| Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * jchuff.h |
| 3 | * |
| 4 | * Copyright (C) 1991-1995, Thomas G. Lane. |
| 5 | * This file is part of the Independent JPEG Group's software. |
| 6 | * For conditions of distribution and use, see the accompanying README file. |
| 7 | * |
| 8 | * This file contains declarations for Huffman entropy encoding routines |
| 9 | * that are shared between the sequential encoder (jchuff.c) and the |
| 10 | * progressive encoder (jcphuff.c). No other modules need to see these. |
| 11 | */ |
| 12 | |
| 13 | /* Derived data constructed for each Huffman table */ |
| 14 | |
| 15 | typedef struct { |
| 16 | unsigned int ehufco[256]; /* code for each symbol */ |
| 17 | char ehufsi[256]; /* length of code for each symbol */ |
| 18 | /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */ |
| 19 | } c_derived_tbl; |
| 20 | |
| 21 | /* Short forms of external names for systems with brain-damaged linkers. */ |
| 22 | |
| 23 | #ifdef NEED_SHORT_EXTERNAL_NAMES |
| 24 | #define jpeg_make_c_derived_tbl jMkCDerived |
| 25 | #define jpeg_gen_optimal_table jGenOptTbl |
| 26 | #endif /* NEED_SHORT_EXTERNAL_NAMES */ |
| 27 | |
| 28 | /* Expand a Huffman table definition into the derived format */ |
| 29 | EXTERN void jpeg_make_c_derived_tbl JPP((j_compress_ptr cinfo, |
| 30 | JHUFF_TBL * htbl, c_derived_tbl ** pdtbl)); |
| 31 | |
| 32 | /* Generate an optimal table definition given the specified counts */ |
| 33 | EXTERN void jpeg_gen_optimal_table JPP((j_compress_ptr cinfo, |
| 34 | JHUFF_TBL * htbl, long freq[])); |