/*
* huffman_encode_file huffman encodes in to out.
*/
int
huffman_encode_file(FILE *in, FILE *out)
{
SymbolFrequencies sf;
SymbolEncoder *se;
huffman_node *root = NULL;
int rc;
unsigned int symbol_count;
/* Get the frequency of each symbol in the input file. */
symbol_count = get_symbol_frequencies(&sf, in);
/* Build an optimal table from the symbolCount. */
se = calculate_huffman_codes(&sf);
root = sf[0];
/* Scan the file again and, using the table
previously built, encode it into the output file. */
rewind(in);
rc = write_code_table(out, se, symbol_count);
if(rc == 0)
rc = do_file_encode(in, out, se);
/* Free the Huffman tree. */
free_huffman_tree(root);
free_encoder(se);
return rc;
}
/* 把 in 压缩成 out */
int huffman_encode_file(FILE *in, FILE *out)
{
symfreq sf;
symcode *sc;
node *root = NULL;
int rc;
unsigned int syms;
/* 获取输入文件中符号出现频率 */
syms = get_symfreq(&sf, in);
/* 生成编码表 */
sc = calc_code(&sf);
root = sf[0];
/* 再次扫描文件，使用之前生成的编码表来编码 */
rewind(in);
rc = write_code_table(out, sc, syms);
if (rc == 0)
rc = do_file_encode(in, out, sc);
/* 释放空间 */
free_tree(root);
free_encoder(sc);
return rc;
}