Update brotli to v1.0.0-snapshot.

third_party/brotli/enc/utf8_util.cc

-/* Copyright 2013 Google Inc. All Rights Reserved.
-
-   Distributed under MIT license.
-   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
-*/
-
-// Heuristics for deciding about the UTF8-ness of strings.
-
-#include "./utf8_util.h"
-
-#include "./types.h"
-
-namespace brotli {
-
-namespace {
-
-size_t ParseAsUTF8(int* symbol, const uint8_t* input, size_t size) {
-  // ASCII
-  if ((input[0] & 0x80) == 0) {
-    *symbol = input[0];
-    if (*symbol > 0) {
-      return 1;
-    }
-  }
-  // 2-byte UTF8
-  if (size > 1u &&
-      (input[0] & 0xe0) == 0xc0 &&
-      (input[1] & 0xc0) == 0x80) {
-    *symbol = (((input[0] & 0x1f) << 6) |
-               (input[1] & 0x3f));
-    if (*symbol > 0x7f) {
-      return 2;
-    }
-  }
-  // 3-byte UFT8
-  if (size > 2u &&
-      (input[0] & 0xf0) == 0xe0 &&
-      (input[1] & 0xc0) == 0x80 &&
-      (input[2] & 0xc0) == 0x80) {
-    *symbol = (((input[0] & 0x0f) << 12) |
-               ((input[1] & 0x3f) << 6) |
-               (input[2] & 0x3f));
-    if (*symbol > 0x7ff) {
-      return 3;
-    }
-  }
-  // 4-byte UFT8
-  if (size > 3u &&
-      (input[0] & 0xf8) == 0xf0 &&
-      (input[1] & 0xc0) == 0x80 &&
-      (input[2] & 0xc0) == 0x80 &&
-      (input[3] & 0xc0) == 0x80) {
-    *symbol = (((input[0] & 0x07) << 18) |
-               ((input[1] & 0x3f) << 12) |
-               ((input[2] & 0x3f) << 6) |
-               (input[3] & 0x3f));
-    if (*symbol > 0xffff && *symbol <= 0x10ffff) {
-      return 4;
-    }
-  }
-  // Not UTF8, emit a special symbol above the UTF8-code space
-  *symbol = 0x110000 | input[0];
-  return 1;
-}
-
-}  // namespace
-
-// Returns true if at least min_fraction of the data is UTF8-encoded.
-bool IsMostlyUTF8(const uint8_t* data, const size_t pos, const size_t mask,
-                  const size_t length, const double min_fraction) {
-  size_t size_utf8 = 0;
-  size_t i = 0;
-  while (i < length) {
-    int symbol;
-    size_t bytes_read = ParseAsUTF8(
-        &symbol, &data[(pos + i) & mask], length - i);
-    i += bytes_read;
-    if (symbol < 0x110000) size_utf8 += bytes_read;
-  }
-  return size_utf8 > min_fraction * static_cast<double>(length);
-}
-
-}  // namespace brotli