list.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3
   4
   5 #include <list.h>
   6
   7 list* freelist = NULL;
   8
   9
  10 list* make_new(list* next, void* item){
  11         list* ptr;
  12
  13         if(freelist == NULL){
  14                 ptr = malloc(sizeof(struct list));
  15         }
  16         else{
  17                 ptr = freelist;
  18                 freelist = ptr->next;
  19         }
  20
  21         ptr->next = next;
  22         ptr->item = item;
  23         return ptr;
  24 }
  25
  26 void remove_from_list(list* prev, list* node){
  27         prev->next = node->next;
  28         node->item = NULL;
  29         node->next = freelist;
  30         freelist = node;
  31 }
  32
  33
  34 list* empty(){
  35         return make_new(NULL, NULL);
  36 }
  37
  38 void push(list* L, void* item){
  39         list* ptr = make_new(L->next, item);
  40         L->next = ptr;
  41 }
  42
  43 void* pop(list* L){
  44         if(L->next){
  45                 void* item = L->next->item;
  46                 remove_from_list(L, L->next);
  47                 return item;
  48         }
  49         else{
  50                 return NULL;
  51         }
  52 }
  53
  54 void append(list* L, void* item){
  55         list* ptr = L;
  56         while(ptr->next){
  57                 ptr = ptr->next;
  58         }
  59         ptr->next = make_new(NULL, item);
  60 }
  61
  62 void recycle(list* L){
  63         list* ptr = L;
  64         while(ptr->next){
  65                 ptr->next->item = NULL;
  66                 ptr = ptr->next;
  67         }
  68         ptr->next = freelist;
  69         freelist = L;
  70 }
  71
  72 int length(list* L){
  73         list* ptr = L->next;
  74         int c = 0;
  75         while(ptr){
  76                 c += 1;
  77                 ptr = ptr->next;
  78         }
  79         return c;
  80 }
  81
  82
  83
  84
  85 void print_list(list* L, void (*print)(void* item)){
  86         list* ptr = L->next;
  87         printf("(");
  88         while(ptr){
  89                 print(ptr->item);
  90                 if(ptr->next)
  91                         printf(", ");
  92                 ptr = ptr->next;
  93         }
  94         printf(")");
  95 }
  96
  97 void println_list(list* L, void (*print)(void* item)){
  98         print_list(L, print);
  99         printf("\n");
 100 }
 101
 102 void list_print_free(){
 103         list* ptr = freelist;
 104         printf("(");
 105         while(ptr){
 106                 printf("_");
 107                 if(ptr->next){
 108                         printf(", ");
 109                 }
 110                 ptr = ptr->next;
 111         }
 112         printf(")\n");
 113 }
 114
 115 void print(void* item){
 116         char* s = item;
 117         printf("%s", s);
 118 }
 119