Files
mozjpeg/jchuff.h
Kornel c6d33b6d69 Merge commit '15274b901acb75d6d2433e8578f3cfbc6f4f5fd9' into mozjpeg
* commit '15274b901acb75d6d2433e8578f3cfbc6f4f5fd9': (98 commits)
  AppVeyor: Use SignPath release cert/only sign tags
  xform fuzz: Use only xform opts to set entropy alg
  jchuff.c: Test for out-of-range coefficients
  turbojpeg.h: Make customFilter() proto match doc
  ChangeLog.md: Fix typo
  djpeg: Fix -map option with 12-bit data precision
  Disallow color quantization with lossless decomp
  tj3Transform: Calc dst buf size from xformed dims
  README.md: Include link to project home page
  AppVeyor: Only add installers to zip file
  AppVeyor: Integrate with SignPath.io
  Fix build warnings/errs w/ -DNO_GETENV/-DNO_PUTENV
  GitHub: Fix x32 build
  Bump version to 3.0.0
  tjexample.c: Prevent integer overflow
  Disallow merged upsampling with lossless decomp
  SECURITY.md: Wordsmithing and clarifications
  GitHub: Add security policy
  ChangeLog.md: List CVE ID fixed by 9f756bc6
  jpeg_crop_scanline: Fix calc w/sclg + 2x4,4x2 samp
  ...
2024-12-23 01:25:43 +00:00

50 lines
2.1 KiB
C

/*
* jchuff.h
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1997, Thomas G. Lane.
* libjpeg-turbo Modifications:
* Copyright (C) 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
* Copyright (C) 2014, Mozilla Corporation.
*
* 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.
*/
/* The progressive Huffman encoder uses an unsigned 16-bit data type to store
* absolute values of coefficients, because it is possible to inject a
* coefficient value of -32768 into the encoder by attempting to transform a
* malformed 12-bit JPEG image, and the absolute value of -32768 would overflow
* a signed 16-bit integer.
*/
typedef unsigned short UJCOEF;
/* 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) quantize_trellis
(j_compress_ptr cinfo, c_derived_tbl *dctbl, c_derived_tbl *actbl, JBLOCKROW coef_blocks, JBLOCKROW src, JDIMENSION num_blocks,
JQUANT_TBL * qtbl, double *norm_src, double *norm_coef, JCOEF *last_dc_val,
JBLOCKROW coef_blocks_above, JBLOCKROW src_above);
EXTERN(void) jpeg_gen_optimal_table(j_compress_ptr cinfo, JHUFF_TBL *htbl,
long freq[]);