I'm trying to get the md5 hash of a file in Go, like thus:
running_hash := md5.New(); // type hash.Hash
running_hash.Write(data); // data is []byte
sum := running_hash.Sum(); // []uint8 according to the compiler
But when I try to get the string of the hash's 'sum' (http://golang.org/pkg/hash/), via
sumstring := string(sum); // returns 'Ӿ��]앿��N��' or similar
when the hash is supposed to be d3be9e835dec95bfbef34ebe1fbf03da. I get the same sort of nonsense, only with different characters, when I try to convert on a byte-by-byte basis.
How am I meant to get the hash's string?
Basically, you've got the binary data but it looks like you're expecting hex. Have a look at the hex package for conversion routines, especially EncodeToString. I'm not a Go programmer, but I think if you just pass sum into hex.EncodeToString, you'll get the answer you expected.
alternately, you can get the hex representation of a string or byte slice easily using fmt.Sprintf("%x", sum)
Related
I'm trying to figure out if the two encodings of the character are the same:
SELECT
~b"1",
code_points_to_string([0x380]),
"\u0380"
The first is base64-encoded and the second is a string. How can I determine if these are equivalent? Is there some sort of function where I can, for example extract the code point from a base64-string in BigQuery?
You have mentioned ~b"1" as base64-encoded but according to this google cloud documentation ~ X is a Bitwise not operator. Here you are converting the string value to bytes and then performing Bitwise Not operation on it (Though while showing in UI BQ shows in base64 encoded). To convert it into base64-encoded you can use the TO_BASE64 function.
You can use the to_code_points function to extract the code points from a base 64 encoded string.
select *
,from_base64(d) decoded_val_bytes
,SAFE_CONVERT_BYTES_TO_STRING(from_base64(d)) sring_value
,to_code_points(from_base64(d)) cp
from (
select
~b"foo" a,
code_points_to_string([102,111,111]) b
,to_base64(b"foo") d
,to_code_points("foo") e
)
to_code_points function is to convert string or bytes into an array of INT64 and code_points_to_string function is to convert an array of INT64 into STRING.
i am facing issue while converting unicode data into national characters.
When i convert the Unicode data into national using national-of function, some junk character like # is appended after the string.
E.g
Ws-unicode pic X(200)
Ws-national pic N(600)
--let the value in Ws-Unicode is これらの変更は. getting from java end.
move function national-of ( Ws-unicode ,1208 ) to Ws-national.
--after converting value is like これらの変更は #.
i do not want the extra # character added after conversion.
please help me to find out the possible solution, i have tried to replace N'#' with space using inspect clause.
it worked well but failed in some specific scenario like if we have # in input from user end. in that case genuine # also converted to space.
Below is a snippet of code I used to convert EBCDIC to UTF. Before I was capturing string lengths, I was also getting # symbols:
STRING
FUNCTION DISPLAY-OF (
FUNCTION NATIONAL-OF (
WS-EBCDIC-STRING(1:WS-XML-EBCDIC-LENGTH)
WS-EBCDIC-CCSID
)
WS-UTF8-CCSID
)
DELIMITED BY SIZE
INTO WS-UTF8-STRING
WITH POINTER WS-XML-UTF8-LENGTH
END-STRING
SUBTRACT 1 FROM WS-XML-UTF8-LENGTH
What this code does is string the UTF8 representation of the EBCIDIC string into another variable. The WITH POINTER clause will capture the new length of the string + 1 (+ 1 because the pointer is positioned to the next position after the string ended).
Using this method, you should be able to know exactly how long second string is and use that string with the exact length.
That should remove the unwanted #s.
EDIT:
One thing I forgot to mention, in my case, the # signs were actually EBCDIC low values when viewing the actual hex on the mainframe
Use inspect with reverse and stop after first occurence of #
How does one calculate the info_hash parameter? Aka the hash corresponding to the info dictionar??
From official specs:
info_hash
The 20 byte sha1 hash of the bencoded form of the info value from the metainfo file. Note that this is a substring of the metainfo file.
This value will almost certainly have to be escaped.
Does this mean simply get the substring from the meta-info file and do a sha-1 hash on the reprezentative bytes??
.... because this is how i tried 12 times but without succes meaning I have compared the resulting hash with the one i should end up with..and they differ ..that + tracker response is FAILURE, unknown torrent ...or something
So how do you calculate the info_hash?
The metafile is already bencoded so I don't understand why you encode it again?
I finally got this working in Java code, here is my code:
byte metaData[]; //the raw .torrent file
int infoIdx = ?; //index of 'd' right after the "4:info" string
info_hash = SHAsum(Arrays.copyOfRange(metaData, infoIdx, metaData.length-1));
This assumes the 'info' block is the last block in the torrent file (wrong?)
Don't sort or anything like that, just use a substring of the raw torrent file.
Works for me.
bdecode the metafile. Then it's simply sha1(bencode(metadata['info']))
(i.e. bencode only the info dict again, then hash that).
I have a problem using this query:
select decode(to_hex(ascii('ل')::int),'hex')
When I execute it, I get:
ERROR: invalid hexadecimal data: odd number of digits
decode(..., 'hex') doesn't mean convert this hexadecimal number to something. Hex encoding is a particular encoding format for bytes, and it requires two hexadecimal digits per octet. On the other hand, to_hex converts an integer to a hexadecimal representation, and that could have an even or odd number of digits.
So the answer is, you can't do that (without some manual fixups). And it's not clear why you would want to, either. It looks like you could just do 'ل'::bytea, but that might not be what you wanted either.
May be it's simpler to use something like this:
select encode('ل','escape');
I have some code where I am converting some data elements in a flat file. I save the old:new values to a hash which is written to a file at the end of processing. On subsequence execution, I reload into a hash so I can reuse previously converted values on additional data files. I also save the last conversion value so if I encounter an unconverted value, I can assign it a new converted value and add it to the hash.
I had used this code before (back in Feb) on six files with no issues. I have a variable that is set to ZCKL0 (last character is a zero) which is retrieved from a file holding the last used value. I apply the increment operator
...
$data{$olddata} = ++$dataseed;
...
and the resultant value in $dataseed is 1 instead of ZCKL1. The original starting seed value was ZAAA0.
What am I missing here?
Do you use the $dataseed variable in a numeric context in your code?
From perlop:
If you increment a variable that is
numeric, or that has ever been used in
a numeric context, you get a normal
increment. If, however, the variable
has been used in only string contexts
since it was set, and has a value that
is not the empty string and matches
the pattern /^[a-zA-Z][0-9]\z/ , the
increment is done as a string,
preserving each character within its
range.
As prevously mentioned, ++ on strings is "magic" in that it operates differently based on the content of the string and the context in which the string is used.
To illustrate the problem and assuming:
my $s='ZCL0';
then
print ++$s;
will print:
ZCL1
while
$s+=0; print ++$s;
prints
1
NB: In other popular programming languages, the ++ is legal for numeric values only.
Using non-intuitive, "magic" features of Perl is discouraged as they lead to confusing and possibly unsupportable code.
You can write this almost as succinctly without relying on the magic ++ behavior:
s/(\d+)$/ $1 + 1 /e
The e flag makes it an expression substitution.