1 |
/* printf */ |
2 |
#include <stdio.h> |
3 |
/* EXIT_SUCCESS */ |
4 |
#include <stdlib.h> |
5 |
/* NULL */ |
6 |
#include <stddef.h> |
7 |
/* dlopen, dlsym, dlerror */ |
8 |
#include <dlfcn.h> |
9 |
/* assert */ |
10 |
#include <assert.h> |
11 |
|
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#define HASHTBLSIZE 65536 |
13 |
|
14 |
typedef struct stack_item |
15 |
{ |
16 |
enum { |
17 |
value, /* Integer */ |
18 |
string, |
19 |
ref, /* Reference (to an element in the |
20 |
hash table) */ |
21 |
func, /* Function pointer */ |
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symbol, |
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list |
24 |
} type; /* Type of stack element */ |
25 |
|
26 |
union { |
27 |
void* ptr; /* Pointer to the content */ |
28 |
int val; /* ...or an integer */ |
29 |
} content; /* Stores a pointer or an integer */ |
30 |
|
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char* id; /* Symbol name */ |
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struct stack_item* next; /* Next element */ |
33 |
} stackitem; |
34 |
|
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|
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typedef stackitem* hashtbl[HASHTBLSIZE]; /* Hash table declaration */ |
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typedef void (*funcp)(stackitem**); /* funcp is a pointer to a |
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void function (stackitem **) */ |
39 |
|
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/* Initialize a newly created hash table. */ |
41 |
void init_hashtbl(hashtbl out_hash) |
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{ |
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long i; |
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|
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for(i= 0; i<HASHTBLSIZE; i++) |
46 |
out_hash[i]= NULL; |
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} |
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|
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/* Returns a pointer to a pointer to an element in the hash table. */ |
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stackitem** hash(hashtbl in_hashtbl, const char* in_string) |
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{ |
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long i= 0; |
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unsigned long out_hash= 0; |
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char key= '\0'; |
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stackitem** position; |
56 |
|
57 |
while(1){ /* Hash in_string */ |
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key= in_string[i++]; |
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if(key=='\0') |
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break; |
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out_hash= out_hash*32+key; |
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} |
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|
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out_hash= out_hash%HASHTBLSIZE; |
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position= &(in_hashtbl[out_hash]); |
66 |
|
67 |
while(1){ |
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if(*position==NULL) /* If empty */ |
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return position; |
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|
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if(strcmp(in_string, (*position)->id)==0) /* If match */ |
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return position; |
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|
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position= &((*position)->next); /* Try next */ |
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} |
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} |
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|
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/* Generic push function. */ |
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int push(stackitem** stack_head, stackitem* in_item) |
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{ |
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in_item->next= *stack_head; |
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*stack_head= in_item; |
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return 1; |
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} |
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|
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/* Push a value on the stack. */ |
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int push_val(stackitem** stack_head, int in_val) |
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{ |
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stackitem* new_item= malloc(sizeof(stackitem)); |
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assert(new_item != NULL); |
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new_item->content.val= in_val; |
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new_item->type= value; |
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|
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push(stack_head, new_item); |
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return 1; |
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} |
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|
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/* Copy a string onto the stack. */ |
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int push_cstring(stackitem** stack_head, const char* in_string) |
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{ |
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stackitem* new_item= malloc(sizeof(stackitem)); |
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new_item->content.ptr= malloc(strlen(in_string)+1); |
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strcpy(new_item->content.ptr, in_string); |
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new_item->type= string; |
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|
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push(stack_head, new_item); |
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return 1; |
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} |
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|
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/* Create a new hash entry. */ |
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int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id) |
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{ |
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in_item->id= malloc(strlen(id)+1); |
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|
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strcpy(in_item->id, id); |
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push(hash(in_hashtbl, id), in_item); |
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|
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return 1; |
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} |
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|
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/* Define a new function in the hash table. */ |
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void def_func(hashtbl in_hashtbl, funcp in_func, const char* id) |
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{ |
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stackitem* temp= malloc(sizeof(stackitem)); |
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|
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temp->type= func; |
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temp->content.ptr= in_func; |
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|
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mk_hashentry(in_hashtbl, temp, id); |
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} |
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|
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/* Define a new symbol in the hash table. */ |
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void def_sym(hashtbl in_hashtbl, const char* id) |
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{ |
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stackitem* temp= malloc(sizeof(stackitem)); |
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|
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temp->type= symbol; |
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mk_hashentry(in_hashtbl, temp, id); |
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} |
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|
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/* Push a reference to an entry in the hash table onto the stack. */ |
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int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string) |
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{ |
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static void* handle= NULL; |
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void* symbol; |
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|
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stackitem* new_item= malloc(sizeof(stackitem)); |
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new_item->content.ptr= *hash(in_hash, in_string); |
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new_item->type= ref; |
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|
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if(new_item->content.ptr==NULL) { /* If hash entry empty */ |
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if(handle==NULL) /* If no handle */ |
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handle= dlopen(NULL, RTLD_LAZY); |
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|
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symbol= dlsym(handle, in_string); /* Get function pointer */ |
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if(dlerror()==NULL) /* If existing function pointer */ |
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def_func(in_hash, symbol, in_string); /* Store function pointer */ |
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else |
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def_sym(in_hash, in_string); /* Make symbol */ |
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|
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new_item->content.ptr= *hash(in_hash, in_string); /* The new reference |
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shouldn't point at |
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NULL */ |
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new_item->type= ref; |
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} |
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|
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push(stack_head, new_item); |
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return 1; |
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} |
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|
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void printerr(const char* in_string) { |
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fprintf(stderr, "Err: %s\n", in_string); |
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} |
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|
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/* Discard the top element of the stack. */ |
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extern void toss(stackitem** stack_head) |
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{ |
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stackitem* temp= *stack_head; |
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|
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if((*stack_head)==NULL) { |
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printerr("Stack empty"); |
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return; |
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} |
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|
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if((*stack_head)->type==string) |
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free((*stack_head)->content.ptr); |
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|
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*stack_head= (*stack_head)->next; |
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free(temp); |
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} |
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|
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/* Print newline. */ |
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extern void nl() |
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{ |
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printf("\n"); |
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} |
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|
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/* Prints the top element of the stack. */ |
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extern void print_(stackitem** stack_head) |
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{ |
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stackitem* temp= *stack_head; |
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|
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if(temp==NULL) { |
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printerr("Stack empty"); |
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return; |
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} |
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|
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while(temp->type==ref) { |
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temp= temp->content.ptr; |
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|
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if(temp->type!=ref) { |
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printf("ref-> %s", temp->id); |
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return; |
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} |
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} |
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|
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switch(temp->type) { |
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case value: |
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printf("%d", temp->content.val); |
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break; |
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case string: |
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printf("\"%s\"", (char*)temp->content.ptr); |
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break; |
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case symbol: |
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case func: |
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printf("%s", temp->id); |
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break; |
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default: |
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printf("%p", temp->content.ptr); |
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break; |
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} |
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} |
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|
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/* Prints the top element of the stack and then discards it. */ |
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extern void print(stackitem** stack_head) |
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{ |
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print_(stack_head); |
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toss(stack_head); |
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} |
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|
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/* Only to be called by function printstack. */ |
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void print_st(stackitem* stack_head, long counter) |
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{ |
244 |
if(stack_head->next != NULL) |
245 |
print_st(stack_head->next, counter+1); |
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|
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printf("%ld: ", counter); |
248 |
print_(&stack_head); |
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nl(); |
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} |
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|
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/* Prints the stack. */ |
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extern void printstack(stackitem** stack_head) |
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{ |
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if(*stack_head != NULL) { |
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print_st(*stack_head, 1); |
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nl(); |
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} else { |
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printerr("Stack empty"); |
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} |
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} |
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|
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/* Swap the two top elements on the stack. */ |
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extern void swap(stackitem** stack_head) |
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{ |
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stackitem* temp= (*stack_head); |
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|
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if((*stack_head)==NULL) { |
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printerr("Stack empty"); |
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return; |
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} |
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|
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if((*stack_head)->next==NULL) |
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return; |
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|
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*stack_head= (*stack_head)->next; |
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temp->next= (*stack_head)->next; |
278 |
(*stack_head)->next= temp; |
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} |
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|
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stackitem* copy(stackitem* in_item) |
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{ |
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stackitem* out_item= malloc(sizeof(stackitem)); |
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|
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memcpy(out_item, in_item, sizeof(stackitem)); |
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out_item->next= NULL; |
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|
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return out_item; |
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} |
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|
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|
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/* If the top element is a reference, determine if it's a reference to a |
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function, and if it is, toss the reference and execute the function. */ |
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extern void eval(stackitem** stack_head) |
295 |
{ |
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funcp in_func; |
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stackitem* temp= *stack_head; |
298 |
|
299 |
if(temp==NULL) { |
300 |
printerr("Stack empty"); |
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return; |
302 |
} |
303 |
|
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while(temp->type==ref) |
305 |
temp= temp->content.ptr; |
306 |
|
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if(temp->type==func) { |
308 |
in_func= (funcp)(temp->content.ptr); |
309 |
toss(stack_head); |
310 |
(*in_func)(stack_head); |
311 |
return; |
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} |
313 |
|
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push(stack_head, copy(temp)); |
315 |
swap(stack_head); |
316 |
toss(stack_head); |
317 |
} |
318 |
|
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/* Make a list. */ |
320 |
extern void pack(stackitem** stack_head) |
321 |
{ |
322 |
void* delimiter; |
323 |
stackitem *iterator, *temp, *pack; |
324 |
|
325 |
delimiter= (*stack_head)->content.ptr; /* Get delimiter */ |
326 |
toss(stack_head); |
327 |
|
328 |
iterator= *stack_head; |
329 |
|
330 |
if(iterator==NULL || iterator->content.ptr==delimiter) { |
331 |
temp= NULL; |
332 |
toss(stack_head); |
333 |
} else { |
334 |
/* Search for first delimiter */ |
335 |
while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter) |
336 |
iterator= iterator->next; |
337 |
|
338 |
/* Extract list */ |
339 |
temp= *stack_head; |
340 |
*stack_head= iterator->next; |
341 |
iterator->next= NULL; |
342 |
|
343 |
if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter) |
344 |
toss(stack_head); |
345 |
} |
346 |
|
347 |
/* Push list */ |
348 |
pack= malloc(sizeof(stackitem)); |
349 |
pack->type= list; |
350 |
pack->content.ptr= temp; |
351 |
|
352 |
push(stack_head, pack); |
353 |
} |
354 |
|
355 |
/* Parse input. */ |
356 |
int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line) |
357 |
{ |
358 |
char *temp, *rest; |
359 |
int itemp; |
360 |
size_t inlength= strlen(in_line)+1; |
361 |
int convert= 0; |
362 |
static int non_eval_flag= 0; |
363 |
|
364 |
temp= malloc(inlength); |
365 |
rest= malloc(inlength); |
366 |
|
367 |
do { |
368 |
/* If string */ |
369 |
if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) { |
370 |
push_cstring(stack_head, temp); |
371 |
break; |
372 |
} |
373 |
/* If value */ |
374 |
if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) { |
375 |
push_val(stack_head, itemp); |
376 |
break; |
377 |
} |
378 |
/* Escape ';' with '\' */ |
379 |
if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) { |
380 |
temp[1]= '\0'; |
381 |
push_ref(stack_head, in_hash, temp); |
382 |
break; |
383 |
} |
384 |
/* If symbol */ |
385 |
if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) { |
386 |
push_ref(stack_head, in_hash, temp); |
387 |
break; |
388 |
} |
389 |
/* If single char */ |
390 |
if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) { |
391 |
if(*temp==';') { |
392 |
if(!non_eval_flag) { |
393 |
eval(stack_head); /* Evaluate top element */ |
394 |
break; |
395 |
} |
396 |
|
397 |
push_ref(stack_head, in_hash, ";"); |
398 |
break; |
399 |
} |
400 |
|
401 |
if(*temp==']') { |
402 |
push_ref(stack_head, in_hash, "["); |
403 |
pack(stack_head); |
404 |
if(non_eval_flag!=0) |
405 |
non_eval_flag--; |
406 |
break; |
407 |
} |
408 |
|
409 |
if(*temp=='[') { |
410 |
push_ref(stack_head, in_hash, "["); |
411 |
non_eval_flag++; |
412 |
break; |
413 |
} |
414 |
} |
415 |
} while(0); |
416 |
|
417 |
|
418 |
free(temp); |
419 |
|
420 |
if(convert<2) { |
421 |
free(rest); |
422 |
return 0; |
423 |
} |
424 |
|
425 |
stack_read(stack_head, in_hash, rest); |
426 |
|
427 |
free(rest); |
428 |
return 1; |
429 |
} |
430 |
|
431 |
/* Relocate elements of the list on the stack. */ |
432 |
extern void expand(stackitem** stack_head) |
433 |
{ |
434 |
stackitem *temp, *new_head; |
435 |
|
436 |
/* Is top element a list? */ |
437 |
if((*stack_head)==NULL || (*stack_head)->type!=list) { |
438 |
printerr("Stack empty or not a list"); |
439 |
return; |
440 |
} |
441 |
|
442 |
/* The first list element is the new stack head */ |
443 |
new_head= temp= (*stack_head)->content.ptr; |
444 |
toss(stack_head); |
445 |
|
446 |
if(temp==NULL) |
447 |
return; |
448 |
|
449 |
/* Search the end of the list */ |
450 |
while(temp->next!=NULL) |
451 |
temp= temp->next; |
452 |
|
453 |
/* Connect the the tail of the list with the old stack head */ |
454 |
temp->next= *stack_head; |
455 |
*stack_head= new_head; /* ...and voila! */ |
456 |
} |
457 |
|
458 |
/* Compares two elements by reference. */ |
459 |
extern void eq(stackitem** stack_head) |
460 |
{ |
461 |
void *left, *right; |
462 |
int result; |
463 |
|
464 |
if((*stack_head)==NULL || (*stack_head)->next==NULL) { |
465 |
printerr("Not enough elements to compare"); |
466 |
return; |
467 |
} |
468 |
|
469 |
left= (*stack_head)->content.ptr; |
470 |
swap(stack_head); |
471 |
right= (*stack_head)->content.ptr; |
472 |
result= (left==right); |
473 |
|
474 |
toss(stack_head); toss(stack_head); |
475 |
push_val(stack_head, (left==right)); |
476 |
} |
477 |
|
478 |
/* Negates the top element on the stack. */ |
479 |
extern void not(stackitem** stack_head) |
480 |
{ |
481 |
int value; |
482 |
|
483 |
if((*stack_head)==NULL || (*stack_head)->type!=value) { |
484 |
printerr("Stack empty or element is not a value"); |
485 |
return; |
486 |
} |
487 |
|
488 |
value= (*stack_head)->content.val; |
489 |
toss(stack_head); |
490 |
push_val(stack_head, !value); |
491 |
} |
492 |
|
493 |
/* Compares the two top elements on the stack and return 0 if they're the |
494 |
same. */ |
495 |
extern void neq(stackitem** stack_head) |
496 |
{ |
497 |
eq(stack_head); |
498 |
not(stack_head); |
499 |
} |
500 |
|
501 |
/* Give a symbol some content. */ |
502 |
extern void def(stackitem** stack_head) |
503 |
{ |
504 |
stackitem *temp, *value; |
505 |
|
506 |
if(*stack_head==NULL || (*stack_head)->next==NULL |
507 |
|| (*stack_head)->type!=ref) { |
508 |
printerr("Define what?"); |
509 |
return; |
510 |
} |
511 |
|
512 |
temp= (*stack_head)->content.ptr; |
513 |
value= (*stack_head)->next; |
514 |
temp->content= value->content; |
515 |
value->content.ptr=NULL; |
516 |
temp->type= value->type; |
517 |
|
518 |
toss(stack_head); toss(stack_head); |
519 |
} |
520 |
|
521 |
/* Quit stack. */ |
522 |
extern void quit() |
523 |
{ |
524 |
exit(EXIT_SUCCESS); |
525 |
} |
526 |
|
527 |
/* Clear stack */ |
528 |
extern void clear(stackitem** stack_head) |
529 |
{ |
530 |
while(*stack_head!=NULL) |
531 |
toss(stack_head); |
532 |
} |
533 |
|
534 |
int main() |
535 |
{ |
536 |
stackitem* s= NULL; |
537 |
hashtbl myhash; |
538 |
char in_string[100]; |
539 |
|
540 |
init_hashtbl(myhash); |
541 |
|
542 |
printf("okidok\n "); |
543 |
|
544 |
while(fgets(in_string, 100, stdin) != NULL) { |
545 |
stack_read(&s, myhash, in_string); |
546 |
printf("okidok\n "); |
547 |
} |
548 |
|
549 |
exit(EXIT_SUCCESS); |
550 |
} |