// cse 373
// header file for adaptive huffman project

// a number from 0 to MAXNODE-1, or NONE
typedef int NodeIndex;

// a number from 0 to NUMSYMBOLS-1
typedef int Symbol;

typedef unsigned char Bit;	// zero or one

// a node in the Huffman tree
struct _HuffNode {
	NodeIndex parent;	// index of parent node
	NodeIndex self;		// index of myself
	NodeIndex c0;		// index of left child
	NodeIndex c1;		// index of right child
	int weight;			// count of occurrences
	Symbol value;		// the symbol
	int isLeftChild;	// 0 if left, 1 if right
};
typedef struct _HuffNode HuffNode;

const int NUMCHARS = 256;
const int NUMSYMBOLS = NUMCHARS + 2;
const int MAXNODE = NUMSYMBOLS*2-1;
// the two special symbols:
const int ENDOFFILE = 256;
const int UNKNOWN = 257;
// used to represent a nonexistent node
const int NONE = 999;

// the master Huffman structure
struct _Huff {
	HuffNode nodes[NUMSYMBOLS * 2];
	NodeIndex symbols[NUMSYMBOLS];
	NodeIndex root;
	NodeIndex nextFree;
};
typedef struct _Huff Huff, *PHuff;

// an encoded symbol has 'bitcount' bits, stored in the right
// side of 'code'
struct _EncSymbol {
	unsigned int code;
	int bitcount;
};
typedef struct _EncSymbol EncSymbol;