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      1 // SPDX-License-Identifier: 0BSD
      2 
      3 ///////////////////////////////////////////////////////////////////////////////
      4 //
      5 /// \file       index.h
      6 /// \brief      Handling of Index
      7 /// \note       This header file does not include common.h or lzma.h because
      8 ///             this file is needed by both liblzma internally and by the
      9 ///             tests. Including common.h will include and define many things
     10 ///             the tests do not need and prevents issues with header file
     11 ///             include order. This way, if lzma.h or common.h are not
     12 ///             included before this file it will break on every OS instead
     13 ///             of causing more subtle errors.
     14 //
     15 //  Author:     Lasse Collin
     16 //
     17 ///////////////////////////////////////////////////////////////////////////////
     18 
     19 #ifndef LZMA_INDEX_H
     20 #define LZMA_INDEX_H
     21 
     22 
     23 /// Minimum Unpadded Size
     24 #define UNPADDED_SIZE_MIN LZMA_VLI_C(5)
     25 
     26 /// Maximum Unpadded Size
     27 #define UNPADDED_SIZE_MAX (LZMA_VLI_MAX & ~LZMA_VLI_C(3))
     28 
     29 /// Index Indicator based on xz specification
     30 #define INDEX_INDICATOR 0
     31 
     32 
     33 /// Get the size of the Index Padding field. This is needed by Index encoder
     34 /// and decoder, but applications should have no use for this.
     35 extern uint32_t lzma_index_padding_size(const lzma_index *i);
     36 
     37 
     38 /// Set for how many Records to allocate memory the next time
     39 /// lzma_index_append() needs to allocate space for a new Record.
     40 /// This is used only by the Index decoder.
     41 extern void lzma_index_prealloc(lzma_index *i, lzma_vli records);
     42 
     43 
     44 /// Round the variable-length integer to the next multiple of four.
     45 static inline lzma_vli
     46 vli_ceil4(lzma_vli vli)
     47 {
     48 	assert(vli <= UNPADDED_SIZE_MAX);
     49 	return (vli + 3) & ~LZMA_VLI_C(3);
     50 }
     51 
     52 
     53 /// Calculate the size of the Index field excluding Index Padding
     54 static inline lzma_vli
     55 index_size_unpadded(lzma_vli count, lzma_vli index_list_size)
     56 {
     57 	// Index Indicator + Number of Records + List of Records + CRC32
     58 	return 1 + lzma_vli_size(count) + index_list_size + 4;
     59 }
     60 
     61 
     62 /// Calculate the size of the Index field including Index Padding
     63 static inline lzma_vli
     64 index_size(lzma_vli count, lzma_vli index_list_size)
     65 {
     66 	return vli_ceil4(index_size_unpadded(count, index_list_size));
     67 }
     68 
     69 
     70 /// Calculate the total size of the Stream
     71 static inline lzma_vli
     72 index_stream_size(lzma_vli blocks_size,
     73 		lzma_vli count, lzma_vli index_list_size)
     74 {
     75 	return LZMA_STREAM_HEADER_SIZE + blocks_size
     76 			+ index_size(count, index_list_size)
     77 			+ LZMA_STREAM_HEADER_SIZE;
     78 }
     79 
     80 #endif
     81