vli.h File Reference

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Macros
#define	LZMA_VLI_MAX   (UINT64_MAX / 2)
	Maximum supported value of a variable-length integer.
#define	LZMA_VLI_UNKNOWN   UINT64_MAX
	VLI value to denote that the value is unknown.
#define	LZMA_VLI_BYTES_MAX   9
	Maximum supported encoded length of variable length integers.
#define	LZMA_VLI_C(n)
	VLI constant suffix.
#define	lzma_vli_is_valid(vli)
	Validate a variable-length integer.

Functions
	LZMA_API (lzma_ret) lzma_vli_encode(lzma_vli vli
	Encode a variable-length integer.
	LZMA_API (uint32_t) lzma_vli_size(lzma_vli vli) lzma_nothrow lzma_attr_pure
	Get the number of bytes required to encode a VLI.

Variables
size_t *	vli_pos
size_t uint8_t *	out
size_t uint8_t size_t *	out_pos
size_t uint8_t size_t size_t out_size	lzma_nothrow
size_t const uint8_t *	in
size_t const uint8_t size_t *	in_pos

Macro Definition Documentation

LZMA_VLI_BYTES_MAX

#define LZMA_VLI_BYTES_MAX   9

Maximum supported encoded length of variable length integers.

LZMA_VLI_C

#define LZMA_VLI_C

(

n

)

Value:

UINT64_C(n)

VLI constant suffix.

lzma_vli_is_valid

#define lzma_vli_is_valid

(

vli

)

Value:

    ((vli) <= LZMA_VLI_MAX || (vli) == LZMA_VLI_UNKNOWN)

Validate a variable-length integer.

This is useful to test that application has given acceptable values for example in the uncompressed_size and compressed_size variables.

Returns

True if the integer is representable as a VLI or if it indicates an unknown value. False otherwise.

LZMA_VLI_MAX

#define LZMA_VLI_MAX   (UINT64_MAX / 2)

Maximum supported value of a variable-length integer.

LZMA_VLI_UNKNOWN

#define LZMA_VLI_UNKNOWN   UINT64_MAX

VLI value to denote that the value is unknown.

Function Documentation

LZMA_API() [1/2]

LZMA_API ( lzma_ret )

extern

Encode a variable-length integer.

Decode a variable-length integer.

This function has two modes: single-call and multi-call. Single-call mode encodes the whole integer at once; it is an error if the output buffer is too small. Multi-call mode saves the position in *vli_pos, and thus it is possible to continue encoding if the buffer becomes full before the whole integer has been encoded.

Parameters

	vli	Integer to be encoded
[out]	vli_pos	How many VLI-encoded bytes have already been written out. When starting to encode a new integer in multi-call mode, *vli_pos must be set to zero. To use single-call encoding, set vli_pos to NULL.
[out]	out	Beginning of the output buffer
[out]	out_pos	The next byte will be written to out[*out_pos].
	out_size	Size of the out buffer; the first byte into which no data is written to is out[out_size].

Returns

Slightly different return values are used in multi-call and single-call modes.

Single-call (vli_pos == NULL):

• LZMA_OK: Integer successfully encoded.
• LZMA_PROG_ERROR: Arguments are not sane. This can be due to too little output space; single-call mode doesn't use LZMA_BUF_ERROR, since the application should have checked the encoded size with lzma_vli_size().

Multi-call (vli_pos != NULL):

• LZMA_OK: So far all OK, but the integer is not completely written out yet.
• LZMA_STREAM_END: Integer successfully encoded.
• LZMA_BUF_ERROR: No output space was provided.
• LZMA_PROG_ERROR: Arguments are not sane.

Like lzma_vli_encode(), this function has single-call and multi-call modes.

Parameters

[out]	vli	Pointer to decoded integer. The decoder will initialize it to zero when *vli_pos == 0, so application isn't required to initialize *vli.
[out]	vli_pos	How many bytes have already been decoded. When starting to decode a new integer in multi-call mode, *vli_pos must be initialized to zero. To use single-call decoding, set vli_pos to NULL.
	in	Beginning of the input buffer
[out]	in_pos	The next byte will be read from in[*in_pos].
	in_size	Size of the input buffer; the first byte that won't be read is in[in_size].

Returns

Slightly different return values are used in multi-call and single-call modes.

Single-call (vli_pos == NULL):

• LZMA_OK: Integer successfully decoded.
• LZMA_DATA_ERROR: Integer is corrupt. This includes hitting the end of the input buffer before the whole integer was decoded; providing no input at all will use LZMA_DATA_ERROR.
• LZMA_PROG_ERROR: Arguments are not sane.

Multi-call (vli_pos != NULL):

• LZMA_OK: So far all OK, but the integer is not completely decoded yet.
• LZMA_STREAM_END: Integer successfully decoded.
• LZMA_DATA_ERROR: Integer is corrupt.
• LZMA_BUF_ERROR: No input was provided.
• LZMA_PROG_ERROR: Arguments are not sane.

LZMA_API() [2/2]

LZMA_API ( uint32_t ) const

extern

Get the number of bytes required to encode a VLI.

Parameters

vli	Integer whose encoded size is to be determined

Returns

Number of bytes on success (1-9). If vli isn't valid, zero is returned.

Get the number of bytes required to encode a VLI.

Run-time version number as an integer.

Get the number of processor cores or threads.

Calculate CRC32.

Although not all Check IDs have a check algorithm associated, the size of every Check is already frozen. This function returns the size (in bytes) of the Check field with the specified Check ID. The values are: { 0, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 32, 64, 64, 64 }

If the argument is not in the range [0, 15], UINT32_MAX is returned.

Calculate CRC32 using the polynomial from the IEEE 802.3 standard.

Parameters

buf	Pointer to the input buffer
size	Size of the input buffer
crc	Previously returned CRC value. This is used to calculate the CRC of a big buffer in smaller chunks. Set to zero when starting a new calculation.

Returns

Updated CRC value, which can be passed to this function again to continue CRC calculation.

Variable Documentation

in

size_t const uint8_t* in

in_pos

size_t const uint8_t size_t* in_pos

lzma_nothrow

size_t const uint8_t size_t size_t in_size lzma_nothrow

out

size_t uint8_t* out

out_pos

size_t uint8_t size_t* out_pos

vli_pos

size_t* vli_pos