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diff base64_decode.c @ 15:6362d3854bb4 libtomcrypt-orig

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0.96 release of LibTomCrypt
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:07:21 +0000
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/base64_decode.c	Tue Jun 15 14:07:21 2004 +0000
@@ -0,0 +1,76 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+
+/* compliant base64 code donated by Wayne Scott ([email protected]) */
+#include "mycrypt.h"
+
+#ifdef BASE64
+
+static const unsigned char map[256] = {
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255,  62, 255, 255, 255,  63,
+ 52,  53,  54,  55,  56,  57,  58,  59,  60,  61, 255, 255,
+255, 254, 255, 255, 255,   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, 255, 255, 255, 255, 255,
+255,  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, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255 };
+
+int base64_decode(const unsigned char *in,  unsigned long len, 
+                        unsigned char *out, unsigned long *outlen)
+{
+   unsigned long t, x, y, z;
+   unsigned char c;
+   int           g;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   g = 3;
+   for (x = y = z = t = 0; x < len; x++) {
+       c = map[in[x]&0xFF];
+       if (c == 255) continue;
+       if (c == 254) { c = 0; g--; }
+       t = (t<<6)|c;
+       if (++y == 4) {
+          if (z + g > *outlen) { 
+             return CRYPT_BUFFER_OVERFLOW; 
+          }
+          out[z++] = (unsigned char)((t>>16)&255);
+          if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
+          if (g > 2) out[z++] = (unsigned char)(t&255);
+          y = t = 0;
+       }
+   }
+   if (y != 0) {
+       return CRYPT_INVALID_PACKET;
+   }
+   *outlen = z;
+   return CRYPT_OK;
+}
+
+#endif
+