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Enhance 'r' command to lookup values in the huffman tree

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This commit is contained in:
James Bowes 2012-09-06 11:51:37 -03:00
parent 8d59720195
commit 3262f44afb
4 changed files with 70 additions and 28 deletions
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3
README.md
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@ -56,6 +56,9 @@ etc):
`./unpack s this-cert.bin`
To dump the raw packed file as text:
`./unpack r this-cert.bin`
To reconstruct the content sets and dump them to stdout:
`./unpack d this-cert.bin`

49
huffman.c
View file

@ -105,3 +105,52 @@ huffman_lookup (struct huffman_node *tree, unsigned char *bits, int *bits_read,
}
}
}
struct stack {
struct stack *next;
bool val;
};
static void
huffman_lookup_driver (struct huffman_node *tree, void *value,
struct stack *head, struct stack *cur)
{
if (tree->value == value) {
struct stack *x = head->next;
while (x != NULL) {
if (x->val) {
putchar ('1');
} else {
putchar ('0');
}
x = x->next;
}
return;
}
struct stack *next = malloc (sizeof (struct stack));
next->next = NULL;
cur->next = next;
if (tree->left != NULL) {
next->val = false;
huffman_lookup_driver (tree->left, value, head, next);
}
if (tree->right != NULL) {
next->val = true;
huffman_lookup_driver (tree->right, value, head, next);
}
cur->next = NULL;
free (next);
}
// given a value, print its code to stdout.
void
huffman_reverse_lookup (struct huffman_node *tree, void *value)
{
struct stack head;
head.next = NULL;
huffman_lookup_driver (tree, value, &head, &head);
}

2
huffman.h
View file

@ -11,3 +11,5 @@ struct huffman_node *huffman_build_tree(void **values, int count);
void *huffman_lookup (struct huffman_node *tree, unsigned char *bits,
int *bits_read, bool print);
void huffman_reverse_lookup (struct huffman_node *tree, void *value);

44
unpack.c
View file

@ -176,12 +176,14 @@ load_content_sets(FILE *stream, struct node **list, int *node_count,
node->children = malloc (sizeof (struct node *) * 64);
if (raw) {
printf ("\tNode:\n");
printf (" Node - ");
huffman_reverse_lookup (tree, node);
printf (":\n");
}
while (true) {
if (raw) {
printf("\t\t");
printf(" ");
}
char *path = (char *) huffman_lookup (dictionary_tree,
@ -192,13 +194,13 @@ load_content_sets(FILE *stream, struct node **list, int *node_count,
if (path[0] == '\0') {
if (raw) {
printf("\n");
printf(" (<end>)\n");
}
break;
}
if (raw) {
printf (" :: ");
printf (" (%s) :: ", path);
}
struct node *child =
@ -354,33 +356,19 @@ check_content_set (struct node *content_sets, const char *path)
}
static void
print_dictionary (char **dictionary, int dictionary_size)
print_dictionary (char **dictionary, int dictionary_size,
struct huffman_node *dictionary_tree)
{
int i;
printf ("Path Dictionary (%d entries):\n", dictionary_size);
for (i = 0; i < dictionary_size; i++) {
printf ("\t%s\n", dictionary[i]);
}
}
static void
print_node (struct node *content_set)
{
int i;
printf ("\tNode:\n");
for (i = 0; i < content_set->count; i++) {
printf ("\t\t%s\n", content_set->paths[i]);
}
}
static void
print_nodes (struct node **content_sets, int content_set_size)
{
int i;
printf ("Node Dictionary (%d entries):\n", content_set_size);
for (i = 0; i < content_set_size; i++) {
print_node (content_sets[i]);
for (i = 0; i < dictionary_size - 1; i++) {
printf (" %s - ", dictionary[i]);
huffman_reverse_lookup (dictionary_tree, dictionary[i]);
printf("\n");
}
printf (" <end of node indicator> - ");
huffman_reverse_lookup (dictionary_tree, dictionary[i]);
printf ("\n");
}
int
@ -445,7 +433,7 @@ main(int argc, char **argv) {
huffman_build_tree ((void **) dictionary, dictionary_size);
if (raw) {
print_dictionary (dictionary, dictionary_size);
print_dictionary (dictionary, dictionary_size, dictionary_tree);
}
if (load_content_sets(fp, &content_sets, &content_set_size,