summaryrefslogtreecommitdiffstats
path: root/src/util/base64_code.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/util/base64_code.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/src/util/base64_code.c b/src/util/base64_code.c
new file mode 100644
index 0000000..e607218
--- /dev/null
+++ b/src/util/base64_code.c
@@ -0,0 +1,228 @@
+/*++
+/* NAME
+/* base64_code 3
+/* SUMMARY
+/* encode/decode data, base 64 style
+/* SYNOPSIS
+/* #include <base64_code.h>
+/*
+/* VSTRING *base64_encode(result, in, len)
+/* VSTRING *result;
+/* const char *in;
+/* ssize_t len;
+/*
+/* VSTRING *base64_decode(result, in, len)
+/* VSTRING *result;
+/* const char *in;
+/* ssize_t len;
+/*
+/* VSTRING *base64_encode_opt(result, in, len, flags)
+/* VSTRING *result;
+/* const char *in;
+/* ssize_t len;
+/* int flags;
+/*
+/* VSTRING *base64_decode_opt(result, in, len, flags)
+/* VSTRING *result;
+/* const char *in;
+/* ssize_t len;
+/* int flags;
+/* DESCRIPTION
+/* base64_encode() takes a block of len bytes and encodes it as one
+/* null-terminated string. The result value is the result argument.
+/*
+/* base64_decode() performs the opposite transformation. The result
+/* value is the result argument. The result is null terminated, whether
+/* or not that makes sense.
+/*
+/* base64_encode_opt() and base64_decode_opt() provide extended
+/* interfaces. In both cases the flags arguments is the bit-wise
+/* OR of zero or more the following:
+/* .IP BASE64_FLAG_APPEND
+/* Append the result, instead of overwriting the result buffer.
+/* .PP
+/* For convenience, BASE64_FLAG_NONE specifies none of the above.
+/* DIAGNOSTICS
+/* base64_decode () returns a null pointer when the input contains
+/* characters not in the base 64 alphabet.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include "sys_defs.h"
+#include <ctype.h>
+#include <string.h>
+#include <limits.h>
+
+#ifndef UCHAR_MAX
+#define UCHAR_MAX 0xff
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstring.h>
+#include <base64_code.h>
+
+/* Application-specific. */
+
+static unsigned char to_b64[] =
+"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+#define UNSIG_CHAR_PTR(x) ((unsigned char *)(x))
+
+/* base64_encode - raw data to encoded */
+
+#undef base64_encode
+
+extern VSTRING *base64_encode(VSTRING *, const char *, ssize_t);
+
+VSTRING *base64_encode(VSTRING *result, const char *in, ssize_t len)
+{
+ return (base64_encode_opt(result, in, len, BASE64_FLAG_NONE));
+}
+
+VSTRING *base64_encode_opt(VSTRING *result, const char *in, ssize_t len,
+ int flags)
+{
+ const unsigned char *cp;
+ ssize_t count;
+
+ /*
+ * Encode 3 -> 4.
+ */
+ if ((flags & BASE64_FLAG_APPEND) == 0)
+ VSTRING_RESET(result);
+ for (cp = UNSIG_CHAR_PTR(in), count = len; count > 0; count -= 3, cp += 3) {
+ VSTRING_ADDCH(result, to_b64[cp[0] >> 2]);
+ if (count > 1) {
+ VSTRING_ADDCH(result, to_b64[(cp[0] & 0x3) << 4 | cp[1] >> 4]);
+ if (count > 2) {
+ VSTRING_ADDCH(result, to_b64[(cp[1] & 0xf) << 2 | cp[2] >> 6]);
+ VSTRING_ADDCH(result, to_b64[cp[2] & 0x3f]);
+ } else {
+ VSTRING_ADDCH(result, to_b64[(cp[1] & 0xf) << 2]);
+ VSTRING_ADDCH(result, '=');
+ break;
+ }
+ } else {
+ VSTRING_ADDCH(result, to_b64[(cp[0] & 0x3) << 4]);
+ VSTRING_ADDCH(result, '=');
+ VSTRING_ADDCH(result, '=');
+ break;
+ }
+ }
+ VSTRING_TERMINATE(result);
+ return (result);
+}
+
+/* base64_decode - encoded data to raw */
+
+#undef base64_decode
+
+extern VSTRING *base64_decode(VSTRING *, const char *, ssize_t);
+
+VSTRING *base64_decode(VSTRING *result, const char *in, ssize_t len)
+{
+ return (base64_decode_opt(result, in, len, BASE64_FLAG_NONE));
+}
+
+VSTRING *base64_decode_opt(VSTRING *result, const char *in, ssize_t len,
+ int flags)
+{
+ static unsigned char *un_b64 = 0;
+ const unsigned char *cp;
+ ssize_t count;
+ unsigned int ch0;
+ unsigned int ch1;
+ unsigned int ch2;
+ unsigned int ch3;
+
+#define CHARS_PER_BYTE (UCHAR_MAX + 1)
+#define INVALID 0xff
+
+ /*
+ * Sanity check.
+ */
+ if (len % 4)
+ return (0);
+
+ /*
+ * Once: initialize the decoding lookup table on the fly.
+ */
+ if (un_b64 == 0) {
+ un_b64 = (unsigned char *) mymalloc(CHARS_PER_BYTE);
+ memset(un_b64, INVALID, CHARS_PER_BYTE);
+ for (cp = to_b64; cp < to_b64 + sizeof(to_b64) - 1; cp++)
+ un_b64[*cp] = cp - to_b64;
+ }
+
+ /*
+ * Decode 4 -> 3.
+ */
+ if ((flags & BASE64_FLAG_APPEND) == 0)
+ VSTRING_RESET(result);
+ for (cp = UNSIG_CHAR_PTR(in), count = 0; count < len; count += 4) {
+ if ((ch0 = un_b64[*cp++]) == INVALID
+ || (ch1 = un_b64[*cp++]) == INVALID)
+ return (0);
+ VSTRING_ADDCH(result, ch0 << 2 | ch1 >> 4);
+ if ((ch2 = *cp++) == '=')
+ break;
+ if ((ch2 = un_b64[ch2]) == INVALID)
+ return (0);
+ VSTRING_ADDCH(result, ch1 << 4 | ch2 >> 2);
+ if ((ch3 = *cp++) == '=')
+ break;
+ if ((ch3 = un_b64[ch3]) == INVALID)
+ return (0);
+ VSTRING_ADDCH(result, ch2 << 6 | ch3);
+ }
+ VSTRING_TERMINATE(result);
+ return (result);
+}
+
+#ifdef TEST
+
+ /*
+ * Proof-of-concept test program: convert to base 64 and back.
+ */
+
+#define STR(x) vstring_str(x)
+#define LEN(x) VSTRING_LEN(x)
+
+int main(int unused_argc, char **unused_argv)
+{
+ VSTRING *b1 = vstring_alloc(1);
+ VSTRING *b2 = vstring_alloc(1);
+ char test[256];
+ int n;
+
+ for (n = 0; n < sizeof(test); n++)
+ test[n] = n;
+ base64_encode(b1, test, sizeof(test));
+ if (base64_decode(b2, STR(b1), LEN(b1)) == 0)
+ msg_panic("bad base64: %s", STR(b1));
+ if (LEN(b2) != sizeof(test))
+ msg_panic("bad decode length: %ld != %ld",
+ (long) LEN(b2), (long) sizeof(test));
+ for (n = 0; n < sizeof(test); n++)
+ if (STR(b2)[n] != test[n])
+ msg_panic("bad decode value %d != %d",
+ (unsigned char) STR(b2)[n], (unsigned char) test[n]);
+ vstring_free(b1);
+ vstring_free(b2);
+ return (0);
+}
+
+#endif