Module Name: othersrc
Committed By: agc
Date: Mon Feb 24 05:59:14 UTC 2014
Update of /cvsroot/othersrc/external/bsd/transit
In directory ivanova.netbsd.org:/tmp/cvs-serv13510
Log Message:
Initial import of transit-20140222 into othersrc
transit is a simple data serialisation library, in contrast to JSON or
CBOR (RFC 7049). It is much simplified from CBOR, and has none of the
binary string or escaped character issues that JSON faces.
There are two atomic types in the transit library
+ a numeric value, encoded using the bottom 7 bits in a byte, and only
using the necessary number of bytes to fully represent the value.
+ a string of bytes (which can be of any value). The bytes are preceded
by a numeric atom giving the length of the byte string. Byte strings do
not need to be NUL-terminated, nor do any characters need escaping
within the byte string.
As in JSON, there are two types of structured data based on top of these
two atoms:
+ a list of elements, and
+ a dictionary of pairs of elements
and each element in a list or dictionary can be any of the other
types, although the keys of dictionary pairs are usually represented
as strings.
A specific marker in the encoding represents the end of a list or
dictionary (similar to CBOR's indefinite length construction).
libtransit(3) gives a worked example of the data representation:
to represent the abstract array "[1,["two",3],["four",5]]",
the encoding would look like:
03 -- List follows
01 -- Number follows
01 -- 1
03 -- List follows
02 -- String follows
03 -- 3 bytes in string
74776f -- "two"
01 -- Number follows
03 -- 3
05 -- End of list (inner list)
03 -- List follows
02 -- String follows
04 -- 4 bytes in string
666f7572 -- "four"
01 -- Number follows
05 -- 5
05 -- End of list (inner list)
05 -- End of list (outer list)
as can be seen from the following dump of the JSON conversion output
% transit -j '[1,["two",3],["four",5]]' | hexdump -C
00000000 03 01 01 03 02 03 74 77 6f 01 03 05 03 02 04 66
|......two......f|
00000010 6f 75 72 01 05 05 05 |our....|
00000017
% transit -j '[1,["two",3],["four",5]]' | transit -d
list
number 1
list
string two
number 3
list
string four
number 5
%
As can be seen above, there is a primitive provided to convert from
encoded JSON into the encoded transit representation.
When decoding transit-encoded streams, the transit_decode(3) function is
the main means of getting the individual parts into a parsed stream of
atoms. In addition, a number of accessor functions for the transit tree
as a whole, and the tree of atoms in particular, are provided. This can
be seen in the walk functions provided in the main transit program.
An additional walk function, from a different program, is shown below:
static int
walk(transit_t *t)
{
transit_atom_t *list;
transit_atom_t *atom;
uint64_t *els;
unsigned i;
/* the input is a list of dicts */
list = transit_atom(t, 0);
/* the indices of the elements are in the array in the "list"
atom */
els = transit_atom_ptr(list);
for (i = 0 ; i < transit_atom_size(list) - 1 ; i++) {
/* add 1 field for the "name" key in the dict pair */
/* add 1 field for the "value" of the pair */
atom = transit_atom(t, els[i] + 1 + 1);
printf("name: %s\n", transit_atom_ptr(atom));
}
return 1;
}
Status:
Vendor Tag: CROOKS
Release Tags: transit-20140222-base
N othersrc/external/bsd/transit/Makefile
N othersrc/external/bsd/transit/bin/1.expected
N othersrc/external/bsd/transit/bin/Makefile
N othersrc/external/bsd/transit/bin/2.expected
N othersrc/external/bsd/transit/bin/3.expected
N othersrc/external/bsd/transit/bin/4.expected
N othersrc/external/bsd/transit/bin/5.expected
N othersrc/external/bsd/transit/bin/6.expected
N othersrc/external/bsd/transit/bin/7.expected
N othersrc/external/bsd/transit/bin/12.expected
N othersrc/external/bsd/transit/bin/9.in
N othersrc/external/bsd/transit/bin/10.in
N othersrc/external/bsd/transit/bin/8.expected
N othersrc/external/bsd/transit/bin/9.expected
N othersrc/external/bsd/transit/bin/10.expected
N othersrc/external/bsd/transit/bin/11.expected
N othersrc/external/bsd/transit/dist/transit.1
N othersrc/external/bsd/transit/dist/Makefile
N othersrc/external/bsd/transit/dist/libtransit.3
N othersrc/external/bsd/transit/dist/main.c
N othersrc/external/bsd/transit/dist/transit.c
N othersrc/external/bsd/transit/dist/transit.h
N othersrc/external/bsd/transit/lib/shlib_version
N othersrc/external/bsd/transit/lib/Makefile
No conflicts created by this import
