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         void* item = L->next->item;
  45         remove_from_list(L, L->next);
  46         return item;
  47 }
  48
  49 void append(list* L, void* item){
  50         list* ptr = L->next;
  51         while(ptr->next){
  52                 ptr = ptr->next;
  53         }
  54         ptr->next = make_new(NULL, item);
  55 }
  56
  57 void recycle(list* L){
  58         list* ptr = L;
  59         while(ptr->next){
  60                 ptr->next->item = NULL;
  61                 ptr = ptr->next;
  62         }
  63         ptr->next = freelist;
  64         freelist = L;
  65 }
  66
  67
  68
  69
  70
  71 void print_list(list* L, void (*print)(void* item)){
  72         list* ptr = L->next;
  73         printf("(");
  74         while(ptr){
  75                 print(ptr->item);
  76                 if(ptr->next)
  77                         printf(", ");
  78                 ptr = ptr->next;
  79         }
  80         printf(")");
  81 }
  82
  83 void println_list(list* L, void (*print)(void* item)){
  84         print_list(L, print);
  85         printf("\n");
  86 }
  87
  88 void list_print_free(){
  89         list* ptr = freelist;
  90         printf("(");
  91         while(ptr){
  92                 printf("_");
  93                 if(ptr->next){
  94                         printf(", ");
  95                 }
  96                 ptr = ptr->next;
  97         }
  98         printf(")\n");
  99 }
 100
 101 void print(void* item){
 102         char* s = item;
 103         printf("%s", s);
 104 }
 105
 106 void list_sanitytest(){
 107         list* L = empty();
 108         char* s;
 109         printf("empty: ");
 110         println_list(L, print);
 111
 112         printf("push a b c: ");
 113         push(L, "a");
 114         push(L, "b");
 115         push(L, "c");
 116         println_list(L, print);
 117
 118         printf("pop: ");
 119         s = pop(L);
 120         printf("%s ", s);
 121         println_list(L, print);
 122
 123         printf("freelist: ");
 124         list_print_free();
 125
 126         printf("pop: ");
 127         s = pop(L);
 128         printf("%s ", s);
 129         println_list(L, print);
 130
 131         printf("freelist: ");
 132         list_print_free();
 133
 134         printf("append a b c: ");
 135         append(L, "a");
 136         append(L, "b");
 137         append(L, "c");
 138         println_list(L, print);
 139
 140         printf("freelist: ");
 141         list_print_free();
 142
 143         printf("recycle: ");
 144         recycle(L);
 145         list_print_free();
 146
 147 }