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From: "Lakshmipathi.G" <lakshmipathi.g@gmail.com>
Date: Tue, 12 Nov 2013 09:44:51 +0530
Subject: Reading c struct via python
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Hi -
We have C code which writes following struct into berkeley db ("my_db.db").

struct my_info {
    unsigned long int i, e;
    int o;
    char *f;
    char *s;
};

How to read this via Python? Google search gave this code
---
$ cat pybsd2.py
from bsddb import db
fruitDB = db.DB()
fruitDB.open('my_db.db', None, db.DB_BTREE, db.DB_DIRTY_READ)
cursor = fruitDB.cursor()
rec = cursor.first()
while rec:
    print rec
    rec = cursor.next()
fruitDB.close()
---

While storing an entry (o=>500,f=>/home/laks/abcde,s=>OSr,i=>4668368
,e=>10000) and reading it back i get

$ python pybsd2.py
("\x10'\x00\x00\x00\x00\x00\x00",
"\xf4\x01\x00\x00\xd0;G\x00\x00\x00\x00\x00\x10'\x00\x00\x00\x00\x00\x00/home/laks/abcde\x00OSr\x00")

And this http://docs.python.org/2/library/bsddb.html says bdb module is
removed  recently.

Further Searching provides modules like cpickle,ctypes,struct - not sure
which is the right approach/way to proceed.
Should we proceed with bdb module and find out how to retrive integer from
db or use others like ctypes/(c)pickle/struct etc?

Thanks for any help.

Ps : If this question already answered and discussed often, please redirect
me to that thread.

-- 
----
Cheers,
Lakshmipathi.G
FOSS Programmer.
www.giis.co.in

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<div dir=3D"ltr"><div style>Hi -</div><div>We have C code which writes foll=
owing struct into berkeley db (&quot;my_db.db&quot;).</div><div><br></div><=
div>struct my_info {</div><div>=A0 =A0 unsigned long int i, e;</div><div>=
=A0 =A0 int o;</div>

<div>=A0 =A0 char *f;</div><div>=A0 =A0 char *s;</div><div>};</div><div><br=
></div><div>How to read this via Python? Google search gave this code</div>=
<div>---</div><div>$ cat pybsd2.py=A0</div><div>from bsddb import db</div><=
div>fruitDB =3D db.DB()</div>

<div>fruitDB.open(&#39;my_db.db&#39;, None, db.DB_BTREE, db.DB_DIRTY_READ)<=
/div><div>cursor =3D fruitDB.cursor()</div><div>rec =3D cursor.first()</div=
><div>while rec:</div><div>=A0 =A0 print rec</div><div>=A0 =A0 rec =3D curs=
or.next()</div>

<div>fruitDB.close()</div><div>---</div><div><br></div><div>While storing a=
n entry (o=3D&gt;500,f=3D&gt;/home/laks/abcde,s=3D&gt;OSr,i=3D&gt;4668368 ,=
e=3D&gt;10000) and reading it back i get=A0</div><div><br></div><div>$ pyth=
on pybsd2.py=A0</div>

<div>(&quot;\x10&#39;\x00\x00\x00\x00\x00\x00&quot;, &quot;\xf4\x01\x00\x00=
\xd0;G\x00\x00\x00\x00\x00\x10&#39;\x00\x00\x00\x00\x00\x00/home/laks/abcde=
\x00OSr\x00&quot;)</div><div><br></div><div>And this <a href=3D"http://docs=
.python.org/2/library/bsddb.html">http://docs.python.org/2/library/bsddb.ht=
ml</a> says bdb module is removed =A0recently.</div>

<div><br></div><div>Further Searching provides modules like cpickle,ctypes,=
struct - not sure which is the right approach/way to proceed.=A0</div><div>=
Should we proceed with bdb module and find out how to retrive integer from =
db or use others like ctypes/(c)pickle/struct etc?</div>

<div><br></div><div>Thanks for any help.<br></div><div><br></div><div style=
>Ps : If this question already answered and discussed often, please redirec=
t me to that thread.=A0</div><div style><br></div><div>--=A0<br></div>----<=
br>

Cheers,<br>Lakshmipathi.G<br>FOSS Programmer.<br><a href=3D"http://www.giis=
.co.in" target=3D"_blank">www.giis.co.in</a>
</div>

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