/**************************************************************************************
 Copyright (c) 2002 The UbixOS Project
 All rights reserved.

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in the documentation and/or other materials provided with the distribution. Neither the name of the UbixOS Project nor the names of its
contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 $Id: kmalloc.c,v 1.3 2003/01/10 16:47:26 reddawg Exp $

**************************************************************************************/

#include <lib/kmalloc.h>
#include <lib/kstdio.h>
#include <vmm/paging.h>

struct memDescriptor *kernDesc = 0x0;

void initMalloc(pidType pid) {
  int i = 0;
  struct memDescriptor *tmpDesc = 0x0;
  kernDesc = (void *)getFreeKernelPage(pid);
  tmpDesc = kernDesc;
  for (i=0;i<4096;i+=sizeof(struct memDescriptor)) {
    tmpDesc->basePage = 0x0;
    tmpDesc->baseAddr = 0x0;
    tmpDesc->limit    = 0x0;
    tmpDesc->status   = 0x0;
    tmpDesc->numPages = 0x1;
    if ((i+sizeof(struct memDescriptor)) < 4096) {
      tmpDesc->next = (struct memDescriptor *)((uInt32)tmpDesc+sizeof(struct memDescriptor));
      }
    else {
      tmpDesc->next = 0x0;
      }
    tmpDesc = tmpDesc->next;
    }
  }

void *findFreeDesc(pidType pid) {
  int i = 0;
  struct memDescriptor *findDesc = 0x0,*tmpDesc = 0x0;
  for (findDesc=(struct memDescriptor *)kernDesc;(findDesc != 0x0);findDesc=(struct memDescriptor *)findDesc->next) {
    if (findDesc->baseAddr == 0x0) {
      return(findDesc);
      }
    if (findDesc->next == 0x0) { break; }
    }
  tmpDesc = (void *)getFreeKernelPage(pid);
  findDesc->next = tmpDesc;
  for (i=0;i<4096;i+=sizeof(struct memDescriptor)) {
    tmpDesc->basePage = 0x0;
    tmpDesc->baseAddr = 0x0;
    tmpDesc->limit    = 0x0;
    tmpDesc->status   = 0x0;
    tmpDesc->numPages = 0x1;
    if ((i+sizeof(struct memDescriptor)) < 4096) {
      tmpDesc->next = (struct memDescriptor *)((uInt32)tmpDesc+sizeof(struct memDescriptor));
      }
    else {
      tmpDesc->next = 0x0;
      }
    tmpDesc = tmpDesc->next;
    }
  return(findFreeDesc(pid));
  return(0);
  }

void *kmalloc(uInt32 len,pidType pid) {
  struct memDescriptor *tmpDesc = 0x0,*newDesc = 0x0;
  if (!kernDesc) {
    initMalloc(pid);
    }  
  for(tmpDesc=kernDesc;tmpDesc;tmpDesc=tmpDesc->next) {    
    if (tmpDesc->status == 0) {
      if (tmpDesc->limit >= len) {
        if (tmpDesc->limit > len+4) {
          newDesc = findFreeDesc(pid);
          newDesc->basePage = tmpDesc->basePage;
          newDesc->baseAddr = tmpDesc->baseAddr + len + 1;
          newDesc->limit = tmpDesc->limit - len - 1;
          tmpDesc->limit = len;
          }
        tmpDesc->status = 1;
        return(tmpDesc->baseAddr);
        }         
      else if (tmpDesc->basePage == 0x0) {
        tmpDesc->basePage = (void *)getFreeKernelPage(pid);
        tmpDesc->baseAddr = tmpDesc->basePage;
        tmpDesc->limit = len;
        tmpDesc->status = 1;
        newDesc = findFreeDesc(pid);
        newDesc->basePage = tmpDesc->basePage;
        newDesc->baseAddr = tmpDesc->baseAddr + len + 1;
        newDesc->limit = 4096 - tmpDesc->limit;
        return(tmpDesc->baseAddr);
        }
      }
    }
  return(0x0);
  }
  

void kfree(void *baseAddr) {
 struct memDescriptor *tmpDesc = 0x0;
 for (tmpDesc=kernDesc;tmpDesc;tmpDesc=tmpDesc->next) {
   if (tmpDesc->baseAddr == baseAddr) {
     //tmpDesc->status = 0;
     return;
     }
   }
 kprintf("Error Freeing!!!\n");
 return;
 }
