fpc/packages/pasjpeg/examples/rdswitch.pas

Unit RdSwitch;

{ This file contains routines to process some of cjpeg's more complicated
  command-line switches.  Switches processed here are:
        -qtables file           Read quantization tables from text file
        -scans file             Read scan script from text file
        -qslots N[,N,...]       Set component quantization table selectors
        -sample HxV[,HxV,...]   Set component sampling factors  }

{ Original: rdswitch.c ; Copyright (C) 1991-1996, Thomas G. Lane.   }


interface

{$I jconfig.inc}

uses
  cdjpeg,               { Common decls for cjpeg/djpeg applications }
  {ctype,}              { to declare isdigit(), isspace() }
  jinclude,
  jmorecfg,
  jcparam,
  jpeglib;

{GLOBAL}
function set_quant_slots (cinfo : j_compress_ptr; argtxt : string) : boolean;
{ Process a quantization-table-selectors parameter string, of the form
      N[,N,...]
  If there are more components than parameters, the last value is re0licated.
 }


{GLOBAL}
function set_sample_factors (cinfo : j_compress_ptr;
                             argtxt : string) : boolean;
{ Process a sample-factors parameter string, of the form
      HxV[,HxV,...]
  If there are more components than parameters, "1x1" is assumed for the rest.
 }

{GLOBAL}
function read_quant_tables (cinfo : j_compress_ptr;
                            const filename : string;
                            scale_factor : int;
                            force_baseline : boolean) : boolean;

{ Read a set of quantization tables from the specified file.
  The file is plain ASCII text: decimal numbers with whitespace between.
  Comments preceded by '#' may be included in the file.
  There may be one to NUM_QUANT_TBLS tables in the file, each of 64 values.
  The tables are implicitly numbered 0,1,etc.
  NOTE: does not affect the qslots mapping, which will default to selecting
  table 0 for luminance (or primary) components, 1 for chrominance components.
  You must use -qslots if you want a different component->table mapping. }

{GLOBAL}
function read_scan_script (cinfo : j_compress_ptr;
                           const filename : string) : boolean;
{ Read a scan script from the specified text file.
  Each entry in the file defines one scan to be emitted.
  Entries are separated by semicolons ';'.
  An entry contains one to four component indexes,
  optionally followed by a colon ':' and four progressive-JPEG parameters.
  The component indexes denote which component(s) are to be transmitted
  in the current scan.  The first component has index 0.
  Sequential JPEG is used if the progressive-JPEG parameters are omitted.
  The file is free format text: any whitespace may appear between numbers
  and the ':' and ';' punctuation marks.  Also, other punctuation (such
  as commas or dashes) can be placed between numbers if desired.
  Comments preceded by '#' may be included in the file.
  Note: we do very little validity checking here;
  jcmaster.c will validate the script parameters. }

implementation

uses
  fcache;

const
  BLANK = ' ';
  TAB = ^I; { #9 }
  CR = #13; { ^M }
  LF = #10; { }

{LOCAL}
function text_getc (var fc : Cache) : char;
{ Read next char, skipping over any comments (# to end of line) }
{ A comment/newline sequence is returned as a newline }
var
  ch : char; {register }
begin
  ch := char(fc_GetC(fc));
  if (ch = '#') then
  repeat
    ch := char(fc_GetC(fc));
  Until (ch = #13) or (ch = EOF);
  text_getc := ch;
end;

{LOCAL}
function read_text_integer (var f : Cache;
                            var outval : long;
                            var termchar : char) : boolean;
{ Read an unsigned decimal integer from a file, store it in outval }
{ Reads one trailing character after the integer; returns it in termchar }
var
  {register} ch : char;
  {register} val : long;
begin
  { Skip any leading whitespace, detect EOF }
  repeat
    ch := text_getc(f);
    if (ch = EOF) then
    begin
      termchar := EOF;
      read_text_integer := FALSE;
      exit;
    end;
  Until (ch <> BLANK) and (ch <> TAB) and (ch <> CR) and (ch <> LF);

  if not (ch in ['0'..'9']) then
  begin
    termchar := ch;
    read_text_integer := FALSE;
    exit;
  end;

  val := ord(ch) - ord('0');
  repeat
    ch := text_getc(f);
    if (ch <> EOF) then
    begin
      if not (ch in ['0'..'9']) then
        break;
      val := val * 10;
      Inc(val, ord(ch) - ord('0'));
    end;
  until ch = EOF;
  outval := val;
  termchar := ch;
  read_text_integer := TRUE;
end;

{GLOBAL}
function read_quant_tables (cinfo : j_compress_ptr;
                            const filename : string;
                            scale_factor : int;
                            force_baseline : boolean) : boolean;
{ Read a set of quantization tables from the specified file.
  The file is plain ASCII text: decimal numbers with whitespace between.
  Comments preceded by '#' may be included in the file.
  There may be one to NUM_QUANT_TBLS tables in the file, each of 64 values.
  The tables are implicitly numbered 0,1,etc.
  NOTE: does not affect the qslots mapping, which will default to selecting
  table 0 for luminance (or primary) components, 1 for chrominance components.
  You must use -qslots if you want a different component->table mapping. }
var
  f : file;
  fp : Cache;
  tblno, i : int;
  termchar : char;
  val : long;
  table : array[0..DCTSIZE2-1] of uInt;
begin
  Assign(f, filename);
  {$push}{$I-}
  Reset(f, 1);
  {$pop}
  if (IOresult <> 0) then
  begin
    WriteLn(output, 'Can''t open table file ', filename);
    read_quant_tables := FALSE;
    exit;
  end;
  fc_Init(fp, f, 0);

  tblno := 0;

  while (read_text_integer(fp, val, termchar)) do
  begin { read 1st element of table }
    if (tblno >= NUM_QUANT_TBLS) then
    begin
      WriteLn(output, 'Too many tables in file ', filename);
      fc_close(fp);
      read_quant_tables := FALSE;
      exit;
    end;
    table[0] := uInt (val);
    for i := 1 to pred(DCTSIZE2) do
    begin
      if (not read_text_integer(fp, val, termchar)) then
      begin
        WriteLn(output, 'Invalid table data in file ', filename);
        fc_close(fp);
        read_quant_tables := FALSE;
        exit;
      end;
      table[i] := uInt (val);
    end;
    jpeg_add_quant_table(cinfo, tblno, table, scale_factor, force_baseline);
    Inc(tblno);
  end;

  if (termchar <> EOF) then
  begin
    WriteLn(output, 'Non-numeric data in file ', filename);
    fc_close(fp);
    read_quant_tables := FALSE;
    exit;
  end;

  fc_close(fp);
  read_quant_tables := TRUE;
end;


{$ifdef C_MULTISCAN_FILES_SUPPORTED}

{LOCAL}
function read_scan_integer (var f : cache;
                            var outval : long;
                            var termchar : char) : boolean;
{ Variant of read_text_integer that always looks for a non-space termchar;
  this simplifies parsing of punctuation in scan scripts. }
var
  ch : char; { register }
begin
  if not read_text_integer(f, outval, termchar) then
  begin
    read_scan_integer := FALSE;
    exit;
  end;
  ch := termchar;
  while (ch <> EOF) and (ch in [BLANK, TAB]) do
    ch := text_getc(f);
  if (ch in ['0'..'9']) then
  begin         { oops, put it back }
    if fc_ungetc(f, ch) = Byte(EOF) then
    begin
      read_scan_integer := FALSE;
      exit;
    end;
    ch := BLANK;
  end
  else
  begin
    { Any separators other than ';' and ':' are ignored;
      this allows user to insert commas, etc, if desired. }

    if (ch <> EOF) and (ch <> ';') and (ch <> ':') then
      ch := BLANK;
  end;
  termchar := ch;
  read_scan_integer := TRUE;
end;


{GLOBAL}
function read_scan_script (cinfo : j_compress_ptr;
                           const filename : string) : boolean;
{ Read a scan script from the specified text file.
  Each entry in the file defines one scan to be emitted.
  Entries are separated by semicolons ';'.
  An entry contains one to four component indexes,
  optionally followed by a colon ':' and four progressive-JPEG parameters.
  The component indexes denote which component(s) are to be transmitted
  in the current scan.  The first component has index 0.
  Sequential JPEG is used if the progressive-JPEG parameters are omitted.
  The file is free format text: any whitespace may appear between numbers
  and the ':' and ';' punctuation marks.  Also, other punctuation (such
  as commas or dashes) can be placed between numbers if desired.
  Comments preceded by '#' may be included in the file.
  Note: we do very little validity checking here;
  jcmaster.c will validate the script parameters. }
label
  bogus;
var
  f : file;
  fp : Cache;
  scanno, ncomps : int;
  termchar : char;
  val : long;
  scanptr : jpeg_scan_info_ptr;
const
  MAX_SCANS = 100;              { quite arbitrary limit }
var
  scans : array[0..MAX_SCANS-1] of jpeg_scan_info;
begin
  Assign(f,filename);
  {$push}{$I-}
  Reset(f, 1);
  {$pop}
  if (IOresult <> 0) then
  begin
    WriteLn('Can''t open scan definition file ', filename);
    read_scan_script := FALSE;
    exit;
  end;
  fc_Init(fp, f, 0);
  scanptr := @scans[0];
  scanno := 0;

  while (read_scan_integer(fp, val, termchar)) do
  begin
    if (scanno >= MAX_SCANS) then
    begin
      WriteLn(output, 'Too many scans defined in file ', filename);
      fc_Close(fp);
      read_scan_script := FALSE;
      exit;
    end;
    scanptr^.component_index[0] := int(val);
    ncomps := 1;
    while (termchar = BLANK) do
    begin
      if (ncomps >= MAX_COMPS_IN_SCAN) then
      begin
        WriteLn(output, 'Too many components in one scan in file ',
                filename);
        fc_close(fp);
        read_scan_script := FALSE;
        exit;
      end;
      if (not read_scan_integer(fp, val, termchar)) then
        goto bogus;
      scanptr^.component_index[ncomps] := int (val);
      Inc(ncomps);
    end;
    scanptr^.comps_in_scan := ncomps;
    if (termchar = ':') then
    begin
      if (not read_scan_integer(fp, val, termchar)) or (termchar <> BLANK) then
        goto bogus;
      scanptr^.Ss := int (val);
      if (not read_scan_integer(fp, val, termchar)) or (termchar <> BLANK) then
        goto bogus;
      scanptr^.Se := int (val);
      if (not read_scan_integer(fp, val, termchar)) or (termchar <> BLANK) then
        goto bogus;
      scanptr^.Ah := int (val);
      if (not read_scan_integer(fp, val, termchar)) then
        goto bogus;
      scanptr^.Al := int (val);
    end
    else
    begin
      { set non-progressive parameters }
      scanptr^.Ss := 0;
      scanptr^.Se := DCTSIZE2-1;
      scanptr^.Ah := 0;
      scanptr^.Al := 0;
    end;
    if (termchar <> ';') and (termchar <> EOF) then
    begin
bogus:
      WriteLn(output, 'Invalid scan entry format in file ', filename);
      fc_close(fp);
      read_scan_script := FALSE;
      exit;
    end;
    Inc(scanptr);
    Inc(scanno);
  end;

  if (termchar <> EOF) then
  begin
    WriteLn(output, 'Non-numeric data in file ', filename);
    fc_close(fp);
    read_scan_script := FALSE;
    exit;
  end;

  if (scanno > 0) then
  begin
    { Stash completed scan list in cinfo structure.
      NOTE: for cjpeg's use, JPOOL_IMAGE is the right lifetime for this data,
      but if you want to compress multiple images you'd want JPOOL_PERMANENT. }
    scanptr := jpeg_scan_info_ptr (
       cinfo^.mem^.alloc_small ( j_common_ptr(cinfo), JPOOL_IMAGE,
                                  scanno * SIZEOF(jpeg_scan_info)) );
    MEMCOPY(scanptr, @scans, scanno * SIZEOF(jpeg_scan_info));
    cinfo^.scan_info := scanptr;
    cinfo^.num_scans := scanno;
  end;

  fc_close(fp);
  read_scan_script := TRUE;
end;

{$endif} { C_MULTISCAN_FILES_SUPPORTED }

function sscanf(var lineptr : PChar;
                var val : int;
                var ch : char) : boolean;
var
  digits : int;
begin
  digits := 0;
  while (lineptr^=BLANK) do { advance to next segment of the string }
    Inc(lineptr);
  val := 0;
  while lineptr^ in ['0'..'9'] do
  begin
    val := val * 10 + (ord(lineptr^) - ord('0'));
    Inc(lineptr);
    Inc(digits);
  end;
  if lineptr^<>#0 then
  begin
    ch := lineptr^;
    Inc(lineptr);
  end;
  sscanf := (digits > 0);
end;

{GLOBAL}
function set_quant_slots (cinfo : j_compress_ptr;
                          argtxt : string) : boolean;
{ Process a quantization-table-selectors parameter string, of the form
      N[,N,...]
  If there are more components than parameters, the last value is replicated.
 }
var
  val : int;    { default table # }
  ci : int;
  ch : char;
var
  arg_copy : string;
  arg : PChar;
begin
  arg_copy := argtxt + #0;
  if arg_copy[Length(arg_copy)] <> #0 then
    arg_copy[Length(arg_copy)] := #0;
  arg := @arg_copy[1];
  val := 0;
  for ci := 0 to pred(MAX_COMPONENTS) do
  begin
    if (arg^ <> #0) then
    begin
      ch := ',';                { if not set by sscanf, will be ',' }
      if not sscanf(arg, val, ch) then
      begin
        set_quant_slots := FALSE;
        exit;
      end;
      if (ch <> ',') then       { syntax check }
      begin
        set_quant_slots := FALSE;
        exit;
      end;
      if (val < 0) or (val >= NUM_QUANT_TBLS) then
      begin
        WriteLn(output, 'JPEG quantization tables are numbered 0..',
                NUM_QUANT_TBLS-1);
        set_quant_slots := FALSE;
        exit;
      end;
      cinfo^.comp_info^[ci].quant_tbl_no := val;
    end
    else
    begin
      { reached end of parameter, set remaining components to last table }
      cinfo^.comp_info^[ci].quant_tbl_no := val;
    end;
  end;
  set_quant_slots := TRUE;
end;


{GLOBAL}
function set_sample_factors (cinfo : j_compress_ptr;
                             argtxt : string) : boolean;
{ Process a sample-factors parameter string, of the form
      HxV[,HxV,...]
  If there are more components than parameters, "1x1" is assumed for the rest.
 }
var
  ci, val1, val2 : int;
  ch1, ch2 : char;
var
  arg_copy : string;
  arg : PChar;
begin
  arg_copy := argtxt + #0;
  if arg_copy[Length(arg_copy)] <> #0 then
    arg_copy[Length(arg_copy)] := #0;
  arg := @arg_copy[1];
  for ci := 0 to pred(MAX_COMPONENTS) do
  begin
    if (arg^ <> #0) then
    begin
      ch2 := ',';               { if not set by sscanf, will be ',' }
      if not (sscanf(arg, val1, ch1) and
              sscanf(arg, val2, ch2)) then
      begin
        set_sample_factors := FALSE;
        exit;
      end;
      if ((ch1 <> 'x') and (ch1 <> 'X')) or (ch2 <> ',') then { syntax check }
      begin
        set_sample_factors := FALSE;
        exit;
      end;
      if (val1 <= 0) or (val1 > 4) or (val2 <= 0) or (val2 > 4) then
      begin
        WriteLn(output, 'JPEG sampling factors must be 1..4');
        set_sample_factors := FALSE;
        exit;
      end;
      cinfo^.comp_info^[ci].h_samp_factor := val1;
      cinfo^.comp_info^[ci].v_samp_factor := val2;
    end
    else
    begin
      { reached end of parameter, set remaining components to 1x1 sampling }
      cinfo^.comp_info^[ci].h_samp_factor := 1;
      cinfo^.comp_info^[ci].v_samp_factor := 1;
    end;
  end;
  set_sample_factors := TRUE;
end;

end.