[ruby-dev:650] Re: pack/unpack base64

わたなべです.

Yukihiro Matsumoto <[e-mail]> writes:

:パッチください．1.1には取り込みましょう．

unpack のほうはひとつにするのは難しいので, 別々になってます.
もうちょっといじるかもしれない.

-- 
わたなべひろふみ

--- pack.c.orig	Tue Aug 19 16:23:58 1997
+++ pack.c	Mon Oct  6 18:29:50 1997
@@ -444,2 +444,3 @@
 	  case 'u':
+	  case 'm':
 	    from = obj_as_string(NEXTFROM);
@@ -459,3 +460,3 @@
 		    todo = plen;
-		encodes(res, ptr, todo);
+		encodes(res, ptr, todo, type);
 		plen -= todo;
@@ -473,4 +474,9 @@
 
+static char uu_table[64] =
+"`!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_";
+static char b64_table[64] =
+"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
 static void
-encodes(str, s, len)
+encodes(str, s, len, type)
     struct RString *str;
@@ -478,2 +484,3 @@
     int len;
+    int type;
 {
@@ -481,10 +488,13 @@
     UCHAR *p, *pend;
+    char *trans = type == 'u' ? uu_table : b64_table;
 
-    *hunk = len + ' ';
-    str_cat(str, hunk, 1);
+    if (type == 'u') {
+	*hunk = len + ' ';
+	str_cat(str, hunk, 1);
+    }
     while (len > 0) {
-	hunk[0] = ' ' + (077 & (*s >> 2));
-	hunk[1] = ' ' + (077 & (((*s << 4) & 060) | ((s[1] >> 4) & 017)));
-	hunk[2] = ' ' + (077 & (((s[1] << 2) & 074) | ((s[2] >> 6) & 03)));
-	hunk[3] = ' ' + (077 & (s[2] & 077));
+	hunk[0] = trans[077 & (*s >> 2)];
+	hunk[1] = trans[077 & (((*s << 4) & 060) | ((s[1] >> 4) & 017))];
+	hunk[2] = trans[077 & (((s[1] << 2) & 074) | ((s[2] >> 6) & 03))];
+	hunk[3] = trans[077 & s[2]];
 	str_cat(str, hunk, 4);
@@ -495,6 +505,10 @@
     pend = str->ptr + str->len;
-    while (p < pend) {
-	if (*p == ' ')
-	    *p = '`';
-	p++;
+    if (type != 'u') {
+	if (len == -1) {
+	    pend[-1] = '=';
+	}
+	else if (len == -2) {
+	    pend[-2] = '=';
+	    pend[-1] = '=';
+	}
     }
@@ -849,2 +863,53 @@
 		RSTRING(str)->len = total;
+		ary_push(ary, str);
+	    }
+	    break;
+
+	  case 'm':
+	    {
+		VALUE str = str_new(0, (send - s)*3/4);
+		UCHAR *ptr = RSTRING(str)->ptr;
+		int total = 0;
+		int a,b,c,d;
+		static int first = 1;
+		static int b64_xtable[256];
+
+		if (first) {
+		    int i;
+		    first = 0;
+
+		    for (i = 0; i < 256; i++) {
+			b64_xtable[i] = -1;
+		    }
+		    for (i = 0; i < 64; i++) {
+			b64_xtable[b64_table[i]] = i;
+		    }
+		}
+		for (;;) {
+		    char hunk[3];
+		    while (*s == '\r' || *s == '\n') { s++; }
+		    if ((a = b64_xtable[s[0]]) == -1) break;
+		    while (*s == '\r' || *s == '\n') { s++; }
+		    if ((b = b64_xtable[s[1]]) == -1) break;
+		    while (*s == '\r' || *s == '\n') { s++; }
+		    if ((c = b64_xtable[s[2]]) == -1) break;
+		    while (*s == '\r' || *s == '\n') { s++; }
+		    if ((d = b64_xtable[s[3]]) == -1) break;
+		    hunk[0] = a << 2 | b >> 4;
+		    hunk[1] = b << 4 | c >> 2;
+		    hunk[2] = c << 6 | d;
+		    memcpy(ptr, hunk, 3);
+		    ptr += 3;
+		    s += 4;
+		}
+		if (a != -1 && b != -1 && s[2] == '=') {
+		    ptr[0] = a << 2 | b >> 4;
+		    ptr++;
+		}
+		if (a != -1 && b != -1 && c != -1 && s[3] == '=') {
+		    ptr[0] = a << 2 | b >> 4;
+		    ptr[1] = b << 4 | c >> 2;
+		    ptr += 2;
+		}
+		RSTRING(str)->len = ptr - RSTRING(str)->ptr;
 		ary_push(ary, str);