diff options
Diffstat (limited to 'misc/efgcvt_r-template.c')
| -rw-r--r-- | misc/efgcvt_r-template.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/misc/efgcvt_r-template.c b/misc/efgcvt_r-template.c new file mode 100644 index 0000000000..1cd335afe7 --- /dev/null +++ b/misc/efgcvt_r-template.c @@ -0,0 +1,196 @@ +/* Compatibility functions for floating point formatting, reentrant versions. + Copyright (C) 1995-2019 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, see + <https://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <stdio.h> +#include <string.h> +#include <ctype.h> +#include <math.h> +#include <stdlib.h> +#include <sys/param.h> +#include <math_ldbl_opt.h> + + +#define APPEND(a, b) APPEND2 (a, b) +#define APPEND2(a, b) a##b +#define __APPEND(a, b) __APPEND2 (a, b) +#define __APPEND2(a, b) __##a##b + +int +__APPEND (FUNC_PREFIX, fcvt_r) (FLOAT_TYPE value, int ndigit, int *decpt, + int *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; +} + +int +__APPEND (FUNC_PREFIX, ecvt_r) (FLOAT_TYPE value, int ndigit, int *decpt, + int *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; + /* For denormalized numbers the d < 1.0 case below won't work, + as f can overflow to +Inf. */ + if (d < FLOAT_MIN_10_NORM) + { + value /= FLOAT_MIN_10_NORM; + if (value < 0.0) + d = -value; + else + d = value; + exponent += FLOAT_MIN_10_EXP; + } + 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; +} |