a

libmp/mpfmt.c

@@ -0,0 +1,193 @@
+#include "os.h"
+#include <mp.h>
+#include <libsec.h>
+#include "dat.h"
+
+static int
+to64(mpint *b, char *buf, int len)
+{
+	uchar *p;
+	int n, rv;
+
+	p = nil;
+	n = mptobe(b, nil, 0, &p);
+	if(n < 0)
+		return -1;
+	rv = enc64(buf, len, p, n);
+	free(p);
+	return rv;
+}
+
+static int
+to32(mpint *b, char *buf, int len)
+{
+	uchar *p;
+	int n, rv;
+
+	// leave room for a multiple of 5 buffer size
+	n = b->top*Dbytes + 5;
+	p = malloc(n);
+	if(p == nil)
+		return -1;
+	n = mptobe(b, p, n, nil);
+	if(n < 0)
+		return -1;
+
+	// round up buffer size, enc32 only accepts a multiple of 5
+	if(n%5)
+		n += 5 - (n%5);
+	rv = enc32(buf, len, p, n);
+	free(p);
+	return rv;
+}
+
+static char set16[] = "0123456789ABCDEF";
+
+static int
+to16(mpint *b, char *buf, int len)
+{
+	mpdigit *p, x;
+	int i, j;
+	char *out, *eout;
+
+	if(len < 1)
+		return -1;
+
+	out = buf;
+	eout = buf+len;
+	for(p = &b->p[b->top-1]; p >= b->p; p--){
+		x = *p;
+		for(i = Dbits-4; i >= 0; i -= 4){
+			j = 0xf & (x>>i);
+			if(j != 0 || out != buf){
+				if(out >= eout)
+					return -1;
+				*out++ = set16[j];
+			}
+		}
+	}
+	if(out == buf)
+		*out++ = '0';
+	if(out >= eout)
+		return -1;
+	*out = 0;
+	return 0;
+}
+
+static char*
+modbillion(int rem, ulong r, char *out, char *buf)
+{
+	ulong rr;
+	int i;
+
+	for(i = 0; i < 9; i++){
+		rr = r%10;
+		r /= 10;
+		if(out <= buf)
+			return nil;
+		*--out = '0' + rr;
+		if(rem == 0 && r == 0)
+			break;
+	}
+	return out;
+}
+
+static int
+to10(mpint *b, char *buf, int len)
+{
+	mpint *d, *r, *billion;
+	char *out;
+
+	if(len < 1)
+		return -1;
+
+	d = mpcopy(b);
+	r = mpnew(0);
+	billion = uitomp(1000000000, nil);
+	out = buf+len;
+	*--out = 0;
+	do {
+		mpdiv(d, billion, d, r);
+		out = modbillion(d->top, r->p[0], out, buf);
+		if(out == nil)
+			break;
+	} while(d->top != 0);
+	mpfree(d);
+	mpfree(r);
+	mpfree(billion);
+
+	if(out == nil)
+		return -1;
+	len -= out-buf;
+	if(out != buf)
+		memmove(buf, out, len);
+	return 0;
+}
+
+int
+mpfmt(Fmt *fmt)
+{
+	mpint *b;
+	char *p;
+
+	b = va_arg(fmt->args, mpint*);
+	if(b == nil)
+		return fmtstrcpy(fmt, "*");
+	
+	p = mptoa(b, fmt->prec, nil, 0);
+	fmt->flags &= ~FmtPrec;
+
+	if(p == nil)
+		return fmtstrcpy(fmt, "*");
+	else{
+		fmtstrcpy(fmt, p);
+		free(p);
+		return 0;
+	}
+}
+
+char*
+mptoa(mpint *b, int base, char *buf, int len)
+{
+	char *out;
+	int rv, alloced;
+
+	alloced = 0;
+	if(buf == nil){
+		len = ((b->top+1)*Dbits+2)/3 + 1;
+		buf = malloc(len);
+		if(buf == nil)
+			return nil;
+		alloced = 1;
+	}
+
+	if(len < 2)
+		return nil;
+
+	out = buf;
+	if(b->sign < 0){
+		*out++ = '-';
+		len--;
+	}
+	switch(base){
+	case 64:
+		rv = to64(b, out, len);
+		break;
+	case 32:
+		rv = to32(b, out, len);
+		break;
+	default:
+	case 16:
+		rv = to16(b, out, len);
+		break;
+	case 10:
+		rv = to10(b, out, len);
+		break;
+	}
+	if(rv < 0){
+		if(alloced)
+			free(buf);
+		return nil;
+	}
+	return buf;
+}