE; - double fraction, dblExp; - const double *d; - register const char *p; - register int c; - int exp = 0; /* Exponent read from "EX" field. */ - int fracExp = 0; /* Exponent that derives from the fractional - * part. Under normal circumstatnces, it is - * the negative of the number of digits in F. - * However, if I is very long, the last digits - * of I get dropped (otherwise a long I with a - * large negative exponent could cause an - * unnecessary overflow on I alone). In this - * case, fracExp is incremented one for each - * dropped digit. */ - int mantSize; /* Number of digits in mantissa. */ - int decPt; /* Number of mantissa digits BEFORE decimal - * point. */ - const char *pExp; /* Temporarily holds location of exponent in - * string. */ - - /* - * Strip off leading blanks and check for a sign. - */ - - p = string; - while (isspace(UCHAR(*p))) { - p += 1; - } - if (*p == '-') { - sign = TRUE; - p += 1; - } else { - if (*p == '+') { - p += 1; - } - sign = FALSE; - } - - /* - * Count the number of digits in the mantissa (including the decimal - * point), and also locate the decimal point. - */ - - decPt = -1; - for (mantSize = 0; ; mantSize += 1) - { - c = *p; - if (!isdigit(c)) { - if ((c != '.') || (decPt >= 0)) { - break; - } - decPt = mantSize; - } - p += 1; - } - - /* - * Now suck up the digits in the mantissa. Use two integers to collect 9 - * digits each (this is faster than using floating-point). If the mantissa - * has more than 18 digits, ignore the extras, since they can't affect the - * value anyway. - */ - - pExp = p; - p -= mantSize; - if (decPt < 0) { - decPt = mantSize; - } else { - mantSize -= 1; /* One of the digits was the point. */ - } - if (mantSize > 18) { - fracExp = decPt - 18; - mantSize = 18; - } else { - fracExp = decPt - mantSize; - } - if (mantSize == 0) { - fraction = 0.0; - p = string; - goto done; - } else { - int frac1, frac2; - - frac1 = 0; - for ( ; mantSize > 9; mantSize -= 1) { - c = *p; - p += 1; - if (c == '.') { - c = *p; - p += 1; - } - frac1 = 10*frac1 + (c - '0'); - } - frac2 = 0; - for (; mantSize > 0; mantSize -= 1) { - c = *p; - p += 1; - if (c == '.') { - c = *p; - p += 1; - } - frac2 = 10*frac2 + (c - '0'); - } - fraction = (1.0e9 * frac1) + frac2; - } - - /* - * Skim off the exponent. - */ - - p = pExp; - if ((*p == 'E') || (*p == 'e')) { - p += 1; - if (*p == '-') { - expSign = TRUE; - p += 1; - } else { - if (*p == '+') { - p += 1; - } - expSign = FALSE; - } - if (!isdigit(UCHAR(*p))) { - p = pExp; - goto done; - } - while (isdigit(UCHAR(*p))) { - exp = exp * 10 + (*p - '0'); - p += 1; - } - } - if (expSign) { - exp = fracExp - exp; - } else { - exp = fracExp + exp; - } - - /* - * Generate a floating-point number that represents the exponent. Do this - * by processing the exponent one bit at a time to combine many powers of - * 2 of 10. Then combine the exponent with the fraction. - */ - - if (exp < 0) { - expSign = TRUE; - exp = -exp; - } else { - expSign = FALSE; - } - if (exp > maxExponent) { - exp = maxExponent; - errno = ERANGE; - } - dblExp = 1.0; - for (d = powersOf10; exp != 0; exp >>= 1, ++d) { - if (exp & 01) { - dblExp *= *d; - } - } - if (expSign) { - fraction /= dblExp; - } else { - fraction *= dblExp; - } - - done: - if (endPtr != NULL) { - *endPtr = (char *) p; - } - - if (sign) { - return -fraction; - } - return fraction; -} |