180 lines
6.9 KiB
C++
180 lines
6.9 KiB
C++
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// +-------------------------------------------------------------------------+
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// | StreamFilters library vers. 0.2.03 |
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// | Copyright (c) Andrey V. Stolyarov <croco at croco dot net> 2022-2025 |
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// | ----------------------------------------------------------------------- |
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// | This is free software. Permission is granted to everyone to use, copy |
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// | or modify this software under the terms and conditions of |
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// | GNU LESSER GENERAL PUBLIC LICENSE, v. 2.1 |
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// | as published by Free Software Foundation (see the file LGPL.txt) |
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// | |
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// | Please visit http://www.croco.net/software/stfilter to get a fresh copy |
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// | ----------------------------------------------------------------------- |
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// | This code is provided strictly and exclusively on the "AS IS" basis. |
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// | !!! THERE IS NO WARRANTY OF ANY KIND, NEITHER EXPRESSED NOR IMPLIED !!! |
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// +-------------------------------------------------------------------------+
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#ifndef STFHTML_HPP_SENTRY
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#define STFHTML_HPP_SENTRY
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#include "stfilter.hpp"
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#include "stfencod.hpp"
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//! Filter off HTML tags that aren't explicitly allowed
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class StreamFilterHtmlTags : public StreamFilter {
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const char * const * names;
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const char * const * attrs;
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const char * const * pre_tags;
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enum {
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start, just_started_tag, unnamed_tag, tag_name,
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allowed_tag,
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altag_attrname, altag_expect_eq, altag_expect_val,
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altag_badattr, altag_goodattr, altag_slashclose,
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prohibited_tag,
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comment_in_excl, /* seen ``<!'' */
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comment_in_dash, /* seen ``<!-'' */
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comment, /* inside the comment */
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comment_out_dash, /* seen ``-'' */
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comment_out_dash2 /* seen ``--'' */
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};
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enum { unquoted, single_quoted, double_quoted };
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char astate, qstate; // astate <- start... ; qstate <- unquoted...
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bool negtag;
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/* qstate can only become anything other than unquoted within the
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tags AND when the tag name is known, that is, in allowed_tag,
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altag_* and progibited_tag states;
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in case qstate!=unquoted, the astate is simply ignored until
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the matching quote is found and qstate is unquoted again
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*/
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StreamFilterBuffer namebuf, attrbuf;
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int pre_level;
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public:
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//! The constructor
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/*! \param both allowed_names and allowed_tags must be
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NULL-terminated arrays of string pointers;
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neither the arrays nor the strings are copied nor owned;
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make sure they exist all the time the object is in use,
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and that they don't change after the filtering is started
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(but it's ok to change them between the construction of the
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object and the first time the FeedChar method is called).
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This is because the object calculates the length of the
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longest name/attr and only stores that many chars of the analysed
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name/attr; if the name is longer, the tag is assumed prohibited.
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NULL means all tags/attrs are allowed (makes sense if we're going
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to call AddControlledNLReplacer so nothing will be filtered off
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but the object will still tell the NLReplacer where not to
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replace NLs); to prohibit all tags, pass a pointer to a NULL
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pointer (that is, an array of zero length, as opposite to NULL).
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Within the allowed_attrs array, a string containing no ``=''
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means this attr is allowed for any allowed tag, while a
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string of the form ``name=attr'' means the attr is only allowed
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for the particular tag, e.g., "img=src", "a=href"...
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*/
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StreamFilterHtmlTags(const char * const * allowed_names,
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const char * const * allowed_attrs,
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StreamFilter *next);
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~StreamFilterHtmlTags();
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void FeedChar(int c);
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void FeedEnd();
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void Reset();
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void AddControlledNLReplacer(const char * const *pre_tags, bool texstyle);
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private:
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void HandleStart(int c);
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void HandleJustStartedTag(int c);
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void HandleUnnamedTag(int c);
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void HandleTagName(int c);
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void HandleAllowedTag(int c);
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void HandleAltagAttrname(int c);
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void HandleAltagExpectEq(int c);
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void HandleAltagExpectVal(int c);
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void HandleAltagBadAttr(int c);
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void HandleAltagGoodAttr(int c);
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void HandleAltagSlashClose(int c);
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void HandleProhibitedTag(int c);
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void HandleCommentInExcl(int c);
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void HandleCommentInDash(int c);
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void HandleComment(int c);
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void HandleCommentOutDash(int c);
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void HandleCommentOutDash2(int c);
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void ProcessCharInsideSkippedTag(int c);
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bool CommitAttrName();
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void CloseAllowedTag();
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void NLModeBlock(bool b);
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void UpdateNLMode();
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};
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//! Turn NLs into paragraph breaks.
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/*! This filter can work in two modes, the default and the TeX-style.
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By default, it replaces a single NL with ``<br />'', and an empty
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line (that is, two NLs separated with nothing but spaces) with
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a new paragraph; actually, ``<p>'' is being placed in front of
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the first non-space char, the ``</p>\n'' is placed in the end of
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the stream, and for NLs, if there's the second one, ``</p>\n<p>''
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is transmitted, otherwise ``<br />'' is out. All subsequent
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NLs are ignored, as well as all whitespace beetween them.
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In TeX-style, only empty lines are taken into account, which
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effectively means no ``<br />''s are output, and for <p>/</p>
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the behaviour is the same.
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\note In case a '\r' (CR) char is encountered at least once,
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all the CRs are ignored, but a CR is transmitted in front of
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each NL.
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*/
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class StreamFilterHtmlReplaceNL : public StreamFilter {
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bool texstyle;
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enum { start, plain, after_single_nl, disabled };
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int state;
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int lead_spaces;
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bool blocked;
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bool out_cr;
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public:
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StreamFilterHtmlReplaceNL(bool texs, StreamFilter *next)
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: StreamFilter(next), texstyle(texs), state(start),
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blocked(false), out_cr(false) {}
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~StreamFilterHtmlReplaceNL() {}
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void FeedChar(int c);
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void FeedEnd();
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void Reset();
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void TagStart();
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void TagEnd();
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void Enable();
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void Disable();
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private:
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void XPutChar(int c);
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void PutNL(); //!< output [<CR>]<LF>
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void CommitSingleNL();
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};
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//! Replace <, > and & with HTML entites
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class StreamFilterHtmlProtect : public StreamFilter {
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public:
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StreamFilterHtmlProtect(StreamFilter *next)
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: StreamFilter(next) {}
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~StreamFilterHtmlProtect() {}
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void FeedChar(int c);
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};
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//! Decode utf8 replacing unknown chars with HTML entities
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class StreamFilterUtf8ToHtml : public StreamFilterUtf8ToExtAscii {
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public:
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StreamFilterUtf8ToHtml(const int * const *table, StreamFilter *next)
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: StreamFilterUtf8ToExtAscii(table, next) {}
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void UnknownCode(int code);
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};
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#endif
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