1 files changed, 327 insertions, 0 deletions
diff --git a/source/fitz/ftoa.c b/source/fitz/ftoa.c
new file mode 100644
index 00000000..dc3ce73b
--- /dev/null
+++ b/source/fitz/ftoa.c
@@ -0,0 +1,327 @@
+/* The authors of this software are Rob Pike and Ken Thompson.
+ * Copyright (c) 2002 by Lucent Technologies.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose without fee is hereby granted, provided that this entire notice
+ * is included in all copies of any software which is or includes a copy
+ * or modification of this software and in all copies of the supporting
+ * documentation for such software.
+ * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
+ * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
+ * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ */
+
+#include "mupdf/fitz.h"
+
+#include <stdio.h>
+#include <math.h>
+#include <float.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#ifndef INFINITY
+#define INFINITY (DBL_MAX+DBL_MAX)
+#endif
+#ifndef NAN
+#define NAN (INFINITY-INFINITY)
+#endif
+
+typedef unsigned long ulong;
+
+enum { NSIGNIF	= 9 };
+
+/*
+ * first few powers of 10
+ */
+static float pows10[] =
+{
+	1e0,	1e1,	1e2,	1e3,	1e4,	1e5,	1e6,	1e7,	1e8,	1e9,
+	1e10,	1e11,	1e12,	1e13,	1e14,	1e15,	1e16,	1e17,	1e18,	1e19,
+	1e20,	1e21,	1e22,	1e23,	1e24,	1e25,	1e26,	1e27,	1e28,	1e29,
+	1e30,	1e31,	1e32,	1e33,	1e34,	1e35,	1e36,	1e37,	1e38,	1e39,
+};
+#define	npows10 ((int)(sizeof(pows10)/sizeof(pows10[0])))
+#define	pow10(x) fmtpow10(x)
+
+static float
+pow10(int n)
+{
+	float d;
+	int neg;
+
+	neg = 0;
+	if(n < 0){
+		neg = 1;
+		n = -n;
+	}
+
+	if(n < npows10)
+		d = pows10[n];
+	else{
+		d = pows10[npows10-1];
+		for(;;){
+			n -= npows10 - 1;
+			if(n < npows10){
+				d *= pows10[n];
+				break;
+			}
+			d *= pows10[npows10 - 1];
+		}
+	}
+	if(neg)
+		return 1./d;
+	return d;
+}
+
+/*
+ * add 1 to the decimal integer string a of length n.
+ * if 99999 overflows into 10000, return 1 to tell caller
+ * to move the virtual decimal point.
+ */
+static int
+xadd1(char *a, int n)
+{
+	char *b;
+	int c;
+
+	if(n < 0 || n > NSIGNIF)
+		return 0;
+	for(b = a+n-1; b >= a; b--) {
+		c = *b + 1;
+		if(c <= '9') {
+			*b = c;
+			return 0;
+		}
+		*b = '0';
+	}
+	/*
+	 * need to overflow adding digit.
+	 * shift number down and insert 1 at beginning.
+	 * decimal is known to be 0s or we wouldn't
+	 * have gotten this far. (e.g., 99999+1 => 00000)
+	 */
+	a[0] = '1';
+	return 1;
+}
+
+/*
+ * subtract 1 from the decimal integer string a.
+ * if 10000 underflows into 09999, make it 99999
+ * and return 1 to tell caller to move the virtual
+ * decimal point. this way, xsub1 is inverse of xadd1.
+ */
+static int
+xsub1(char *a, int n)
+{
+	char *b;
+	int c;
+
+	if(n < 0 || n > NSIGNIF)
+		return 0;
+	for(b = a+n-1; b >= a; b--) {
+		c = *b - 1;
+		if(c >= '0') {
+			if(c == '0' && b == a) {
+				/*
+				 * just zeroed the top digit; shift everyone up.
+				 * decimal is known to be 9s or we wouldn't
+				 * have gotten this far. (e.g., 10000-1 => 09999)
+				 */
+				*b = '9';
+				return 1;
+			}
+			*b = c;
+			return 0;
+		}
+		*b = '9';
+	}
+	/*
+	 * can't get here. the number a is always normalized
+	 * so that it has a nonzero first digit.
+	 */
+	return 0;
+}
+
+/*
+ * format exponent like sprintf(p, "e%+d", e)
+ */
+static void
+fmtexp(char *p, int e)
+{
+	char se[9];
+	int i;
+
+	*p++ = 'e';
+	if(e < 0) {
+		*p++ = '-';
+		e = -e;
+	} else
+		*p++ = '+';
+	i = 0;
+	while(e) {
+		se[i++] = e % 10 + '0';
+		e /= 10;
+	}
+	while(i < 1)
+		se[i++] = '0';
+	while(i > 0)
+		*p++ = se[--i];
+	*p++ = '\0';
+}
+
+/*
+ * compute decimal integer m, exp such that:
+ *	f = m*10^exp
+ *	m is as short as possible with losing exactness
+ * assumes special cases (NaN, +Inf, -Inf) have been handled.
+ */
+void
+fz_ftoa(float f, char *s, int *exp, int *neg, int *ns)
+{
+	int c, d, e2, e, ee, i, ndigit, oerrno;
+	char tmp[NSIGNIF+10];
+	float g;
+
+	oerrno = errno; /* in case strtod smashes errno */
+
+	/*
+	 * make f non-negative.
+	 */
+	*neg = 0;
+	if(f < 0) {
+		f = -f;
+		*neg = 1;
+	}
+
+	/*
+	 * must handle zero specially.
+	 */
+	if(f == 0){
+		*exp = 0;
+		s[0] = '0';
+		s[1] = '\0';
+		*ns = 1;
+		return;
+	}
+
+	/*
+	 * find g,e such that f = g*10^e.
+	 * guess 10-exponent using 2-exponent, then fine tune.
+	 */
+	frexpf(f, &e2);
+	e = (int)(e2 * .301029995664f);
+	g = f * pow10(-e);
+	while(g < 1) {
+		e--;
+		g = f * pow10(-e);
+	}
+	while(g >= 10) {
+		e++;
+		g = f * pow10(-e);
+	}
+
+	/*
+	 * convert NSIGNIF digits as a first approximation.
+	 */
+	for(i=0; i<NSIGNIF; i++) {
+		d = (int)g;
+		s[i] = d+'0';
+		g = (g-d) * 10;
+	}
+	s[i] = 0;
+
+	/*
+	 * adjust e because s is 314159... not 3.14159...
+	 */
+	e -= NSIGNIF-1;
+	fmtexp(s+NSIGNIF, e);
+
+	/*
+	 * adjust conversion until strtod(s) == f exactly.
+	 */
+	for(i=0; i<10; i++) {
+		g = fz_strtod(s, NULL);
+		if(f > g) {
+			if(xadd1(s, NSIGNIF)) {
+				/* gained a digit */
+				e--;
+				fmtexp(s+NSIGNIF, e);
+			}
+			continue;
+		}
+		if(f < g) {
+			if(xsub1(s, NSIGNIF)) {
+				/* lost a digit */
+				e++;
+				fmtexp(s+NSIGNIF, e);
+			}
+			continue;
+		}
+		break;
+	}
+
+	/*
+	 * play with the decimal to try to simplify.
+	 */
+
+	/*
+	 * bump last few digits up to 9 if we can
+	 */
+	for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
+		c = s[i];
+		if(c != '9') {
+			s[i] = '9';
+			g = fz_strtod(s, NULL);
+			if(g != f) {
+				s[i] = c;
+				break;
+			}
+		}
+	}
+
+	/*
+	 * add 1 in hopes of turning 9s to 0s
+	 */
+	if(s[NSIGNIF-1] == '9') {
+		strcpy(tmp, s);
+		ee = e;
+		if(xadd1(tmp, NSIGNIF)) {
+			ee--;
+			fmtexp(tmp+NSIGNIF, ee);
+		}
+		g = fz_strtod(tmp, NULL);
+		if(g == f) {
+			strcpy(s, tmp);
+			e = ee;
+		}
+	}
+
+	/*
+	 * bump last few digits down to 0 as we can.
+	 */
+	for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
+		c = s[i];
+		if(c != '0') {
+			s[i] = '0';
+			g = fz_strtod(s, NULL);
+			if(g != f) {
+				s[i] = c;
+				break;
+			}
+		}
+	}
+
+	/*
+	 * remove trailing zeros.
+	 */
+	ndigit = NSIGNIF;
+	while(ndigit > 1 && s[ndigit-1] == '0'){
+		e++;
+		--ndigit;
+	}
+	s[ndigit] = 0;
+	*exp = e;
+	*ns = ndigit;
+	errno = oerrno;
+}