Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:lib\xz\xz_dec_lzma2.c Create Date:2022-07-28 07:08:50
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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Name:Take care of the LZMA2 control layer, and forward the job of actual LZMA* decoding or copying of uncompressed chunks to other functions.

Proto:enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s, struct xz_buf *b)

Type:enum xz_ret

Parameter:

TypeParameterName
struct xz_dec_lzma2 *s
struct xz_buf *b
936  When in_pos < in_size || Position in xz_dec_lzma2_run(). == SEQ_LZMA_RUN cycle
938  Case Position in xz_dec_lzma2_run(). == SEQ_CONTROL
970  tmp = in[in_pos++]
972  If tmp == 0x00 Then Return XZ_STREAM_END
975  If tmp >= 0xE0 || tmp == 0x01 Then
979  Else if * True if dictionary reset is needed. This is false before * the first chunk (LZMA or uncompressed). Then
980  Return XZ_DATA_ERROR
983  If tmp >= 0x80 Then
1006  Else
1014  Break
1016  Case Position in xz_dec_lzma2_run(). == SEQ_UNCOMPRESSED_1
1017  Uncompressed size of LZMA chunk (2 MiB at maximum) += in[in_pos++] << 8
1019  Position in xz_dec_lzma2_run(). = SEQ_UNCOMPRESSED_2
1020  Break
1022  Case Position in xz_dec_lzma2_run(). == SEQ_UNCOMPRESSED_2
1023  Uncompressed size of LZMA chunk (2 MiB at maximum) += in[in_pos++] + 1
1025  Position in xz_dec_lzma2_run(). = SEQ_COMPRESSED_0
1026  Break
1028  Case Position in xz_dec_lzma2_run(). == SEQ_COMPRESSED_0
1029  * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) = in[in_pos++] << 8
1031  Position in xz_dec_lzma2_run(). = SEQ_COMPRESSED_1
1032  Break
1034  Case Position in xz_dec_lzma2_run(). == SEQ_COMPRESSED_1
1035  * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) += in[in_pos++] + 1
1037  Position in xz_dec_lzma2_run(). = Next position after decoding the compressed size of the chunk.
1038  Break
1040  Case Position in xz_dec_lzma2_run(). == SEQ_PROPERTIES
1041  If Not Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks* from the decoded lp and pb values. On success, the LZMA decoder state is* reset and true is returned. Then Return XZ_DATA_ERROR
1044  Position in xz_dec_lzma2_run(). = SEQ_LZMA_PREPARE
1048  Case Position in xz_dec_lzma2_run(). == SEQ_LZMA_PREPARE
1049  If * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) < Range decoder initialization eats the first five bytes of each LZMA chunk. Then Return XZ_DATA_ERROR
1052  If Not Read the first five initial bytes into rc->code if they haven't been* read already. (Yes, the first byte gets completely ignored.) Then Return XZ_OK
1055  * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) -= Range decoder initialization eats the first five bytes of each LZMA chunk.
1056  Position in xz_dec_lzma2_run(). = SEQ_LZMA_RUN
1060  Case Position in xz_dec_lzma2_run(). == SEQ_LZMA_RUN
1070  Set dictionary write limit
1073  If Not The LZMA decoder assumes that if the input limit (s->rc Then Return XZ_DATA_ERROR
1076  Uncompressed size of LZMA chunk (2 MiB at maximum) -= Flush pending data from dictionary to b->out. It is assumed that there is* enough space in b->out. This is guaranteed because caller uses dict_limit()* before decoding data into the dictionary.
1078  If Uncompressed size of LZMA chunk (2 MiB at maximum) == 0 Then
1086  Else if out_pos == out_size || in_pos == in_size && size < * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) Then
1090  Return XZ_OK
1093  Break
1095  Case Position in xz_dec_lzma2_run(). == SEQ_COPY
1096  Copy uncompressed data as is from input to dictionary and output buffers.
1097  If * Compressed size of LZMA chunk or compressed/uncompressed * size of uncompressed chunk (64 KiB at maximum) > 0 Then Return XZ_OK
1100  Position in xz_dec_lzma2_run(). = SEQ_CONTROL
1101  Break
1105  Return XZ_OK
Caller
NameDescribe
dec_blockDecode the Compressed Data field from a Block