Re: [RFC 0/6] Add support of formats for the pattern input

[Jens Axboe <axboe@kernel.dk>]

On 08/19/2015 04:33 AM, Roman Pen wrote:
> Hello, all.
>
> The intention of this patchset is to support dynamic formats for pattern
> input which is used for writing and verifying data, e.g. in the latest patch
> I added '%o' format, which means that current block offset will be written to
> the buffer and then verified back, i.e. this option can be used as the
> following:
>
>   verify_pattern=%o
>
> and the hexdump of generated file in my case is (few last lines):
>
>    ...
>    000f5c00  00 5c 0f 00 00 00 00 00  00 5c 0f 00 00 00 00 00  |.\.......\......|
>    *
>    000fdc00  00 dc 0f 00 00 00 00 00  00 dc 0f 00 00 00 00 00  |................|
>    *
>    000ffc00  00 fc 0f 00 00 00 00 00  00 fc 0f 00 00 00 00 00  |................|
>    *
>    00100000
>
> So, each block is filled in with block offset in little endian order and 8 bytes
> long.
>
> Unfortunately, 'buffer_pattern' option does not support formats, because it
> turned out to be a lot of changes which should be made to pass correct
> io_u->offset through the whole stack of calls. I left this task for future.
>
> Additionally, I moved all 'pattern' parsing/substituting logic to separate
> library file 'lib/pattern.[ch]'. Also, now 'verify_pattern' and 'buffer_pattern'
> support combined input which can consist of strings, numbers and formats
> (as was said formats are supported only by 'verify_pattern' option), e.g. let's
> consider the following example, where 'in' is a 'verify_pattern' or
> 'buffer_pattern' and 'out' is an output buffer filled in with bytes regarding
> specified pattern:
>
>    #1                 #2                 #3        #4
>      in="abcd"          in=-1024           in=66     in=0xFF0X1
>     out=61 62 63 64    out=00 fc ff ff    out=42    out=ff 01
>
>    #5                               #6
>      in=%o                            in="123"0xFFeeCC
>     out=00 00 00 00 00 00 00 00      out=31 32 33 ff ec cc
>
>    #7
>      in=-100xab"1"%o"2"
>      out=f6 ff ff ff ab 31 00 00 00 00 00 00 00 00 32
>
>    #8
>      in=%o0xdeadbeef%o
>     out=00 00 00 00 00 00 00 00 de ad be ef 00 00 00 00 00 00 00 00
>
>    #9
>       in=0xfefefefefefefefefefefefefefefefefefefefefe
>      out=fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>
> For %o format 8 bytes reserved in pattern, and when buffer is ready
> substitution occurs.
>
> The old behaviour is preserved: strings are in quotes, decimals are in the
> range [INT_MIN, INT_MAX], hexidecimals start from 0[Xx] and can be of any
> size (the limit is the maximum size of the pattern, which is 512).
>
> New behaviour: now you can combine everything together and additionally
> use formats (now %o is supported).

Sorry for the late response. This looks good, I have applied it. Care to 
send updates for the HOWTO/man page as well?

-- 
Jens Axboe