StringSlice

Simple length-based string library for C. Ditch null termination for good. Note that the library is still a work in progress.

Note: StringSlice depends on my arena allocator library. Arenas offer a fast and hassle-free way to manage memory, especially useful for string operations which often require frequent allocations. The library is included as a git submodule. To learn more about arenas, see this awesome article by Ryan Fleury: www.rfleury.com/p/untangling-lifetimes-the-arena-allocator

If you're not ready to switch to arenas, there is an option to use malloc-based allocations. Just make sure to select stringslice_malloc.h.

Memory Management

There are two options for memory management: arena-based and malloc-based allocation. The arena-based header is simple to work with. If a function needs to allocate memory, it takes an arena as an argument. This makes it easy to track which functions make allocations. In order to free the memory, you free the arena at the end of the group's lifetime. See the usage sample for an example. The malloc-based header has identical functions, but without any arena arguments. If a string was allocated on the heap, the allocated field gets flipped to true. This way you can simply pass every string into str_free, and only the ones allocated will be freed.

You can swap out the arena allocator used by this library with your own implemention simply by defining SS_ARENA_STRUCT with your structure and SS_ARENA_ALLOC with your allocation function before you include the header. Alternatively, they may be changed from inside the library header.

Usage example

#include <stdio.h>
#include "stringslice.h"

int main(void)
{
  Arena arena = create_arena(MiB(1));

  String string = str("Hello, ");
  string = str_concat(string, str("world"), &arena);
  string = str_to_upper(&string, &arena);
  string = str_substr(&string, 1, 6);
  long location = str_find(string, str("LLO"));
  printf("%li\n", location);

  StringArray string_array = str_create_array(3, &arena);
  string_array.e[0] = str("string");
  string_array.e[1] = str("slice"); 
  string_array.e[2] = str("library");

  String output = str_join(string_array, str(", "), &arena);
  output = str_nullify(output, &arena);
  printf("%s\n", output.str);

  return 0;
}

Documentation

str(s) ((String) {s, cstr_len(s)-1})

• Creates a string given a cstring literal

u64 cstr_len(i8 *s)

• Returns the length of a null-terminated string

String str_alloc(u64 len, Arena *arena)

• Allocates len bytes of memory to str field of String and returns new string

str_bool str_free(String *s) (malloc only)

• If string was alloced, frees memory and returns true. Otherwise returns false

String str_from_cstring(char *cstr)

• Returns a copy of the cstr as a String

bool str_equals(String s1, String s2)

• Returns true if the characters in s1 match s2

bool str_contains(String s, String substr)

• Returns true if s contains substr

i64 str_find(String s, String substr, u64 start, u64 end)

• Returns the index of the first instance of substr in s from index start to index end

i64 str_find_char(String s, i8 c, u64 start, u64 end)

• Returns the index of the first instance of c in s from index start to index end

String str_copy(String s, Arena *arena)

• Allocates and returns a copy of s

String str_insert_at(String s, String substr, size_t loc, Arena *arena)

• Returns a new string with substr inserted into s at index loc

String str_concat(String s1, String s2, Arena *arena)

• Returns a new string combining s1 and s2 such that the characters of s2 follow s1

String str_substr(String s, u64 start, u64 end)

• Returns a substring of s starting at index start and ending before index end

String str_strip_front(String s, String substr)

• Returns a substring of s with the first substr.len characters of s removed if they equal substr

String str_strip_back(String s, String substr)

• Returns a substring of s with the last substr.len characters of s removed if they equal substr

String str_nullify(String s, Arena *arena)

• Returns a new string with a null terminator appended to the end

String str_to_lower(String s, Arena *arena)

• Returns a new string with each uppercase character in s a lowercase character

String str_to_upper(String s, Arena *arena)

• Returns a new string with each lowercase character in s a uppercase character

String str_join(StringArray arr, String delimiter, Arena *arena)

• Returns a new string consisting of each string in arr. delimiter added between each string

StringArray str_split(String s, String delimiter, Arena *arena)

• Splits s into substrings separated by delimiter and returns a StringArray (NOT IMPLEMENTED)

StringArray str_create_array(size_t count, Arena *arena)

• Intializes and returns a new StringArray of size count

void str_clear_array(StringArray *arr, Arena *arena)

• Clears arr and resets count to zero