1 files changed, 109 insertions, 0 deletions
diff --git a/src/lib9/u32.c b/src/lib9/u32.c
new file mode 100644
index 00000000..1eb0c6e0
--- /dev/null
+++ b/src/lib9/u32.c
@@ -0,0 +1,109 @@
+#include <lib9.h>
+
+int
+dec32(uchar *dest, int ndest, char *src, int nsrc)
+{
+	char *s, *tab;
+	uchar *start;
+	int i, u[8];
+
+	if(ndest+1 < (5*nsrc+7)/8)
+		return -1;
+	start = dest;
+	tab = "23456789abcdefghijkmnpqrstuvwxyz";
+	while(nsrc>=8){
+		for(i=0; i<8; i++){
+			s = strchr(tab,(int)src[i]);
+			u[i] = s ? s-tab : 0;
+		}
+		*dest++ = (u[0]<<3) | (0x7 & (u[1]>>2));
+		*dest++ = ((0x3 & u[1])<<6) | (u[2]<<1) | (0x1 & (u[3]>>4));
+		*dest++ = ((0xf & u[3])<<4) | (0xf & (u[4]>>1));
+		*dest++ = ((0x1 & u[4])<<7) | (u[5]<<2) | (0x3 & (u[6]>>3));
+		*dest++ = ((0x7 & u[6])<<5) | u[7];
+		src  += 8;
+		nsrc -= 8;
+	}
+	if(nsrc > 0){
+		if(nsrc == 1 || nsrc == 3 || nsrc == 6)
+			return -1;
+		for(i=0; i<nsrc; i++){
+			s = strchr(tab,(int)src[i]);
+			u[i] = s ? s-tab : 0;
+		}
+		*dest++ = (u[0]<<3) | (0x7 & (u[1]>>2));
+		if(nsrc == 2)
+			goto out;
+		*dest++ = ((0x3 & u[1])<<6) | (u[2]<<1) | (0x1 & (u[3]>>4));
+		if(nsrc == 4)
+			goto out;
+		*dest++ = ((0xf & u[3])<<4) | (0xf & (u[4]>>1));
+		if(nsrc == 5)
+			goto out;
+		*dest++ = ((0x1 & u[4])<<7) | (u[5]<<2) | (0x3 & (u[6]>>3));
+	}
+out:
+	return dest-start;
+}
+
+int
+enc32(char *dest, int ndest, uchar *src, int nsrc)
+{
+	char *tab, *start;
+	int j;
+
+	if(ndest <= (8*nsrc+4)/5 )
+		return -1;
+	start = dest;
+	tab = "23456789abcdefghijkmnpqrstuvwxyz";
+	while(nsrc>=5){
+		j = (0x1f & (src[0]>>3));
+		*dest++ = tab[j];
+		j = (0x1c & (src[0]<<2)) | (0x03 & (src[1]>>6));
+		*dest++ = tab[j];
+		j = (0x1f & (src[1]>>1));
+		*dest++ = tab[j];
+		j = (0x10 & (src[1]<<4)) | (0x0f & (src[2]>>4));
+		*dest++ = tab[j];
+		j = (0x1e & (src[2]<<1)) | (0x01 & (src[3]>>7));
+		*dest++ = tab[j];
+		j = (0x1f & (src[3]>>2));
+		*dest++ = tab[j];
+		j = (0x18 & (src[3]<<3)) | (0x07 & (src[4]>>5));
+		*dest++ = tab[j];
+		j = (0x1f & (src[4]));
+		*dest++ = tab[j];
+		src  += 5;
+		nsrc -= 5;
+	}
+	if(nsrc){
+		j = (0x1f & (src[0]>>3));
+		*dest++ = tab[j];
+		j = (0x1c & (src[0]<<2));
+		if(nsrc == 1)
+			goto out;
+		j |= (0x03 & (src[1]>>6));
+		*dest++ = tab[j];
+		j = (0x1f & (src[1]>>1));
+		if(nsrc == 2)
+			goto out;
+		*dest++ = tab[j];
+		j = (0x10 & (src[1]<<4));
+		if(nsrc == 3)
+			goto out;
+		j |= (0x0f & (src[2]>>4));
+		*dest++ = tab[j];
+		j = (0x1e & (src[2]<<1));
+		if(nsrc == 4)
+			goto out;
+		j |= (0x01 & (src[3]>>7));
+		*dest++ = tab[j];
+		j = (0x1f & (src[3]>>2));
+		*dest++ = tab[j];
+		j = (0x18 & (src[3]<<3));
+out:
+		*dest++ = tab[j];
+	}
+	*dest = 0;
+	return dest-start;
+}