An update.

git-svn-id: https://svn.code.sf.net/p/fteqw/code/trunk@1597 fc73d0e0-1445-4013-8a0c-d673dee63da5

plugins/memory.c

@@ -0,0 +1,120 @@
+//a qvm compatable malloc/free interface
+
+//This is seperate from qvm_api.c because this has a chunk of memory that simply isn't needed in all plugins.
+
+#include "plugin.h"
+
+struct memhead_s
+{
+	int size;
+	int isfree;
+	struct memhead_s *next;
+	struct memhead_s *prev;
+};
+
+#ifndef MEMSIZE
+#define MEMSIZE 1024*64 //64kb
+#endif
+
+static struct memhead_s *head;
+static char memory[MEMSIZE];
+
+//we create two dummies at the start and end
+//these will never be freed
+//we then have dynamic allocation in the middle.
+//sizes include the headers
+
+void *malloc(int size)
+{
+	struct memhead_s *lasthead;
+
+	if (size <= 0)
+		return NULL;
+
+	size = ((size+4) & 3) + sizeof(struct memhead_s);	//round up
+	if (!head)
+	{	//first call
+		struct memhead_s *last;
+		struct memhead_s *middle;
+		struct memhead_s *first;
+
+		first = (struct memhead_s*)memory;
+		last= (struct memhead_s*)((char*)memory - sizeof(struct memhead_s));
+		first->size = last->size = sizeof(struct memhead_s);
+		first->isfree = last->isfree = false;
+
+		middle = (struct memhead_s*)((char*)first+first->size);
+		middle->size = sizeof(memory) - sizeof(struct memhead_s)*3;
+		middle->isfree = true;
+
+		last->next = first;
+		last->prev = middle;
+		first->next = middle;
+		first->prev = last;
+		middle->next = last;
+		middle->prev = first;
+
+		head = middle;
+	}
+	lasthead = head;
+
+	do
+	{
+		if (head->isfree)
+			if (head->size >= size)
+			{
+				if (head->size > size + sizeof(struct memhead_s)+1)
+				{	//split
+					struct memhead_s *split;
+					split = (struct memhead_s*)((char*)head + size);
+					split->size = head->size - size;
+					head->size = size;
+					split->next = head->next;
+					split->prev = head;
+					head->next = split;
+					split->next->prev = split;
+					split->isfree = true;
+					head->isfree = false;
+				}
+				else
+				{	//no point in splitting
+					head->isfree = false;
+				}
+
+				return (char*)head + sizeof(struct memhead_s);
+			}
+		head = head->next;
+	} while (lasthead != head);
+
+	return NULL;
+}
+
+static struct memhead_s *mergeblock(struct memhead_s *b1, struct memhead_s *b2)
+{
+	//b1 and b2 must be in logical order
+
+	b1->next = b2->next;
+	b2->next->prev = b1;
+	b1->size += b2->size;
+
+	return b1;
+}
+
+void free(void *mem)
+{	//the foot hopefully isn't going to be freed
+	struct memhead_s *block;
+	block = (struct memhead_s*)((char*)mem - sizeof(struct memhead_s));
+
+	if (block->isfree)
+		Sys_Error("(plugin) Double free\n");
+	block->isfree = true;
+
+	if (block->prev->isfree)
+	{	//merge previous with this
+		block = mergeblock(block->prev, block);
+	}
+	if (block->next)
+	{	//merge next with this
+		block = mergeblock(block, block->next);
+	}
+}