b64decode correct decode of some strings

[platform/upstream/libwebsockets.git] / lib / base64-decode.c

diff --git a/lib/base64-decode.c b/lib/base64-decode.c
index b89db7a..4dfce67 100644 (file)
--- a/lib/base64-decode.c
+++ b/lib/base64-decode.c
@@ -33,8 +33,8 @@
  *               Bob Trower 08/04/01 -- Create Version 0.00.00B
  *
  * I cleaned it up quite a bit to match the (linux kernel) style of the rest
- * of libwebsockets; this version is under LGPL2 like the rest of libwebsockets
- * since he explictly allows sublicensing, but I give the URL above so you can
+ * of libwebsockets; this version is under LGPL2.1 + SLE like the rest of lws
+ * since he explicitly allows sublicensing, but I give the URL above so you can
  * get the original with Bob's super-liberal terms directly if you prefer.
  */
 
@@ -67,8 +67,6 @@ lws_b64_encode_string(const char *in, int in_len, char *out, int out_size)
                        } else
                                triple[i] = 0;
                }
-               if (!len)
-                       continue;
 
                if (done + 4 >= out_size)
                        return -1;
@@ -91,3 +89,99 @@ lws_b64_encode_string(const char *in, int in_len, char *out, int out_size)
 
        return done;
 }
+
+/*
+ * returns length of decoded string in out, or -1 if out was too small
+ * according to out_size
+ */
+
+LWS_VISIBLE int
+lws_b64_decode_string(const char *in, char *out, int out_size)
+{
+       int len;
+       int i, c;
+       int done = 0;
+       unsigned char v;
+       unsigned char quad[4];
+
+       while (*in) {
+
+               len = 0;
+               for (i = 0; i < 4 && *in; i++) {
+
+                       v = 0;
+                       c = 0;
+                       while (*in && !v) {
+                               c = v = *in++;
+                               v = (v < 43 || v > 122) ? 0 : decode[v - 43];
+                               if (v)
+                                       v = (v == '$') ? 0 : v - 61;
+                       }
+                       if (c) {
+                               len++;
+                               if (v)
+                                       quad[i] = v - 1;
+                       } else
+                               quad[i] = 0;
+               }
+
+               if (out_size < (done + len - 1))
+                       /* out buffer is too small */
+                       return -1;
+
+               if (len >= 2)
+                       *out++ = quad[0] << 2 | quad[1] >> 4;
+               if (len >= 3)
+                       *out++ = quad[1] << 4 | quad[2] >> 2;
+               if (len >= 4)
+                       *out++ = ((quad[2] << 6) & 0xc0) | quad[3];
+
+               done += len - 1;
+       }
+
+       if (done + 1 >= out_size)
+               return -1;
+
+       *out++ = '\0';
+
+       return done;
+}
+
+#if 0
+int
+lws_b64_selftest(void)
+{
+       char buf[64];
+       unsigned int n;
+       unsigned int test;
+       static const char * const plaintext[] = {
+               "sanity check base 64"
+       };
+       static const char * const coded[] = {
+               "c2FuaXR5IGNoZWNrIGJhc2UgNjQ="
+       };
+
+       for (test = 0; test < sizeof plaintext / sizeof(plaintext[0]); test++) {
+
+               buf[sizeof(buf) - 1] = '\0';
+               n = lws_b64_encode_string(plaintext[test],
+                                     strlen(plaintext[test]), buf, sizeof buf);
+               if (n != strlen(coded[test]) || strcmp(buf, coded[test])) {
+                       lwsl_err("Failed lws_b64 encode selftest "
+                                          "%d result '%s' %d\n", test, buf, n);
+                       return -1;
+               }
+
+               buf[sizeof(buf) - 1] = '\0';
+               n = lws_b64_decode_string(coded[test], buf, sizeof buf);
+               if (n != strlen(plaintext[test]) ||
+                                                strcmp(buf, plaintext[test])) {
+                       lwsl_err("Failed lws_b64 decode selftest "
+                                          "%d result '%s' %d\n", test, buf, n);
+                       return -1;
+               }
+       }
+
+       return 0;
+}
+#endif