# STC [cvec](../stc/cvec.h): Vector
![Vector](pics/vector.jpg)

A **cvec** is a sequence container that encapsulates dynamic size arrays.

The storage of the vector is handled automatically, being expanded and contracted as needed. Vectors usually occupy more space than static arrays, because more memory is allocated to handle future growth. This way a vector does not need to reallocate each time an element is inserted, but only when the additional memory is exhausted. The total amount of allocated memory can be queried using *cvec_X_capacity()* function. Extra memory can be returned to the system via a call to *cvec_X_shrink_to_fit()*.

Reallocations are usually costly operations in terms of performance. The *cvec_X_reserve()* function can be used to eliminate reallocations if the number of elements is known beforehand.

See the c++ class [std::vector](https://en.cppreference.com/w/cpp/container/vector) for a functional description.

## Declaration

```c
using_cvec(X, Value);
using_cvec(X, Value, valueCompare);
using_cvec(X, Value, valueCompare, valueDel, valueClone);
using_cvec(X, Value, valueCompareRaw, valueDel, valueFromRaw, valueToRaw, RawValue);

using_cvec_str()
```
The macro `using_cvec()` must be instantiated in the global scope. `X` is a type tag name and
will affect the names of all cvec types and methods. E.g. declaring `using_cvec(i, int);`, `X` should
be replaced by `i` in all of the following documentation.

`using_cvec_str()` is a shorthand for:
```
using_cvec(str, cstr_t, cstr_compare_raw, cstr_del, cstr_from, cstr_c_str, const char*)
```

## Header file

All cvec definitions and prototypes may be included in your C source file by including a single header file.

```c
#include "stc/cvec.h"
```
## Methods

```c
cvec_X              cvec_X_init(void);
cvec_X              cvec_X_with_size(size_t size, Value fill);
cvec_X              cvec_X_with_capacity(size_t size);
cvec_X              cvec_X_clone(cvec_X vec);

void                cvec_X_clear(cvec_X* self);
void                cvec_X_shrink_to_fit(cvec_X* self);
void                cvec_X_reserve(cvec_X* self, size_t cap);
void                cvec_X_resize(cvec_X* self, size_t size, Value fill);
void                cvec_X_swap(cvec_X* a, cvec_X* b);

void                cvec_X_del(cvec_X* self);      // destructor

bool                cvec_X_empty(cvec_X vec);
size_t              cvec_X_size(cvec_X vec);
size_t              cvec_X_capacity(cvec_X vec);

cvec_X_value_t*     cvec_X_at(cvec_X* self, size_t idx);
cvec_X_value_t*     cvec_X_front(cvec_X* self);
cvec_X_value_t*     cvec_X_back(cvec_X* self);

void                cvec_X_push_back(cvec_X* self, Value value);
void                cvec_X_emplace_back(cvec_X* self, RawValue raw);
void                cvec_X_emplace_n(cvec_X *self, const cvec_X_rawvalue_t arr[], size_t size);

void                cvec_X_pop_back(cvec_X* self);

cvec_X_iter_t       cvec_X_insert(cvec_X* self, size_t idx, Value value);
cvec_X_iter_t       cvec_X_insert_at(cvec_X* self, cvec_X_iter_t pos, Value value);
cvec_X_iter_t       cvec_X_insert_range(cvec_X* self, cvec_X_iter_t pos,
                                        cvec_X_iter_t first, cvec_X_iter_t finish);
cvec_X_iter_t       cvec_X_insert_range_p(cvec_X* self, cvec_X_value_t* pos,
                                          const cvec_X_value_t* pfirst, const cvec_X_value_t* pfinish);
cvec_X_iter_t       cvec_X_emplace(cvec_X* self, size_t idx, RawValue raw);
cvec_X_iter_t       cvec_X_emplace_at(cvec_X* self, cvec_X_iter_t pos, RawValue raw);

cvec_X_iter_t       cvec_X_erase(cvec_X* self, size_t idx, size_t n);
cvec_X_iter_t       cvec_X_erase_at(cvec_X* self, cvec_X_iter_t pos);
cvec_X_iter_t       cvec_X_erase_range(cvec_X* self, cvec_X_iter_t first, cvec_X_iter_t finish);
cvec_X_iter_t       cvec_X_erase_range_p(cvec_X* self, cvec_X_value_t* pfirst, cvec_X_value_t* pfinish);

cvec_X_iter_t       cvec_X_find(const cvec_X* self, RawValue raw);
cvec_X_iter_t       cvec_X_find_in_range(cvec_X_iter_t i1, cvec_X_iter_t i2, RawValue raw);
cvec_X_iter_t       cvec_X_bsearch(const cvec_X* self, RawValue raw);
cvec_X_iter_t       cvec_X_bsearch_in_range(cvec_X_iter_t i1, cvec_X_iter_t i2, RawValue raw);
void                cvec_X_sort(cvec_X* self);
void                cvec_X_sort_range(cvec_X_iter_t i1, cvec_X_iter_t i2,
                                      int(*cmp)(const cvec_X_value_t*, const cvec_X_value_t*));

cvec_X_iter_t       cvec_X_begin(const cvec_X* self);
cvec_X_iter_t       cvec_X_end(const cvec_X* self);
void                cvec_X_next(cvec_X_iter_t* it);
cvec_X_value_t*     cvec_X_itval(cvec_X_iter_t it);
size_t              cvec_X_index(const cvec_X vec, cvec_X_iter_t it);

cvec_X_value_t      cvec_X_value_clone(cvec_X_value_t val);
```

## Types

| Type name            | Type definition                     | Used to represent...   |
|:---------------------|:------------------------------------|:-----------------------|
| `cvec_X`             | `struct { cvec_X_value_t* data; }`  | The cvec type          |
| `cvec_X_value_t`     | `Value`                             | The cvec value type    |
| `cvec_X_rawvalue_t`  | `RawValue`                          | The raw value type     |
| `cvec_X_iter_t`      | `struct { cvec_X_value_t* ref; }`   | The iterator type      |

## Examples
```c
#include <stdio.h>
#include "stc/cvec.h"
using_cvec(i, int);

int main()
{
    // Create a vector containing integers
    cvec_i vec = cvec_i_init();
    c_emplace_items(&vec, cvec_i, {7, 5, 16, 8});

    // Add two more integers to vector
    cvec_i_push_back(&vec, 25);
    cvec_i_push_back(&vec, 13);

    printf("initial: ");
    c_foreach (n, cvec_i, vec) {
        printf(" %d", *n.ref);
    }

    // Sort the vector
    cvec_i_sort(&vec);

    printf("\nsorted: ");
    c_foreach (n, cvec_i, vec) {
        printf(" %d", *n.ref);
    }

    cvec_i_del(&vec);
}
```
Output:
```
initial:  7 5 16 8 25 13
sorted:  5 7 8 13 16 25
```
### Example 2
```c
#include "stc/cstr.h"
#include "stc/cvec.h"

using_cvec_str();

int main() {
    cvec_str names = cvec_str_init();
    cvec_str_emplace_back(&names, "Mary");
    cvec_str_emplace_back(&names, "Joe");
    cstr_assign(&names.data[1], "Jake"); // replace "Joe".

    cstr_t tmp = cstr_from_fmt("%d elements so far", cvec_str_size(names));

    // emplace_back() will not compile if adding a new cstr_t type. Use push_back():
    cvec_str_push_back(&names, tmp); // tmp is moved to names, do not del() it.

    printf("%s\n", names.data[1].str); // Access the second element

    c_foreach (i, cvec_str, names)
        printf("item: %s\n", i.ref->str);
    cvec_str_del(&names);
}
```
Output:
```
Jake
item: Mary
item: Jake
item: 2 elements so far
```
### Example 3

Container with elements of structs:
```c
#include <stc/cstr.h>
#include <stc/cvec.h>

typedef struct {
    cstr name; // dynamic string
    int id;
} User;

int User_compare(const User* a, const User* b) {
    int c = strcmp(a->name.str, b->name.str);
    return c != 0 ? c : a->id - b->id;
}
void User_del(User* self) {
    cstr_del(&self->name);
}
User User_clone(User user) {
    user.name = cstr_clone(user.name);
    return user;
}

// declare a memory managed, clonable vector of users:
using_cvec(u, User, User_compare, User_del, User_clone);

int main(void) {
    cvec_u vec = cvec_u_init();
    cvec_u_push_back(&vec, (User) {cstr_from("admin"), 0});
    cvec_u_push_back(&vec, (User) {cstr_from("joe"), 1});
    
    cvec_u vec2 = cvec_u_clone(vec);
    c_foreach (i, cvec_u, vec2)
        printf("%s: %d\n", i.ref->name.str, i.ref->id);

    c_del(cvec_u, &vec, &vec2); // cleanup
}
```