kc3-lang/libjpeg-turbo/src/jdmainct.h

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• Hash : e69dd40c
  Author :
  Date : 2024-01-23T13:26:41
  

  Reorganize source to make things easier to find
  
  - Move all libjpeg documentation, except for README.ijg, into the doc/
    subdirectory.
  
  - Move the TurboJPEG C API documentation from doc/html/ into
    doc/turbojpeg/.
  
  - Move all C source code and headers into a src/ subdirectory.
  
  - Move turbojpeg-jni.c into the java/ subdirectory.
  
  Referring to #226, there is no ideal solution to this problem.  A
  semantically ideal solution would have involved placing all source code,
  including the SIMD and Java source code, under src/ (or perhaps placing
  C library source code under lib/ and C test program source code under
  test/), all header files under include/, and all documentation under
  doc/.  However:
  
  - To me it makes more sense to have separate top-level directories for
    each language, since the SIMD extensions and the Java API are
    technically optional features.  src/ now contains only the code that
    is relevant to the core C API libraries and associated programs.
  - I didn't want to bury the java/ and simd/ directories or add a level
    of depth to them, since both directories already contain source code
    that is 3-4 levels deep.
  - I would prefer not to separate the header files from the C source
    code, because:
    1. It would be disruptive.  libjpeg and libjpeg-turbo have
       historically placed C source code and headers in the same
       directory, and people who are familiar with both projects (self
       included) are used to looking for the headers in the same directory
       as the C source code.
    2. In terms of how the headers are used internally in libjpeg-turbo,
       the distinction between public and private headers is a bit fuzzy.
  - It didn't make sense to separate the test source code from the library
    source code, since there is not a clear distinction in some cases.
    (For instance, the IJG image I/O functions are used by cjpeg and djpeg
    as well as by the TurboJPEG API.)
  
  This solution is minimally disruptive, since it keeps all C source code
  and headers together and keeps java/ and simd/ as top-level directories.
  It is a bit awkward, because java/ and simd/ technically contain source
  code, even though they are not under src/.  However, other solutions
  would have been more awkward for different reasons.
  
  Closes #226
  

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• src/jdmainct.h

• /*
   * jdmainct.h
   *
   * This file was part of the Independent JPEG Group's software:
   * Copyright (C) 1994-1996, Thomas G. Lane.
   * libjpeg-turbo Modifications:
   * Copyright (C) 2022, D. R. Commander.
   * For conditions of distribution and use, see the accompanying README.ijg
   * file.
   */
  
  #define JPEG_INTERNALS
  #include "jpeglib.h"
  #include "jpegapicomp.h"
  #include "jsamplecomp.h"
  
  
  #if BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED)
  
  /* Private buffer controller object */
  
  typedef struct {
    struct jpeg_d_main_controller pub; /* public fields */
  
    /* Pointer to allocated workspace (M or M+2 row groups). */
    _JSAMPARRAY buffer[MAX_COMPONENTS];
  
    boolean buffer_full;          /* Have we gotten an iMCU row from decoder? */
    JDIMENSION rowgroup_ctr;      /* counts row groups output to postprocessor */
  
    /* Remaining fields are only used in the context case. */
  
    /* These are the master pointers to the funny-order pointer lists. */
    _JSAMPIMAGE xbuffer[2];       /* pointers to weird pointer lists */
  
    int whichptr;                 /* indicates which pointer set is now in use */
    int context_state;            /* process_data state machine status */
    JDIMENSION rowgroups_avail;   /* row groups available to postprocessor */
    JDIMENSION iMCU_row_ctr;      /* counts iMCU rows to detect image top/bot */
  } my_main_controller;
  
  typedef my_main_controller *my_main_ptr;
  
  
  /* context_state values: */
  #define CTX_PREPARE_FOR_IMCU    0       /* need to prepare for MCU row */
  #define CTX_PROCESS_IMCU        1       /* feeding iMCU to postprocessor */
  #define CTX_POSTPONED_ROW       2       /* feeding postponed row group */
  
  
  LOCAL(void)
  set_wraparound_pointers(j_decompress_ptr cinfo)
  /* Set up the "wraparound" pointers at top and bottom of the pointer lists.
   * This changes the pointer list state from top-of-image to the normal state.
   */
  {
    my_main_ptr main_ptr = (my_main_ptr)cinfo->main;
    int ci, i, rgroup;
    int M = cinfo->_min_DCT_scaled_size;
    jpeg_component_info *compptr;
    _JSAMPARRAY xbuf0, xbuf1;
  
    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         ci++, compptr++) {
      rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
        cinfo->_min_DCT_scaled_size; /* height of a row group of component */
      xbuf0 = main_ptr->xbuffer[0][ci];
      xbuf1 = main_ptr->xbuffer[1][ci];
      for (i = 0; i < rgroup; i++) {
        xbuf0[i - rgroup] = xbuf0[rgroup * (M + 1) + i];
        xbuf1[i - rgroup] = xbuf1[rgroup * (M + 1) + i];
        xbuf0[rgroup * (M + 2) + i] = xbuf0[i];
        xbuf1[rgroup * (M + 2) + i] = xbuf1[i];
      }
    }
  }
  
  #endif /* BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) */
  

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