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
  73
  74
  75
  76 void print_list(list* L, void (*print)(void* item)){
  77         list* ptr = L->next;
  78         printf("(");
  79         while(ptr){
  80                 print(ptr->item);
  81                 if(ptr->next)
  82                         printf(", ");
  83                 ptr = ptr->next;
  84         }
  85         printf(")");
  86 }
  87
  88 void println_list(list* L, void (*print)(void* item)){
  89         print_list(L, print);
  90         printf("\n");
  91 }
  92
  93 void list_print_free(){
  94         list* ptr = freelist;
  95         printf("(");
  96         while(ptr){
  97                 printf("_");
  98                 if(ptr->next){
  99                         printf(", ");
 100                 }
 101                 ptr = ptr->next;
 102         }
 103         printf(")\n");
 104 }
 105
 106 void print(void* item){
 107         char* s = item;
 108         printf("%s", s);
 109 }
 110
 111 void list_sanitytest(){
 112         list* L = empty();
 113         char* s;
 114         printf("empty: ");
 115         println_list(L, print);
 116
 117         printf("push a b c: ");
 118         push(L, "a");
 119         push(L, "b");
 120         push(L, "c");
 121         println_list(L, print);
 122
 123         printf("pop: ");
 124         s = pop(L);
 125         printf("%s ", s);
 126         println_list(L, print);
 127
 128         printf("freelist: ");
 129         list_print_free();
 130
 131         printf("pop: ");
 132         s = pop(L);
 133         printf("%s ", s);
 134         println_list(L, print);
 135
 136         printf("freelist: ");
 137         list_print_free();
 138
 139         printf("append a b c: ");
 140         append(L, "a");
 141         append(L, "b");
 142         append(L, "c");
 143         println_list(L, print);
 144
 145         printf("freelist: ");
 146         list_print_free();
 147
 148         printf("recycle: ");
 149         recycle(L);
 150         list_print_free();
 151
 152 }