/* The malloc() function allocates size bytes and returns a pointer to
* the allocated memory. The memory is not initialized. If size is 0,
* then malloc() returns either NULL, or a unique pointer value that can
* later be successfully passed to free().
* ----
* Implementation notes:
* So, somebody wants a block of memory... fine! Here's the game
* plan for getting them said memory:
*
* 1) Scan each block in our free list to see if any of them are
* big enough. If we find one that is big enough, we will
* either use that memory as-is or chunk it into a couple smaller
* pieces (part of which is used, the other which is a new
* entry in the free linked list.
* 2) If we do not find an item in the free list, we will add the
* new block onto the end of our heap. We will attempt to expand
* the heap if needed.
*/
void * po_malloc(size_t size)
{
block_header_t *current_header, *new_free_header, *block_header;
void *memory_to_use = NULL;
const size_t size_plus_header = size + sizeof(block_header_t);
new_free_header = block_header = NULL;
current_header = free_ll_head;
while (current_header) {
if (current_header->block_length >= size) {
memory_to_use = FREE_BLOCK_MEMORY(current_header);
if (current_header->block_length > size_plus_header) {
new_free_header = (block_header_t *)((unsigned long)memory_to_use + size);
new_free_header->block_length = current_header->block_length - size;
ll_replace(current_header, new_free_header);
} else {
ll_remove(current_header);
}
return memory_to_use;
} else {
current_header = current_header->next_free_chunk;
}
}
// if we are here, we didn't get what we needed from scanning the
// freed list, tack on to the end of memory
size_t expand_size;
if (current_header) {
expand_size = (size_plus_header - current_header->block_length);
} else {
expand_size = size_plus_header;
}
block_header = (block_header_t *)sbrk(expand_size);
memory_to_use = FREE_BLOCK_MEMORY(block_header);
if (!block_header) {
/* failed to allocate more memory, return NULL */
return NULL;
}
/* current_header points to end of current LL unless first */
block_header->next_free_chunk = NULL;
block_header->prev_free_chunk = NULL;
block_header->block_length = size;
return memory_to_use;
}
static void write_cf(void)
{
char tmp[0x100], rv[0x40];
struct conf_item *ci = NULL;
char *lp, *cp;
int add, i;
char *cfname = get_confname();
int cfld = ll_create();
FILE *fd = fopen(cfname, "w");
if (fd == NULL)
err_sys("failed to open configuration file '%s'", cfname);
for (ll_reset(conf_items); (ci = ll_getall(conf_items)); ) {
if (ci->type != t_sep && ci->type != t_func &&
(!ci->dep || (ci->dep && *ci->dep))) {
switch (ci->type) {
case t_int:
sprintf(rv, "%d", *ci->v.i);
break;
case t_list:
if (!argv_count(ci->list))
continue;
sprintf(rv, "%s", ci->list[*ci->v.i]);
str_tolower(rv);
break;
case t_sep:
case t_func:
break;
}
add = 1;
for (i = 0; i < ll_size(cfld); i++) {
lp = ll_get(cfld, i);
cp = lp += strspn(lp, " ");
if (!strncasecmp(cp, ci->cfname, strcspn(cp, " ="))
&& strlen(ci->cfname) == strcspn(cp, " =")) {
add = 0;
cp += strcspn(cp, "=") + 1;
cp += strspn(cp, " ");
strncpy(tmp, cp, strcspn(cp, " #\n"));
if (strcasecmp(tmp, rv)) {
strncpy(tmp, lp, strcspn(lp, " ="));
tmp[strcspn(lp, " =")] = '\0';
strcat(tmp, " = ");
strcat(tmp, rv);
strcat(tmp, "\n");
ll_replace(cfld, i, "s", tmp);
}
}
}
if (add) {
strcpy(tmp, ci->cfname);
strcat(tmp, " = ");
strcat(tmp, rv);
strcat(tmp, "\n");
ll_push(cfld, "s", tmp);
}
}
}
for (ll_reset(cfld); (lp = ll_getall(cfld)); )
fputs(lp, fd);
fclose(fd);
ll_destroy(cfld);
free(cfname);
}