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extern/draco/dracoenc/src/draco/core/varint_decoding.h
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| // Copyright 2016 The Draco Authors. | |||||
| // | |||||
| // 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. | |||||
| // | |||||
| #ifndef DRACO_CORE_VARINT_DECODING_H_ | |||||
| #define DRACO_CORE_VARINT_DECODING_H_ | |||||
| #include <type_traits> | |||||
| #include "draco/core/bit_utils.h" | |||||
| #include "draco/core/decoder_buffer.h" | |||||
| namespace draco { | |||||
| // Decodes a specified integer as varint. Note that the IntTypeT must be the | |||||
| // same as the one used in the corresponding EncodeVarint() call. | |||||
| template <typename IntTypeT> | |||||
| bool DecodeVarint(IntTypeT *out_val, DecoderBuffer *buffer) { | |||||
| if (std::is_unsigned<IntTypeT>::value) { | |||||
| // Coding of unsigned values. | |||||
| // 0-6 bit - data | |||||
| // 7 bit - next byte? | |||||
| uint8_t in; | |||||
| if (!buffer->Decode(&in)) | |||||
| return false; | |||||
| if (in & (1 << 7)) { | |||||
| // Next byte is available, decode it first. | |||||
| if (!DecodeVarint<IntTypeT>(out_val, buffer)) | |||||
| return false; | |||||
| // Append decoded info from this byte. | |||||
| *out_val <<= 7; | |||||
| *out_val |= in & ((1 << 7) - 1); | |||||
| } else { | |||||
| // Last byte reached | |||||
| *out_val = in; | |||||
| } | |||||
| } else { | |||||
| // IntTypeT is a signed value. Decode the symbol and convert to signed. | |||||
| typename std::make_unsigned<IntTypeT>::type symbol; | |||||
| if (!DecodeVarint(&symbol, buffer)) | |||||
| return false; | |||||
| *out_val = ConvertSymbolToSignedInt(symbol); | |||||
| } | |||||
| return true; | |||||
| } | |||||
| } // namespace draco | |||||
| #endif // DRACO_CORE_VARINT_DECODING_H_ | |||||