buffer options

[Allen]

Hi all,

I want to make a buffer of structs but I don't want to have a static
size; I want it to be as dynamic as possible. Ordinarily, I would use a
list, but in this case I really want to avoid that. Right now, I'm thinking
something along the lines of:

MyStruct mystruct[1];

mystruct = (MyStruct*)LocalAlloc(sizeof(MyStruct)*MAX_BUF); //MS-specific
I know, sorry

But this still limits me to MAX_BUF items in the buffer at once. I was
also thinking about some kind of conditional re-sizing scheme but couldn't
think of a non-messy or fast enough solution along those lines.

Anyone have any suggestions?
--

Best wishes,
Allen

No SPAM in my email !!

 

[John Harrison]

Hi all,

I want to make a buffer of structs but I don't want to have a static
size; I want it to be as dynamic as possible. Ordinarily, I would use a
list, but in this case I really want to avoid that. Right now, I'm thinking
something along the lines of:

MyStruct mystruct[1];

mystruct = (MyStruct*)LocalAlloc(sizeof(MyStruct)*MAX_BUF); //MS-specific
I know, sorry

This is not legal code, even with MS compiler. I think you meant

MyStruct* mystruct;
mystruct = (MyStruct*)LocalAlloc(sizeof(MyStruct)*MAX_BUF);

But this still limits me to MAX_BUF items in the buffer at once. I was
also thinking about some kind of conditional re-sizing scheme but couldn't
think of a non-messy or fast enough solution along those lines.

Anyone have any suggestions?

Yes use a vector. Your situation is exactly what vector was designed for.

#include <vector>

std::vector<MyStruct> mystruct;

Add items to the vector using push_back (for instance)

MyStruct a_struct;
....
mystruct.push_back(a_struct);

the vector will grow dynamically. Or just call resize, if you have a
particular size in mind

mystruct.resize(100);

john

 

[Mike Wahler]

Hi all,

I want to make a buffer of structs but I don't want to have a static
size; I want it to be as dynamic as possible. Ordinarily, I would use a
list, but in this case I really want to avoid that. Right now, I'm thinking
something along the lines of:

MyStruct mystruct[1];

mystruct = (MyStruct*)LocalAlloc(sizeof(MyStruct)*MAX_BUF); file://MS-specific
I know, sorry

But this still limits me to MAX_BUF items in the buffer at once. I was
also thinking about some kind of conditional re-sizing scheme but couldn't
think of a non-messy or fast enough solution along those lines.

Anyone have any suggestions?

std::vector<Mystruct> buffer;

-Mike

 

[Samuele Armondi]

Hi John, Samuele,

Thanks for the help. I've heard of vectors before but have never
bothered reading up on them. I would do so now, but my compiler is rather
old--I'm using MSVC++ 4.0--and doesn't seem to have them. I don't suppose
it's a simple matter of getting a copy of the .h and .lib files is it?

Allen,
I do not think getting the headers would be enough, since you will need a
compiler that supports templates. Maybe it's time for a compiler update...
if you are on a budget, it is worth checking out dev-cpp, it is free to
download and it supports most of the features you will need. Just search for
it using google.
HTH,
S. Armondi

 

[John Harrison]

Hi John, Samuele,

Thanks for the help. I've heard of vectors before but have never
bothered reading up on them. I would do so now, but my compiler is rather
old--I'm using MSVC++ 4.0--and doesn't seem to have them. I don't suppose
it's a simple matter of getting a copy of the .h and .lib files is it?

Thanks and best wishes,
Allen

Try here http://www.stlport.org, not sure if it compiles for VC++ 4 though.
That is a really old compiler and the STL (of which vector is a part) makes
heavy use of templates. An old compiler might struggle.

john

 

[John Harrison]

Try here http://www.stlport.org, not sure if it compiles for VC++ 4 though.
That is a really old compiler and the STL (of which vector is a part) makes
heavy use of templates. An old compiler might struggle.

Just checked and it claims to support VC++ 4.

john