string_bytes: strip padding from base64 strings

Because of variations in different base64 implementation, it's been
decided to strip all padding from the end of a base64 string and
calculate its size from that.

1 files changed, 7 insertions, 8 deletions

diff --git a/src/string_bytes.cc b/src/string_bytes.cc
index 5bf0a30e27..7ba2caf93d 100644
--- a/src/string_bytes.cc
+++ b/src/string_bytes.cc
@@ -63,16 +63,15 @@ static inline size_t base64_decoded_size_fast(size_t size) {
 }
 
 static inline size_t base64_decoded_size(const char* src, size_t size) {
-  size = base64_decoded_size_fast(size);
+  if (size == 0)
+    return 0;
 
-  const char* end = src + size;
-  // check for trailing padding (1 or 2 bytes)
-  if (size > 0) {
-    if (end[-1] == '=') size--;
-    if (size > 0 && end[-2] == '=') size--;
-  }
+  if (src[size - 1] == '=')
+    size--;
+  if (size > 0 && src[size - 1] == '=')
+    size--;
 
-  return size;
+  return base64_decoded_size_fast(size);
 }