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Clean up the lossless JPEG feature

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- Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the
  function so that it stores the lossless parameters directly in the Ss
  and Al fields of jpeg_compress_struct rather than using a scan script.

- Move the cjpeg -lossless switch into "Switches for advanced users".

- Document the libjpeg API and run-time features that are unavailable in
  lossless mode, and ensure that all parameters, functions, and switches
  related to unavailable features are ignored or generate errors in
  lossless mode.

- Defer any action that depends on whether lossless mode is enabled
  until jpeg_start_compress()/jpeg_start_decompress() is called.

- Document the purpose of the point transform value.

- "Codec" stands for coder/decoder, so it is a bit awkward to say
  "lossless compression codec" and "lossless decompression codec".
  Use "lossless compressor" and "lossless decompressor" instead.

- Restore backward API/ABI compatibility with libjpeg v6b:

  * Move the new 'lossless' field from the exposed jpeg_compress_struct
    and jpeg_decompress_struct structures into the opaque
    jpeg_comp_master and jpeg_decomp_master structures, and allocate the
    master structures in the body of jpeg_create_compress() and
    jpeg_create_decompress().

  * Remove the new 'process' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with the old
    'progressive_mode' field and the new 'lossless' field.

  * Remove the new 'data_unit' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with a locally-computed
    data unit variable.

  * Restore the names of macros and fields that refer to DCT blocks, and
    document that they have a different meaning in lossless mode.  (Most
    of them aren't very meaningful in lossless mode anyhow.)

  * Remove the new alloc_darray() method from jpeg_memory_mgr and
    replace it with an internal macro that wraps the alloc_sarray()
    method.

  * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into
    jpegint.h.

  * Remove the new 'codec' field from jpeg_compress_struct and
    jpeg_decompress_struct and instead reuse the existing internal
    coefficient control, forward/inverse DCT, and entropy
    encoding/decoding structures for lossless compression/decompression.

  * Repurpose existing error codes rather than introducing new ones.
    (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain,
    although JWRN_MUST_DOWNSCALE will probably be removed in
    libjpeg-turbo, since we have a different way of handling multiple
    data precisions.)

- Automatically enable lossless mode when a scan script with parameters
  that are only valid for lossless mode is detected, and document the
  use of scan scripts to generate lossless JPEG images.

- Move the sequential and shared Huffman routines back into jchuff.c and
  jdhuff.c, and document that those routines are shared with jclhuff.c
  and jdlhuff.c as well as with jcphuff.c and jdphuff.c.

- Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where
  it is used.

- Move the predictor and scaler code into jclossls.c and jdlossls.c.

- Streamline register usage in the [un]differencers (inspired by similar
  optimizations in the color [de]converters.)

- Restructure the logic in a few places to reduce duplicated code.

- Ensure that all lossless-specific code is guarded by
  C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can
  be built successfully if either or both of those macros is undefined.

- Remove all short forms of external names introduced by the lossless
  JPEG patch.  (These will not be needed by libjpeg-turbo, so there is
  no use cleaning them up.)

- Various wordsmithing, formatting, and punctuation tweaks

- Eliminate various compiler warnings.
This commit is contained in:
DRC
2022-11-08 15:01:18 -06:00
parent ec6e451d05
commit 217d1a75f5
67 changed files with 3171 additions and 3871 deletions
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134
jdinput.c
View File

@@ -2,9 +2,10 @@
* jdinput.c
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1998, Thomas G. Lane.
* Copyright (C) 1991-1997, Thomas G. Lane.
* Lossless JPEG Modifications:
* Copyright (C) 1999, Ken Murchison.
* Copyright (C) 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains input control logic for the JPEG decompressor.
@@ -44,19 +45,19 @@ initial_setup (j_decompress_ptr cinfo)
{
int ci;
jpeg_component_info *compptr;
int data_unit = cinfo->master->lossless ? 1 : DCTSIZE;
/* Make sure image isn't bigger than I can handle */
if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
(long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
if (cinfo->process == JPROC_LOSSLESS) {
if (cinfo->master->lossless) {
/* If precision > compiled-in value, we must downscale */
if (cinfo->data_precision > BITS_IN_JSAMPLE)
WARNMS2(cinfo, JWRN_MUST_DOWNSCALE,
cinfo->data_precision, BITS_IN_JSAMPLE);
}
else { /* Lossy processes */
} else {
/* For now, precision must match compiled-in value... */
if (cinfo->data_precision != BITS_IN_JSAMPLE)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
@@ -81,23 +82,23 @@ initial_setup (j_decompress_ptr cinfo)
compptr->v_samp_factor);
}
/* We initialize codec_data_unit and min_codec_data_unit to data_unit.
* In the full decompressor, this will be overridden by jdmaster.c;
/* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE in lossy
* mode. In the full decompressor, this will be overridden by jdmaster.c;
* but in the transcoder, jdmaster.c is not used, so we must do it here.
*/
cinfo->min_codec_data_unit = cinfo->data_unit;
cinfo->min_DCT_scaled_size = data_unit;
/* Compute dimensions of components */
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
compptr->codec_data_unit = cinfo->data_unit;
compptr->DCT_scaled_size = data_unit;
/* Size in data units */
compptr->width_in_data_units = (JDIMENSION)
compptr->width_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
(long) (cinfo->max_h_samp_factor * cinfo->data_unit));
compptr->height_in_data_units = (JDIMENSION)
(long) (cinfo->max_h_samp_factor * data_unit));
compptr->height_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
(long) (cinfo->max_v_samp_factor * cinfo->data_unit));
(long) (cinfo->max_v_samp_factor * data_unit));
/* downsampled_width and downsampled_height will also be overridden by
* jdmaster.c if we are doing full decompression. The transcoder library
* doesn't use these values, but the calling application might.
@@ -118,11 +119,10 @@ initial_setup (j_decompress_ptr cinfo)
/* Compute number of fully interleaved MCU rows. */
cinfo->total_iMCU_rows = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height,
(long) (cinfo->max_v_samp_factor*cinfo->data_unit));
(long) (cinfo->max_v_samp_factor*data_unit));
/* Decide whether file contains multiple scans */
if (cinfo->comps_in_scan < cinfo->num_components ||
cinfo->process == JPROC_PROGRESSIVE)
if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
cinfo->inputctl->has_multiple_scans = TRUE;
else
cinfo->inputctl->has_multiple_scans = FALSE;
@@ -136,31 +136,32 @@ per_scan_setup (j_decompress_ptr cinfo)
{
int ci, mcublks, tmp;
jpeg_component_info *compptr;
int data_unit = cinfo->master->lossless ? 1 : DCTSIZE;
if (cinfo->comps_in_scan == 1) {
/* Noninterleaved (single-component) scan */
compptr = cinfo->cur_comp_info[0];
/* Overall image size in MCUs */
cinfo->MCUs_per_row = compptr->width_in_data_units;
cinfo->MCU_rows_in_scan = compptr->height_in_data_units;
cinfo->MCUs_per_row = compptr->width_in_blocks;
cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
/* For noninterleaved scan, always one data unit per MCU */
compptr->MCU_width = 1;
compptr->MCU_height = 1;
compptr->MCU_data_units = 1;
compptr->MCU_sample_width = compptr->codec_data_unit;
compptr->MCU_blocks = 1;
compptr->MCU_sample_width = compptr->DCT_scaled_size;
compptr->last_col_width = 1;
/* For noninterleaved scans, it is convenient to define last_row_height
* as the number of data unit rows present in the last iMCU row.
*/
tmp = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
if (tmp == 0) tmp = compptr->v_samp_factor;
compptr->last_row_height = tmp;
/* Prepare array describing MCU composition */
cinfo->data_units_in_MCU = 1;
cinfo->blocks_in_MCU = 1;
cinfo->MCU_membership[0] = 0;
} else {
@@ -173,33 +174,33 @@ per_scan_setup (j_decompress_ptr cinfo)
/* Overall image size in MCUs */
cinfo->MCUs_per_row = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width,
(long) (cinfo->max_h_samp_factor*cinfo->data_unit));
(long) (cinfo->max_h_samp_factor*data_unit));
cinfo->MCU_rows_in_scan = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height,
(long) (cinfo->max_v_samp_factor*cinfo->data_unit));
(long) (cinfo->max_v_samp_factor*data_unit));
cinfo->data_units_in_MCU = 0;
cinfo->blocks_in_MCU = 0;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* Sampling factors give # of data units of component in each MCU */
compptr->MCU_width = compptr->h_samp_factor;
compptr->MCU_height = compptr->v_samp_factor;
compptr->MCU_data_units = compptr->MCU_width * compptr->MCU_height;
compptr->MCU_sample_width = compptr->MCU_width * compptr->codec_data_unit;
compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_scaled_size;
/* Figure number of non-dummy data units in last MCU column & row */
tmp = (int) (compptr->width_in_data_units % compptr->MCU_width);
tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
if (tmp == 0) tmp = compptr->MCU_width;
compptr->last_col_width = tmp;
tmp = (int) (compptr->height_in_data_units % compptr->MCU_height);
tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
if (tmp == 0) tmp = compptr->MCU_height;
compptr->last_row_height = tmp;
/* Prepare array describing MCU composition */
mcublks = compptr->MCU_data_units;
if (cinfo->data_units_in_MCU + mcublks > D_MAX_DATA_UNITS_IN_MCU)
mcublks = compptr->MCU_blocks;
if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
while (mcublks-- > 0) {
cinfo->MCU_membership[cinfo->data_units_in_MCU++] = ci;
cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
}
}
@@ -207,6 +208,54 @@ per_scan_setup (j_decompress_ptr cinfo)
}
/*
* Save away a copy of the Q-table referenced by each component present
* in the current scan, unless already saved during a prior scan.
*
* In a multiple-scan JPEG file, the encoder could assign different components
* the same Q-table slot number, but change table definitions between scans
* so that each component uses a different Q-table. (The IJG encoder is not
* currently capable of doing this, but other encoders might.) Since we want
* to be able to dequantize all the components at the end of the file, this
* means that we have to save away the table actually used for each component.
* We do this by copying the table at the start of the first scan containing
* the component.
* The JPEG spec prohibits the encoder from changing the contents of a Q-table
* slot between scans of a component using that slot. If the encoder does so
* anyway, this decoder will simply use the Q-table values that were current
* at the start of the first scan for the component.
*
* The decompressor output side looks only at the saved quant tables,
* not at the current Q-table slots.
*/
LOCAL(void)
latch_quant_tables (j_decompress_ptr cinfo)
{
int ci, qtblno;
jpeg_component_info *compptr;
JQUANT_TBL * qtbl;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* No work if we already saved Q-table for this component */
if (compptr->quant_table != NULL)
continue;
/* Make sure specified quantization table is present */
qtblno = compptr->quant_tbl_no;
if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
cinfo->quant_tbl_ptrs[qtblno] == NULL)
ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
/* OK, save away the quantization table */
qtbl = (JQUANT_TBL *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(JQUANT_TBL));
MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
compptr->quant_table = qtbl;
}
}
/*
* Initialize the input modules to read a scan of compressed data.
* The first call to this is done by jdmaster.c after initializing
@@ -218,15 +267,18 @@ METHODDEF(void)
start_input_pass (j_decompress_ptr cinfo)
{
per_scan_setup(cinfo);
(*cinfo->codec->start_input_pass) (cinfo);
cinfo->inputctl->consume_input = cinfo->codec->consume_data;
if (! cinfo->master->lossless)
latch_quant_tables(cinfo);
(*cinfo->entropy->start_pass) (cinfo);
(*cinfo->coef->start_input_pass) (cinfo);
cinfo->inputctl->consume_input = cinfo->coef->consume_data;
}
/*
* Finish up after inputting a compressed-data scan.
* This is called by the coefficient controller after it's read all
* the expected data of the scan.
* This is called by the coefficient or difference controller after it's read
* all the expected data of the scan.
*/
METHODDEF(void)
@@ -242,8 +294,8 @@ finish_input_pass (j_decompress_ptr cinfo)
* Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
*
* The consume_input method pointer points either here or to the
* coefficient controller's consume_data routine, depending on whether
* we are reading a compressed data segment or inter-segment markers.
* coefficient or difference controller's consume_data routine, depending on
* whether we are reading a compressed data segment or inter-segment markers.
*/
METHODDEF(int)
@@ -261,12 +313,6 @@ consume_markers (j_decompress_ptr cinfo)
case JPEG_REACHED_SOS: /* Found SOS */
if (inputctl->inheaders) { /* 1st SOS */
initial_setup(cinfo);
/*
* Initialize the decompression codec. We need to do this here so that
* any codec-specific fields and function pointers are available to
* the rest of the library.
*/
jinit_d_codec(cinfo);
inputctl->inheaders = FALSE;
/* Note: start_input_pass must be called by jdmaster.c
* before any more input can be consumed. jdapimin.c is