An allocated array variable keeps track of
- a (nonzero) pointer to a dynamically allocated region of memory;
- the number of bytes allocated (always positive); and
- the number of bytes initialized (between 0 and the number of bytes allocated).
There are two other possibilities for the state of an array variable: unallocated and failed. In both cases, there is no dynamically allocated region of memory.
A new array variable is normally created as a static variable:
static array x;
At this point it is unallocated. The array library provides various allocation and inspection functions.
A new array variable can also be created dynamically. It must be initialized to all-0, meaning unallocated, before it is given to any of the array functions. It must be returned to the unallocated (or failed) state, for example with array_reset, before it is destroyed. These rules prevent all memory leaks.
Expansion and inspection
t* p1 = array_allocate(&x,sizeof(t),pos);
t* p2 = array_get(&x,sizeof(t),pos);
t* p3 = array_start(&x);
int64 len = array_length(&x,sizeof(t));
int64 bytes = array_bytes(&x);
Truncation and deallocation
/* arrays are equal... */
array_cats0(&x,"fnord"); /* also append the \0 */
array_cat0(&x); /* append \0 */
array_cate(&x,"fnord",1,4); /* append "nor" */
Original API Definition
array_get(3), array_start(3), array_fail(3)