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authorMattias Andrée <maandree@kth.se>2022-01-16 19:58:57 +0100
committerMattias Andrée <maandree@kth.se>2022-01-16 19:58:57 +0100
commit8bdc2e4929068210d523c34c0b171b51ce96057f (patch)
treec77331e77b9777a37716bffb7365c4486a6df9a0 /libar2_decode_base64.c
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First commit1.0
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to '')
-rw-r--r--libar2_decode_base64.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/libar2_decode_base64.c b/libar2_decode_base64.c
new file mode 100644
index 0000000..df35a60
--- /dev/null
+++ b/libar2_decode_base64.c
@@ -0,0 +1,68 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+#define FF 0xFF
+static const unsigned char lut[256] = {
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, 62, FF, FF, FF, 63,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, FF, FF, FF, FF, FF, FF,
+ FF, 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, FF, FF, FF, FF, FF,
+ FF, 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, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+ FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF
+};
+
+
+size_t
+libar2_decode_base64(const char *str_, void *data_, size_t *lenp)
+{
+ const unsigned char *str = (const unsigned char *)str_;
+ unsigned char *data = data_;
+ unsigned char a, b, c, d;
+ size_t ret = 0;
+
+ *lenp = 0;
+
+ for(;; str += 4) {
+ if (lut[str[0]] == FF || lut[str[1]] == FF)
+ break;
+ a = lut[str[0]];
+ b = lut[str[1]];
+ ret += 2;
+ if (data)
+ *data++ = (unsigned char)((a << 2) | (b >> 4));
+ ++*lenp;
+
+ if (lut[str[2]] == FF) {
+ ret += (str[2] == '=');
+ ret += (str[2] == '=' && str[3] == '=');
+ break;
+ }
+ c = lut[str[2]];
+ ret += 1;
+ if (data)
+ *data++ = (unsigned char)((b << 4) | (c >> 2));
+ ++*lenp;
+
+ if (lut[str[3]] == FF) {
+ ret += (str[3] == '=');
+ break;
+ }
+ d = lut[str[3]];
+ ret += 1;
+ if (data)
+ *data++ = (unsigned char)((c << 6) | (d >> 0));
+ ++*lenp;
+ }
+
+ return ret;
+}