char_vector.c

// This code and all comments, written by Daniel Trebbien, are hereby entered into the Public Domain by their author.

#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifndef SIZE_MAX
#define SIZE_MAX ((size_t) -1)
#endif

#undef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))

#include "char_vector.h"

struct st_char_vector
{
	char *buf;
	size_t vec_capacity;
	size_t vec_length;
};

st_char_vector *char_vector_alloc()
{
	st_char_vector *vec = (st_char_vector *) malloc(sizeof (st_char_vector));

	if (vec == NULL)
		return NULL;

	vec->vec_capacity = 255;

	vec->buf = (char *) malloc(vec->vec_capacity);
	if (vec->buf == NULL)
	{
		free(vec);
		return NULL;
	}

	vec->vec_length = 0;

	return vec;
}

void char_vector_free(st_char_vector *vec)
{
	assert(vec->buf != NULL);
	free(vec->buf);
#ifndef NDEBUG
	vec->buf = NULL;
#endif
	free(vec);
}

size_t char_vector_length(const st_char_vector *vec)
{
	return vec->vec_length;
}

char* char_vector_get_ptr(st_char_vector *vec)
{
	return vec->buf;
}

int char_vector_append(st_char_vector *vec, const char *str, size_t str_length)
{
	if (SIZE_MAX - MAX(255, str_length) < vec->vec_capacity)
	{
		return E2BIG;
	}

	if (vec->vec_capacity < (vec->vec_length + str_length))
	{
		// Need to allocate more space
		size_t new_capacity = vec->vec_capacity + MAX(255, str_length);
		char *tmp = (char *) malloc(new_capacity);
		if (tmp == NULL)
		{
			return ENOMEM;
		}

		memcpy(tmp, vec->buf, vec->vec_length);

		vec->buf = tmp;
		vec->vec_capacity = new_capacity;
	}

	memmove(vec->buf + vec->vec_length, str, str_length); // Use memmove() because str may be a pointer within [vec->buf, vec->buf + vec->vec_length)
	vec->vec_length += str_length;

	return 0;
}

int char_vector_strcat(st_char_vector *vec, const char *str)
{
	return char_vector_append(vec, str, strlen(str));
}