函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:lib\xz\xz_dec_stream.c Create Date:2022-07-27 08:06:23
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：dec_main

函数原型：static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)

返回类型：enum xz_ret

参数：

类型参数名称
struct xz_dec *s
struct xz_buf *b
557  Saved in_pos and out_pos 等于in_pos
559  当(true)循环
561  当: Position in dec_main() 恒等于SEQ_STREAM_HEADER
570  如果非Fill s->temp by copying data starting from b->in[b->in_pos]. Caller* must have set s->temp.pos to indicate how much data we are supposed* to copy into s->temp.buf. Return true once s->temp.pos has reached则返回:XZ_OK
580  Position in dec_main() 等于SEQ_BLOCK_START
582  ret等于Decode the Stream Header field (the first 12 bytes of the .xz Stream).
583  如果ret不等于XZ_OK则返回:ret
588  当: Position in dec_main() 恒等于SEQ_BLOCK_START
590  如果in_pos恒等于in_size则返回:XZ_OK
594  如果in[in_pos]恒等于0则
604  Size of the Block Header field 等于in[in_pos]加1的和乘4
607  size等于Size of the Block Header field
608  pos等于0
609  Position in dec_main() 等于SEQ_BLOCK_HEADER
613  当: Position in dec_main() 恒等于SEQ_BLOCK_HEADER
614  如果非Fill s->temp by copying data starting from b->in[b->in_pos]. Caller* must have set s->temp.pos to indicate how much data we are supposed* to copy into s->temp.buf. Return true once s->temp.pos has reached则返回:XZ_OK
617  ret等于Decode the Block Header and initialize the filter chain.
618  如果ret不等于XZ_OK则返回:ret
621  Position in dec_main() 等于SEQ_BLOCK_UNCOMPRESS
625  当: Position in dec_main() 恒等于SEQ_BLOCK_UNCOMPRESS
626  ret等于Decode the Compressed Data field from a Block
627  如果ret不等于XZ_STREAM_END则返回:ret
630  Position in dec_main() 等于SEQ_BLOCK_PADDING
634  当: Position in dec_main() 恒等于SEQ_BLOCK_PADDING
642  当Observed compressed size of the current Block 按位与3循环
643  如果in_pos恒等于in_size则返回:XZ_OK
646  如果in[in_pos++]不等于0则返回:XZ_DATA_ERROR
649  Observed compressed size of the current Block 先自加
652  Position in dec_main() 等于SEQ_BLOCK_CHECK
656  当: Position in dec_main() 恒等于SEQ_BLOCK_CHECK
657  如果 Type of the integrity check calculated from uncompressed data 恒等于XZ_CHECK_CRC32则
668  Position in dec_main() 等于SEQ_BLOCK_START
669  退出
671  当: Position in dec_main() 恒等于SEQ_INDEX
672  ret等于Decode the Number of Records, Unpadded Size, and Uncompressed Size* fields from the Index field. That is, Index Padding and CRC32 are not* decoded by this function.* This can return XZ_OK (more input needed), XZ_STREAM_END (everything
673  如果ret不等于XZ_STREAM_END则返回:ret
676  Position in dec_main() 等于SEQ_INDEX_PADDING
680  当: Position in dec_main() 恒等于SEQ_INDEX_PADDING
681  当Size of the Index in bytes 加in_pos减 Saved in_pos and out_pos 按位与3循环
683  如果in_pos恒等于in_size则
688  如果in[in_pos++]不等于0则返回:XZ_DATA_ERROR
693  Update the Index size and the CRC32 value.
696  如果非FIXME: Not all basic memory functions are provided in architecture-specific* files (yet). We define our own versions here for now, but this should be* only a temporary solution.* memeq and memzero are not used much and any remotely sane implementation则返回:XZ_DATA_ERROR
700  Position in dec_main() 等于SEQ_INDEX_CRC32
704  当: Position in dec_main() 恒等于SEQ_INDEX_CRC32
705  ret等于Validate that the next four input bytes match the value of s->crc32.
706  如果ret不等于XZ_STREAM_END则返回:ret
709  size等于See the .xz file format specification at* http://tukaani.org/xz/xz-file-format.txt* to understand the container format.
710  Position in dec_main() 等于SEQ_STREAM_FOOTER
714  当: Position in dec_main() 恒等于SEQ_STREAM_FOOTER
715  如果非Fill s->temp by copying data starting from b->in[b->in_pos]. Caller* must have set s->temp.pos to indicate how much data we are supposed* to copy into s->temp.buf. Return true once s->temp.pos has reached则返回:XZ_OK
718  返回:Decode the Stream Footer field (the last 12 bytes of the .xz Stream)
调用者
名称描述
xz_dec_runxz_dec_run() is a wrapper for dec_main() to handle some special cases in* multi-call and single-call decoding.* In multi-call mode, we must return XZ_BUF_ERROR when it seems clear that we* are not going to make any progress anymore