vec

A type-safe dynamic array implementation for C.

Installation

The vec.c and vec.h files can be dropped into an existing C project and compiled along with it.

Usage

Before using a vector it should first be initialised using the vec_init() function.

vec_int_t v;
vec_init(&v);
vec_push(&v, 123);
vec_push(&v, 456);

To access the elements of the vector directly the vector's data field can be used.

printf("%d\n", v.data[1]); /* Prints the value at index 1 */

The current length of the vector is stored in the length field of the vector

printf("%d\n", v.length); /* Prints the length of the vector */

When you are done with the vector the vec_deinit() function should be called on it. This will free any memory the vector allocated during use.

vec_deinit(&v);

Types

vec.h provides the following predefined vector types:

To define a new vector type the vec_t() macro should be used:

/* Creates the type uint_vec_t for storing unsigned ints */
typedef vec_t(unsigned int) uint_vec_t;

Functions

All vector functions are macro functions. The parameter v in each function should be a pointer to the vec struct which the operation is to be performed on.

vec_t(T)

Creates a vec struct for containing values of type T.

/* Typedefs the struct `fp_vec_t` as a container for type FILE* */
typedef vec_t(FILE*) fp_vec_t;

vec_init(v)

Initialises the vector, this must be called before the vector can be used.

vec_deinit(v)

Deinitialises the vector, freeing the memory the vector allocated during use; this should be called when we're finished with a vector.

vec_push(v, val)

Pushes a value to the end of the vector. Returns 0 if the operation was successful, otherwise -1 is returned and the vector remains unchanged.

vec_pop(v)

Removes and returns the value at the end of the vector.

vec_splice(v, start, count)

Removes the number of values specified by count, starting at the index start.

vec_splice(&v, 2, 4); /* Removes the values at indices 2, 3, 4 and 5 */

vec_swapsplice(v, start, count)

Removes the number of values specified by count, starting at the index start; the removed values are replaced with the last count values of the vector. This does not preserve ordering but is O(1).

vec_insert(v, idx, val)

Inserts the value val at index idx shifting the elements after the index to make room for the new value.

/* Inserts the value 123 at the beginning of the vec */
vec_insert(&v, 0, 123);

Returns 0 if the operation was successful, otherwise -1 is returned and the vector remains unchanged.

vec_sort(v, fn)

Sorts the values of the vector; fn should be a qsort-compatible compare function.

vec_swap(v, idx1, idx2)

Swaps the values at the indices idx1 and idx2 with one another.

vec_truncate(v, len)

Truncates the vector's length to len. If len is greater than the vector's current length then no change is made.

vec_clear(v)

Clears all values from the vector reducing the vector's length to 0.

vec_first(v)

Returns the first value in the vector. This should not be used on an empty vector.

vec_last(v)

Returns the last value in the vector. This should not be used on an empty vector.

vec_reserve(v, n)

Reserves capacity for at least n elements in the given vector; if n is less than the current capacity then vec_reserve() does nothing. Returns 0 if the operation was successful, otherwise -1 is returned and the vector remains unchanged.

vec_compact(v)

Reduces the vector's capacity to the smallest size required to store its current number of values. Returns 0 if the operation is successful, otherwise -1 is returned and the vector remains unchanged.

vec_pusharr(v, arr, count)

Pushes the contents of the array arr to the end of the vector. count should be the number of elements in the array.

vec_extend(v, v2)

Appends the contents of the v2 vector to the v vector.

vec_find(v, val, idx)

Finds the first occurrence of the value val in the vector. idx should be an int where the value's index will be written; idx is set to -1 if val could not be found in the vector.

vec_remove(v, val)

Removes the first occurrence of the value val from the vector. If the val is not contained in the vector then vec_remove() does nothing.

vec_reverse(v)

Reverses the order of the vector's values in place. For example, a vector containing 4, 5, 6 would contain 6, 5, 4 after reversing.

vec_foreach(v, var, iter)

Iterates the values of the vector from the first to the last. var should be a variable of the vector's contained type where the value will be stored with each iteration. iter should be an int used to store the index during iteration.

/* Iterates and prints the value and index of each value in the float vec */
int i; float val;
vec_foreach(&v, val, i) {
  printf("%d : %f\n", i, val);
}

vec_foreach_rev(v, var, iter)

Iterates the values of the vector from the last to the first. See vec_foreach()

vec_foreach_ptr(v, var, iter)

Iterates the value pointers of the vector from first to last. var should be a variable of the vector's contained type's pointer. See vec_foreach().

/* Iterates and prints the value and index of each value in the float vector */
int i; float *val;
vec_foreach_ptr(&v, val, i) {
  printf("%d : %f\n", i, *val);
}

vec_foreach_ptr_rev(v, var, iter)

Iterates the value pointers of the vector from last to first. See vec_foreach_ptr()

License

This library is free software; you can redistribute it and/or modify it under the terms of the MIT license. See LICENSE for details.