Initial commit.

1 files changed, 95 insertions, 0 deletions

diff --git a/src/base64.c b/src/base64.c
new file mode 100644
index 0000000..6a2c873
--- /dev/null
+++ b/src/base64.c
@@ -0,0 +1,95 @@
+#include "base64.h"
+
+static void
+base64_decode_block(const char *src, char *dest)
+{
+	int i;
+	char buf[4];
+
+	/* Convert base 64 characters into values. */
+	/* Supports ASCII and EBCDIC systems. */
+	for (i = 0; i < 4; ++i) {
+		if (src[i] >= 'A' && src[i] <= 'I') {
+			buf[i] = src[i] - 'A' + 0;
+		} else if (src[i] >= 'J' && src[i] <= 'R') {
+			buf[i] = src[i] - 'J' + 9;
+		} else if (src[i] >= 'S' && src[i] <= 'Z') {
+			buf[i] = src[i] - 'S' + 18;
+		} else if (src[i] >= 'a' && src[i] <= 'i') {
+			buf[i] = src[i] - 'a' + 26;
+		} else if (src[i] >= 'j' && src[i] <= 'r') {
+			buf[i] = src[i] - 'j' + 35;
+		} else if (src[i] >= 's' && src[i] <= 'z') {
+			buf[i] = src[i] - 's' + 44;
+		} else if (src[i] >= '0' && src[i] <= '9') {
+			buf[i] = src[i] - '0' + 52;
+		} else if (src[i] == '+') {
+			buf[i] = 62;
+		} else if (src[i] == '/') {
+			buf[i] = 63;
+		} else {
+			buf[i] = '\0';
+		}
+	}
+
+	/* Map four decoded value bytes into three output bytes. */
+	dest[0] = (buf[0] << 2) | (buf[1] >> 4);
+	dest[1] = (buf[1] << 4) | (buf[2] >> 2);
+	dest[2] = (buf[2] << 6) | (buf[3] >> 0);
+}
+	
+void
+base64_decode(const char *src, char *dest, size_t dest_len)
+{
+	size_t i;
+
+	/* Decode the input one entire block at a time. */
+	for (i = 0; i < (dest_len - 1) / 3; ++i) {
+		if (src[i * 4] == '\0' || 
+				src[i * 4 + 1] == '\0' || 
+				src[i * 4 + 2] == '\0' || 
+				src[i * 4 + 3] == '\0') {
+			dest[i * 3] = '\0';
+			break;
+		}
+		base64_decode_block(src + i * 4, dest + i * 3);
+	}
+
+	/* Ensure NUL termination. */
+	dest[dest_len - 1] = '\0';
+}
+
+#if 0
+int
+main()
+{
+	char dest[1024];
+	base64_decode(
+			"TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5v"
+			"dCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1"
+			"dCBieSB0aGlzIHNpbmd1bGFyIHBhc3Np"
+			"b24gZnJvbSBvdGhlciBhbmltYWxzLCB3"
+			"aGljaCBpcyBhIGx1c3Qgb2YgdGhlIG1p"
+			"bmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFu"
+			"Y2Ugb2YgZGVsaWdodCBpbiB0aGUgY29u"
+			"dGludWVkIGFuZCBpbmRlZmF0aWdhYmxl"
+			"IGdlbmVyYXRpb24gb2Yga25vd2xlZGdl"
+			"LCBleGNlZWRzIHRoZSBzaG9ydCB2ZWhl"
+			"bWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVh"
+			"c3VyZS4=", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhc3VyZS4=", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhc3VyZQ==", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhc3Vy", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhc3U=", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhcw==", dest, 1024);
+	printf("Decoded string: \"%s\"\n", dest);
+	base64_decode("YW55IGNhcm5hbCBwbGVhcw==", dest, 4);
+	printf("Decoded string: \"%s\"\n", dest);
+	return 0;
+}
+#endif