Move description of escaping to code that does the escaping rather than the CalculateBase64EscapedLenInternal helper method.

Note that output padding is conditional on do_padding.

PiperOrigin-RevId: 499901986
Change-Id: I8c1d28fe372b3e0e2216654db83f949caa297892

1 files changed, 12 insertions, 10 deletions

diff --git a/absl/strings/internal/escaping.cc b/absl/strings/internal/escaping.cc
index cfea0961..8bd0890d 100644
--- a/absl/strings/internal/escaping.cc
+++ b/absl/strings/internal/escaping.cc
@@ -28,19 +28,11 @@ size_t CalculateBase64EscapedLenInternal(size_t input_len, bool do_padding) {
   // Base64 encodes three bytes of input at a time. If the input is not
   // divisible by three, we pad as appropriate.
   //
-  // (from https://tools.ietf.org/html/rfc3548)
-  // Special processing is performed if fewer than 24 bits are available
-  // at the end of the data being encoded.  A full encoding quantum is
-  // always completed at the end of a quantity.  When fewer than 24 input
-  // bits are available in an input group, zero bits are added (on the
-  // right) to form an integral number of 6-bit groups.  Padding at the
-  // end of the data is performed using the '=' character.  Since all base
-  // 64 input is an integral number of octets, only the following cases
-  // can arise:
-
   // Base64 encodes each three bytes of input into four bytes of output.
   size_t len = (input_len / 3) * 4;
 
+  // Since all base 64 input is an integral number of octets, only the following
+  // cases can arise:
   if (input_len % 3 == 0) {
     // (from https://tools.ietf.org/html/rfc3548)
     // (1) the final quantum of encoding input is an integral multiple of 24
@@ -83,6 +75,16 @@ size_t Base64EscapeInternal(const unsigned char* src, size_t szsrc, char* dest,
   char* const limit_dest = dest + szdest;
   const unsigned char* const limit_src = src + szsrc;
 
+  // (from https://tools.ietf.org/html/rfc3548)
+  // Special processing is performed if fewer than 24 bits are available
+  // at the end of the data being encoded.  A full encoding quantum is
+  // always completed at the end of a quantity.  When fewer than 24 input
+  // bits are available in an input group, zero bits are added (on the
+  // right) to form an integral number of 6-bit groups.
+  //
+  // If do_padding is true, padding at the end of the data is performed. This
+  // output padding uses the '=' character.
+
   // Three bytes of data encodes to four characters of cyphertext.
   // So we can pump through three-byte chunks atomically.
   if (szsrc >= 3) {                    // "limit_src - 3" is UB if szsrc < 3.