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-rw-r--r--libc/misc/internals/dtostr.c368
1 files changed, 262 insertions, 106 deletions
diff --git a/libc/misc/internals/dtostr.c b/libc/misc/internals/dtostr.c
index d9ab80bbb..9fe7b2624 100644
--- a/libc/misc/internals/dtostr.c
+++ b/libc/misc/internals/dtostr.c
@@ -1,55 +1,27 @@
/*
- * Copyright (C) 2000 Manuel Novoa III
+ * Copyright (C) 2000, 2001 Manuel Novoa III
*
- * Function: const char *__dtostr(double x)
+ * Function: int __dtostr(FILE * fp, size_t size, double x,
+ * char flag[], int width, int preci, char mode)
*
- * This was written for uClibc to give it the ability to at least output
- * floating point values in exponential form. No formatting is done.
- * No trailing 0's are removed. Number of digits generated is not
- * runtime selectable. It does however handle +/- infinity and nan on i386.
- *
- * The goal was usable floating point %e-type output in minimal size. For
- * me, "gcc -c -Os -fomit-frame-pointer dtostr.c && size dtostr.o" gives
- * text data bss dec hex filename
- * 535 9 26 570 23a dtostr.o (WANT_EXP_FORM = 1)
- * 530 9 26 565 235 dtostr.o (WANT_EXP_FORM = 0)
- *
- * Output is of the form [-][#].######{e|E}{+|-}##. Choices of upper or
- * lower case exponent character, and initial digit/initial decimal forms
- * are compile-time options. Number of digits generated is also selected
- * at compile time (MAX_DIGITS).
+ * This was written for uClibc to provide floating point support for
+ * the printf functions. It handles +/- infinity and nan on i386.
*
* Notes:
*
- * The primary objective of this implementation was minimal size while
- * maintaining reasonable accuracy. It should also be fairly portable,
- * as not assumptions are made about the bit-layout of doubles.
+ * It should also be fairly portable, as not assumptions are made about the
+ * bit-layout of doubles.
*
* It should be too difficult to convert this to handle long doubles on i386.
* For information, see the comments below.
*
- * There are 2 compile-time options below, as well as some tuning parameters.
- *
* TODO:
* long double and/or float version? (note: for float can trim code some).
+ *
+ * Decrease the size. This is really much bigger than I'd like.
*/
/*****************************************************************************/
-/* OPTIONS */
-/*****************************************************************************/
-
-/*
- * Set this if you want output results with 1 digit before the decimal point.
- * If this is 0, all digits follow a leading decimal point.
- */
-#define WANT_EXP_FORM 1
-
-/*
- * Set if you want exponent character 'E' rather than 'e'.
- */
-#define EXP_UPPERCASE 1
-
-/*****************************************************************************/
/* Don't change anything that follows unless you know what you're doing. */
/*****************************************************************************/
@@ -68,6 +40,11 @@
#define MAX_DIGITS 17
/*
+ * Set this to the smallest integer type capable of storing a pointer.
+ */
+#define INT_OR_PTR int
+
+/*
* This is really only used to check for infinities. The macro produces
* smaller code for i386 and, since this is tested before any floating point
* calculations, it doesn't appear to suffer from the excess precision problem
@@ -90,9 +67,25 @@ extern int _zero_or_inf_check(double x);
/* Don't change anything that follows peroid!!! ;-) */
/*****************************************************************************/
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
#include <float.h>
#include <limits.h>
+extern int fnprintf(FILE * fp, size_t size, const char *fmt, ...);
+
+/* from printf.c -- should really be in an internal header file */
+enum {
+ FLAG_PLUS = 0,
+ FLAG_MINUS_LJUSTIFY,
+ FLAG_HASH,
+ FLAG_0_PAD,
+ FLAG_SPACE,
+};
+
+/*****************************************************************************/
+
/*
* Set things up for the scaling power table.
*/
@@ -119,60 +112,88 @@ extern int _zero_or_inf_check(double x);
#if (INT_MAX >> 30)
#define DIGIT_BLOCK_TYPE int
+#define DB_FMT "%.*d"
#elif (LONG_MAX >> 30)
#define DIGIT_BLOCK_TYPE long
+#define DB_FMT "%.*ld"
#else
#error need at least 32 bit longs
#endif
-/*
- * This is kind of a place-holder for LONG_DOUBLE support to show what I
- * think needs to be changed. I haven't tried it though. Changing this
- * from 3 to 4 and converting double to long double should work on i386.
- * DON'T FORGET to increase EXP_TABLE_SIZE and MAX_DIGITS.
- * DON'T FORGET the "larger EXP_TABLE_SIZE needed" check above.
- */
-#define MAX_EXP_DIGITS 3
+/* Are there actually any machines where this might fail? */
+#if 'A' > 'a'
+#error ordering assumption violated : 'A' > 'a'
+#endif
+
+/* Maximum number of calls to fnprintf to output double. */
+#define MAX_CALLS 8
/*****************************************************************************/
#define NUM_DIGIT_BLOCKS ((MAX_DIGITS+DIGITS_PER_BLOCK-1)/DIGITS_PER_BLOCK)
-static char infstr[] = " inf"; /* save space for a - sign */
-static char nanstr[] = "nan";
-
/* extra space for '-', '.', 'e+###', and nul */
-/*static char buf[ 5 + MAX_EXP_DIGITS + NUM_DIGIT_BLOCKS * DIGITS_PER_BLOCK];*/
-#define BUF_SIZE ( 5 + MAX_EXP_DIGITS + NUM_DIGIT_BLOCKS * DIGITS_PER_BLOCK )
+#define BUF_SIZE ( 3 + NUM_DIGIT_BLOCKS * DIGITS_PER_BLOCK )
/*****************************************************************************/
-const char *__dtostr(char *buf, double x)
+static const char *fmts[] = {
+ "%0*d", "%.*s", ".", "inf", "INF", "nan", "NAN", "%*s"
+};
+
+/*****************************************************************************/
+
+int __dtostr(FILE * fp, size_t size, double x,
+ char flag[], int width, int preci, char mode)
{
double exp_table[EXP_TABLE_SIZE];
double p10;
DIGIT_BLOCK_TYPE digit_block; /* int of at least 32 bits */
int i, j;
+ int round, o_exp;
int exp, exp_neg;
- int negative = 0;
- char *pos;
-
+ char *s;
+ char *e;
+ char buf[BUF_SIZE];
+ char buf2[BUF_SIZE];
+ INT_OR_PTR pc_fwi[2*MAX_CALLS];
+ INT_OR_PTR *ppc;
+ char exp_buf[8];
+ char drvr[8];
+ char *pdrvr;
+ int npc;
+ int cnt;
+ char sign_str[2];
+ char o_mode;
+
+ /* check that INT_OR_PTR is sufficiently large */
+ assert( sizeof(INT_OR_PTR) == sizeof(char *) );
+
+ *sign_str = flag[FLAG_PLUS];
+ *(sign_str+1) = 0;
if (isnan(x)) { /* nan check */
- return nanstr;
+ pdrvr = drvr + 1;
+ *pdrvr++ = 5 + (mode < 'a');
+ pc_fwi[2] = 3;
+ flag[FLAG_0_PAD] = 0;
+ goto EXIT_SPECIAL;
}
if (x == 0) { /* handle 0 now to avoid false positive */
- exp = 0; /* with inf test, and to avoid scaling */
- goto GENERATE_DIGITS; /* note: time vs space tradeoff */
+ exp = -1;
+ goto GENERATE_DIGITS;
}
if (x < 0) { /* convert negatives to positives */
- negative = 1;
+ *sign_str = '-';
x = -x;
}
if (_zero_or_inf_check(x)) { /* must be inf since zero handled above */
- pos = infstr + 1;
- goto DO_SIGN;
+ pdrvr = drvr + 1;
+ *pdrvr++ = 3 + + (mode < 'a');
+ pc_fwi[2] = 3;
+ flag[FLAG_0_PAD] = 0;
+ goto EXIT_SPECIAL;
}
/* need to build the scaling table */
@@ -186,11 +207,7 @@ const char *__dtostr(char *buf, double x)
exp_neg = 1;
}
-#if WANT_EXP_FORM
exp = DIGITS_PER_BLOCK - 1;
-#else
- exp = DIGITS_PER_BLOCK;
-#endif
i = EXP_TABLE_SIZE;
j = EXP_TABLE_MAX;
@@ -208,64 +225,203 @@ const char *__dtostr(char *buf, double x)
}
j >>= 1;
}
+ if (x >= 1e9) { /* handle bad rounding case */
+ x /= 10;
+ ++exp;
+ }
+ assert(x < 1e9);
GENERATE_DIGITS:
- pos = buf - BUF_SIZE + 1 + DIGITS_PER_BLOCK + 1; /* leave space for '.' and - */
+ s = buf2 + 2; /* leave space for '\0' and '0' */
for (i = 0 ; i < NUM_DIGIT_BLOCKS ; ++i ) {
- digit_block = (int) x;
+ digit_block = (DIGIT_BLOCK_TYPE) x;
x = (x - digit_block) * 1e9;
- for (j = 0 ; j < DIGITS_PER_BLOCK ; j++) {
- *--pos = '0' + (digit_block % 10);
- digit_block /= 10;
+ s += sprintf(s, DB_FMT, DIGITS_PER_BLOCK, digit_block);
+ }
+
+ /*************************************************************************/
+
+ *exp_buf = 'e';
+ if (mode < 'a') {
+ *exp_buf = 'E';
+ mode += ('a' - 'A');
+ }
+
+ o_mode = mode;
+
+ round = preci;
+
+ if ((mode == 'g') && (round > 0)){
+ --round;
+ }
+
+ if (mode == 'f') {
+ round += exp;
+ }
+
+ RESTART:
+ memcpy(buf,buf2,sizeof(buf2)); /* backup in case g need to be f */
+
+ s = buf;
+ *s++ = 0; /* terminator for rounding and 0-triming */
+ *s = '0'; /* space to round */
+
+ i = 0;
+ e = s + MAX_DIGITS + 1;
+ if (round < MAX_DIGITS) {
+ e = s + round + 2;
+ if (*e >= '5') {
+ i = 1;
}
- pos += (2*DIGITS_PER_BLOCK);
}
- pos -= (DIGITS_PER_BLOCK*(NUM_DIGIT_BLOCKS+1))-MAX_DIGITS;
- /* start generating the exponent */
-#if EXP_UPPERCASE
- *pos = 'E';
-#else
- *pos = 'e';
-#endif
- *++pos = '+';
- if (exp < 0) {
- *pos = '-';
- exp = -exp;
+ do { /* handle rounding and trim trailing 0s */
+ *--e += i; /* add the carry */
+ } while ((*e == '0') || (*e > '9'));
+
+ o_exp = exp;
+ if (e <= s) { /* we carried into extra digit */
+ ++o_exp;
+ e = s; /* needed if all 0s */
+ } else {
+ ++s;
+ }
+ *++e = 0; /* ending nul char */
+
+ if ((mode == 'g') && ((o_exp >= -4) && (o_exp < round))) {
+ mode = 'f';
+ goto RESTART;
}
- pos += 3; /* WARNING: Assumes max exp < 1000!!! */
- if (exp >= 100) {
- ++pos;
-#if MAX_EXP_DIGITS > 4
-#error need to modify exponent string generation code
-#elif MAX_EXP_DIGITS > 3
- if (exp >= 1000) { /* WARNING: hasn't been checked */
- ++pos; /* but should work */
+
+ exp = o_exp;
+ if (mode != 'f') {
+ o_exp = 0;
+ }
+
+ if (o_exp < 0) {
+ *--s = '0'; /* fake the first digit */
+ }
+
+ pdrvr = drvr+1;
+ ppc = pc_fwi+2;
+
+ *pdrvr++ = 0;
+ *ppc++ = 1;
+ *ppc++ = (INT_OR_PTR)(*s++ - '0');
+
+ i = e - s; /* total digits */
+ if (o_exp >= 0) {
+ if (o_exp >= i) { /* all digit(s) left of decimal */
+ *pdrvr++ = 1;
+ *ppc++ = i;
+ *ppc++ = (INT_OR_PTR)(s);
+ o_exp -= i;
+ i = 0;
+ if (o_exp>0) { /* have 0s left of decimal */
+ *pdrvr++ = 0;
+ *ppc++ = o_exp;
+ *ppc++ = 0;
+ }
+ } else if (o_exp > 0) { /* decimal between digits */
+ *pdrvr++ = 1;
+ *ppc++ = o_exp;
+ *ppc++ = (INT_OR_PTR)(s);
+ s += o_exp;
+ i -= o_exp;
}
-#endif
+ o_exp = -1;
+ }
+
+ if (flag[FLAG_HASH] || (i) || ((o_mode != 'g') && (preci > 0))) {
+ *pdrvr++ = 2; /* need decimal */
+ *ppc++ = 1; /* needed for width calc */
+ ppc++;
}
- *pos = '\0';
-
- for (j = 0 ; (j < 2) || exp ; j++) { /* standard says at least 2 digits */
- *--pos = '0' + (exp % 10);
- exp /= 10;
+
+ if (++o_exp < 0) { /* have 0s right of decimal */
+ *pdrvr++ = 0;
+ *ppc++ = -o_exp;
+ *ppc++ = 0;
+ }
+ if (i) { /* have digit(s) right of decimal */
+ *pdrvr++ = 1;
+ *ppc++ = i;
+ *ppc++ = (INT_OR_PTR)(s);
+ }
+
+ if (o_mode != 'g') {
+ i -= o_exp;
+ if (i < preci) { /* have 0s right of digits */
+ i = preci - i;
+ *pdrvr++ = 0;
+ *ppc++ = i;
+ *ppc++ = 0;
+ }
}
- /* insert the decimal point */
- pos = buf - BUF_SIZE + 1;
+ /* build exponent string */
+ if (mode != 'f') {
+ *pdrvr++ = 1;
+ *ppc++ = sprintf(exp_buf,"%c%+.2d", *exp_buf, exp);
+ *ppc++ = (INT_OR_PTR) exp_buf;
+ }
-#if WANT_EXP_FORM
- *pos = *(pos+1);
- *(pos+1) = '.';
+ EXIT_SPECIAL:
+ npc = pdrvr - drvr;
+ ppc = pc_fwi + 2;
+ for (i=1 ; i< npc ; i++) {
+ width -= *(ppc++);
+ ppc++;
+ }
+ i = 0;
+ if (*sign_str) {
+ i = 1;
+ }
+ width -= i;
+ if (width <= 0) {
+ width = 0;
+ } else {
+ if (flag[FLAG_MINUS_LJUSTIFY]) { /* padding on right */
+ ++npc;
+ *pdrvr++ = 7;
+ *ppc = width;
+ *++ppc = (INT_OR_PTR)("");
+ width = 0;
+ } else if (flag[FLAG_0_PAD] == '0') { /* 0 padding */
+ pc_fwi[2] += width;
+ width = 0;
+ }
+ }
+ *drvr = 7;
+ ppc = pc_fwi;
+ *ppc++ = width + i;
+ *ppc = (INT_OR_PTR) sign_str;
+
+ pdrvr = drvr;
+ ppc = pc_fwi;
+ cnt = 0;
+ for (i=0 ; i<npc ; i++) {
+#if 1
+ fnprintf(fp, size, fmts[(int)(*pdrvr++)], (INT_OR_PTR)(*(ppc)),
+ (INT_OR_PTR)(*(ppc+1)));
#else
- *pos = '.';
+ j = fnprintf(fp, size, fmts[(int)(*pdrvr++)], (INT_OR_PTR)(*(ppc)),
+ (INT_OR_PTR)(*(ppc+1)));
+ assert(j == *ppc);
#endif
-
- DO_SIGN:
- if (negative) {
- *--pos = '-';
+ if (size > *ppc) {
+ size -= *ppc;
+ }
+ cnt += *ppc; /* to avoid problems if j == -1 */
+ ppc += 2;
}
- return pos;
+ return cnt;
}
+
+
+
+
+
+
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