Question

Please change the following code to python form.

#include<stdio.h>
#include<stdlib.h>
#define MIN_PID 300
#define MAX_PID 5000
#define TRUE 1
#define FALSE 0
struct PidTable{
        int PID;
        int isAvailable;
}*pId;

int allocate_map(){
        int i;
        pId=(struct PidTable *)calloc((MAX_PID-MIN_PID+1),sizeof(struct PidTable));
        if(pId==NULL)
                return -1;
        pId[0].PID=MIN_PID;
        pId[0].isAvailable=TRUE;
        for( i=1;i<MAX_PID-MIN_PID+1;i++){
      pId[i].PID=pId[i-1].PID+1;
          pId[i].isAvailable=TRUE;
        }   
        return 1;
}
int allocate_pid(){
   int i ;
   for( i=0;i<MAX_PID-MIN_PID+1;i++){
                if(pId[i].isAvailable==TRUE){
                        pId[i].isAvailable=FALSE;
                        return pId[i].PID;
                }
   }
   if(i==MAX_PID-MIN_PID+1)
        return -1;
}
void release_pid(int pid){
        pId[pid-MIN_PID].isAvailable=TRUE;
}


int main(){
  int pid;
  allocate_map();
  
  if((pid=allocate_pid())!=-1);
  printf("New Process Allocated Pid= %d \n",pid);
  if((pid=allocate_pid())!=-1);
  printf("New Process Allocated Pid= %d \n",pid);
  if((pid=allocate_pid())!=-1);
  printf("New Process Allocated Pid= %d \n",pid);
  if((pid=allocate_pid())!=-1);
  printf("New Process Allocated Pid= %d \n",pid);
  
  printf("Process %d now Releasing \n",pid);
  release_pid(pid);
  if((pid=allocate_pid())!=-1);
  printf("New Process Allocated Pid= %d \n",pid);
  return 0;
}

Answer 1

Basically the Memory Management in python involves a private heap which contains data members and data structure.Python Memory Manager Manages the Private heap internally.To avoid memory corruption we should not operate 

Python converted code of c program

import sys
MIN_PID = 300
MAX_PID = 5000
TRUE = 1
FALSE =0

#Python Doesn't Contains Structure so we Can Use Class Instead of Structure
#Here I defined class called PIDTable Which Consists of 2 data Memebers/Variables
class PidTable:
    PID=0
    isAvailable=0

# Method for allocating the Process Availablity status and Process Id
def allocate_map(pidlist):
    print (sys.getsizeof(pid))
    if(pidlist is None):
        return -1
    pidlist[0].PID = MIN_PID;
    pidlist[0].isAvailable = TRUE;
    print(pidlist[0].PID)
    print(len(pidlist))
    for i in range(1,len(pidlist)):
        print (i)
        pidlist[i].PID=pidlist[i-1].PID+1
        pidlist[i].isAvailable = TRUE
    return 1;

# Method to get the currently allocated Process from a pool of available Process and change its Available status to false Since the current Process in been allocted for a process
def allocate_pid(pidlist):
    for i in range(0, len(pidlist)):
        if (pidlist[i].isAvailable == TRUE):
            pidlist[i].isAvailable=FALSE;
            print (pidlist[i].PID)
            return pidlist[i].PID;
    if (i == MAX_PID - MIN_PID + 1):
        return -1;

# Method to release the currently allocated Process and change its Available status to true
def release_pid(pid,pidlist):
    pidlist[pid-MIN_PID].isAvailable=TRUE;


num = MAX_PID - MIN_PID
pid = 0;
# PidList is a list of Class Object or we can call it as Array of Object
PidList = []
for i in range(num):
    PidList.insert(i,PidTable())
num=allocate_map(PidList)
if(num!=-1):
    pid=allocate_pid(PidList)
    if(pid!=-1):
        print("New Process Allocated Pid = ",pid);

    pid=allocate_pid(PidList)
    if(pid!=-1):
        print("New Process Allocated Pid = ",pid);

    pid=allocate_pid(PidList)
    if(pid!=-1):
        print("New Process Allocated Pid = ",pid);

    pid = allocate_pid(PidList)
    if (pid != -1):
        print("New Process Allocated Pid = ", pid);

    print("Process %d now Releasing = ", pid)
    release_pid(pid,PidList)

    pid=allocate_pid(PidList)
    if(pid!=-1):
        print("New Process Allocated Pid =",pid)