huff.h

#pragma once
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

//If compiling for Windows environment, import libraries to ensure compatibility
#ifdef _WIN32
#include <io.h>
#include <fcntl.h>
#endif

//When ASCIIONLY is defined through compiler options, set MAXCHAR to 128
#ifdef ASCIIONLY
#define MAXCHAR 128
#else
#define MAXCHAR 256
#endif

//Following definitions are guarded to allow modification through compiler flags
#ifndef BUFFSIZE
#define BUFFSIZE 1024 * 1024 * 4 // 4MiB
#endif

#ifndef MAXHCODE
#define MAXHCODE 32         //Set maximum huffman code to 32 bit
#endif

#define SPACE 5

//Macro for raisng memory allocation error
#define MEMALLOCERR() {\
fprintf(stderr, "sbc: Failed to allocate memory. \n");\
exit(-1);\
}
//Macro for raising fread error
#define FREADERR() {\
fprintf(stderr, "sbc: Failed to read file.\n");\
exit(-1);\
}

//Structure that contains both the element and the frequency of the element
typedef struct freqdict {
    unsigned int freq;                      //Frequency of the value
    unsigned char ele;                      //The element i.e. the 8 bit value it is representing

} freqdict;

//Node of tree data structure
typedef struct node
{
    unsigned int key;                       //Same as freq
    struct node *left;
    struct node *right;
    unsigned char ele;
    char isleaf;
}node;

/*
TODO: Use struct to make writing function more consise
Need to rewrite functions that takes size to accept *size
typedef struct heapargs {
    void *arr;
    size_t *size;
    size_t bytes;
    int (*cmp)(const void*, const void*);
}
*/

void swap(void * a, void* b, size_t bytes);
int freqcmp(const void *pa, const void *pb);
int nodecmp(const void *pa, const void *pb);
int nodeptrcmp(const void *pa, const void *pb);
void heapify(void *arr, size_t size, size_t bytes, int (*cmp)(const void*, const void*), unsigned int i);
void minheap(void *arr, size_t size, size_t bytes, int (*cmp)(const void*, const void*));
void *extract(void *arr, size_t *size, size_t bytes, int(*cmp)(const void*, const void*));
void insert(void *arr, size_t *size, size_t bytes, int(*cmp)(const void*, const void*), void* new);
void hsort(void *arr, size_t size, size_t bytes, int(*cmp)(const void*, const void*));

void char_dist(FILE* in);
void stdin_char_dist(FILE *temp);
node *newsubtree();
void buildhufftree(freqdict *arr0, size_t *size0, node *arr1, size_t *size1);
void buildht(freqdict *arr0, size_t *size0, node **arr1, size_t *size1);
void encode(node *hufftree, char *code, unsigned int len);
void treecheck(node *hufftree);
void comp(FILE *in, char *name);
void decomp(FILE *in, char *name);
node *tbltoht();
void drawhufftree(FILE *in);
void treeprint(node *hufftree, int depth, char *path, int right, int inputdepth);
int isprintable(unsigned char var);
int searchhuffcode(node *hufftree, char *code, unsigned int len, unsigned char target);
void cleantree(node *tree);