1 /* 2 * jchuff.h 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * It was modified by The libjpeg-turbo Project to include only code relevant 7 * to libjpeg-turbo. 8 * mozjpeg Modifications: 9 * Copyright (C) 2014, Mozilla Corporation. 10 * For conditions of distribution and use, see the accompanying README file. 11 * 12 * This file contains declarations for Huffman entropy encoding routines 13 * that are shared between the sequential encoder (jchuff.c) and the 14 * progressive encoder (jcphuff.c). No other modules need to see these. 15 */ 16 17 /* The legal range of a DCT coefficient is 18 * -1024 .. +1023 for 8-bit data; 19 * -16384 .. +16383 for 12-bit data. 20 * Hence the magnitude should always fit in 10 or 14 bits respectively. 21 */ 22 23 #if BITS_IN_JSAMPLE == 8 24 #define MAX_COEF_BITS 10 25 #else 26 #define MAX_COEF_BITS 14 27 #endif 28 29 /* Derived data constructed for each Huffman table */ 30 31 typedef struct { 32 unsigned int ehufco[256]; /* code for each symbol */ 33 char ehufsi[256]; /* length of code for each symbol */ 34 /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */ 35 } c_derived_tbl; 36 37 /* Expand a Huffman table definition into the derived format */ 38 EXTERN(void) jpeg_make_c_derived_tbl(j_compress_ptr cinfo, boolean isDC, 39 int tblno, c_derived_tbl **pdtbl); 40 41 /* Generate an optimal table definition given the specified counts */ 42 EXTERN(void) jpeg_gen_optimal_table 43 (j_compress_ptr cinfo, JHUFF_TBL *htbl, long freq[]); 44 45 EXTERN(void) quantize_trellis 46 (j_compress_ptr cinfo, c_derived_tbl *dctbl, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks, 47 JQUANT_TBL * qtbl, double *norm_src, double *norm_coef, JCOEF *last_dc_val, 48 JBLOCKROW coef_blocks_above, JBLOCKROW src_above); 49