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Collections-C

Collections-C is a library of generic data structures for the C language.

• Features
• Building and Installing
• Using the library
• Contributing

Features

• Pointer Containers
• Sized Containers
• Memory Pools

Pointer Containers

Structures that store data in the form of void*.

Example

int value = 20;
CC_Array *array;

if (cc_array_new(&array) != CC_OK) { /*Create a new array.*/
    // handle error
}
if (cc_array_add(&array, (void*) &value) != CC_OK) { /* Add the pointer to the value to the array */
    // handle error
}

Sized Containers

Structures that store data of arbitrary length directly.

Example

int value = 20;
CC_SizedArray *array;

if (cc_sized_array_new(sizeof(int), &array) != CC_OK) { /* Create a new array that stores values the size of an int*/
    // handle error
}
if (cc_sized_array_add(&array, &value) != CC_OK) { /* Copy the value into the array */
    // handle error
}

Memory Pools

Memory pools are pre-allocated blocks of contiguous memory

Example

/* CC_StaticPool can enable the use of the structures on the stack */

#include "memory/cc_static_pool.h"
#include "cc_list.h"

CC_StaticPool *pool;

// Alloc wrappers
void *pool_malloc(size_t size)               {cc_static_pool_malloc(size, pool);}
void *pool_calloc(size_t count, size_t size) {cc_static_pool_calloc(count, size, pool);}
void  pool_free(void* ptr)                   {cc_static_pool_free(ptr, pool);}

int main(int argc, char **argv) {
    uint8_t buffer[2000];            /* Large enough buffer. */
    cc_static_pool_new(sizeof(buffer), 0, buffer, buffer, &pool); /* allocate the pool structure inside the buffer */

    CC_ListConf conf;                /* Create a new list config */
    cc_list_conf_init(&conf);        
    conf.mem_alloc  = pool_malloc;   /* Set list memory allocators to pool allocators */
    conf.mem_calloc = pool_calloc;
    conf.mem_free   = pool_free;

    CC_List* list;
    cc_list_new_conf(&conf, &list);  /* The newly created list will be allocated inside the "buffer" array*/

    // Use the list

    return 0;
}

Building and Installation

Dependencies

Linux

• C compiler (gcc or clang)
• cmake (>= 3.5)
• pkg-config

These packages can usually be installed through your distributions package manager.

Windows

• Visual Studio (recommended) or MinGW
• cmake

Building the project

Linux

To build the project, we first need to create a separate build directory (if it doesn't already exist):

mkdir build

From this directory we can run the cmake command and configure the build:

• cmake .. or cmake -DSHARED=True to make Collections-C build as a shared library
• cmake -DSHARED=False to build a static library

Once cmake is done generating makefiles, we can build the library by running make inside our build directory.

An example of cloning and building a static library:

git clone https://github.com/Collections-C.git
cd Collections-C
mkdir build
cd build
cmake -DSHARED=False
make

Running tests

To run tests (from the build directory):

make test

To run individual tests, simply run the appropriate executable. For example:

build/test/array_test

Installing

To install the library run:

sudo make install

By default the libraries and headers will be installed in /usr/local/lib/ and /usr/local/include directories.

You have to make the system's runtime aware of the location of the new library to be able to run dynamically linked applications. This might be as simple as running the following command if your /etc/ld.so.conf contains the install directory.

Note: macOS doesn't support ldconfig.

sudo ldconfig

Using Collections-C in your programs

A simple program

If we already built and installed the library, we can write a simple hello world program and save it to a file named hello.c:

#include <stdio.h>
#include <collectc/cc_array.h>

int main(int argc, char **argv) {
    // Create a new array
    CC_Array *ar;
    cc_array_new(&ar);

    // Add a string to the array
    cc_array_add(ar, "Hello World!\n");

    // Retreive the string and print it
    char *str;
    cc_array_get_at(ar, 0, (void*) &str);
    printf("%s", str);

    return 0;
}

Now we need to compile and link our program. Since make builds both the static and the dynamic library we can choose which one we wish to link into our program.

Linking statically

If we wish to statically link the library to our program we can pass the -static flag to the compiler

Note: On macOS, the -static flag is not very friendly (it requires that all the libraries are statically linked). So we can replace -static -lcollectc with the full path to the static library. Which is /usr/local/lib/libcollectc.a by default.

gcc hello.c -static -lcollectc -o hello

or similarly when compiling with clang:

clang hello.c -static -lcollectc -o hello

This will link the library by copying it into the executable. We can use this option if we don't wish to have Collections-C as a runtime dependency, however this comes at the expense of generating a larger executable.

Linking dynamically

We can also choose to link with the library dynamically at runtime. This is the default behaviour if omit the -static compiler flag:

gcc hello.c -lcollectc -o hello

or with clang:

clang hello.c -lcollectc -o hello

Linking dynamically produces a smaller executable, but requires libcollectc.so to be present on every system on which the program is going to be executed.

Linking problems

Sometimes the compiler may have trouble finding the library or the headers. This is usually because it's looking for them in the wrong directory, which may happen if the library or the headers or both are installed in a non-standard directory or not installed at all.

If this is the case, we can explicitly tell the compiler where to look for them by passing the -I[path to headers] and -L[path to libraries] options:

gcc hello.c `pkg-config --cflags --libs collectionc` -o hello

Running the program

If everything went well with the compilation we can run the executable:

./hello

and it should print Hello, World! to the console.

Contributing

Contributions are welcome.

If you have a feature request, or have found a bug, feel free to open a new issue. If you wish to contribute code, see CONTRIBUTING.md for more details.