/**************************************************************************** * libc/unistd/lib_libdtoa.c * * This file was ported to NuttX by Yolande Cates. * * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Chris Torek. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include "libc.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define MAX_PREC 16 #ifndef MIN # define MIN(a,b) (a < b ? a : b) #endif #ifndef MAX # define MAX(a,b) (a > b ? a : b) #endif /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Public Constant Data ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Constant Data ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: zeroes * * Description: * Print the specified number of zeres * ****************************************************************************/ static void zeroes(FAR struct lib_outstream_s *obj, int nzeroes) { int i; for (i = nzeroes; i > 0; i--) { obj->put(obj, '0'); } } /**************************************************************************** * Name: lib_dtoa_string * * Description: * Print the specified string * ****************************************************************************/ static void lib_dtoa_string(FAR struct lib_outstream_s *obj, const char *str) { while (*str) { obj->put(obj, *str++); } } /**************************************************************************** * Name: lib_dtoa * * Description: * This is part of lib_vsprintf(). It handles the floating point formats. * This version supports only the %f (with precision). If no precision * was provided in the format, this will use precision == 0 which is * probably not what you want. * * Input Parameters: * obj - The output stream object * fmt - The format character. Not used 'f' is always assumed * prec - The number of digits to the right of the decimal point. If no * precision is provided in the format, this will be zero. And, * unfortunately in this case, it will be treated literally as * a precision of zero. * flags - Only ALTFORM and SHOWPLUS flags are supported. ALTFORM only * applies if prec == 0 which is not supported anyway. * value - The floating point value to convert. * ****************************************************************************/ static void lib_dtoa(FAR struct lib_outstream_s *obj, int fmt, int prec, uint8_t flags, double value) { FAR char *digits; /* String returned by __dtoa */ FAR char *rve; /* Points to the end of the return value */ int expt; /* Integer value of exponent */ int numlen; /* Actual number of digits returned by cvt */ int nchars; /* Number of characters to print */ int dsgn; /* Unused sign indicator */ int i; /* This function may *NOT* be called within interrupt level logic. That is * because the logic in __dtoa may attempt to allocate memory. That will * lead to cryptic failures down the road within the memory manager. * Better to explicitly assert upstream here. Rule: Don't use floating * point formats on any output from interrupt handling logic. */ DEBUGASSERT(up_interrupt_context() == false); /* Special handling for NaN and Infinity */ if (isnan(value)) { lib_dtoa_string(obj, "NaN"); return; } if (isinf(value)) { if (value < 0.0) { obj->put(obj, '-'); } lib_dtoa_string(obj, "Infinity"); return; } /* Non-zero... positive or negative */ if (value < 0) { value = -value; SET_NEGATE(flags); } /* Perform the conversion */ digits = __dtoa(value, 3, prec, &expt, &dsgn, &rve); numlen = rve - digits; /* Avoid precision error from missing trailing zeroes */ numlen = MAX(expt, numlen); if (IS_NEGATE(flags)) { obj->put(obj, '-'); } else if (IS_SHOWPLUS(flags)) { obj->put(obj, '+'); } /* Special case exact zero or the case where the number is smaller than * the print precision. */ if (value == 0 || expt < -prec) { /* kludge for __dtoa irregularity */ obj->put(obj, '0'); /* A decimal point is printed only in the alternate form or if a * particular precision is requested. */ if (prec > 0 || IS_ALTFORM(flags)) { obj->put(obj, '.'); /* Always print at least one digit to the right of the decimal point. */ prec = MAX(1, prec); } } /* A non-zero value will be printed */ else { /* Handle the case where the value is less than 1.0 (in magnitude) and * will need a leading zero. */ if (expt <= 0) { /* Print a single zero to the left of the decimal point */ obj->put(obj, '0'); /* Print the decimal point */ obj->put(obj, '.'); /* Print any leading zeros to the right of the decimal point */ if (expt < 0) { nchars = MIN(-expt, prec); zeroes(obj, nchars); prec -= nchars; } } /* Handle the general case where the value is greater than 1.0 (in * magnitude). */ else { /* Print the integer part to the left of the decimal point */ for (i = expt; i > 0; i--) { if (*digits != '\0') { obj->put(obj, *digits); digits++; } else { obj->put(obj, '0'); } } /* Get the length of the fractional part */ numlen -= expt; /* If there is no fractional part, then a decimal point is printed * only in the alternate form or if a particular precision is * requested. */ if (numlen > 0 || prec > 0 || IS_ALTFORM(flags)) { /* Print the decimal point */ obj->put(obj, '.'); /* Always print at least one digit to the right of the decimal * point. */ prec = MAX(1, prec); } } /* If a precision was specified, then limit the number digits to the * right of the decimal point. */ if (prec > 0) { nchars = MIN(numlen, prec); } else { nchars = numlen; } /* Print the fractional part to the right of the decimal point */ for (i = nchars; i > 0; i--) { obj->put(obj, *digits); digits++; } /* Decrement to get the number of trailing zeroes to print */ prec -= nchars; } /* Finally, print any trailing zeroes */ zeroes(obj, prec); } /**************************************************************************** * Public Functions ****************************************************************************/