Fix a floating point presentation error
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5012 42af7a65-404d-4744-a932-0658087f49c3
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@ -3125,3 +3125,8 @@
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* lib/stdio/lib_libvsprintf.c: Fieldwidth and justification were not
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supported for the %s format. As a result, %s, %12s, and %-12s all
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produced the same output.
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* lib/stdio/lib_libdtoa.c: Fix several issues with presenting floating
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point numbers (conversions are fine, but presentation was bad). This
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is a critical bug fix if you use printf or sprintf to deal with floating
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point numbers.
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8
TODO
8
TODO
@ -15,7 +15,7 @@ nuttx/
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(5) Binary loaders (binfmt/)
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(17) Network (net/, drivers/net)
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(3) USB (drivers/usbdev, drivers/usbhost)
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(9) Libraries (lib/)
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(10) Libraries (lib/)
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(10) File system/Generic drivers (fs/, drivers/)
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(5) Graphics subystem (graphics/)
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(1) Pascal add-on (pcode/)
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@ -685,6 +685,12 @@ o Libraries (lib/)
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Status: Open
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Priority: Low -- more of a roadmap
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Title: FLOATING POINT FORMATS
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Description: Only the %f floating point format is supported. Others are accepted
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but treated like %f.
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Status: Open
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Priority: Medium (this might important to someone.
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o File system / Generic drivers (fs/, drivers/)
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -48,7 +48,13 @@
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* Pre-processor Definitions
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****************************************************************************/
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#define MAXEXP 308
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#ifndef MIN
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# define MIN(a,b) (a < b ? a : b)
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#endif
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#ifndef MAX
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# define MAX(a,b) (a > b ? a : b)
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#endif
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/****************************************************************************
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* Private Type Declarations
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@ -58,10 +64,6 @@
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* Private Function Prototypes
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****************************************************************************/
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static char* cvt(double value, int ndigits, int flags, char *sign,
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int *decpt, int ch, int *length);
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static int exponent(char *p0, int exp, int fmtch);
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/****************************************************************************
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* Global Constant Data
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****************************************************************************/
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@ -78,269 +80,123 @@ static int exponent(char *p0, int exp, int fmtch);
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Name: zeroes
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*
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* Description:
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* Print the specified number of zeres
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*
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****************************************************************************/
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static void zeroes(FAR struct lib_outstream_s *obj, int nzeroes)
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{
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int i;
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for (i = nzeroes; i > 0; i--)
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{
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obj->put(obj, '0');
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}
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}
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: cvt
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****************************************************************************/
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static char* cvt(double value, int ndigits, int flags, char *sign,
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int *decpt, int ch, int *length)
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{
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int mode, dsgn;
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char *digits, *bp, *rve;
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if (ch == 'f')
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{
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mode = 3; /* ndigits after the decimal point */
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}
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else
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{
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/* To obtain ndigits after the decimal point for the 'e' and 'E'
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* formats, round to ndigits + 1 significant figures.
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*/
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if (ch == 'e' || ch == 'E')
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{
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ndigits++;
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}
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mode = 2; /* ndigits significant digits */
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}
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if (value < 0)
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{
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value = -value;
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*sign = '-';
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}
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else
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{
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*sign = '\000';
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}
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digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
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if ((ch != 'g' && ch != 'G') || IS_ALTFORM(flags))
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{
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/* Print trailing zeros */
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bp = digits + ndigits;
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if (ch == 'f')
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{
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if (*digits == '0' && value)
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{
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*decpt = -ndigits + 1;
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}
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bp += *decpt;
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}
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if (value == 0)
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{
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/* kludge for __dtoa irregularity */
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rve = bp;
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}
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while (rve < bp)
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{
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*rve++ = '0';
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}
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}
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*length = rve - digits;
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return digits;
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}
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/****************************************************************************
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* Name: exponent
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****************************************************************************/
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static int exponent(FAR char *p0, int exp, int fmtch)
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{
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FAR char *p;
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FAR char *t;
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char expbuf[MAXEXP];
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p = p0;
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*p++ = fmtch;
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if (exp < 0)
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{
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exp = -exp;
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*p++ = '-';
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}
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else
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{
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*p++ = '+';
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}
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t = expbuf + MAXEXP;
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if (exp > 9)
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{
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do
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{
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*--t = (exp % 10) + '0';
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}
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while ((exp /= 10) > 9);
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*--t = exp + '0';
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for (; t < expbuf + MAXEXP; *p++ = *t++);
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}
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else
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{
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*p++ = '0';
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*p++ = exp + '0';
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}
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return (p - p0);
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}
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/****************************************************************************
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* Name: lib_dtoa
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*
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* Description:
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* This is part of lib_vsprintf(). It handles the floating point formats.
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* This version supports only the &f (with precision).
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*
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****************************************************************************/
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static void lib_dtoa(FAR struct lib_outstream_s *obj, int ch, int prec,
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uint8_t flags, double _double)
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static void lib_dtoa(FAR struct lib_outstream_s *obj, int fmt, int prec,
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uint8_t flags, double value)
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{
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FAR char *cp; /* Handy char pointer (short term usage) */
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FAR char *cp_free = NULL; /* BIONIC: copy of cp to be freed after usage */
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char expstr[7]; /* Buffer for exponent string */
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char sign; /* Temporary negative sign for floats */
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int expt; /* Integer value of exponent */
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int expsize = 0; /* Character count for expstr */
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int ndig; /* Actual number of digits returned by cvt */
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int size; /* Size of converted field or string */
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FAR char *digits; /* String returned by __dtoa */
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FAR char *digalloc; /* Copy of digits to be freed after usage */
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FAR char *rve; /* Points to the end of the return value */
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char sign; /* Temporary negative sign for floats */
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int expt; /* Integer value of exponent */
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int numlen; /* Actual number of digits returned by cvt */
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int nchars; /* Number of characters to print */
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int dsgn; /* Unused sign indicator */
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int i;
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cp = cvt(_double, prec, flags, &sign, &expt, ch, &ndig);
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cp_free = cp;
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/* Non-zero... positive or negative */
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if (ch == 'g' || ch == 'G')
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if (value < 0)
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{
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/* 'g' or 'G' fmt */
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if (expt <= -4 || expt > prec)
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{
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ch = (ch == 'g') ? 'e' : 'E';
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}
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else
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{
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ch = 'g';
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}
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}
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if (ch <= 'e')
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{
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/* 'e' or 'E' fmt */
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--expt;
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expsize = exponent(expstr, expt, ch);
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size = expsize + ndig;
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if (ndig > 1 || IS_ALTFORM(flags))
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{
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++size;
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}
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}
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else if (ch == 'f')
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{
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/* f fmt */
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if (expt > 0)
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{
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size = expt;
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if (prec || IS_ALTFORM(flags))
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{
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size += prec + 1;
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}
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}
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else /* "0.X" */
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{
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size = prec + 2;
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}
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}
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else if (expt >= ndig)
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{
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/* fixed g fmt */
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size = expt;
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if (IS_ALTFORM(flags))
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{
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++size;
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}
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value = -value;
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sign = '-';
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}
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else
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{
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size = ndig + (expt > 0 ? 1 : 2 - expt);
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sign = '\0';
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}
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/* Perform the conversion */
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digits = __dtoa(value, 3, prec, &expt, &dsgn, &rve);
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digalloc = digits;
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numlen = rve - digits;
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if (sign)
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{
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obj->put(obj, '-');
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}
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if (_double == 0)
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/* Always print at least one digit to the right of the decimal point. */
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prec = MAX(1, prec);
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/* Special case exact zero or the case where the number is smaller than
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* the print precision.
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*/
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if (value == 0 || expt < -prec)
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{
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/* kludge for __dtoa irregularity */
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obj->put(obj, '0');
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if (expt < ndig || IS_ALTFORM(flags))
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{
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obj->put(obj, '.');
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i = ndig - 1;
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while (i > 0)
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{
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obj->put(obj, '0');
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i--;
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}
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}
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obj->put(obj, '.');
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}
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else if (expt <= 0)
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{
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obj->put(obj, '0');
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obj->put(obj, '.');
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i = ndig;
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while (i > 0)
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/* Print leading zeros */
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if (expt < 0)
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{
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obj->put(obj, *cp);
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i--;
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cp++;
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nchars = MIN(-expt, prec);
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zeroes(obj, nchars);
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prec -= nchars;
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}
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}
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else if (expt >= ndig)
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{
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i = ndig;
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while (i > 0)
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/* Print the significant digits */
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nchars = MIN(numlen, prec);
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for (i = nchars; i > 0; i--)
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{
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obj->put(obj, *cp);
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i--;
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cp++;
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obj->put(obj, *digits);
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digits++;
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}
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i = expt - ndig;
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while (i > 0)
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{
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obj->put(obj, '0');
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i--;
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}
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/* Decremnt to get the number of trailing zeroes to print */
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if (IS_ALTFORM(flags))
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{
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obj->put(obj, '.');
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}
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prec -= nchars;
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}
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else
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{
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/* Print the integer */
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/* Print the integer part */
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i = expt;
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while (i > 0)
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for (i = expt; i > 0; i--)
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{
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obj->put(obj, *cp);
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i--;
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cp++;
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obj->put(obj, *digits);
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digits++;
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}
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/* Print the decimal place */
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@ -349,14 +205,32 @@ static void lib_dtoa(FAR struct lib_outstream_s *obj, int ch, int prec,
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/* Print the decimal */
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i = ndig - expt;
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while (i > 0)
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numlen -= expt;
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nchars = MIN(numlen, prec);
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for (i = nchars; i > 0; i--)
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{
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obj->put(obj, *cp);
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i--;
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cp++;
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obj->put(obj, *digits);
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digits++;
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}
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/* Decremnt to get the number of trailing zeroes to print */
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prec -= nchars;
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}
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/* Finally, print any trailing zeroes */
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zeroes(obj, prec);
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/* Is this memory supposed to be freed or not? */
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#if 0
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if (digalloc)
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{
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free(digalloc);
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}
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#endif
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}
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/****************************************************************************
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