recordReader.h

/*
 * recordReader.h
 *
 *  Created on: Aug 2, 2013
 *      Author: gokhan
 */

#ifndef RECORDREADER_H_
#define RECORDREADER_H_

#include "postgres.h"
#include "nodes/primnodes.h"

#include "orc.pb-c.h"
#include "inputStream.h"

#define DATA_STREAM 			0
#define LENGTH_STREAM 			1
#define SECONDARY_STREAM 		1
#define DICTIONARY_DATA_STREAM	2

#define MAX_STREAM_COUNT			3
#define STRING_STREAM_COUNT			3
#define STRING_DIRECT_STREAM_COUNT	2
#define TIMESTAMP_STREAM_COUNT		2
#define BINARY_STREAM_COUNT			2
#define COMMON_STREAM_COUNT			1

#define MAX_POSTSCRIPT_SIZE		255
#define DEFAULT_DICTIONARY_ITEM_LENGTH    255

/* timestamp related values */
#define SECONDS_PER_DAY					86400
#define MICROSECONDS_PER_SECOND			1000000L
#define NANOSECONDS_PER_MICROSECOND		1000
#define POSTGRESQL_EPOCH_IN_SECONDS		946677600L
#define ORC_EPOCH_IN_SECONDS			1420063200L
#define ORC_DIFF_POSTGRESQL				473385600L
#define ORC_PSQL_EPOCH_IN_DAYS			10957

/*
 * The conversion from signed integer to ORC format is as follows:
 * 0, -1, 1, -2, 2, -3, 3, ......  --> 0, 1, 2, 3, 4, 5, 6, ...
 * 
 * So, in ORC even numbers are the non-negative and odd numbers are the negative numbers.
 * Functions to convert to/from ORC format from/to regular format are defined below.
 */
#define ToUnsignedInteger(x) (uint64_t)( ((x) < 0) ? ( ((uint64_t)-(x+1)) * 2 + 1) : (2 * (uint64_t)(x)))
#define ToSignedInteger(x)   ( int64_t)( ((x) % 2) ? (-(int64_t)((x - 1) / 2) - 1) : ((x) / 2) )

#define IsComplexType(type) (type == FIELD_TYPE__KIND__LIST || type == FIELD_TYPE__KIND__STRUCT || type == FIELD_TYPE__KIND__MAP)


typedef enum
{
	VARIABLE_LENGTH, RLE
} EncodingType;


typedef struct
{
	/* stream to read from the file */
	FileStream *stream;

	/* type of the encoding */
	EncodingType currentEncodingType;

	/* byte that is used currently */
	uint64_t data;

	/* no of bytes left in the current run */
	short noOfLeftItems;

	/* mask is for boolean, step is for int, float&double is for floating point readers */
	union
	{
		uint8_t mask;
		char step;
		float floatData;
		double doubleData;
	};

} StreamReader;


/**
 * Base structure to represent a field reader.
 * Its fieldreader variable contains the streams of the type.
 */
typedef struct
{
	StreamReader presentBitReader;
	FieldType__Kind kind;
	RowIndex* rowIndex;

	int orcColumnNo;

	/* Length reader for list & map complex types */
	char hasPresentBitReader;
	char required;

	/* Actual field reader, can be struct, list, or primitive */
	void* fieldReader;

	/* psql column information */
	Var* psqlVariable;
} FieldReader;


/**
 * Reader for primitive types
 * (boolean, byte, binary, short, integer, long, float, double, string)
 */
typedef struct
{
	StreamReader readers[MAX_STREAM_COUNT];
	ColumnEncoding__Kind encoding;

	/* for string type to store the dictionary */
	char hasDictionary;
	int dictionarySize;
	int *wordLength;
	char **dictionary;
} PrimitiveFieldReader;


/*
 * Reader for list types.
 */
typedef struct
{
	StreamReader lengthReader;
	FieldReader itemReader;
} ListFieldReader;


typedef struct
{
	int noOfFields;
	FieldReader **fields;
} StructFieldReader;


int StreamReaderFree(StreamReader *streamReader);
int StreamReaderInit(StreamReader *streamReader, FieldType__Kind streamKind, FILE *file,
		long offset, long limit, CompressionParameters *parameters);
void StreamReaderSeek(StreamReader *streamReader, FieldType__Kind fieldType,
		FieldType__Kind streamKind, OrcStack *stack);


void FillDictionary(FieldReader* stringFieldReader);


/*
 * Functions to read the column value directly into the native PSQL format
 */
Datum ReadPrimitiveFieldAsDatum(FieldReader *fieldReader, bool *isNull);
Datum ReadListFieldAsDatum(FieldReader *fieldReader, bool *isNull);


/**
 * Helper functions to get the kth stream and its type
 */
FieldType__Kind GetStreamKind(FieldType__Kind type, ColumnEncoding__Kind encoding, int streamIndex);
int GetStreamCount(FieldType__Kind type, ColumnEncoding__Kind encoding);


#endif /* RECORDREADER_H_ */