csplit

A single header C library that can be used to easily handle splitting strings and other string operations in C.

Installation

Because csplit is a single-header library, all you need to do is copy the csplit.h file into your project, and include it at the top of your source file in which you would like to use it. You can get this file by via the appropriate link in the releases tab, or by cloning the entire repository as follows:

git clone https://github.com/jwlodek/csplit

Then copy csplit.h into your repository, add the

#include "csplit.h"

line at the top of your code, and, if necessary, update your project's include path.

Usage

The core functions that csplit provides are the following:

CSplitError_t csplit(CSplitList_t* list, char* input_str, char* token);

This will split the input string based on the token, as many times as possible. You may also limit the number of splits with:

CSplitError_t csplit_lim(CSplitList_t* list, char* input_str, char* token, int max_splits);

where max_splits is the maximum number of splits allowed. If max_splits is negative, csplit will perform the splits from the end of the string first, instead of from the front.

There are also some utility functions included as well:

char* csplit_get_fragment_at_index(CSplitList_t* list, int index); /* Will return text at given index in list */
char* csplit_strip(char* input_str); /* Strips whitespace from front and rear of string */
int csplit_startswith(char* input_str, char* starts_with); /* Checks if string starts with given token. */

and several other string utility/manipulation functions. Full documentation can be seen here.

Running Unit Tests

Unit testing for csplit is done with the help of the Criterion library. To simplify setup, scripts have been added to the tests/ directory that setup this libarary, and run the tests. Simply run:

cd tests
./initUnitTests.sh

to initialize the Criterion Library, and then

./runUnitTests.sh

to run the tests. Note that this only works on linux systems, and on windows you must set up the unit testing environment manually.

Examples

To build csplit examples, enter the examples directory, and run:

make clean all

or

make clean debug

to have access to gdb debugging of the examples. This has been tested on linux, as well as on Windows with gcc and make included in MinGW.

Basic Example

Example demonstrating using csplit for splitting string on single character and getting split fragments based on indexes.

// include csplit and stdio
#include "csplit.h"
#include <stdio.h>


int main(int argc, char** argv){
    // our test string
    char* test_string = "Hello how are you doing?";
    printf("Our demo string is: %s\n", test_string);

    // initialize our output list.
    CSplitList_t* list = csplit_init_list();

    // split on the " " (space) character
    CSplitError_t err = csplit(list, test_string, " ");

    // print the list of split fragments to stdout
    csplit_print_list_info(list, stdout);

    // print a separator
    printf("----------------------------\n");

    // demo of getting fragment string at an index, 3 index will give us "you"
    char* test_get_index = get_fragment_at_index(list, 3);

    // demo of getting fragment string using reverse index, -1 will give us the last
    // fragment, in this case "doing?"
    char* test_get_r_index = get_fragment_at_index(list, -1);

    // print results
    printf("Get index: %s\n", test_get_index);
    printf("Get reverse index: %s\n", test_get_r_index);

    // free memory
    csplit_clear_list(list);
}

.csv reading example

Example of using csplit to read .csv files.

// include csplit and stdio
#include "csplit.h"
#include <stdio.h>


int main(int argc, char** argv){
    // open the file, return if NULL
    FILE* csv_file = fopen("exampleFiles/test.csv", "r");
    if(csv_file == NULL){
        printf("Failed to open file, exiting.\n");
        return -1;
    }

    // buffer for reading from file
    char buffer[256];
    while(fgets(buffer, 256, csv_file)) {

        // ignore lines that are blank
        if(strlen(buffer) > 1){
            // initialize the list, strip whitespace, and call csplit on commas
            CSplitList_t* list = csplit_init_list();
            char* temp = csplit_strip(buffer);
            CSplitError_t err = csplit(list, temp, ",");
            free(temp); /* Make sure to free stripped line */

            // print the split values
            print_csplit_list_info(list, stdout);

            // example iterating through resulting list and summing values read from .csv file
            CSplitFragment_t* current_fragment = list->head;
            int sum = 0;
            while(current_fragment != NULL){
                sum = sum + atoi(current_fragment->text);
                current_fragment = current_fragment->next;
            }

            // print sum of numbers in line, and free memory
            printf("The sum of the elements in the line = %d\n", sum);
            csplit_clear_list(list);

            printf("----------------------\n");
        }
    }
    fclose(csv_file);
    return 0;
}

More examples are available in the examples directory of this repository.

Why does it exist?

I wrote csplit because I found string manipulation in C to be very difficult, particularly the strtok built in function. I have successfully used csplit in several projects, primarily for parsing input files, and I hope it proves to be of use to you.

License

MIT (c) 2019 - Jakub Wlodek