Decoding working for C

huffman.c

@@ -43,7 +43,7 @@ huffman_build_tree(void **values, int count)
 			malloc (sizeof (struct huffman_node));
 
 		node->value = values[i];
-		node->weight = i;
+		node->weight = i + 1;
 		node->left = NULL;
 		node->right = NULL;
 
@@ -77,9 +77,11 @@ huffman_lookup (struct huffman_node *tree, unsigned char *bits, int *bits_read)
 {
 
 	struct huffman_node *node = tree;
-	*bits_read = 0;
 
 	while (true) {
+		if (node == NULL) {
+			return NULL;
+		}
 		if (node->value != NULL) {
 			return node->value;
 		}

thing.rb

@@ -22,20 +22,22 @@ end
 require './huffman'
 
 $log = Logger.new(STDOUT)
-#$log.level = Logger::DEBUG
+$log.level = Logger::DEBUG
-$log.level = Logger::FATAL
+#$log.level = Logger::FATAL
+
+$sentinal = "SENTINAL"
 
 class BitWriter
 
   def initialize(stream)
     @stream = stream
     @byte = 0x00
-    @count = 8
+    @count = 7
   end
 
   def write(char)
     if char == '1'
-      @byte |= 1 << @count
+      @byte |= 0x01 << @count
     end
     @count -= 1
     if @count == -1
@@ -50,8 +52,8 @@ class BitWriter
   end
 
   def pad()
-    @count = 8
+    @stream.write(Array(@byte).pack('c'))
-    @stream.write(Array(@byte).pack('C'))
+    @count = 7
     @byte = 0x00
   end
 end
@@ -199,33 +201,20 @@ def ran_char(val)
   return val
 end
 
-def binary_write(file, parent, string_huff, node_huff)
+def binary_write(file, node_list, string_huff, node_huff)
-#  file.write(parent.path)
+  node_list.each do |node|
-#  file.write("\0")
+    $log.debug('binary_write') { "begin node: " + node_huff.encode(node) }
-  #offset to child node indicies
+    node.children.each do |path, child|
-   # not needed, can just go write to children indicies
-  #file.write(ran_char)
-  if parent.written
-    return
-  end
-
-  parent.children.each do |path, child|
-#    puts "PATH: " + child.path
-#    file.write(child.path)
-#    file.write("\0")
       # index of path string
-    $log.debug('binary_write') { "path: " + path.inspect + "; encoded: " + string_huff.encode(path).inspect }
+      $log.debug('binary_write') { "\tpath: " + path.inspect + "; encoded: " + string_huff.encode(path).inspect }
       file.write_bits(string_huff.encode(path))
       # offset to node
       # index of node, that is.
       file.write_bits(node_huff.encode(child))
+      $log.debug('binary_write') { "\tnode encoded: " + node_huff.encode(child) }
     end
-  # reserve null byte for end of node info
+    # end of node is indicated by the special sentinal huffman coding of \0
-  # 3 0s are reserved in our name huffman table to denote end of node
+    file.write_bits(string_huff.encode($sentinal))
-  file.write_bits("000")
-  parent.children.each do |path, child|
-      binary_write(file, child, string_huff, node_huff)
-      child.written = true
   end
 end
 
@@ -281,22 +270,38 @@ def build_huffman_for_strings(strings)
       i.times { paths << string }
       i += 1
     end
+    # add on sentinal string
+    i.times { paths << $sentinal }
+    puts paths
     HuffmanEncoding.new paths
 end
 
-def build_huffman_for_nodes(parent)
+def build_node_frequencies(parent)
   nodes = parent.flatten.uniq
   refs = {}
   nodes.each do |node|
-      node.children.each do |key, node|
+    node.children.each do |key, child|
-        refs[node] ||= 0
+      refs[child] ||= 0
-        refs[node] += 1
+      refs[child] += 1
     end
   end
-    refs[parent] = 1
+
+  list = []
+  refs.sort { |l, r| l[1] <=> r[1] }.each do |node, weight|
+    list << node
+  end
+
+  list
+end
+
+
+def build_huffman_for_nodes(list)
+    # parent doesn't have to go into the table
+    i = 1
     expanded = []
-    refs.each do |node, freq|
+    list.each do |node|
-      freq.times {expanded << node}
+      i.times {expanded << node}
+      i += 1
     end
     table = HuffmanEncoding.new expanded
 end
@@ -359,7 +364,12 @@ if $0 == __FILE__
     #      parent = compress_prefix(parent)
 
       puts "building huffman table for nodes"
-      node_huff = build_huffman_for_nodes(parent)
+      node_list = build_node_frequencies(parent)
+      node_huff = build_huffman_for_nodes(node_list)
+
+      # XXX add sentinal value to strings to indicate end of node.
+      # should be most frequent one. the string itself doesn't have to
+      # be stored, since we just care about the bitstring.
       
       strings = collect_strings(parent)
     
@@ -368,8 +378,19 @@ if $0 == __FILE__
  
       puts "writing"
       write_strings(file, strings)
+
+      # write out the number of unique path nodes into 1 or more bytes.  if <
+      # 128 nodes, write in a single byte. if > 128 nodes, the first byte will
+      # begin with a '1' to indicate as such. the following bits in the byte
+      # indicate how many bytes following the first byte are used to store the
+      # size.
+
+      node_count = node_list.count + 1
+      puts node_count
+      file.write([node_count].pack("c"))
+
       bit_file = BitWriter.new file
-      binary_write(bit_file, parent, string_huff, node_huff)
+      binary_write(bit_file, [parent] + node_list, string_huff, node_huff)
       bit_file.pad
     end
 

unpack.c

@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <zlib.h>
 
 #include "huffman.h"
@@ -8,9 +9,9 @@
 #define CHUNK 1024
 
 struct node {
-	struct node *next;
+	int count;
-	unsigned int path;
+	char **paths;
-	unsigned int children[];
+	struct node **children;
 };
 
 static int 
@@ -99,11 +100,17 @@ load_dictionary(FILE *source, char ***dictionary, int *dictionary_size)
 		}
 	}
 
-	*dictionary = malloc (sizeof (char *) * offset_size);
+	*dictionary = malloc (sizeof (char *) * (*dictionary_size + 1));
-	for (i = 0; i < offset_size; i++) {
+	for (i = 0; i < *dictionary_size; i++) {
 		(*dictionary)[i] = (char *) buf + dictionary_offsets[i];
 	}
 
+	(*dictionary_size)++;
+	// Add in the end of node sentinal string
+	char *sentinal = malloc (sizeof (char));
+	sentinal[0] = 0x00;
+	(*dictionary)[i] = sentinal;
+
 	// rewind back to unused zlib bytes
 	if (fseek(source, (long) strm.avail_in * -1, SEEK_CUR)) {
 		printf("Error seeking back in stream\n");
@@ -120,25 +127,117 @@ load_dictionary(FILE *source, char ***dictionary, int *dictionary_size)
 }
 
 static int
-load_node_list(FILE *stream, struct node **list) {
+load_content_sets(FILE *stream, struct node **list,
+		  struct huffman_node *dictionary_tree) {
 
-	unsigned char buf[CHUNK];
+	unsigned char *buf = malloc (sizeof (char *) * CHUNK);
 	size_t read;
-	struct node *np = malloc(sizeof(struct node));
+	struct node **nodes;
-	*list = np;
+	int i;
 
-	read = fread(buf, 1, CHUNK, stream);
+	unsigned char count;
+	fread(&count, sizeof (unsigned char), 1, stream);
+	printf("number of nodes: %hd\n", count);
+
+
+	nodes = malloc (sizeof (struct node *) * (unsigned short) count);
+	for (i = 0; i < (unsigned short) count; i++) {
+		nodes[i] = malloc (sizeof (struct node));
+	}
+
+	read = fread (buf, sizeof (char), CHUNK, stream);
 	printf("Read %zu bytes\n", read);
 
+	/* 
+	 * the parent node doesn't go in the huffman tree, as nothing else
+	 * references it.
+	 */
+	struct huffman_node *tree =
+		huffman_build_tree ((void **) nodes + 1,
+				    (unsigned short) count - 1);
+
+	int bits_read = 0;
+	for (i = 0; i < count; i++) {
+		struct node *node = nodes[i];
+		node->count = 0;
+
+		// XXX hard coded
+		node->paths = malloc (sizeof (char *) * 64);
+		node->children = malloc (sizeof (struct node *) * 64);
+
+		while (true) {
+			char *path = (char *) huffman_lookup (dictionary_tree,
+							      buf, &bits_read);
+			buf = buf + bits_read / 8;
+			bits_read = bits_read % 8;
+
+			if (path[0] == '\0') {
+				break;
+			}
+
+			struct node *child =
+				(struct node *) huffman_lookup (tree, buf,
+								&bits_read);
+			buf = buf + bits_read / 8;
+			bits_read = bits_read % 8;
+		
+			node->paths[node->count] = path;
+			node->children[node->count] = child;
+			node->count++;
+		}
+	}
+
+	*list = nodes[0];
 	return 0;
 }
 
+struct stack {
+	struct stack *next;
+	struct stack *prev;
+	char *path;
+};
+
+static void
+dump_content_set (struct node *content_sets, struct stack *head,
+		  struct stack *tail)
+{
+	int i;
+	struct stack stack;
+	stack.prev = tail;
+	tail->next = &stack;
+
+	for (i = 0; i < content_sets->count; i++) {
+		stack.path = content_sets->paths[i];
+		dump_content_set(content_sets->children[i], head, &stack);
+	}
+
+	if (content_sets->count == 0) {
+		struct stack *cur = head;
+
+		for (cur = head->next; cur != &stack; cur = cur->next) {
+			printf("/%s", cur->path);
+		}
+		printf("\n");
+	}
+}
+
+static void
+dump_content_sets (struct node *content_sets)
+{
+	struct stack stack;
+	stack.next = NULL;
+	stack.prev = NULL;
+	stack.path = NULL;
+
+	dump_content_set (content_sets, &stack, &stack);
+}
+
 int
 main(int argc, char **argv) {
 	FILE *fp;
 	char **dictionary;
 	int dictionary_size;
-	struct node *list;
+	struct node *content_sets;
 
 	if (argc != 2) {
 		printf("usage: unpack <bin file>\n");
@@ -156,18 +255,15 @@ main(int argc, char **argv) {
 		return -1;
 	}
 
-	struct huffman_node *tree = huffman_build_tree ((void **) dictionary,
+	struct huffman_node *dictionary_tree =
-							dictionary_size);
+		huffman_build_tree ((void **) dictionary, dictionary_size);
 
-	int bits_read;
+	if (load_content_sets(fp, &content_sets, dictionary_tree)) {
-	short bits = 0xC0;
-
-	printf("\n\n%s\n", huffman_lookup (tree, (unsigned char *) &bits, &bits_read));
-	
-	if (load_node_list(fp, &list)) {
 		printf("node list parsing failed. exiting\n");
 		return -1;
 	}
 
+	dump_content_sets (content_sets);
+
 	return 0;
 }