| /* |
| * Copyright (C) 2013 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "suggest/policyimpl/dictionary/utils/format_utils.h" |
| |
| #include "suggest/policyimpl/dictionary/utils/byte_array_utils.h" |
| |
| namespace latinime { |
| |
| const uint32_t FormatUtils::MAGIC_NUMBER = 0x9BC13AFE; |
| |
| // Magic number (4 bytes), version (2 bytes), flags (2 bytes), header size (4 bytes) = 12 |
| const int FormatUtils::DICTIONARY_MINIMUM_SIZE = 12; |
| |
| /* static */ FormatUtils::FORMAT_VERSION FormatUtils::detectFormatVersion( |
| const uint8_t *const dict, const int dictSize) { |
| // The magic number is stored big-endian. |
| // If the dictionary is less than 4 bytes, we can't even read the magic number, so we don't |
| // understand this format. |
| if (dictSize < DICTIONARY_MINIMUM_SIZE) { |
| return UNKNOWN_VERSION; |
| } |
| const uint32_t magicNumber = ByteArrayUtils::readUint32(dict, 0); |
| switch (magicNumber) { |
| case MAGIC_NUMBER: |
| // Version 2 header is as follows: |
| // Magic number (4 bytes) 0x9B 0xC1 0x3A 0xFE |
| // Dictionary format version number (2 bytes) |
| // Options (2 bytes) |
| // Header size (4 bytes) : integer, big endian |
| if (ByteArrayUtils::readUint16(dict, 4) == 2) { |
| return VERSION_2; |
| } else if (ByteArrayUtils::readUint16(dict, 4) == 3) { |
| return VERSION_3; |
| } else { |
| return UNKNOWN_VERSION; |
| } |
| default: |
| return UNKNOWN_VERSION; |
| } |
| } |
| |
| } // namespace latinime |