mirror of
https://github.com/cc65/cc65.git
synced 2024-11-19 06:31:31 +00:00
ca815af077
Change the isxxx functions to correctly handle values outside of character range. git-svn-id: svn://svn.cc65.org/cc65/trunk@33 b7a2c559-68d2-44c3-8de9-860c34a00d81
108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/*
|
|
* _hadd.c
|
|
*
|
|
* Ullrich von Bassewitz, 19.06.1998
|
|
*/
|
|
|
|
|
|
|
|
#include <stddef.h>
|
|
#include "_heap.h"
|
|
|
|
|
|
|
|
void _hadd (void* mem, size_t size)
|
|
/* Add an arbitrary memory block to the heap. This function is used by
|
|
* free(), but it does also allow usage of otherwise unused memory
|
|
* blocks as heap space. The given block is entered in the free list
|
|
* without any checks, so beware!
|
|
*/
|
|
{
|
|
struct freeblock* f;
|
|
struct freeblock* left;
|
|
struct freeblock* right;
|
|
|
|
if (size >= sizeof (struct freeblock)) {
|
|
|
|
/* Set the admin data */
|
|
f = (struct freeblock*) mem;
|
|
f->size = size;
|
|
|
|
/* Check if the freelist is empty */
|
|
if (_hfirst == 0) {
|
|
|
|
/* The freelist is empty until now, insert the block */
|
|
f->prev = 0;
|
|
f->next = 0;
|
|
_hfirst = f;
|
|
_hlast = f;
|
|
|
|
} else {
|
|
|
|
/* We have to search the free list. As we are doing so, we check
|
|
* if it is possible to combine this block with another already
|
|
* existing block. Beware: The block may be the "missing link"
|
|
* between *two* other blocks.
|
|
*/
|
|
left = 0;
|
|
right = _hfirst;
|
|
while (right && f > right) {
|
|
left = right;
|
|
right = right->next;
|
|
}
|
|
|
|
|
|
/* Ok, the current block must be inserted between left and right (but
|
|
* beware: one of the two may be zero!). Also check for the condition
|
|
* that we have to merge two or three blocks.
|
|
*/
|
|
if (right) {
|
|
/* Check if we must merge the block with the right one */
|
|
if (((unsigned) f) + size == (unsigned) right) {
|
|
/* Merge with the right block */
|
|
f->size += right->size;
|
|
if (f->next = right->next) {
|
|
f->next->prev = f;
|
|
} else {
|
|
/* This is now the last block */
|
|
_hlast = f;
|
|
}
|
|
} else {
|
|
/* No merge, just set the link */
|
|
f->next = right;
|
|
right->prev = f;
|
|
}
|
|
} else {
|
|
f->next = 0;
|
|
/* Special case: This is the new freelist end */
|
|
_hlast = f;
|
|
}
|
|
if (left) {
|
|
/* Check if we must merge the block with the left one */
|
|
if ((unsigned) f == ((unsigned) left) + left->size) {
|
|
/* Merge with the left block */
|
|
left->size += f->size;
|
|
if (left->next = f->next) {
|
|
left->next->prev = left;
|
|
} else {
|
|
/* This is now the last block */
|
|
_hlast = left;
|
|
}
|
|
} else {
|
|
/* No merge, just set the link */
|
|
left->next = f;
|
|
f->prev = left;
|
|
}
|
|
} else {
|
|
f->prev = 0;
|
|
/* Special case: This is the new freelist start */
|
|
_hfirst = f;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|