media/libjpeg/jchuff.h@6474c204b198 (annotated)
media/libjpeg/jchuff.h
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* |
| michael@0 | 2 | * jchuff.h |
| michael@0 | 3 | * |
| michael@0 | 4 | * Copyright (C) 1991-1997, Thomas G. Lane. |
| michael@0 | 5 | * This file is part of the Independent JPEG Group's software. |
| michael@0 | 6 | * For conditions of distribution and use, see the accompanying README file. |
| michael@0 | 7 | * |
| michael@0 | 8 | * This file contains declarations for Huffman entropy encoding routines |
| michael@0 | 9 | * that are shared between the sequential encoder (jchuff.c) and the |
| michael@0 | 10 | * progressive encoder (jcphuff.c). No other modules need to see these. |
| michael@0 | 11 | */ |
| michael@0 | 12 | |
| michael@0 | 13 | /* The legal range of a DCT coefficient is |
| michael@0 | 14 | * -1024 .. +1023 for 8-bit data; |
| michael@0 | 15 | * -16384 .. +16383 for 12-bit data. |
| michael@0 | 16 | * Hence the magnitude should always fit in 10 or 14 bits respectively. |
| michael@0 | 17 | */ |
| michael@0 | 18 | |
| michael@0 | 19 | #if BITS_IN_JSAMPLE == 8 |
| michael@0 | 20 | #define MAX_COEF_BITS 10 |
| michael@0 | 21 | #else |
| michael@0 | 22 | #define MAX_COEF_BITS 14 |
| michael@0 | 23 | #endif |
| michael@0 | 24 | |
| michael@0 | 25 | /* Derived data constructed for each Huffman table */ |
| michael@0 | 26 | |
| michael@0 | 27 | typedef struct { |
| michael@0 | 28 | unsigned int ehufco[256]; /* code for each symbol */ |
| michael@0 | 29 | char ehufsi[256]; /* length of code for each symbol */ |
| michael@0 | 30 | /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */ |
| michael@0 | 31 | } c_derived_tbl; |
| michael@0 | 32 | |
| michael@0 | 33 | /* Short forms of external names for systems with brain-damaged linkers. */ |
| michael@0 | 34 | |
| michael@0 | 35 | #ifdef NEED_SHORT_EXTERNAL_NAMES |
| michael@0 | 36 | #define jpeg_make_c_derived_tbl jMkCDerived |
| michael@0 | 37 | #define jpeg_gen_optimal_table jGenOptTbl |
| michael@0 | 38 | #endif /* NEED_SHORT_EXTERNAL_NAMES */ |
| michael@0 | 39 | |
| michael@0 | 40 | /* Expand a Huffman table definition into the derived format */ |
| michael@0 | 41 | EXTERN(void) jpeg_make_c_derived_tbl |
| michael@0 | 42 | JPP((j_compress_ptr cinfo, boolean isDC, int tblno, |
| michael@0 | 43 | c_derived_tbl ** pdtbl)); |
| michael@0 | 44 | |
| michael@0 | 45 | /* Generate an optimal table definition given the specified counts */ |
| michael@0 | 46 | EXTERN(void) jpeg_gen_optimal_table |
| michael@0 | 47 | JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])); |
