diff options
Diffstat (limited to 'src/jpeg-6b/jchuff.h')
-rw-r--r-- | src/jpeg-6b/jchuff.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/src/jpeg-6b/jchuff.h b/src/jpeg-6b/jchuff.h new file mode 100644 index 00000000..a9599fc1 --- /dev/null +++ b/src/jpeg-6b/jchuff.h @@ -0,0 +1,47 @@ +/* + * jchuff.h + * + * Copyright (C) 1991-1997, Thomas G. Lane. + * This file is part of the Independent JPEG Group's software. + * For conditions of distribution and use, see the accompanying README file. + * + * This file contains declarations for Huffman entropy encoding routines + * that are shared between the sequential encoder (jchuff.c) and the + * progressive encoder (jcphuff.c). No other modules need to see these. + */ + +/* The legal range of a DCT coefficient is + * -1024 .. +1023 for 8-bit data; + * -16384 .. +16383 for 12-bit data. + * Hence the magnitude should always fit in 10 or 14 bits respectively. + */ + +#if BITS_IN_JSAMPLE == 8 +#define MAX_COEF_BITS 10 +#else +#define MAX_COEF_BITS 14 +#endif + +/* Derived data constructed for each Huffman table */ + +typedef struct { + unsigned int ehufco[256]; /* code for each symbol */ + char ehufsi[256]; /* length of code for each symbol */ + /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */ +} c_derived_tbl; + +/* Short forms of external names for systems with brain-damaged linkers. */ + +#ifdef NEED_SHORT_EXTERNAL_NAMES +#define jpeg_make_c_derived_tbl jMkCDerived +#define jpeg_gen_optimal_table jGenOptTbl +#endif /* NEED_SHORT_EXTERNAL_NAMES */ + +/* Expand a Huffman table definition into the derived format */ +EXTERN(void) jpeg_make_c_derived_tbl + JPP((j_compress_ptr cinfo, boolean isDC, int tblno, + c_derived_tbl ** pdtbl)); + +/* Generate an optimal table definition given the specified counts */ +EXTERN(void) jpeg_gen_optimal_table + JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])); |