1 files changed, 122 insertions, 0 deletions

diff --git a/base64.c b/base64.c
new file mode 100644
index 0000000..ea8b777
--- /dev/null
+++ b/base64.c
@@ -0,0 +1,122 @@
+#include "base64.h"
+#include "stralloc.h"
+#include "substdio.h"
+#include "str.h"
+
+static char *b64alpha =
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+#define B64PAD '='
+
+/* returns 0 ok, 1 illegal, -1 problem */
+
+int b64decode(in,l,out)
+const unsigned char *in;
+int l;
+stralloc *out; /* not null terminated */
+{
+  int p = 0;
+  int n;
+  unsigned int x;
+  int i, j;
+  char *s;
+  unsigned char b[3];
+
+  if (l == 0)
+  {
+    if (!stralloc_copys(out,"")) return -1;
+    return 0;
+  }
+
+  while(in[l-1] == B64PAD) {
+    p ++;
+    l--;
+  }
+
+  n = (l + p) / 4;
+  out->len = (n * 3) - p;
+  if (!stralloc_ready(out,out->len)) return -1;
+  s = out->s;
+
+  for(i = 0; i < n - 1 ; i++) {
+    x = 0;
+    for(j = 0; j < 4; j++) {
+      if(in[j] >= 'A' && in[j] <= 'Z')
+        x = (x << 6) + (unsigned int)(in[j] - 'A' + 0);
+      else if(in[j] >= 'a' && in[j] <= 'z')
+        x = (x << 6) + (unsigned int)(in[j] - 'a' + 26);
+      else if(in[j] >= '0' && in[j] <= '9')
+        x = (x << 6) + (unsigned int)(in[j] - '0' + 52);
+      else if(in[j] == '+')
+        x = (x << 6) + 62;
+      else if(in[j] == '/')
+        x = (x << 6) + 63;
+      else if(in[j] == '=')
+        x = (x << 6);
+    }
+
+    s[2] = (unsigned char)(x & 255); x >>= 8;
+    s[1] = (unsigned char)(x & 255); x >>= 8;
+    s[0] = (unsigned char)(x & 255); x >>= 8;
+    s += 3; in += 4;
+  }
+
+  x = 0;
+  for(j = 0; j < 4; j++) {
+    if(in[j] >= 'A' && in[j] <= 'Z')
+      x = (x << 6) + (unsigned int)(in[j] - 'A' + 0);
+    else if(in[j] >= 'a' && in[j] <= 'z')
+      x = (x << 6) + (unsigned int)(in[j] - 'a' + 26);
+    else if(in[j] >= '0' && in[j] <= '9')
+      x = (x << 6) + (unsigned int)(in[j] - '0' + 52);
+    else if(in[j] == '+')
+      x = (x << 6) + 62;
+    else if(in[j] == '/')
+      x = (x << 6) + 63;
+    else if(in[j] == '=')
+      x = (x << 6);
+  }
+
+  b[2] = (unsigned char)(x & 255); x >>= 8;
+  b[1] = (unsigned char)(x & 255); x >>= 8;
+  b[0] = (unsigned char)(x & 255); x >>= 8;
+
+  for(i = 0; i < 3 - p; i++)
+    s[i] = b[i];
+
+  return 0;
+}
+
+int b64encode(in,out)
+stralloc *in;
+stralloc *out; /* not null terminated */
+{
+  unsigned char a, b, c;
+  int i;
+  char *s;
+
+  if (in->len == 0)
+  {
+    if (!stralloc_copys(out,"")) return -1;
+    return 0;
+  }
+
+  if (!stralloc_ready(out,in->len / 3 * 4 + 4)) return -1;
+  s = out->s;
+
+  for (i = 0;i < in->len;i += 3) {
+    a = in->s[i];
+    b = i + 1 < in->len ? in->s[i + 1] : 0;
+    c = i + 2 < in->len ? in->s[i + 2] : 0;
+
+    *s++ = b64alpha[a >> 2];
+    *s++ = b64alpha[((a & 3 ) << 4) | (b >> 4)];
+
+    if (i + 1 >= in->len) *s++ = B64PAD;
+    else *s++ = b64alpha[((b & 15) << 2) | (c >> 6)];
+
+    if (i + 2 >= in->len) *s++ = B64PAD;
+    else *s++ = b64alpha[c & 63];
+  }
+  out->len = s - out->s;
+  return 0;
+}