Friday, 24 January 2014
Binary Cheatsheet
I have been using Tcl for years, but I still need to lookup the manual every
time I use binary format and binary scan. If you are like me, you will find
this cheatsheet a handy reference.
| ` ` | Endian | |||
| Little | Big | Host | Type | Notes |
a |
byte string | format pads with nulls | ||
A |
byte string | format pads with spaces, scan strips trailing spaces/nulls | ||
b |
B |
binary digits | ||
h |
H |
hex digits | ||
c |
8 bit integer list | In other words, ASCII chars | ||
s |
S |
t |
16 bit integer list | |
i |
I |
n |
32 bit integer list | |
w |
W |
m |
64 bit integer list | |
r |
R |
f |
single prec. float list | |
q |
Q |
d |
double prec. float list | |
x |
null bytes | count is number of bytes | ||
X |
move cursor back | count is number of bytes to back up | ||
@ |
move cursor to location | count is byte position, zero based |
Examples
set bin [binary format I2sH2a* {0x123 0x456} 17 ab "testing"]
# This returns 4 (number of conversions)
binary scan $bin I2sH2a* intlist intval hexval str
Steve Bennett (steveb@workware.net.au)
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