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https://gitlab.com/freepascal.org/lazarus/lazarus.git
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LazUtils: Improve THTML2TextRenderer class. Add property LineEndMark.
git-svn-id: trunk@55325 -
This commit is contained in:
juha
parent
7252c9bfd0
commit
1afa4599a9
@ -31,39 +31,42 @@ type
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private
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fHTML, fOutput: string;
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fMaxLines: integer;
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fInHeader: Boolean;
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fLineEndMark: String;
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fInHeader, fInDivTitle: Boolean;
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fPendingSpace: Boolean;
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fPendingNewLineCnt: Integer;
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fCurTag: String;
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fIndent: integer;
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fLineCnt, fHtmlLen: Integer;
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p: Integer;
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procedure AddNewLine;
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procedure AddOneNewLine;
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function AddOutput(aText: String): Boolean;
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function AddOutput(const aText: String): Boolean; overload;
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function HtmlTag: Boolean;
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procedure HtmlEntity;
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function HtmlEntity: Boolean;
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procedure Reset;
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public
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constructor Create(aHTML: string);
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constructor Create(Stream: TStream);
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constructor Create(const aHTML: string);
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constructor Create(const Stream: TStream);
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destructor Destroy; override;
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function Render(aMaxLines: integer = MaxInt): string;
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public
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property LineEndMark: String read fLineEndMark write fLineEndMark;
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end;
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implementation
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{ THTML2TextRenderer }
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constructor THTML2TextRenderer.Create(aHTML: string);
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constructor THTML2TextRenderer.Create(const aHTML: string);
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begin
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fHTML:=aHTML;
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// remove UTF8 BOM
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if copy(fHTML,1,3)=UTF8BOM then
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delete(fHTML,1,3);
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fLineEndMark:=LineEnding; // Can be changed by user later.
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end;
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constructor THTML2TextRenderer.Create(Stream: TStream);
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constructor THTML2TextRenderer.Create(const Stream: TStream);
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var
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s: string;
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begin
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@ -100,7 +103,7 @@ begin
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fPendingNewLineCnt:=1;
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end;
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function THTML2TextRenderer.AddOutput(aText: String): Boolean;
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function THTML2TextRenderer.AddOutput(const aText: String): Boolean;
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var
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i: Integer;
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begin
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@ -110,12 +113,12 @@ begin
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fPendingSpace:=False;
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for i:=0 to fPendingNewLineCnt-1 do
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begin
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fOutput:=fOutput+LineEnding;
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fOutput:=fOutput+fLineEndMark;
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Inc(fLineCnt);
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// Return False if max # of lines exceeded.
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if fLineCnt>fMaxLines then
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begin
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fOutput:=fOutput+LineEnding+'...';
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fOutput:=fOutput+fLineEndMark+'...';
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Exit(False);
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end;
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end;
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@ -129,44 +132,73 @@ end;
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function THTML2TextRenderer.HtmlTag: Boolean;
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// separate a html tag and use it for layout. '<' is already found here.
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// ToDo: parse <div class="title"> and use it.
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var
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Start: Integer;
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Tag, AttrName, AttrValue: String;
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begin
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// first separate a html tag.
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inc(p);
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// separate HTML tag itself.
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Start:=p;
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if (p<=fHtmlLen) and (fHTML[p]='/') then
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inc(p);
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while (p<=fHtmlLen) and not (fHTML[p] in [' ','>','"','/',#9,#10,#13]) do
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inc(p);
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fCurTag:=UpperCase(copy(fHTML,Start,p-Start));
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Tag:=UpperCase(copy(fHTML,Start,p-Start));
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while p<=fHtmlLen do
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begin
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if fHTML[p]='"' then begin // skip attribute "value" inside tag
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// Attribute name
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if fHTML[p]=' ' then
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begin
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inc(p);
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Start:=p;
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while (p<=fHtmlLen) and not (fHTML[p] in [' ','>','=',#9,#10,#13]) do
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inc(p);
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if p>fHtmlLen then break;
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if fHTML[p]='=' then
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AttrName:=UpperCase(copy(fHTML,Start,p-Start));
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end;
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// Attribute "value"
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if fHTML[p]='"' then
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begin
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inc(p);
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Start:=p;
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while (p<=fHtmlLen) and (fHTML[p]<>'"') do
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inc(p);
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if p>fHtmlLen then break;
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AttrValue:=UpperCase(copy(fHTML,Start,p-Start));
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end;
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inc(p);
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if (fHTML[p-1]='>') then break; // end of tag
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end;
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// adjust layout based on html tag, then remove it
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// adjust layout based on HTML tag, then remove it
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Result:=True;
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case fCurTag of
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case Tag of
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'HTML':
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fInHeader:=True; // it's a whole page
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'BODY':
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Reset; // start of body => ignore header and all its data
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'P', '/P', 'BR', '/UL':
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AddNewLine;
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'DIV': begin
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AddOneNewLine;
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'DIV':
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begin
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fInDivTitle:=(AttrName='CLASS') and (AttrValue='TITLE');
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if fInDivTitle then
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begin
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AddNewLine;
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Result:=AddOutput('🔹');
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end
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else
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AddOneNewLine;
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Inc(fIndent);
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end;
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'/DIV': begin
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'/DIV':
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begin
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if fInDivTitle then
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begin
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Result:=AddOutput('🔹');
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fInDivTitle:=False;
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end;
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AddOneNewLine;
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Dec(fIndent);
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end;
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@ -175,12 +207,14 @@ begin
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Inc(fIndent);
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// Don't leave empty lines before list item (not sure if this is good)
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AddOneNewLine;
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Result:=AddOutput('* '); // Can return False if MaxLines was exceeded
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Result:=AddOutput('* ');
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end;
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'/LI':
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Dec(fIndent);
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'A', '/A': // Link
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Result:=AddOutput(' _ ');
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'A': // Link
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Result:=AddOutput(' 👀');
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'/A':
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Result:=AddOutput('👀 ');
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'HR':
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begin
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AddOneNewLine;
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@ -190,34 +224,43 @@ begin
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end;
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end;
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procedure THTML2TextRenderer.HtmlEntity;
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// entities: < > &
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function THTML2TextRenderer.HtmlEntity: Boolean;
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// entities: < > & '&' is found already here
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const
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EntityMap: array[0..3] of array[0..1] of String = (
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('lt;', '<'),
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('gt;', '>'),
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('nbsp;', ' '),
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('amp;', '&')
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);
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var
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Ent: String;
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i, j: Integer;
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begin
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if (p+2<fHtmlLen) and (fHTML[p+1]='l') and (fHTML[p+2]='t') and (fHTML[p+3]=';') then
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Inc(p);
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for i:=Low(EntityMap) to High(EntityMap) do
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begin
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Inc(p,4);
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AddOutput('<');
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end else
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if (p+2<fHtmlLen) and (fHTML[p+1]='g') and (fHTML[p+2]='t') and (fHTML[p+3]=';') then
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begin
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Inc(p,4);
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AddOutput('>');
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end else
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if (p+4<fHtmlLen) and (fHTML[p+1]='n') and (fHTML[p+2]='b') and (fHTML[p+3]='s') and (fHTML[p+4]='p') and (fHTML[p+5]=';') then
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begin
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Inc(p,6);
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AddOutput(' ');
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end else
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if (p+3<fHtmlLen) and (fHTML[p+1]='a') and (fHTML[p+2]='m') and (fHTML[p+3]='p') and (fHTML[p+4]=';') then
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begin
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Inc(p,5);
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AddOutput('&');
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Ent:=EntityMap[i][0];
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if (p+Length(Ent) >= fHtmlLen) then Break;
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j:=0;
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while j<Length(Ent) do
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begin
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if Ent[j+1] <> fHTML[p+j] then Break; // No match -> move to next entity.
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Inc(j);
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end;
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if j=Length(Ent) then
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begin
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Inc(p,Length(Ent));
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Exit(AddOutput(EntityMap[i][1])); // Match!
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end;
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end;
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Result:=AddOutput('&'); // Entity not found, add just '&'.
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end;
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function THTML2TextRenderer.Render(aMaxLines: integer): string;
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// Parse the HTML and render to plain text.
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// Output is limited to aMaxLines lines.
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// Note: AddOutput, HtmlTag and HtmlEntity return False if MaxLines was exceeded.
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var
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OkToGo: Boolean;
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begin
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@ -230,7 +273,7 @@ begin
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begin
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case fHTML[p] of
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'<': OkToGo:=HtmlTag; // Can return False if MaxLines was exceeded.
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'&': HtmlEntity;
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'&': OkToGo:=HtmlEntity;
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' ',#9,#10,#13: // WhiteSpace
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begin
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fPendingSpace:=True;
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@ -238,7 +281,7 @@ begin
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end;
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else
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begin
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AddOutput(fHTML[p]); // Add text verbatim.
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OkToGo:=AddOutput(fHTML[p]); // Add text verbatim.
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inc(p);
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end;
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end;
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