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Diffstat (limited to 'media/libjpeg/jchuff.h')
-rw-r--r-- | media/libjpeg/jchuff.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/media/libjpeg/jchuff.h b/media/libjpeg/jchuff.h new file mode 100644 index 0000000000..314a2325c9 --- /dev/null +++ b/media/libjpeg/jchuff.h @@ -0,0 +1,42 @@ +/* + * jchuff.h + * + * This file was part of the Independent JPEG Group's software: + * Copyright (C) 1991-1997, Thomas G. Lane. + * It was modified by The libjpeg-turbo Project to include only code relevant + * to libjpeg-turbo. + * For conditions of distribution and use, see the accompanying README.ijg + * 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; + +/* Expand a Huffman table definition into the derived format */ +EXTERN(void) jpeg_make_c_derived_tbl(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(j_compress_ptr cinfo, JHUFF_TBL *htbl, + long freq[]); |