getline.c

size_t getline(char **lineptr, size_t *n, FILE *stream) {
	char *bufptr = nullptr;
	size_t it = 0;
	int c;

	if (lineptr == nullptr) {
		return -1;
	}
	if (stream == nullptr) {
		return -1;
	}
	if (n == nullptr) {
		return -1;
	}
	bufptr = *lineptr;
	size_t size = *n;

	c = fgetc(stream);
	if (c == EOF) {
		return -1;
	}
	if (bufptr == nullptr) {
		bufptr = (char*)malloc(128);
		if (bufptr == nullptr) {
			return -1;
		}
		size = 128;
	}
	while (c != EOF) {
		if (it >= size)
		{
			size = size + 128;
			bufptr = (char*)realloc(bufptr, size);
			if (bufptr == nullptr) {
				return -1;
			}
		}
		bufptr[it++] = c;
		if (c == '\n')
			break;
		c = fgetc(stream);
	}

	bufptr[it++] = '\0';
	*lineptr = bufptr;
	*n = size;

	return it - 1;
}