request for get-bytes (to join get-int, get-string, etc)

[TedWalther]

I am writing a Postgres module modeled on the MySQL module.



Postgres sometimes sends binary data as a result of queries.



newlisp strings can contain binary data, right?



Although I could probably work out something with (append), would it make sense to have a (get-bytes addr nbytes) function in the base distribution?



My brain is too fried right now to implement it.



Also, it might be more efficient to use the underlying memcpy() function of C in a builtin (get-bytes ...) rather than me implementing it.  Although as my mind works, I do see I could do it in a line or two of code.  Once I take a break.

[Lutz]

This is how you can do it:

Code Select Expand

(set 'buffer (dup "00" nbytes))

(cpymem addr buffer nbytes)


the variable buffer has now the original binary content in the original byte order and with the correct size information.



And here is a slightly more complicated and slower method:

Code Select Expand

(set 'buffer (first (unpack (format "s%d" nbytes) addr)))

[TedWalther]

This is how you can do it:

Code Select Expand

(set 'buffer (dup "00" nbytes))

(cpymem addr buffer nbytes)


the variable buffer has now the original binary content in the original byte order and with the correct size information.



And here is a slightly more complicated and slower method:

Code Select Expand

(set 'buffer (first (unpack (format "s%d" nbytes) addr)))

Thanks Lutz.  Somehow I missed the cpymem function.



Ted