varints.h File Reference

Variable-length integer (VLQ) encoding and decoding. More...

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Macros
#define	VARINTS_MAX_ENCODED_LEN   (10u)
	Maximum size of an encoded 64-bit VLQ/varint value.

Functions
int	varint_encode_u64 (uint64_t input, uint8_t *output, int *bytes_generated)
int	varint_decode_u64 (uint8_t *input, uint64_t *output, int *bytes_consumed)
int	varint_encode_i64 (int64_t input, uint8_t *output, int *bytes_generated)
int	varint_decode_i64 (uint8_t *input, int64_t *output, int *bytes_consumed)

Detailed Description

Variable-length integer (VLQ) encoding and decoding.

Author

Erik K. Nyquist

Function Documentation

varint_decode_i64()

int varint_decode_i64	(	uint8_t *	input,
		int64_t *	output,
		int *	bytes_consumed
	)

Decode a VLQ/varint byte stream into a signed 64-bit integer.

Parameters

input	Pointer to VLQ/varint byte stream to decode.
output	Pointer to location to store decoded integer value.
bytes_consumed	Pointer to location to store number of input bytes consumed before the end of the VLQ/varint value was found, may be NULL.

Returns

0 if successful, 1 if the end of the VLQ/varint byte stream was not found after VARINTS_MAX_ENCODED_LEN bytes, and -1 if a NULL pointer was provided for 'input' or 'output'.

varint_decode_u64()

int varint_decode_u64	(	uint8_t *	input,
		uint64_t *	output,
		int *	bytes_consumed
	)

Decode a VLQ/varint byte stream into an unsigned 64-bit integer.

Parameters

input	Pointer to VLQ/varint byte stream to decode.
output	Pointer to location to store decoded integer value.
bytes_consumed	Pointer to location to store number of input bytes consumed before the end of the VLQ/varint value was found, may be NULL.

Returns

0 if successful, 1 if the end of the VLQ/varint byte stream was not found after VARINTS_MAX_ENCODED_LEN bytes, and -1 if a NULL pointer was provided for 'input' or 'output'.

varint_encode_i64()

int varint_encode_i64	(	int64_t	input,
		uint8_t *	output,
		int *	bytes_generated
	)

Encode a signed 64-bit integer into a VLQ/varint byte stream.

Parameters

input	Input value to encode.
output	Pointer to location to store encoded output bytes. At least VARINTS_MAX_ENCODED_LEN bytes are expected to be available.
bytes_generated	Pointer to location to store number of output bytes generated, may be NULL.

Returns

0 if successful, and -1 if a NULL pointer was provided for 'output'.

varint_encode_u64()

int varint_encode_u64	(	uint64_t	input,
		uint8_t *	output,
		int *	bytes_generated
	)

Encode an unsigned 64-bit integer into a VLQ/varint byte stream.

Parameters

input	Input value to encode.
output	Pointer to location to store encoded output bytes. At least VARINTS_MAX_ENCODED_LEN bytes are expected to be available.
bytes_generated	Pointer to location to store number of output bytes generated, may be NULL.

Returns

0 if successful, and -1 if a NULL pointer was provided for 'output'.