Version: 0.0.1

C++ uses templates to produce type definitions at compile time. This enables generic programming while still maintaining the robustness of a strongly typed language.

But, C doesn't support templates. How does one solve it for C?

The idea is to use the power of void* pointers to develop an interface which acts like a generic data type. Standard data structure and algorithm implementations will exploit the ctemplate interface, while the user will provide elementary functions such as a comparator and an assignment function.

Let's demonstrate by example. Suppose we have an integer array as follows:

#include <ctl.c>
int arr[] = {9, 3, 7, 5, 6, 4, 8, 2}; // the user wants to sort an integer array
int length = 8; // defines the length of the array

We would like to sort the array above without writing a custom sort function. We now use ctemplates to leave the sorting task to the library. First, we must define the compare and assign functions knowing that we perform sorting on an int array.

int compare(ctemplate left, ctemplate right)
{
	// we will compare integer values to sort an int array
	return ( *(int*) left.ptr - *(int*) right.ptr );
}
void assign(ctemplate left, ctemplate right)
{
	// we know that the data is of type int
	*(int*) left.ptr = *(int*) right.ptr;
}

The sort function call is simply called by passing a ctemplate wrapper for the integer array. We specify both the base address and the size of each element in the array.

// Calling the following lines, sorts the array.
ctemplate wrapper = {arr, sizeof(int)};
ctl_merge_sort( wrapper, length, compare, assign );

1. Download the repository and copy the library your local project folder (say, ./myproject).

git clone https://github.com/nmakes/ctl
cp -r ctl/ctlib ./myproject/ctlib

2. Import ctl and get started

#include "ctlib/ctl.c"

Sample demonstrations are available in files named demo_*. To execute them,

cd ctl
gcc demo_sort.c
./a.out