index.h

// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////
//
/// \file       index.h
/// \brief      Handling of Index
/// \note       This header file does not include common.h or lzma.h because
///             this file is needed by both liblzma internally and by the
///             tests. Including common.h will include and define many things
///             the tests do not need and prevents issues with header file
///             include order. This way, if lzma.h or common.h are not
///             included before this file it will break on every OS instead
///             of causing more subtle errors.
//
//  Author:     Lasse Collin
//
///////////////////////////////////////////////////////////////////////////////

#ifndef LZMA_INDEX_H
#define LZMA_INDEX_H


/// Minimum Unpadded Size
#define UNPADDED_SIZE_MIN LZMA_VLI_C(5)

/// Maximum Unpadded Size
#define UNPADDED_SIZE_MAX (LZMA_VLI_MAX & ~LZMA_VLI_C(3))

/// Index Indicator based on xz specification
#define INDEX_INDICATOR 0


/// Get the size of the Index Padding field. This is needed by Index encoder
/// and decoder, but applications should have no use for this.
extern uint32_t lzma_index_padding_size(const lzma_index *i);


/// Set for how many Records to allocate memory the next time
/// lzma_index_append() needs to allocate space for a new Record.
/// This is used only by the Index decoder.
extern void lzma_index_prealloc(lzma_index *i, lzma_vli records);


/// Round the variable-length integer to the next multiple of four.
static inline lzma_vli
vli_ceil4(lzma_vli vli)
{
	assert(vli <= UNPADDED_SIZE_MAX);
	return (vli + 3) & ~LZMA_VLI_C(3);
}


/// Calculate the size of the Index field excluding Index Padding
static inline lzma_vli
index_size_unpadded(lzma_vli count, lzma_vli index_list_size)
{
	// Index Indicator + Number of Records + List of Records + CRC32
	return 1 + lzma_vli_size(count) + index_list_size + 4;
}


/// Calculate the size of the Index field including Index Padding
static inline lzma_vli
index_size(lzma_vli count, lzma_vli index_list_size)
{
	return vli_ceil4(index_size_unpadded(count, index_list_size));
}


/// Calculate the total size of the Stream
static inline lzma_vli
index_stream_size(lzma_vli blocks_size,
		lzma_vli count, lzma_vli index_list_size)
{
	return LZMA_STREAM_HEADER_SIZE + blocks_size
			+ index_size(count, index_list_size)
			+ LZMA_STREAM_HEADER_SIZE;
}

#endif