1 files changed, 58 insertions, 0 deletions
diff --git a/deps/v8/src/base/vlq-base64.cc b/deps/v8/src/base/vlq-base64.cc
new file mode 100644
index 0000000000..62e63ac872
--- /dev/null
+++ b/deps/v8/src/base/vlq-base64.cc
@@ -0,0 +1,58 @@
+// Copyright 2019 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <climits>
+#include <limits>
+
+#include "src/base/logging.h"
+#include "src/base/vlq-base64.h"
+
+namespace v8 {
+namespace base {
+
+namespace {
+constexpr int8_t kCharToDigit[] = {
+    -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
+    -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
+    -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
+    -1,   -1,   -1,   -1,   -1,   -1,   -1,   0x3e, -1,   -1,   -1,   0x3f,
+    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, -1,   -1,
+    -1,   -1,   -1,   -1,   -1,   0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
+    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12,
+    0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, -1,   -1,   -1,   -1,   -1,
+    -1,   0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24,
+    0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
+    0x31, 0x32, 0x33, -1,   -1,   -1,   -1,   -1};
+
+constexpr uint32_t kContinueShift = 5;
+constexpr uint32_t kContinueMask = 1 << kContinueShift;
+constexpr uint32_t kDataMask = kContinueMask - 1;
+
+int8_t charToDigitDecode(uint8_t c) { return c < 128u ? kCharToDigit[c] : -1; }
+}  // namespace
+
+int8_t charToDigitDecodeForTesting(uint8_t c) { return charToDigitDecode(c); }
+
+int32_t VLQBase64Decode(const char* start, size_t sz, size_t* pos) {
+  uint32_t res = 0;
+  uint64_t shift = 0;
+  int32_t digit;
+
+  do {
+    if (*pos >= sz) {
+      return std::numeric_limits<int32_t>::min();
+    }
+    digit = static_cast<int>(charToDigitDecode(start[*pos]));
+    bool is_last_byte = (shift + kContinueShift >= 32);
+    if (digit == -1 || (is_last_byte && (digit >> 2) != 0)) {
+      return std::numeric_limits<int32_t>::min();
+    }
+    res += (digit & kDataMask) << shift;
+    shift += kContinueShift;
+    (*pos)++;
+  } while (digit & kContinueMask);
+  return (res & 1) ? -static_cast<int32_t>(res >> 1) : (res >> 1);
+}
+}  // namespace base
+}  // namespace v8