From be6e50bfea8de4f01e6e30adfa3bcaf3f6243886 Mon Sep 17 00:00:00 2001
From: Fredrik Tolf <fredrik@dolda2000.com>
Date: Thu, 7 Oct 2010 08:41:34 +0200
Subject: [PATCH] lib: Added base64 codec.

---
 lib/utils.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/utils.h |  2 ++
 2 files changed, 92 insertions(+)

diff --git a/lib/utils.c b/lib/utils.c
index 2b251e3..1e3c363 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -26,6 +26,26 @@
 #endif
 #include <utils.h>
 
+static char *base64set = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+static int base64rev[] = {
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
+    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
+    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
+    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+};
+
 void _sizebuf(struct buffer *buf, size_t wanted, size_t el)
 {
     size_t n;
@@ -216,3 +236,73 @@ void replstr(char **p, char *n)
     if(tmp)
 	free(tmp);
 }
+
+char *base64encode(char *data, size_t datalen)
+{
+    struct charbuf buf;
+    
+    if(datalen == 0)
+	return(sstrdup(""));
+    bufinit(buf);
+    while(datalen >= 3)
+    {
+	bufadd(buf, base64set[(data[0] & 0xfc) >> 2]);
+	bufadd(buf, base64set[((data[0] & 0x03) << 4) | ((data[1] & 0xf0) >> 4)]);
+	bufadd(buf, base64set[((data[1] & 0x0f) << 2) | ((data[2] & 0xc0) >> 6)]);
+	bufadd(buf, base64set[data[2] & 0x3f]);
+	datalen -= 3;
+	data += 3;
+    }
+    if(datalen == 1)
+    {
+	bufadd(buf, base64set[(data[0] & 0xfc) >> 2]);
+	bufadd(buf, base64set[(data[0] & 0x03) << 4]);
+	bufcat(buf, "==", 2);
+    }
+    if(datalen == 2)
+    {
+	bufadd(buf, base64set[(data[0] & 0xfc) >> 2]);
+	bufadd(buf, base64set[((data[0] & 0x03) << 4) | ((data[1] & 0xf0) >> 4)]);
+	bufadd(buf, base64set[(data[1] & 0x0f) << 2]);
+	bufadd(buf, '=');
+    }
+    bufadd(buf, 0);
+    return(buf.b);
+}
+
+char *base64decode(char *data, size_t *datalen)
+{
+    int b, c;
+    char cur;
+    struct charbuf buf;
+    
+    bufinit(buf);
+    cur = 0;
+    b = 8;
+    for(; *data > 0; data++)
+    {
+	c = (int)(unsigned char)*data;
+	if(c == '=')
+	    break;
+	if(c == '\n')
+	    continue;
+	if(base64rev[c] == -1)
+	{
+	    buffree(buf);
+	    return(NULL);
+	}
+	b -= 6;
+	if(b <= 0)
+	{
+	    cur |= base64rev[c] >> -b;
+	    bufadd(buf, cur);
+	    b += 8;
+	    cur = 0;
+	}
+	cur |= base64rev[c] << b;
+    }
+    if(datalen != NULL)
+	*datalen = buf.d;
+    bufadd(buf, 0);
+    return(buf.b);
+}
diff --git a/lib/utils.h b/lib/utils.h
index be94c24..b74bfb5 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -72,5 +72,7 @@ int calen(char **a);
 void bvprintf(struct charbuf *buf, char *format, va_list al);
 void bprintf(struct charbuf *buf, char *format, ...);
 void replstr(char **p, char *n);
+char *base64encode(char *data, size_t datalen);
+char *base64decode(char *data, size_t *datalen);
 
 #endif
-- 
2.11.0