/* Compatibility functions for floating point formatting, reentrant versions. Copyright (C) 1995,96,97,98,99,2000,01,02 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <errno.h> #include <float.h> #include <stdio.h> #include <string.h> #include <ctype.h> #include <math.h> #include <stdlib.h> #include <sys/param.h> #ifndef FLOAT_TYPE # define FLOAT_TYPE double # define FUNC_PREFIX # define FLOAT_FMT_FLAG # define FLOAT_NAME_EXT # if DBL_MANT_DIG == 53 # define NDIGIT_MAX 17 # elif DBL_MANT_DIG == 24 # define NDIGIT_MAX 9 # elif DBL_MANT_DIG == 56 # define NDIGIT_MAX 18 # else /* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a compile time constant here, so we cannot use it. */ # error "NDIGIT_MAX must be precomputed" # define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0))) # endif #endif #define APPEND(a, b) APPEND2 (a, b) #define APPEND2(a, b) a##b #define FLOOR APPEND(floor, FLOAT_NAME_EXT) #define FABS APPEND(fabs, FLOAT_NAME_EXT) #define LOG10 APPEND(log10, FLOAT_NAME_EXT) #define EXP APPEND(exp, FLOAT_NAME_EXT) int APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len) FLOAT_TYPE value; int ndigit, *decpt, *sign; char *buf; size_t len; { ssize_t n; ssize_t i; int left; if (buf == NULL) { __set_errno (EINVAL); return -1; } left = 0; if (isfinite (value)) { *sign = signbit (value) != 0; if (*sign) value = -value; if (ndigit < 0) { /* Rounding to the left of the decimal point. */ while (ndigit < 0) { FLOAT_TYPE new_value = value * 0.1; if (new_value < 1.0) { ndigit = 0; break; } value = new_value; ++left; ++ndigit; } } } else /* Value is Inf or NaN. */ *sign = 0; n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX), value); /* Check for a too small buffer. */ if (n >= (ssize_t) len) return -1; i = 0; while (i < n && isdigit (buf[i])) ++i; *decpt = i; if (i == 0) /* Value is Inf or NaN. */ return 0; if (i < n) { do ++i; while (i < n && !isdigit (buf[i])); if (*decpt == 1 && buf[0] == '0' && value != 0.0) { /* We must not have leading zeroes. Strip them all out and adjust *DECPT if necessary. */ --*decpt; while (i < n && buf[i] == '0') { --*decpt; ++i; } } memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i); buf[n - (i - MAX (*decpt, 0))] = '\0'; } if (left) { *decpt += left; if ((ssize_t) --len > n) { while (left-- > 0 && n < (ssize_t) len) buf[n++] = '0'; buf[n] = '\0'; } } return 0; } libc_hidden_def (APPEND (FUNC_PREFIX, fcvt_r)) int APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len) FLOAT_TYPE value; int ndigit, *decpt, *sign; char *buf; size_t len; { int exponent = 0; if (isfinite (value) && value != 0.0) { /* Slow code that doesn't require -lm functions. */ FLOAT_TYPE d; FLOAT_TYPE f = 1.0; if (value < 0.0) d = -value; else d = value; if (d < 1.0) { do { f *= 10.0; --exponent; } while (d * f < 1.0); value *= f; } else if (d >= 10.0) { do { f *= 10; ++exponent; } while (d >= f * 10.0); value /= f; } } else if (value == 0.0) /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0. This could be changed to -1 if we want to return 0. */ exponent = 0; if (ndigit <= 0 && len > 0) { buf[0] = '\0'; *decpt = 1; *sign = isfinite (value) ? signbit (value) != 0 : 0; } else if (APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1, decpt, sign, buf, len)) return -1; *decpt += exponent; return 0; } libc_hidden_def (APPEND (FUNC_PREFIX, ecvt_r))