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
  55 void append(list* L, void* item){
  56         list* ptr = L;
  57         while(ptr->next){
  58                 ptr = ptr->next;
  59         }
  60         ptr->next = make_new(NULL, item);
  61 }
  62
  63 void recycle(list* L){
  64         list* ptr = L;
  65         while(ptr->next){
  66                 ptr->next->item = NULL;
  67                 ptr = ptr->next;
  68         }
  69         ptr->next = freelist;
  70         freelist = L;
  71 }
  72
  73
  74
  75
  76
  77 void print_list(list* L, void (*print)(void* item)){
  78         list* ptr = L->next;
  79         printf("(");
  80         while(ptr){
  81                 print(ptr->item);
  82                 if(ptr->next)
  83                         printf(", ");
  84                 ptr = ptr->next;
  85         }
  86         printf(")");
  87 }
  88
  89 void println_list(list* L, void (*print)(void* item)){
  90         print_list(L, print);
  91         printf("\n");
  92 }
  93
  94 void list_print_free(){
  95         list* ptr = freelist;
  96         printf("(");
  97         while(ptr){
  98                 printf("_");
  99                 if(ptr->next){
 100                         printf(", ");
 101                 }
 102                 ptr = ptr->next;
 103         }
 104         printf(")\n");
 105 }
 106
 107 void print(void* item){
 108         char* s = item;
 109         printf("%s", s);
 110 }
 111
 112 void list_sanitytest(){
 113         list* L = empty();
 114         char* s;
 115         printf("empty: ");
 116         println_list(L, print);
 117
 118         printf("push a b c: ");
 119         push(L, "a");
 120         push(L, "b");
 121         push(L, "c");
 122         println_list(L, print);
 123
 124         printf("pop: ");
 125         s = pop(L);
 126         printf("%s ", s);
 127         println_list(L, print);
 128
 129         printf("freelist: ");
 130         list_print_free();
 131
 132         printf("pop: ");
 133         s = pop(L);
 134         printf("%s ", s);
 135         println_list(L, print);
 136
 137         printf("freelist: ");
 138         list_print_free();
 139
 140         printf("append a b c: ");
 141         append(L, "a");
 142         append(L, "b");
 143         append(L, "c");
 144         println_list(L, print);
 145
 146         printf("freelist: ");
 147         list_print_free();
 148
 149         printf("recycle: ");
 150         recycle(L);
 151         list_print_free();
 152
 153 }