b64_encode: Optimization code

Signed-off-by: Jianhui Zhao <jianhuizhao329@gmail.com>
zhaojh329 · May 13, 2019 · 2444718 · 2444718
1 parent 6c07c96
commit 2444718
Showing 1 changed file with 19 additions and 22 deletions.
diff --git a/src/utils.c b/src/utils.c
@@ -70,7 +70,7 @@ int parse_url(const char *url, char *host, int host_len,
     } else {
         return -1;
     }
-    
+
     host_pos = url;
 
     p = strchr(url, ':');
@@ -166,41 +166,37 @@ int tcp_connect(const char *host, int port, int flags, bool *inprogress, int *ea
 int b64_encode(const void *src, size_t srclen, void *dest, size_t destsize)
 {
     char *Base64 =
-        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
     const uint8_t *input = src;
     char *output = dest;
 
     while (srclen > 0) {
+        int skip = 1;
         int i0 = input[0] >> 2;
-		int skip = 1;
+        int i1 = (input[0] & 0x3) << 4;
+        int i2 = 64;
+        int i3 = 64;
 
         if (destsize < 5)
             return -1;
 
-        *output++ = Base64[i0];
-
         if (srclen > 1) {
-            int i1 = ((input[0] & 0x3) << 4) + (input[1] >> 4);
-            *output++ = Base64[i1];
+            skip++;
+            i1 += input[1] >> 4;
+            i2 = (input[1] & 0xF) << 2;
+
             if (srclen > 2) {
-                int i2 = ((input[1] & 0xF) << 2) + (input[2] >> 6);
-                int i3 = input[2] & 0x3F;
-                *output++ = Base64[i2];
-                *output++ = Base64[i3];
-                skip = 3;
-            } else {
-                int i2 = ((input[1] & 0xF) << 2);
-                *output++ = Base64[i2];
-                *output++ = '=';
-                skip = 2;
+                i2 += input[2] >> 6;
+                i3 = input[2] & 0x3F;
+                skip++;
             }
-        } else {
-            int i1 = (input[0] & 0x3) << 4;
-            *output++ = Base64[i1];
-            *output++ = '=';
-            *output++ = '=';
         }
 
+        *output++ = Base64[i0];
+        *output++ = Base64[i1];
+        *output++ = Base64[i2];
+        *output++ = Base64[i3];
+
         input += skip;
         srclen -= skip;
         destsize -= 4;
@@ -209,3 +205,4 @@ int b64_encode(const void *src, size_t srclen, void *dest, size_t destsize)
     *output++ = 0;
     return output - (char *)dest - 1;
 }
+