| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 QUICKSTEP_COMPRESSION_COMPRESSION_DICTIONARY_LITE_HPP_ |
| #define QUICKSTEP_COMPRESSION_COMPRESSION_DICTIONARY_LITE_HPP_ |
| |
| #include <cstddef> |
| #include <cstdint> |
| #include <limits> |
| |
| #include "types/Type.hpp" |
| #include "types/TypedValue.hpp" |
| #include "utility/Macros.hpp" |
| |
| #include "glog/logging.h" |
| |
| namespace quickstep { |
| |
| /** \addtogroup Compression |
| * @{ |
| */ |
| |
| // In-memory format of a CompressionDictionary is as follows: |
| // std::uint32_t num_codes - number of codes/values stored in dictionary |
| // (excluding NULL) |
| // std::uint32_t null_code - a code representing a NULL value (equal to |
| // num_codes if NULL is present, or the maximum |
| // possible value of std::uint32_t if NULL is not |
| // present) |
| // For fixed-length types: |
| // array of num_codes values |
| // For variable-length types: |
| // array of num_codes offsets of variable-length values |
| // variable-length storage region, with values stored at offsets specified |
| // by previous array. |
| |
| /** |
| * @brief A dictionary which maps short integer codes to typed values. |
| * @note Codes in a CompressionDictionaryLite compare in the same order as the |
| * underlying values. |
| **/ |
| class CompressionDictionaryLite { |
| public: |
| /** |
| * @brief Constructor. |
| * |
| * @param type The type of values being compressed. LessComparison must be |
| * applicable to this Type. |
| * @param dictionary_memory The memory location of the physical dictionary. |
| * @param dictionary_memory_size The size (in bytes) of the physical |
| * dictionary at dictionary_memory. |
| **/ |
| CompressionDictionaryLite(const Type &type, |
| const void *dictionary_memory, |
| const std::size_t dictionary_memory_size); |
| |
| virtual ~CompressionDictionaryLite() = 0; |
| |
| /** |
| * @brief Get the number of code/value mappings in this dictionary. |
| * |
| * @return The number of codes/values in this dictionary. |
| **/ |
| inline std::uint32_t numberOfCodes() const { |
| return number_of_codes_including_null_; |
| } |
| |
| /** |
| * @brief Get the minimum number of bits needed to represent a code for this |
| * dictionary. |
| * |
| * @return The length of codes for this dictionary in bits. |
| **/ |
| inline std::uint8_t codeLengthBits() const { |
| return code_length_bits_; |
| } |
| |
| /** |
| * @brief Determine whether this dictionary contains a code for NULL values. |
| * |
| * @return Whether this dictionary contains NULL. |
| **/ |
| inline bool containsNull() const { |
| return getNullCode() != std::numeric_limits<std::uint32_t>::max(); |
| } |
| |
| /** |
| * @brief Get the code representing NULL in this dictionary, or the maximum |
| * possible value of a std::uint32_t if NULL is not present in this |
| * dictionary. |
| * |
| * @return The code representing NULL in this dictionary, or UINT32_MAX if |
| * NULL is not present in this dictionary. |
| **/ |
| inline std::uint32_t getNullCode() const { |
| return *(static_cast<const std::uint32_t*>(dictionary_memory_) + 1); |
| } |
| |
| /** |
| * @brief Get an untyped pointer to the value represented by the specified |
| * code. |
| * @note This version is for codes of 8 bits or less. Also see |
| * getUntypedValueForShortCode() and getUntypedValueForCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return An untyped pointer to the value that corresponds to code. |
| **/ |
| template <bool check_null = true> |
| inline const void* getUntypedValueForByteCode(const std::uint8_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetUntypedValueHelper<std::uint8_t, check_null>(code); |
| } else { |
| return fixedLengthGetUntypedValueHelper<std::uint8_t, check_null>(code); |
| } |
| } |
| |
| /** |
| * @brief Get an untyped pointer to the value represented by the specified |
| * code. |
| * @note This version is for codes of 16 bits or less. Also see |
| * getUntypedValueForByteCode() and getUntypedValueForCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return An untyped pointer to the value that corresponds to code. |
| **/ |
| template <bool check_null = true> |
| inline const void* getUntypedValueForShortCode(const std::uint16_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetUntypedValueHelper<std::uint16_t, check_null>(code); |
| } else { |
| return fixedLengthGetUntypedValueHelper<std::uint16_t, check_null>(code); |
| } |
| } |
| |
| /** |
| * @brief Get an untyped pointer to the value represented by the specified |
| * code. |
| * @note This version is for any code up to the maximum length of 32 bits. |
| * Also see getUntypedValueForByteCode() and |
| * getUntypedValueForShortCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return An untyped pointer to the value that corresponds to code. |
| **/ |
| template <bool check_null = true> |
| inline const void* getUntypedValueForCode(const std::uint32_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetUntypedValueHelper<std::uint32_t, check_null>(code); |
| } else { |
| return fixedLengthGetUntypedValueHelper<std::uint32_t, check_null>(code); |
| } |
| } |
| |
| /** |
| * @brief Get the value represented by the specified code as a TypedValue. |
| * @note This version is for codes of 8 bits or less. Also see |
| * getTypedValueForShortCode() and getTypedValueForCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return The typed value that corresponds to code. |
| **/ |
| inline TypedValue getTypedValueForByteCode(const std::uint8_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetTypedValueHelper<std::uint8_t>(code); |
| } else { |
| return fixedLengthGetTypedValueHelper<std::uint8_t>(code); |
| } |
| } |
| |
| /** |
| * @brief Get the value represented by the specified code as a TypedValue. |
| * @note This version is for codes of 16 bits or less. Also see |
| * getTypedValueForByteCode() and getTypedValueForCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return The typed value that corresponds to code. |
| **/ |
| inline TypedValue getTypedValueForShortCode(const std::uint16_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetTypedValueHelper<std::uint16_t>(code); |
| } else { |
| return fixedLengthGetTypedValueHelper<std::uint16_t>(code); |
| } |
| } |
| |
| /** |
| * @brief Get the value represented by the specified code as a TypedValue. |
| * @note This version is for any code up to the maximum length of 32 bits. |
| * Also see getTypedValueForByteCode() and getTypedValueForShortCode(). |
| * @warning It is an error to use this method with a code which does not |
| * exist in this dictionary, i.e. code must be less than |
| * numberOfCodes(). |
| * |
| * @param code The compressed code to get the value for. |
| * @return The typed value that corresponds to code. |
| **/ |
| inline TypedValue getTypedValueForCode(const std::uint32_t code) const { |
| if (type_is_variable_length_) { |
| return variableLengthGetTypedValueHelper<std::uint32_t>(code); |
| } else { |
| return fixedLengthGetTypedValueHelper<std::uint32_t>(code); |
| } |
| } |
| |
| protected: |
| template <typename CodeType, bool check_null = true> |
| inline const void* fixedLengthGetUntypedValueHelper(const CodeType code) const { |
| if (check_null && (code == getNullCode())) { |
| return nullptr; |
| } |
| DCHECK_LT(code, numberOfCodes()); |
| return static_cast<const char*>(dictionary_memory_) |
| + 2 * sizeof(std::uint32_t) // Header. |
| + code * type_fixed_byte_length_; // Index into value array. |
| } |
| |
| template <typename CodeType, bool check_null = true> |
| inline const void* variableLengthGetUntypedValueHelper(const CodeType code) const { |
| if (check_null && (code == getNullCode())) { |
| return nullptr; |
| } |
| DCHECK_LT(code, numberOfCodes()); |
| const void *retval = variable_length_data_region_ |
| + static_cast<const std::uint32_t*>(dictionary_memory_)[code + 2]; |
| DCHECK_LT(retval, static_cast<const char*>(dictionary_memory_) + dictionary_memory_size_); |
| return retval; |
| } |
| |
| template <typename CodeType> |
| inline TypedValue fixedLengthGetTypedValueHelper(const CodeType code) const { |
| if (code == getNullCode()) { |
| return TypedValue(type_.getTypeID());; |
| } |
| DCHECK_LT(code, numberOfCodes()); |
| return type_.makeValue(static_cast<const char*>(dictionary_memory_) |
| + 2 * sizeof(std::uint32_t) // Header. |
| + code * type_fixed_byte_length_, // Index into value array. |
| type_fixed_byte_length_); |
| } |
| |
| template <typename CodeType> |
| inline TypedValue variableLengthGetTypedValueHelper(const CodeType code) const { |
| if (code == getNullCode()) { |
| return TypedValue(type_.getTypeID()); |
| } |
| DCHECK_LT(code, numberOfCodes()); |
| |
| std::uint32_t value_offset = static_cast<const std::uint32_t*>(dictionary_memory_)[code + 2]; |
| const void *data_ptr = variable_length_data_region_ + value_offset; |
| |
| DCHECK_LT(data_ptr, static_cast<const char*>(dictionary_memory_) + dictionary_memory_size_); |
| |
| std::size_t data_size = (code == *static_cast<const std::uint32_t*>(dictionary_memory_) - 1) ? |
| (static_cast<const char*>(dictionary_memory_) |
| + dictionary_memory_size_ |
| - static_cast<const char*>(data_ptr)) |
| : (static_cast<const std::uint32_t*>(dictionary_memory_)[code + 3] - value_offset); |
| return TypedValue(type_.getTypeID(), data_ptr, data_size); |
| } |
| |
| const Type &type_; |
| const bool type_is_variable_length_; |
| const void *dictionary_memory_; |
| const std::size_t dictionary_memory_size_; |
| std::uint32_t number_of_codes_including_null_; |
| std::uint8_t code_length_bits_; |
| |
| const std::size_t type_fixed_byte_length_; |
| const char *variable_length_data_region_; |
| |
| private: |
| bool paranoidOffsetsCheck() const; |
| |
| DISALLOW_COPY_AND_ASSIGN(CompressionDictionaryLite); |
| }; |
| |
| /** @} */ |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_COMPRESSION_COMPRESSION_DICTIONARY_LITE_HPP_ |
