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flexar.c
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flexar.c
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#include "flexar.h"
#include <assert.h>
#include <stdlib.h>
struct flexarray *flex_new(void)
{
struct flexarray *a = malloc(sizeof(struct flexarray));
const size_t initial = 64;
/* initial size must be n+1 for positive n */
assert(initial > 1);
if (!a)
return NULL;
/* always keep an extra item for NUL char */
if (!(a->val = malloc(initial + 1)))
{
free(a);
return NULL;
}
*a->val = '\0';
a->len = 0;
a->max = initial;
return a;
}
char *flex_append(struct flexarray *a, char c)
{
char *newbuf;
if (a->len+1 >= a->max)
{
/* resize n+1 -> 2n+1 (= 2(n+1)-1) */
if (!(newbuf = realloc(a->val, a->max*2 - 1)))
return NULL;
a->val = newbuf;
a->max = a->max*2 - 1;
}
a->val[a->len++] = c;
/* write a NUL character ahead for better integration
* with standard C functions */
a->val[a->len+1] = '\0';
return a->val;
}
void flex_free(struct flexarray *a)
{
if (a)
{
if (a->val)
free(a->val);
free(a);
}
}
void flex_trunc(struct flexarray *a)
{
*a->val = '\0';
a->len = 0;
}