/tmp/buildd/xz-utils-5.0.0/src/liblzma/api/lzma/index_hash.h File Reference

Validate Index by using a hash function. More...

Typedefs
typedef struct lzma_index_hash_s	lzma_index_hash
	Opaque data type to hold the Index hash.
Functions
lzma_index_hash *	lzma_index_hash_init (lzma_index_hash *index_hash, lzma_allocator *allocator) lzma_nothrow lzma_attr_warn_unused_result
	Allocate and initialize a new lzma_index_hash structure.
void	lzma_index_hash_end (lzma_index_hash *index_hash, lzma_allocator *allocator) lzma_nothrow
	Deallocate lzma_index_hash structure.
lzma_ret	lzma_index_hash_append (lzma_index_hash *index_hash, lzma_vli unpadded_size, lzma_vli uncompressed_size) lzma_nothrow lzma_attr_warn_unused_result
	Add a new Record to an Index hash.
lzma_ret	lzma_index_hash_decode (lzma_index_hash *index_hash, const uint8_t *in, size_t *in_pos, size_t in_size) lzma_nothrow lzma_attr_warn_unused_result
	Decode and validate the Index field.
lzma_vli	lzma_index_hash_size (const lzma_index_hash *index_hash) lzma_nothrow lzma_attr_pure
	Get the size of the Index field as bytes.

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Detailed Description

Validate Index by using a hash function.

Hashing makes it possible to use constant amount of memory to validate Index of arbitrary size.

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Typedef Documentation

typedef struct lzma_index_hash_s lzma_index_hash

Opaque data type to hold the Index hash.

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Function Documentation

lzma_index_hash* lzma_index_hash_init	(	lzma_index_hash *	index_hash,
		lzma_allocator *	allocator
	)

Allocate and initialize a new lzma_index_hash structure.

If index_hash is NULL, a new lzma_index_hash structure is allocated, initialized, and a pointer to it returned. If allocation fails, NULL is returned.

If index_hash is non-NULL, it is reinitialized and the same pointer returned. In this case, return value cannot be NULL or a different pointer than the index_hash that was given as an argument.

References lzma_alloc(), and lzma_check_init().

void lzma_index_hash_end	(	lzma_index_hash *	index_hash,
		lzma_allocator *	allocator
	)

Deallocate lzma_index_hash structure.

lzma_ret lzma_index_hash_append	(	lzma_index_hash *	index_hash,
		lzma_vli	unpadded_size,
		lzma_vli	uncompressed_size
	)

Add a new Record to an Index hash.

Parameters:

	index	Pointer to a lzma_index_hash structure
	unpadded_size	Unpadded Size of a Block
	uncompressed_size	Uncompressed Size of a Block

Returns:

- LZMA_OK

• LZMA_DATA_ERROR: Compressed or uncompressed size of the Stream or size of the Index field would grow too big.
• LZMA_PROG_ERROR: Invalid arguments or this function is being used when lzma_index_hash_decode() has already been used.

References hash_append(), LZMA_VLI_MAX, and return_if_error.

lzma_ret lzma_index_hash_decode	(	lzma_index_hash *	index_hash,
		const uint8_t *	in,
		size_t *	in_pos,
		size_t	in_size
	)

Decode and validate the Index field.

After telling the sizes of all Blocks with lzma_index_hash_append(), the actual Index field is decoded with this function. Specifically, once decoding of the Index field has been started, no more Records can be added using lzma_index_hash_append().

This function doesn't use lzma_stream structure to pass the input data. Instead, the input buffer is specified using three arguments. This is because it matches better the internal APIs of liblzma.

Parameters:

	index_hash	Pointer to a lzma_index_hash structure
	in	Pointer to the beginning of the input buffer
	in_pos	in[*in_pos] is the next byte to process
	in_size	in[in_size] is the first byte not to process

Returns:

- LZMA_OK: So far good, but more input is needed.

• LZMA_STREAM_END: Index decoded successfully and it matches the Records given with lzma_index_hash_append().
• LZMA_DATA_ERROR: Index is corrupt or doesn't match the information given with lzma_index_hash_append().
• LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size.
• LZMA_PROG_ERROR

References hash_append(), lzma_check_finish(), lzma_check_size(), lzma_crc32(), LZMA_DATA_ERROR, LZMA_STREAM_END, LZMA_VLI_C, lzma_vli_decode(), and return_if_error.

lzma_vli lzma_index_hash_size

(

const lzma_index_hash *

index_hash

)

Get the size of the Index field as bytes.

This is needed to verify the Backward Size field in the Stream Footer.