signet::forge::DictionaryDecoder< T > Class Template Reference

Dictionary decoder for Parquet PLAIN_DICTIONARY / RLE_DICTIONARY encoding. More...

#include <dictionary.hpp>

Public Member Functions
	DictionaryDecoder (const uint8_t *dict_data, size_t dict_size, size_t num_dict_entries, PhysicalType type)
	Construct a decoder by parsing the raw PLAIN-encoded dictionary page.
expected< std::vector< T > >	decode (const uint8_t *indices_data, size_t indices_size, size_t num_values) const
	Decode an RLE_DICTIONARY indices page into original typed values.
size_t	dictionary_size () const
	Number of entries in the dictionary.

Detailed Description

template<typename T>
class signet::forge::DictionaryDecoder< T >

Dictionary decoder for Parquet PLAIN_DICTIONARY / RLE_DICTIONARY encoding.

Reconstructs original typed values from a PLAIN-encoded dictionary page and an RLE_DICTIONARY-encoded indices page. The constructor parses the dictionary page; decode() then maps indices back to values.

Template Parameters

T	The value type (std::string, int32_t, int64_t, float, or double).

See also

DictionaryEncoder, RleDecoder

Definition at line 413 of file dictionary.hpp.

Constructor & Destructor Documentation

DictionaryDecoder()

template<typename T >

signet::forge::DictionaryDecoder< T >::DictionaryDecoder ( const uint8_t *  dict_data, size_t  dict_size, size_t  num_dict_entries, PhysicalType  type  )

inline

Construct a decoder by parsing the raw PLAIN-encoded dictionary page.

Decodes num_dict_entries values from dict_data using the appropriate PLAIN format for type T. The decoded values are stored internally for index-based lookup during decode().

Parameters

dict_data	Pointer to PLAIN-encoded dictionary page bytes.
dict_size	Size of the dictionary page in bytes.
num_dict_entries	Number of entries in the dictionary.
type	The Parquet physical type (retained for metadata; actual decoding dispatches on template type T).

Definition at line 426 of file dictionary.hpp.

Member Function Documentation

decode()

template<typename T >

expected< std::vector< T > > signet::forge::DictionaryDecoder< T >::decode ( const uint8_t *  indices_data, size_t  indices_size, size_t  num_values  ) const

inline

Decode an RLE_DICTIONARY indices page into original typed values.

Reads the 1-byte bit_width prefix, decodes the RLE/Bit-Packing Hybrid index stream, and maps each index back to its dictionary value. Returns an empty vector if any index is out of bounds.

Parameters

indices_data	Pointer to the indices page (1-byte bit_width + RLE payload).
indices_size	Size of the indices page in bytes.
num_values	Number of values to decode.

Returns

Decoded values, or CORRUPT_DATA error on out-of-bounds index (CWE-754).

See also

DictionaryEncoder::indices_page

Definition at line 451 of file dictionary.hpp.

dictionary_size()

template<typename T >

size_t signet::forge::DictionaryDecoder< T >::dictionary_size ( ) const

inline

Number of entries in the dictionary.

Returns

Dictionary cardinality (as parsed from the dictionary page).

Definition at line 482 of file dictionary.hpp.

---

The documentation for this class was generated from the following file:

• include/signet/encoding/dictionary.hpp