170a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* 270a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * jchuff.h 370a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * 470a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * Copyright (C) 1991-1997, Thomas G. Lane. 570a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * This file is part of the Independent JPEG Group's software. 670a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * For conditions of distribution and use, see the accompanying README file. 770a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * 870a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * This file contains declarations for Huffman entropy encoding routines 970a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * that are shared between the sequential encoder (jchuff.c) and the 1070a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * progressive encoder (jcphuff.c). No other modules need to see these. 1170a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine */ 1270a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 1370a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* The legal range of a DCT coefficient is 1470a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * -1024 .. +1023 for 8-bit data; 1570a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * -16384 .. +16383 for 12-bit data. 1670a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine * Hence the magnitude should always fit in 10 or 14 bits respectively. 1770a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine */ 1870a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 1970a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#if BITS_IN_JSAMPLE == 8 2070a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#define MAX_COEF_BITS 10 2170a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#else 2270a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#define MAX_COEF_BITS 14 2370a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#endif 2470a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 2570a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* Derived data constructed for each Huffman table */ 2670a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 2770a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkinetypedef struct { 2870a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine unsigned int ehufco[256]; /* code for each symbol */ 2970a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine char ehufsi[256]; /* length of code for each symbol */ 3070a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */ 3170a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine} c_derived_tbl; 3270a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 3370a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* Short forms of external names for systems with brain-damaged linkers. */ 3470a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 3570a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#ifdef NEED_SHORT_EXTERNAL_NAMES 3670a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#define jpeg_make_c_derived_tbl jMkCDerived 3770a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#define jpeg_gen_optimal_table jGenOptTbl 3870a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine#endif /* NEED_SHORT_EXTERNAL_NAMES */ 3970a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 4070a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* Expand a Huffman table definition into the derived format */ 4170a18cd874a22452aca9e39e22275ed4538ed20bVladimir ChtchetkineEXTERN(void) jpeg_make_c_derived_tbl 4270a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine JPP((j_compress_ptr cinfo, boolean isDC, int tblno, 4370a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine c_derived_tbl ** pdtbl)); 4470a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine 4570a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine/* Generate an optimal table definition given the specified counts */ 4670a18cd874a22452aca9e39e22275ed4538ed20bVladimir ChtchetkineEXTERN(void) jpeg_gen_optimal_table 4770a18cd874a22452aca9e39e22275ed4538ed20bVladimir Chtchetkine JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])); 48