From c30a6232df03e1efbd9f3b226777b07e087a1122 Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Mon, 12 Oct 2020 14:27:29 +0200
Subject: BASELINE: Update Chromium to 85.0.4183.140

Change-Id: Iaa42f4680837c57725b1344f108c0196741f6057
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
---
 chromium/components/base32/base32.cc | 56 ++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

(limited to 'chromium/components/base32/base32.cc')

diff --git a/chromium/components/base32/base32.cc b/chromium/components/base32/base32.cc
index b4ad2ef8e6d..96950b380eb 100644
--- a/chromium/components/base32/base32.cc
+++ b/chromium/components/base32/base32.cc
@@ -13,6 +13,20 @@
 
 namespace base32 {
 
+namespace {
+
+// Returns a 5 bit number between [0,31] matching the provided base 32 encoded
+// character. Returns 0xff on error.
+uint8_t ReverseMapping(char input_char) {
+  if (input_char >= 'A' && input_char <= 'Z')
+    return input_char - 'A';
+  if (input_char >= '2' && input_char <= '7')
+    return input_char - '2' + 26;
+  return 0xff;
+}
+
+}  // namespace
+
 std::string Base32Encode(base::StringPiece input, Base32EncodePolicy policy) {
   if (input.empty())
     return std::string();
@@ -64,4 +78,46 @@ std::string Base32Encode(base::StringPiece input, Base32EncodePolicy policy) {
   return output;
 }
 
+std::string Base32Decode(base::StringPiece input) {
+  // Remove padding, if any
+  const size_t padding_index = input.find(kPaddingChar);
+  if (padding_index != base::StringPiece::npos)
+    input.remove_suffix(input.size() - padding_index);
+
+  if (input.empty())
+    return std::string();
+
+  const size_t decoded_length =
+      (base::MakeCheckedNum(input.size()) * 5 / 8).ValueOrDie();
+
+  std::string output;
+  output.reserve(decoded_length);
+
+  // A bit stream which will be read from the left and appended to from the
+  // right as it's emptied.
+  uint16_t bit_stream = 0;
+  size_t free_bits = 16;
+  for (char input_char : input) {
+    const uint8_t decoded_5bits = ReverseMapping(input_char);
+    // If an invalid character is read from the input, then stop decoding.
+    if (decoded_5bits >= 32)
+      return std::string();
+
+    // Place the next decoded 5-bits in the stream.
+    bit_stream |= decoded_5bits << (free_bits - 5);
+    free_bits -= 5;
+
+    // If the stream is filled with a byte, flush the stream of that byte and
+    // append it to the output.
+    if (free_bits <= 8) {
+      output.push_back(static_cast<char>(bit_stream >> 8));
+      bit_stream <<= 8;
+      free_bits += 8;
+    }
+  }
+
+  DCHECK_EQ(decoded_length, output.size());
+  return output;
+}
+
 }  // namespace base32
-- 
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