markdown.cpp

/******************************************************************************
 *
 * Copyright (C) 1997-2014 by Dimitri van Heesch.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation under the terms of the GNU General Public License is hereby 
 * granted. No representations are made about the suitability of this software 
 * for any purpose. It is provided "as is" without express or implied warranty.
 * See the GNU General Public License for more details.
 *
 * Documents produced by Doxygen are derivative works derived from the
 * input used in their production; they are not affected by this license.
 *
 */

/* Note: part of the code below is inspired by libupskirt written by 
 * Natacha Porté. Original copyright message follows:
 *
 * Copyright (c) 2008, Natacha Porté
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <qglobal.h>
#include <qregexp.h>
#include <qfileinfo.h>
#include <qdict.h>

#include "markdown.h"
#include "growbuf.h"
#include "debug.h"
#include "util.h"
#include "doxygen.h"
#include "commentscan.h"
#include "entry.h"
#include "bufstr.h"
#include "commentcnv.h"
#include "config.h"
#include "section.h"
#include "message.h"

//-----------

// is character at position i in data part of an identifier?
#define isIdChar(i) \
  ((data[i]>='a' && data[i]<='z') || \
   (data[i]>='A' && data[i]<='Z') || \
   (data[i]>='0' && data[i]<='9'))   \

// is character at position i in data allowed before an emphasis section
#define isOpenEmphChar(i) \
  (data[i]=='\n' || data[i]==' ' || data[i]=='\'' || data[i]=='<' || \
   data[i]=='{'  || data[i]=='(' || data[i]=='['  || data[i]==',' || \
   data[i]==':'  || data[i]==';')

// is character at position i in data an escape that prevents ending an emphasis section
// so for example *bla (*.txt) is cool*
#define ignoreCloseEmphChar(i) \
  (data[i]=='('  || data[i]=='{' || data[i]=='[' || data[i]=='<' || \
   data[i]=='='  || data[i]=='+' || data[i]=='-' || data[i]=='\\' || \
   data[i]=='@')

//----------

struct LinkRef
{
  LinkRef(const QCString &l,const QCString &t) : link(l), title(t) {}
  QCString link;
  QCString title;
};

typedef int (*action_t)(GrowBuf &out,const char *data,int offset,int size);

enum Alignment { AlignNone, AlignLeft, AlignCenter, AlignRight };


//----------

static QDict<LinkRef> g_linkRefs(257);
static action_t       g_actions[256];
static Entry         *g_current;
static QCString       g_fileName;
static int            g_lineNr;

// In case a markdown page starts with a level1 header, that header is used
// as a title of the page, in effect making it a level0 header, so the
// level of all other sections needs to be corrected as well.
// This flag is TRUE if corrections are needed.
//static bool           g_correctSectionLevel;


//----------

const int codeBlockIndent = 4;

static void processInline(GrowBuf &out,const char *data,int size);

// escape characters that have a special meaning later on.
static QCString escapeSpecialChars(const QCString &s)
{
  if (s.isEmpty()) return "";
  GrowBuf growBuf;
  const char *p=s;
  char c;
  while ((c=*p++))
  {
    switch (c)
    {
      case '<':  growBuf.addStr("\\<");   break;
      case '>':  growBuf.addStr("\\>");   break;
      case '\\': growBuf.addStr("\\\\");  break;
      case '@':  growBuf.addStr("\\@");   break;
      default:   growBuf.addChar(c);      break;
    }
  }
  growBuf.addChar(0);
  return growBuf.get();
}

static void convertStringFragment(QCString &result,const char *data,int size)
{
  if (size<0) size=0;
  result.resize(size+1);
  memcpy(result.data(),data,size);
  result.at(size)='\0';
}

/** helper function to convert presence of left and/or right alignment markers
 *  to a alignment value
 */
static Alignment markersToAlignment(bool leftMarker,bool rightMarker)
{
  //printf("markerToAlignment(%d,%d)\n",leftMarker,rightMarker);
  if (leftMarker && rightMarker)
  {
    return AlignCenter;
  }
  else if (leftMarker)
  {
    return AlignLeft;
  }
  else if (rightMarker)
  {
    return AlignRight;
  }
  else
  {
    return AlignNone;
  }
}


// Check if data contains a block command. If so returned the command
// that ends the block. If not an empty string is returned.
// Note When offset>0 character position -1 will be inspected.
//
// Checks for and skip the following block commands:
// {@code .. { .. } .. }
// \dot .. \enddot
// \code .. \endcode
// \msc .. \endmsc
// \f$..\f$
// \f[..\f]
// \f{..\f}
// \verbatim..\endverbatim
// \latexonly..\endlatexonly
// \htmlonly..\endhtmlonly
// \xmlonly..\endxmlonly
// \rtfonly..\endrtfonly
// \manonly..\endmanonly
static QCString isBlockCommand(const char *data,int offset,int size)
{
  bool openBracket = offset>0 && data[-1]=='{';
  bool isEscaped = offset>0 && (data[-1]=='\\' || data[-1]=='@');
  if (isEscaped) return QCString();

  int end=1;
  while (end<size && (data[end]>='a' && data[end]<='z')) end++;
  if (end==1) return QCString();
  QCString blockName;
  convertStringFragment(blockName,data+1,end-1);
  if (blockName=="code" && openBracket)
  {
    return "}";
  }
  else if (blockName=="dot"         || 
           blockName=="code"        || 
           blockName=="msc"         ||
           blockName=="verbatim"    || 
           blockName=="latexonly"   || 
           blockName=="htmlonly"    ||
           blockName=="xmlonly"     ||
           blockName=="rtfonly"     ||
           blockName=="manonly"     ||
           blockName=="docbookonly"
     )
  {
    return "end"+blockName;
  }
  else if (blockName=="startuml")
  {
    return "enduml";
  }
  else if (blockName=="f" && end<size)
  {
    if (data[end]=='$')
    {
      return "f$";
    }
    else if (data[end]=='[')
    {
      return "f]";
    }
    else if (data[end]=='}')
    {
      return "f}";
    }
  }
  return QCString();
}

/** looks for the next emph char, skipping other constructs, and
 *  stopping when either it is found, or we are at the end of a paragraph.
 */
static int findEmphasisChar(const char *data, int size, char c, int c_size)
{
  int i = 1;

  while (i<size)
  {
    while (i<size && data[i]!=c    && data[i]!='`' && 
                     data[i]!='\\' && data[i]!='@' &&
                     data[i]!='\n') i++;
    //printf("findEmphasisChar: data=[%s] i=%d c=%c\n",data,i,data[i]);

    // not counting escaped chars or characters that are unlikely 
    // to appear as the end of the emphasis char
    if (i>0 && ignoreCloseEmphChar(i-1))
    {
      i++;
      continue;
    }
    else
    {
      // get length of emphasis token
      int len = 0;
      while (i+len<size && data[i+len]==c)
      {
        len++;
      }

      if (len>0)
      {
        if (len!=c_size || (i<size-len && isIdChar(i+len))) // to prevent touching some_underscore_identifier
        {
          i=i+len;
          continue;
        }
        return i; // found it
      }
    }

    // skipping a code span
    if (data[i]=='`')
    {
      int snb=0;
      while (i<size && data[i]=='`') snb++,i++;

      // find same pattern to end the span
      int enb=0;
      while (i<size && enb<snb)
      {
        if (data[i]=='`') enb++;
        if (snb==1 && data[i]=='\'') break; // ` ended by '
        i++;
      }
    }
    else if (data[i]=='@' || data[i]=='\\')
    { // skip over blocks that should not be processed
      QCString endBlockName = isBlockCommand(data+i,i,size-i);
      if (!endBlockName.isEmpty())
      {
        i++;
        int l = endBlockName.length();
        while (i<size-l)
        {
          if ((data[i]=='\\' || data[i]=='@') && // command
              data[i-1]!='\\' && data[i-1]!='@') // not escaped
          {
            if (qstrncmp(&data[i+1],endBlockName,l)==0)
            {
              break;
            }
          }
          i++;
        }
      }
      else if (i<size-1 && isIdChar(i+1)) // @cmd, stop processing, see bug 690385
      {
        return 0;
      }
      else
      {
        i++;
      }
    }
    else if (data[i]=='\n') // end * or _ at paragraph boundary
    {
      i++;
      while (i<size && data[i]==' ') i++;
      if (i>=size || data[i]=='\n') return 0; // empty line -> paragraph
    }
    else // should not get here!
    {
      i++;
    }

  }
  return 0;
}

/** process single emphasis */
static int processEmphasis1(GrowBuf &out, const char *data, int size, char c)
{
  int i = 0, len;

  /* skipping one symbol if coming from emph3 */
  if (size>1 && data[0]==c && data[1]==c) { i=1; }

  while (i<size)
  {
    len = findEmphasisChar(data+i, size-i, c, 1);
    if (len==0) return 0; 
    i+=len;
    if (i>=size) return 0; 

    if (i+1<size && data[i+1]==c)
    {
      i++;
      continue;
    }
    if (data[i]==c && data[i-1]!=' ' && data[i-1]!='\n')
    {
      out.addStr("<em>");
      processInline(out,data,i);
      out.addStr("</em>");
      return i+1;
    }
  }
  return 0;
}

/** process double emphasis */
static int processEmphasis2(GrowBuf &out, const char *data, int size, char c)
{
  int i = 0, len;

  while (i<size)
  {
    len = findEmphasisChar(data+i, size-i, c, 2);
    if (len==0)
    {
      return 0;
    }
    i += len;
    if (i+1<size && data[i]==c && data[i+1]==c && i && data[i-1]!=' ' && 
        data[i-1]!='\n'
       )
    {
      out.addStr("<strong>");
      processInline(out,data,i);
      out.addStr("</strong>");
      return i + 2;
    }
    i++;
  }
  return 0;
}

/** Parsing tripple emphasis.
 *  Finds the first closing tag, and delegates to the other emph 
 */
static int processEmphasis3(GrowBuf &out, const char *data, int size, char c)
{
  int i = 0, len;

  while (i<size)
  {
    len = findEmphasisChar(data+i, size-i, c, 3);
    if (len==0)
    {
      return 0;
    }
    i+=len;

    /* skip whitespace preceded symbols */
    if (data[i]!=c || data[i-1]==' ' || data[i-1]=='\n')
    {
      continue;
    }

    if (i+2<size && data[i+1]==c && data[i+2]==c)
    {
      out.addStr("<em><strong>");
      processInline(out,data,i);
      out.addStr("</strong></em>");
      return i+3;
    }
    else if (i+1<size && data[i+1]==c)
    {
      // double symbol found, handing over to emph1
      len = processEmphasis1(out, data-2, size+2, c);
      if (len==0)
      {
        return 0;
      }
      else
      {
        return len - 2;
      }
    }
    else
    {
      // single symbol found, handing over to emph2
      len = processEmphasis2(out, data-1, size+1, c);
      if (len==0)
      {
        return 0;
      }
      else
      {
        return len - 1;
      }
    }
  }
  return 0;
}

/** Process ndash and mdashes */
static int processNmdash(GrowBuf &out,const char *data,int off,int size)
{
  // precondition: data[0]=='-'
  int i=1;
  int count=1;
  if (i<size && data[i]=='-') // found --
  {
    count++,i++;
  }
  if (i<size && data[i]=='-') // found ---
  {
    count++,i++;
  }
  if (i<size && data[i]=='-') // found ----
  {
    count++;
  }
  if (count==2 && (off<8 || qstrncmp(data-8,"operator",8)!=0)) // -- => ndash
  {
    out.addStr("&ndash;");
    return 2;
  }
  else if (count==3) // --- => ndash
  {
    out.addStr("&mdash;");
    return 3;
  }
  // not an ndash or mdash
  return 0;
}

/** Process quoted section "...", can contain one embedded newline */
static int processQuoted(GrowBuf &out,const char *data,int,int size)
{
  int i=1;
  int nl=0;
  while (i<size && data[i]!='"' && nl<2) 
  {
    if (data[i]=='\n') nl++;
    i++;
  }
  if (i<size && data[i]=='"' && nl<2)
  {
    out.addStr(data,i+1);
    return i+1;
  }
  // not a quoted section
  return 0;
}

/** Process a HTML tag. Note that <pre>..</pre> are treated specially, in
 *  the sense that all code inside is written unprocessed
 */
static int processHtmlTag(GrowBuf &out,const char *data,int offset,int size)
{
  if (offset>0 && data[-1]=='\\') return 0; // escaped <

  // find the end of the html tag
  int i=1;
  int l=0;
  // compute length of the tag name
  while (i<size && isIdChar(i)) i++,l++;
  QCString tagName;
  convertStringFragment(tagName,data+1,i-1);
  if (tagName.lower()=="pre") // found <pre> tag
  {
    bool insideStr=FALSE;
    while (i<size-6)
    {
      char c=data[i];
      if (!insideStr && c=='<') // potential start of html tag
      {
        if (data[i+1]=='/' &&
            tolower(data[i+2])=='p' && tolower(data[i+3])=='r' &&
            tolower(data[i+4])=='e' && tolower(data[i+5])=='>')
        { // found </pre> tag, copy from start to end of tag
          out.addStr(data,i+6);
          //printf("found <pre>..</pre> [%d..%d]\n",0,i+6);
          return i+6;
        }
      }
      else if (insideStr && c=='"')
      {
        if (data[i-1]!='\\') insideStr=FALSE;
      }
      else if (c=='"')
      {
        insideStr=TRUE;
      }
      i++;
    }
  }
  else // some other html tag
  {
    if (l>0 && i<size)
    {
      if (data[i]=='/' && i<size-1 && data[i+1]=='>') // <bla/>
      {
        //printf("Found htmlTag={%s}\n",QCString(data).left(i+2).data());
        out.addStr(data,i+2);
        return i+2;
      }
      else if (data[i]=='>') // <bla>
      {
        //printf("Found htmlTag={%s}\n",QCString(data).left(i+1).data());
        out.addStr(data,i+1);
        return i+1;
      }
      else if (data[i]==' ') // <bla attr=...
      {
        i++;
        bool insideAttr=FALSE;
        while (i<size)
        {
          if (!insideAttr && data[i]=='"')
          {
            insideAttr=TRUE;
          }
          else if (data[i]=='"' && data[i-1]!='\\')
          {
            insideAttr=FALSE;
          }
          else if (!insideAttr && data[i]=='>') // found end of tag
          {
            //printf("Found htmlTag={%s}\n",QCString(data).left(i+1).data());
            out.addStr(data,i+1);
            return i+1;
          }
          i++;
        }
      }
    }
  }
  //printf("Not a valid html tag\n");
  return 0;
}

static int processEmphasis(GrowBuf &out,const char *data,int offset,int size)
{
  if ((offset>0 && !isOpenEmphChar(-1)) || // invalid char before * or _
      (size>1 && data[0]!=data[1] && !isIdChar(1)) || // invalid char after * or _
      (size>2 && data[0]==data[1] && !isIdChar(2)))   // invalid char after ** or __
  {
    return 0;
  }

  char c = data[0];
  int ret;
  if (size>2 && data[1]!=c) // _bla or *bla
  {
    // whitespace cannot follow an opening emphasis
    if (data[1]==' ' || data[1]=='\n' || 
        (ret = processEmphasis1(out, data+1, size-1, c)) == 0)
    {
      return 0;
    }
    return ret+1;
  }
  if (size>3 && data[1]==c && data[2]!=c) // __bla or **bla
  {
    if (data[2]==' ' || data[2]=='\n' || 
        (ret = processEmphasis2(out, data+2, size-2, c)) == 0)
    {
      return 0;
    }
    return ret+2;
  }
  if (size>4 && data[1]==c && data[2]==c && data[3]!=c) // ___bla or ***bla
  {
    if (data[3]==' ' || data[3]=='\n' || 
        (ret = processEmphasis3(out, data+3, size-3, c)) == 0)
    {
      return 0;
    }
    return ret+3;
  }
  return 0;
}

static int processLink(GrowBuf &out,const char *data,int,int size)
{
  QCString content;
  QCString link;
  QCString title;
  int contentStart,contentEnd,linkStart,titleStart,titleEnd;
  bool isImageLink = FALSE;
  bool isToc = FALSE;
  int i=1;
  if (data[0]=='!')
  {
    isImageLink = TRUE;
    if (size<2 || data[1]!='[')
    {
      return 0;
    }
    i++;
  }
  contentStart=i;
  int level=1;
  int nl=0;
  // find the matching ]
  while (i<size)
  {
    if (data[i-1]=='\\') // skip escaped characters
    {
    }
    else if (data[i]=='[')
    {
      level++;
    }
    else if (data[i]==']')
    {
      level--;
      if (level<=0) break;
    }
    else if (data[i]=='\n')
    {
      nl++;
      if (nl>1) return 0; // only allow one newline in the content
    }
    i++;
  }
  if (i>=size) return 0; // premature end of comment -> no link
  contentEnd=i;
  convertStringFragment(content,data+contentStart,contentEnd-contentStart);
  //printf("processLink: content={%s}\n",content.data());
  if (!isImageLink && content.isEmpty()) return 0; // no link text
  i++; // skip over ]

  // skip whitespace
  while (i<size && data[i]==' ') i++;
  if (i<size && data[i]=='\n') // one newline allowed here
  {
    i++;
    // skip more whitespace
    while (i<size && data[i]==' ') i++;
  }

  bool explicitTitle=FALSE;
  if (i<size && data[i]=='(') // inline link
  {
    i++;
    while (i<size && data[i]==' ') i++;
    if (i<size && data[i]=='<') i++;
    linkStart=i;
    nl=0;
    while (i<size && data[i]!='\'' && data[i]!='"' && data[i]!=')') 
    {
      if (data[i]=='\n')
      {
        nl++;
        if (nl>1) return 0;
      }
      i++;
    }
    if (i>=size || data[i]=='\n') return 0;
    convertStringFragment(link,data+linkStart,i-linkStart);
    link = link.stripWhiteSpace();
    //printf("processLink: link={%s}\n",link.data());
    if (link.isEmpty()) return 0;
    if (link.at(link.length()-1)=='>') link=link.left(link.length()-1);

    // optional title
    if (data[i]=='\'' || data[i]=='"')
    {
      char c = data[i];
      i++;
      titleStart=i;
      nl=0;
      while (i<size && data[i]!=')')
      {
        if (data[i]=='\n') 
        {
          if (nl>1) return 0;
          nl++;
        }
        i++;
      }
      if (i>=size)
      {
        return 0;
      }
      titleEnd = i-1;
      // search back for closing marker
      while (titleEnd>titleStart && data[titleEnd]==' ') titleEnd--;
      if (data[titleEnd]==c) // found it
      {
        convertStringFragment(title,data+titleStart,titleEnd-titleStart);
        //printf("processLink: title={%s}\n",title.data());
      }
      else
      {
        return 0;
      }
    }
    i++;
  }
  else if (i<size && data[i]=='[') // reference link
  {
    i++;
    linkStart=i;
    nl=0;
    // find matching ]
    while (i<size && data[i]!=']')
    {
      if (data[i]=='\n')
      {
        nl++;
        if (nl>1) return 0;
      }
      i++;
    }
    if (i>=size) return 0;
    // extract link
    convertStringFragment(link,data+linkStart,i-linkStart);
    //printf("processLink: link={%s}\n",link.data());
    link = link.stripWhiteSpace();
    if (link.isEmpty()) // shortcut link
    {
      link=content;
    }
    // lookup reference
    LinkRef *lr = g_linkRefs.find(link.lower());
    if (lr) // found it
    {
      link  = lr->link;
      title = lr->title;
      //printf("processLink: ref: link={%s} title={%s}\n",link.data(),title.data());
    }
    else // reference not found! 
    {
      //printf("processLink: ref {%s} do not exist\n",link.lower().data());
      return 0;
    }
    i++;
  }
  else if (i<size && data[i]!=':' && !content.isEmpty()) // minimal link ref notation [some id]
  {
    LinkRef *lr = g_linkRefs.find(content.lower());
    //printf("processLink: minimal link {%s} lr=%p",content.data(),lr);
    if (lr) // found it
    {
      link  = lr->link;
      title = lr->title;
      explicitTitle=TRUE;
      i=contentEnd;
    }
    else if (content=="TOC")
    {
      isToc=TRUE;
      i=contentEnd;
    }
    else
    {
      return 0;
    }
    i++;
  }
  else
  {
    return 0;
  }
  if (isToc) // special case for [TOC]
  {
    if (g_current) g_current->stat=TRUE;
  }
  else if (isImageLink) 
  {
    bool ambig;
    FileDef *fd=0;
    if (link.find("@ref ")!=-1 || link.find("\\ref ")!=-1 ||
        (fd=findFileDef(Doxygen::imageNameDict,link,ambig))) 
        // assume doxygen symbol link or local image link
    {
      out.addStr("@image html ");
      out.addStr(link.mid(fd ? 0 : 5));
      if (!explicitTitle && !content.isEmpty())
      { 
        out.addStr(" \"");
        out.addStr(content);
        out.addStr("\"");
      }
      else if ((content.isEmpty() || explicitTitle) && !title.isEmpty())
      {
        out.addStr(" \"");
        out.addStr(title);
        out.addStr("\"");
      }
    }
    else
    {
      out.addStr("<img src=\"");
      out.addStr(link);
      out.addStr("\" alt=\"");
      out.addStr(content);
      out.addStr("\"");
      if (!title.isEmpty())
      {
        out.addStr(" title=\"");
        out.addStr(substitute(title.simplifyWhiteSpace(),"\"","&quot;"));
        out.addStr("\"");
      }
      out.addStr("/>");
    }
  }
  else
  {
    SrcLangExt lang = getLanguageFromFileName(link);
    int lp=-1;
    if ((lp=link.find("@ref "))!=-1 || (lp=link.find("\\ref "))!=-1 || lang==SrcLangExt_Markdown) 
        // assume doxygen symbol link
    {
      if (lp==-1) // link to markdown page
      {
        out.addStr("@ref ");
      }
      out.addStr(link);
      out.addStr(" \"");
      if (explicitTitle && !title.isEmpty())
      {
        out.addStr(title);
      }
      else
      {
        out.addStr(content);
      }
      out.addStr("\"");
    }
    else if (link.find('/')!=-1 || link.find('.')!=-1 || link.find('#')!=-1) 
    { // file/url link
      out.addStr("<a href=\"");
      out.addStr(link);
      out.addStr("\"");
      if (!title.isEmpty())
      {
        out.addStr(" title=\"");
        out.addStr(substitute(title.simplifyWhiteSpace(),"\"","&quot;"));
        out.addStr("\"");
      }
      out.addStr(">");
      out.addStr(content.simplifyWhiteSpace());
      out.addStr("</a>");
    }
    else // avoid link to e.g. F[x](y)
    {
      //printf("no link for '%s'\n",link.data());
      return 0;
    }
  }
  return i;
}

/** '`' parsing a code span (assuming codespan != 0) */
static int processCodeSpan(GrowBuf &out, const char *data, int /*offset*/, int size)
{
  int end, nb = 0, i, f_begin, f_end;

  /* counting the number of backticks in the delimiter */
  while (nb<size && data[nb]=='`')
  {
    nb++;
  }

  /* finding the next delimiter */
  i = 0;
  int nl=0;
  for (end=nb; end<size && i<nb && nl<2; end++)
  {
    if (data[end]=='`') 
    {
      i++; 
    }
    else if (data[end]=='\n')
    {
      i=0;
      nl++;
    }
    else
    {
      i=0; 
    }
  }
  if (i < nb && end >= size)
  {
    return 0;  // no matching delimiter
  }
  if (nl==2) // too many newlines inside the span
  {
    return 0;
  }

  // trimming outside whitespaces
  f_begin = nb;
  while (f_begin < end && data[f_begin]==' ')
  {
    f_begin++;
  }
  f_end = end - nb;
  while (f_end > nb && data[f_end-1]==' ')
  {
    f_end--;
  }

  if (nb==1) // check for closing ' followed by space within f_begin..f_end
  {
    i=f_begin;
    while (i<f_end-1)
    {
      if (data[i]=='\'' && !isIdChar(i+1)) // reject `some word' and not `it's cool`
      {
        return 0;
      }
      i++;
    }
  }
  //printf("found code span '%s'\n",QCString(data+f_begin).left(f_end-f_begin).data());

  /* real code span */
  if (f_begin < f_end)
  {
    QCString codeFragment;
    convertStringFragment(codeFragment,data+f_begin,f_end-f_begin);
    out.addStr("<tt>");
    //out.addStr(convertToHtml(codeFragment,TRUE));
    out.addStr(escapeSpecialChars(codeFragment));
    out.addStr("</tt>");
  }
  return end;
}


static int processSpecialCommand(GrowBuf &out, const char *data, int offset, int size)
{
  int i=1;
  QCString endBlockName = isBlockCommand(data,offset,size);
  if (!endBlockName.isEmpty())
  {
    int l = endBlockName.length();
    while (i<size-l)
    {
      if ((data[i]=='\\' || data[i]=='@') && // command
          data[i-1]!='\\' && data[i-1]!='@') // not escaped
      {
        if (qstrncmp(&data[i+1],endBlockName,l)==0)
        {
          //printf("found end at %d\n",i);
          out.addStr(data,i+1+l);
          return i+1+l;
        }
      }
      i++;
    }
  }
  if (size>1 && data[0]=='\\')
  {
    char c=data[1];
    if (c=='[' || c==']' || c=='*' || c=='+' || c=='-' ||
        c=='!' || c=='(' || c==')' || c=='.' || c=='`' || c=='_') 
    {
      if (c=='-' && size>3 && data[2]=='-' && data[3]=='-') // \---
      {
        out.addStr(&data[1],3);
        return 4;
      }
      else if (c=='-' && size>2 && data[2]=='-') // \--
      {
        out.addStr(&data[1],2);
        return 3;
      }
      out.addStr(&data[1],1);
      return 2;
    }
  }
  return 0;
}

static void processInline(GrowBuf &out,const char *data,int size)
{
  int i=0, end=0;
  action_t action = 0;
  while (i<size)
  {
    while (end<size && ((action=g_actions[(uchar)data[end]])==0)) end++;
    out.addStr(data+i,end-i);
    if (end>=size) break;
    i=end;
    end = action(out,data+i,i,size-i);
    if (!end)
    {
      end=i+1;
    }
    else
    {
      i+=end;
      end=i;
    }
  }
}

/** returns whether the line is a setext-style hdr underline */
static int isHeaderline(const char *data, int size)
{
  int i=0, c=0;
  while (i<size && data[i]==' ') i++;

  // test of level 1 header
  if (data[i]=='=')
  {
    while (i<size && data[i]=='=') i++,c++;
    while (i<size && data[i]==' ') i++;
    return (c>1 && (i>=size || data[i]=='\n')) ? 1 : 0;
  }
  // test of level 2 header
  if (data[i]=='-')
  {
    while (i<size && data[i]=='-') i++,c++;
    while (i<size && data[i]==' ') i++;
    return (c>1 && (i>=size || data[i]=='\n')) ? 2 : 0;
  }
  return 0;
}

/** returns TRUE if this line starts a block quote */
static bool isBlockQuote(const char *data,int size,int indent)
{
  int i = 0;
  while (i<size && data[i]==' ') i++;
  if (i<indent+codeBlockIndent) // could be a quotation
  {
    // count >'s and skip spaces
    int level=0;
    while (i<size && (data[i]=='>' || data[i]==' ')) 
    {
      if (data[i]=='>') level++;
      i++;
    }
    // last characters should be a space or newline, 
    // so a line starting with >= does not match
    return level>0 && i<size && ((data[i-1]==' ') || data[i]=='\n'); 
  }
  else // too much indentation -> code block
  {
    return FALSE;
  }
  //return i<size && data[i]=='>' && i<indent+codeBlockIndent;
}

/** returns end of the link ref if this is indeed a link reference. */
static int isLinkRef(const char *data,int size,
            QCString &refid,QCString &link,QCString &title)
{
  //printf("isLinkRef data={%s}\n",data);
  // format: start with [some text]:
  int i = 0;
  while (i<size && data[i]==' ') i++;
  if (i>=size || data[i]!='[') return 0;
  i++;
  int refIdStart=i;
  while (i<size && data[i]!='\n' && data[i]!=']') i++;
  if (i>=size || data[i]!=']') return 0;
  convertStringFragment(refid,data+refIdStart,i-refIdStart);
  if (refid.isEmpty()) return 0;
  //printf("  isLinkRef: found refid='%s'\n",refid.data());
  i++;
  if (i>=size || data[i]!=':') return 0;
  i++;

  // format: whitespace* \n? whitespace* (<url> | url)
  while (i<size && data[i]==' ') i++;
  if (i<size && data[i]=='\n')
  {
    i++;
    while (i<size && data[i]==' ') i++;
  }
  if (i>=size) return 0;

  if (i<size && data[i]=='<') i++;
  int linkStart=i;
  while (i<size && data[i]!=' ' && data[i]!='\n') i++;
  int linkEnd=i;
  if (i<size && data[i]=='>') i++;
  if (linkStart==linkEnd) return 0; // empty link
  convertStringFragment(link,data+linkStart,linkEnd-linkStart);
  //printf("  isLinkRef: found link='%s'\n",link.data());
  if (link=="@ref" || link=="\\ref")
  {
    int argStart=i;
    while (i<size && data[i]!='\n' && data[i]!='"') i++;
    QCString refArg;
    convertStringFragment(refArg,data+argStart,i-argStart);
    link+=refArg;
  }

  title.resize(0);

  // format: (whitespace* \n? whitespace* ( 'title' | "title" | (title) ))?
  int eol=0;
  while (i<size && data[i]==' ') i++;
  if (i<size && data[i]=='\n')
  {
    eol=i;
    i++;
    while (i<size && data[i]==' ') i++;
  }
  if (i>=size) 
  {
    //printf("end of isLinkRef while looking for title! i=%d\n",i);
    return i; // end of buffer while looking for the optional title
  }

  char c = data[i];
  if (c=='\'' || c=='"' || c=='(') // optional title present?
  {
    //printf("  start of title found! char='%c'\n",c);
    i++;
    if (c=='(') c=')'; // replace c by end character
    int titleStart=i;
    // search for end of the line
    while (i<size && data[i]!='\n') i++;
    eol = i;

    // search back to matching character
    int end=i-1;
    while (end>titleStart && data[end]!=c) end--;
    if (end>titleStart)
    {
      convertStringFragment(title,data+titleStart,end-titleStart);
    }
    //printf("  title found: '%s'\n",title.data());
  }
  while (i<size && data[i]==' ') i++;
  //printf("end of isLinkRef: i=%d size=%d data[i]='%c' eol=%d\n",
  //    i,size,data[i],eol);
  if      (i>=size)       return i;    // end of buffer while ref id was found
  else if (eol)           return eol;  // end of line while ref id was found
  return 0;                            // invalid link ref
}

static int isHRuler(const char *data,int size)
{
  int i=0;
  if (size>0 && data[size-1]=='\n') size--; // ignore newline character
  while (i<size && data[i]==' ') i++;
  if (i>=size) return 0; // empty line
  char c=data[i];
  if (c!='*' && c!='-' && c!='_') 
  {
    return 0; // not a hrule character
  }
  int n=0;
  while (i<size)
  {
    if (data[i]==c)
    {
      n++; // count rule character
    }
    else if (data[i]!=' ')
    {
      return 0; // line contains non hruler characters
    }
    i++;
  }
  return n>=3; // at least 3 characters needed for a hruler
}

static QCString extractTitleId(QCString &title)
{
  //static QRegExp r1("^[a-z_A-Z][a-z_A-Z0-9\\-]*:");
  static QRegExp r2("\\{#[a-z_A-Z][a-z_A-Z0-9\\-]*\\}");
  int l=0;
  int i = r2.match(title,0,&l);
  if (i!=-1 && title.mid(i+l).stripWhiteSpace().isEmpty()) // found {#id} style id
  {
    QCString id = title.mid(i+2,l-3);
    title = title.left(i);
    //printf("found id='%s' title='%s'\n",id.data(),title.data());
    return id;
  }
  //printf("no id found in title '%s'\n",title.data());
  return "";
}


static int isAtxHeader(const char *data,int size,
                       QCString &header,QCString &id)
{
  int i = 0, end;
  int level = 0, blanks=0;

  // find start of header text and determine heading level
  while (i<size && data[i]==' ') i++;
  if (i>=size || data[i]!='#') 
  {
    return 0;
  }
  while (i<size && level<6 && data[i]=='#') i++,level++;
  while (i<size && data[i]==' ') i++,blanks++;
  if (level==1 && blanks==0) 
  {
    return 0; // special case to prevent #someid seen as a header (see bug 671395)
  }

  // find end of header text
  end=i;
  while (end<size && data[end]!='\n') end++;
  while (end>i && (data[end-1]=='#' || data[end-1]==' ')) end--;

  // store result
  convertStringFragment(header,data+i,end-i);
  id = extractTitleId(header);
  if (!id.isEmpty()) // strip #'s between title and id
  {
    i=header.length()-1;
    while (i>=0 && (header.at(i)=='#' || header.at(i)==' ')) i--;
    header=header.left(i+1);
  }

  return level;
}

static int isEmptyLine(const char *data,int size)
{
  int i=0;
  while (i<size)
  {
    if (data[i]=='\n') return TRUE;
    if (data[i]!=' ') return FALSE;
    i++;
  }
  return TRUE;
}

#define isLiTag(i) \
   (data[(i)]=='<' && \
   (data[(i)+1]=='l' || data[(i)+1]=='L') && \
   (data[(i)+2]=='i' || data[(i)+2]=='I') && \
   (data[(i)+3]=='>'))

// compute the indent from the start of the input, excluding list markers
// such as -, -#, *, +, 1., and <li>
static int computeIndentExcludingListMarkers(const char *data,int size)
{
  int i=0;
  int indent=0;
  bool isDigit=FALSE;
  bool isLi=FALSE;
  bool listMarkerSkipped=FALSE;
  while (i<size && 
         (data[i]==' ' ||                                    // space
          (!listMarkerSkipped &&                             // first list marker
           (data[i]=='+' || data[i]=='-' || data[i]=='*' ||  // unordered list char
            (data[i]=='#' && i>0 && data[i-1]=='-') ||       // -# item
            (isDigit=(data[i]>='1' && data[i]<='9')) ||      // ordered list marker?
            (isLi=(i<size-3 && isLiTag(i)))                  // <li> tag
           )
          )
         )
        ) 
  {
    if (isDigit) // skip over ordered list marker '10. '
    {
      int j=i+1;
      while (j<size && ((data[j]>='0' && data[j]<='9') || data[j]=='.'))
      {
        if (data[j]=='.') // should be end of the list marker
        {
          if (j<size-1 && data[j+1]==' ') // valid list marker
          {
            listMarkerSkipped=TRUE;
            indent+=j+1-i;
            i=j+1;
            break;
          }
          else // not a list marker
          {
            break;
          }
        }
        j++;
      }
    }
    else if (isLi)
    {
      i+=3; // skip over <li>
      indent+=3;
      listMarkerSkipped=TRUE;
    }
    else if (data[i]=='-' && i<size-2 && data[i+1]=='#' && data[i+2]==' ')
    { // case "-# "
      listMarkerSkipped=TRUE; // only a single list marker is accepted
      i++; // skip over #
      indent++;
    }
    else if (data[i]!=' ' && i<size-1 && data[i+1]==' ')
    { // case "- " or "+ " or "* "
      listMarkerSkipped=TRUE; // only a single list marker is accepted
    }
    if (data[i]!=' ' && !listMarkerSkipped)
    { // end of indent
      break;
    }
    indent++,i++;
  }
  //printf("{%s}->%d\n",QCString(data).left(size).data(),indent);
  return indent;
}

static bool isFencedCodeBlock(const char *data,int size,int refIndent,
                             QCString &lang,int &start,int &end,int &offset)
{
  // rules: at least 3 ~~~, end of the block same amount of ~~~'s, otherwise
  // return FALSE
  int i=0;
  int indent=0;
  int startTildes=0;
  while (i<size && data[i]==' ') indent++,i++;
  if (indent>=refIndent+4) return FALSE; // part of code block
  while (i<size && data[i]=='~') startTildes++,i++;
  if (startTildes<3) return FALSE; // not enough tildes
  if (i<size && data[i]=='{') i++; // skip over optional {
  int startLang=i;
  while (i<size && (data[i]!='\n' && data[i]!='}' && data[i]!=' ')) i++;
  convertStringFragment(lang,data+startLang,i-startLang);
  while (i<size && data[i]!='\n') i++; // proceed to the end of the line
  start=i;
  while (i<size)
  {
    if (data[i]=='~')
    {
      end=i-1;
      int endTildes=0;
      while (i<size && data[i]=='~') endTildes++,i++; 
      while (i<size && data[i]==' ') i++;
      if (i==size || data[i]=='\n') 
      {
        offset=i;
        return endTildes==startTildes;
      }
    }
    i++;
  }
  return FALSE;
}

static bool isCodeBlock(const char *data,int offset,int size,int &indent)
{
  //printf("<isCodeBlock(offset=%d,size=%d,indent=%d)\n",offset,size,indent);
  // determine the indent of this line
  int i=0;
  int indent0=0;
  while (i<size && data[i]==' ') indent0++,i++;

  if (indent0<codeBlockIndent)
  {
    //printf(">isCodeBlock: line is not indented enough %d<4\n",indent0);
    return FALSE;
  }
  if (indent0>=size || data[indent0]=='\n') // empty line does not start a code block
  {
    //printf("only spaces at the end of a comment block\n");
    return FALSE;
  }
    
  i=offset;
  int nl=0;
  int nl_pos[3];
  // search back 3 lines and remember the start of lines -1 and -2
  while (i>0 && nl<3)
  {
    if (data[i-offset-1]=='\n') nl_pos[nl++]=i-offset;
    i--;
  }

  // if there are only 2 preceding lines, then line -2 starts at -offset
  if (i==0 && nl==2) nl_pos[nl++]=-offset;
  //printf("  nl=%d\n",nl);

  if (nl==3) // we have at least 2 preceding lines
  {
    //printf("  positions: nl_pos=[%d,%d,%d] line[-2]='%s' line[-1]='%s'\n",
    //    nl_pos[0],nl_pos[1],nl_pos[2],
    //    QCString(data+nl_pos[1]).left(nl_pos[0]-nl_pos[1]-1).data(),
    //    QCString(data+nl_pos[2]).left(nl_pos[1]-nl_pos[2]-1).data());

    // check that line -1 is empty
    if (!isEmptyLine(data+nl_pos[1],nl_pos[0]-nl_pos[1]-1))
    {
      return FALSE;
    }

    // determine the indent of line -2
    indent=computeIndentExcludingListMarkers(data+nl_pos[2],nl_pos[1]-nl_pos[2]);
    
    //printf(">isCodeBlock local_indent %d>=%d+4=%d\n",
    //    indent0,indent2,indent0>=indent2+4);
    // if the difference is >4 spaces -> code block
    return indent0>=indent+codeBlockIndent;
  }
  else // not enough lines to determine the relative indent, use global indent
  {
    // check that line -1 is empty
    if (nl==1 && !isEmptyLine(data-offset,offset-1))
    {
      return FALSE;
    }
    //printf(">isCodeBlock global indent %d>=%d+4=%d nl=%d\n",
    //    indent0,indent,indent0>=indent+4,nl);
    return indent0>=indent+codeBlockIndent;
  }
}

/** Finds the location of the table's contains in the string \a data.
 *  Only one line will be inspected.
 *  @param[in] data pointer to the string buffer.
 *  @param[in] size the size of the buffer.
 *  @param[out] start offset of the first character of the table content
 *  @param[out] end   offset of the last character of the table content
 *  @param[out] columns number of table columns found
 *  @returns The offset until the next line in the buffer.
 */
int findTableColumns(const char *data,int size,int &start,int &end,int &columns)
{
  int i=0,n=0;
  int eol;
  // find start character of the table line
  while (i<size && data[i]==' ') i++;
  if (i<size && data[i]=='|' && data[i]!='\n') i++,n++; // leading | does not count
  start = i;

  // find end character of the table line
  while (i<size && data[i]!='\n') i++;
  eol=i+1;
  i--;
  while (i>0 && data[i]==' ') i--;
  if (i>0 && data[i-1]!='\\' && data[i]=='|') i--,n++; // trailing or escaped | does not count
  end = i;

  // count columns between start and end
  columns=0;
  if (end>start)
  {
    i=start;
    while (i<=end) // look for more column markers
    {
      if (data[i]=='|' && (i==0 || data[i-1]!='\\')) columns++;
      if (columns==1) columns++; // first | make a non-table into a two column table
      i++;
    }
  }
  if (n==2 && columns==0) // table row has | ... |
  {
    columns++;
  }
  //printf("findTableColumns(start=%d,end=%d,columns=%d) eol=%d\n",
  //    start,end,columns,eol);
  return eol;
}

/** Returns TRUE iff data points to the start of a table block */
static bool isTableBlock(const char *data,int size)
{
  int cc0,start,end;

  // the first line should have at least two columns separated by '|'
  int i = findTableColumns(data,size,start,end,cc0);
  if (i>=size || cc0<1) 
  {
    //printf("isTableBlock: no |'s in the header\n");
    return FALSE;
  }

  int cc1;
  int ret = findTableColumns(data+i,size-i,start,end,cc1);
  int j=i+start;
  // separator line should consist of |, - and : and spaces only
  while (j<=end+i)
  {
    if (data[j]!=':' && data[j]!='-' && data[j]!='|' && data[j]!=' ')
    {
      //printf("isTableBlock: invalid character '%c'\n",data[j]);
      return FALSE; // invalid characters in table separator
    }
    j++;
  }
  if (cc1!=cc0) // number of columns should be same as previous line
  {
    return FALSE;
  }

  i+=ret; // goto next line
  int cc2;
  findTableColumns(data+i,size-i,start,end,cc2);

  //printf("isTableBlock: %d\n",cc1==cc2);
  return cc1==cc2;
}

static int writeTableBlock(GrowBuf &out,const char *data,int size)
{
  int i=0,j,k;
  int columns,start,end,cc;

  i = findTableColumns(data,size,start,end,columns);
  
  out.addStr("<table>");

  // write table header, in range [start..end]
  out.addStr("<tr>");

  int headerStart = start;
  int headerEnd = end;

  // read cell alignments
  int ret = findTableColumns(data+i,size-i,start,end,cc);
  k=0;
  Alignment *columnAlignment = new Alignment[columns];

  bool leftMarker=FALSE,rightMarker=FALSE;
  bool startFound=FALSE;
  j=start+i;
  while (j<=end+i)
  {
    if (!startFound)
    {
      if (data[j]==':') { leftMarker=TRUE; startFound=TRUE; }
      if (data[j]=='-') startFound=TRUE; 
      //printf("  data[%d]=%c startFound=%d\n",j,data[j],startFound);
    }
    if      (data[j]=='-') rightMarker=FALSE;
    else if (data[j]==':') rightMarker=TRUE;
    if (j<=end+i && (data[j]=='|' && (j==0 || data[j-1]!='\\'))) 
    {
      if (k<columns)
      {
        columnAlignment[k] = markersToAlignment(leftMarker,rightMarker);
        //printf("column[%d] alignment=%d\n",k,columnAlignment[k]);
        leftMarker=FALSE;
        rightMarker=FALSE;
        startFound=FALSE;
      }
      k++;
    }
    j++;
  }
  if (k<columns)
  {
    columnAlignment[k] = markersToAlignment(leftMarker,rightMarker);
    //printf("column[%d] alignment=%d\n",k,columnAlignment[k]);
  }
  // proceed to next line
  i+=ret;

  int m=headerStart;
  for (k=0;k<columns;k++)
  {
    out.addStr("<th");
    switch (columnAlignment[k])
    {
      case AlignLeft:   out.addStr(" align=\"left\""); break;
      case AlignRight:  out.addStr(" align=\"right\""); break;
      case AlignCenter: out.addStr(" align=\"center\""); break;
      case AlignNone:   break;
    }
    out.addStr(">");
    while (m<=headerEnd && (data[m]!='|' || (m>0 && data[m-1]=='\\')))
    {
      out.addChar(data[m++]);
    }
    m++;
  }
  out.addStr("\n</th>\n");

  // write table cells
  while (i<size)
  {
    int ret = findTableColumns(data+i,size-i,start,end,cc);
    //printf("findTableColumns cc=%d\n",cc);
    if (cc!=columns) break; // end of table

    out.addStr("<tr>");
    j=start+i;
    int columnStart=j;
    k=0;
    while (j<=end+i)
    {
      if (j==columnStart)
      {
        out.addStr("<td");
        switch (columnAlignment[k])
        {
          case AlignLeft:   out.addStr(" align=\"left\""); break;
          case AlignRight:  out.addStr(" align=\"right\""); break;
          case AlignCenter: out.addStr(" align=\"center\""); break;
          case AlignNone:   break;
        }
        out.addStr(">");
      }
      if (j<=end+i && (data[j]=='|' && (j==0 || data[j-1]!='\\'))) 
      {
        columnStart=j+1;
        k++;
      }
      else
      {
        out.addChar(data[j]);
      }
      j++;
    }
    out.addChar('\n');

    // proceed to next line
    i+=ret;
  }

  out.addStr("</table> ");

  delete[] columnAlignment;
  return i;
}


void writeOneLineHeaderOrRuler(GrowBuf &out,const char *data,int size)
{
  int level;
  QCString header;
  QCString id;
  if (isHRuler(data,size))
  {
    out.addStr("<hr>\n");
  }
  else if ((level=isAtxHeader(data,size,header,id)))
  {
    //if (level==1) g_correctSectionLevel=FALSE;
    //if (g_correctSectionLevel) level--;
    QCString hTag;
    if (level<5 && !id.isEmpty())
    {
      SectionInfo::SectionType type = SectionInfo::Anchor;
      switch(level)
      {
        case 1:  out.addStr("@section ");       
                 type=SectionInfo::Section; 
                 break;
        case 2:  out.addStr("@subsection ");    
                 type=SectionInfo::Subsection; 
                 break;
        case 3:  out.addStr("@subsubsection "); 
                 type=SectionInfo::Subsubsection;
                 break;
        default: out.addStr("@paragraph "); 
                 type=SectionInfo::Paragraph;
                 break;
      }
      out.addStr(id);
      out.addStr(" ");
      out.addStr(header);
      out.addStr("\n");
      SectionInfo *si = Doxygen::sectionDict->find(id);
      if (si)
      {
        if (si->lineNr != -1)
        {
          warn(g_fileName,g_lineNr,"multiple use of section label '%s', (first occurrence: %s, line %d)",header.data(),si->fileName.data(),si->lineNr);
        }
        else
        {
          warn(g_fileName,g_lineNr,"multiple use of section label '%s', (first occurrence: %s)",header.data(),si->fileName.data());
        }
      }
      else
      {
        si = new SectionInfo(g_fileName,g_lineNr,id,header,type,level);
        if (g_current)
        {
          g_current->anchors->append(si);
        }
        Doxygen::sectionDict->append(id,si);
      }
    }
    else
    {
      if (!id.isEmpty())
      {
        out.addStr("\\anchor "+id+"\n");
      }
      hTag.sprintf("h%d",level);
      out.addStr("<"+hTag+">");
      out.addStr(header); 
      out.addStr("</"+hTag+">\n");
    }
  }
  else // nothing interesting -> just output the line
  {
    out.addStr(data,size);
  }
}

static int writeBlockQuote(GrowBuf &out,const char *data,int size)
{
  int l;
  int i=0;
  int curLevel=0;
  int end=0;
  while (i<size)
  {
    // find end of this line
    end=i+1;
    while (end<=size && data[end-1]!='\n') end++;
    int j=i;
    int level=0;
    int indent=i;
    // compute the quoting level
    while (j<end && (data[j]==' ' || data[j]=='>'))
    {
      if (data[j]=='>') { level++; indent=j+1; }
      else if (j>0 && data[j-1]=='>') indent=j+1;
      j++;
    }
    if (j>0 && data[j-1]=='>' && 
        !(j==size || data[j]=='\n')) // disqualify last > if not followed by space
    {
      indent--;
      j--;
    }
    if (level>curLevel) // quote level increased => add start markers
    {
      for (l=curLevel;l<level;l++)
      {
        out.addStr("<blockquote>\n");
      }
    }
    else if (level<curLevel) // quote level descreased => add end markers
    {
      for (l=level;l<curLevel;l++)
      {
        out.addStr("</blockquote>\n");
      }
    }
    curLevel=level;
    if (level==0) break; // end of quote block
    // copy line without quotation marks
    out.addStr(data+indent,end-indent);
    // proceed with next line
    i=end;
  }
  // end of comment within blockquote => add end markers
  for (l=0;l<curLevel;l++)
  {
    out.addStr("</blockquote>\n");
  }
  return i;
}

static int writeCodeBlock(GrowBuf &out,const char *data,int size,int refIndent)
{
  int i=0,end;
  //printf("writeCodeBlock: data={%s}\n",QCString(data).left(size).data());
  out.addStr("@verbatim\n");
  int emptyLines=0;
  while (i<size)
  {
    // find end of this line
    end=i+1;
    while (end<=size && data[end-1]!='\n') end++;
    int j=i;
    int indent=0;
    while (j<end && data[j]==' ') j++,indent++;
    //printf("j=%d end=%d indent=%d refIndent=%d tabSize=%d data={%s}\n",
    //    j,end,indent,refIndent,Config_getInt("TAB_SIZE"),QCString(data+i).left(end-i-1).data());
    if (j==end-1) // empty line 
    {
      emptyLines++;
      i=end;
    }
    else if (indent>=refIndent+codeBlockIndent) // enough indent to contine the code block
    {
      while (emptyLines>0) // write skipped empty lines
      {
        // add empty line
        out.addStr("\n");
        emptyLines--;
      }
      // add code line minus the indent
      out.addStr(data+i+refIndent+codeBlockIndent,end-i-refIndent-codeBlockIndent);
      i=end;
    }
    else // end of code block
    {
      break;
    }
  }
  out.addStr("@endverbatim\n"); 
  while (emptyLines>0) // write skipped empty lines
  {
    // add empty line
    out.addStr("\n");
    emptyLines--;
  }
  //printf("i=%d\n",i);
  return i;
}

// start searching for the end of the line start at offset \a i
// keeping track of possible blocks that need to to skipped.
static void findEndOfLine(GrowBuf &out,const char *data,int size,
                          int &pi,int&i,int &end)
{
  // find end of the line
  int nb=0;
  end=i+1;
  while (end<=size && data[end-1]!='\n')
  {
    // while looking for the end of the line we might encounter a block
    // that needs to be passed unprocessed.
    if ((data[end-1]=='\\' || data[end-1]=='@') &&          // command
        (end<=1 || (data[end-2]!='\\' && data[end-2]!='@')) // not escaped
       )
    {
      QCString endBlockName = isBlockCommand(data+end-1,end-1,size-(end-1));
      end++;
      if (!endBlockName.isEmpty())
      {
        int l = endBlockName.length();
        for (;end<size-l-1;end++) // search for end of block marker
        {
          if ((data[end]=='\\' || data[end]=='@') &&
              data[end-1]!='\\' && data[end-1]!='@'
             )
          {
            if (qstrncmp(&data[end+1],endBlockName,l)==0)
            {
              if (pi!=-1) // output previous line if available
              {
                //printf("feol out={%s}\n",QCString(data+pi).left(i-pi).data());
                out.addStr(data+pi,i-pi);
              }
              // found end marker, skip over this block
              //printf("feol.block out={%s}\n",QCString(data+i).left(end+l+1-i).data());
              out.addStr(data+i,end+l+1-i);
              pi=-1;
              i=end+l+1; // continue after block
              end=i+1;
              break;
            }
          }
        }
      }
    }
    else if (nb==0 && data[end-1]=='<' && end<size-6 &&
             (end<=1 || (data[end-2]!='\\' && data[end-2]!='@'))
            )
    {
      if (tolower(data[end])=='p' && tolower(data[end+1])=='r' &&
          tolower(data[end+2])=='e' && data[end+3]=='>') // <pre> tag
      {
        if (pi!=-1) // output previous line if available
        {
          out.addStr(data+pi,i-pi);
        }
        // output part until <pre>
        out.addStr(data+i,end-1-i); 
        // output part until </pre>
        i = end-1 + processHtmlTag(out,data+end-1,end-1,size-end+1);
        pi=-1;
        end = i+1;
        break;
      }
      else
      {
        end++;
      }
    }
    else if (nb==0 && data[end-1]=='`') 
    {
      while (end<=size && data[end-1]=='`') end++,nb++;
    }
    else if (nb>0 && data[end-1]=='`')
    {
      int enb=0;
      while (end<=size && data[end-1]=='`') end++,enb++;
      if (enb==nb) nb=0;
    }
    else
    {
      end++;
    }
  }
  //printf("findEndOfLine pi=%d i=%d end=%d {%s}\n",pi,i,end,QCString(data+i).left(end-i).data());
}

static void writeFencedCodeBlock(GrowBuf &out,const char *data,const char *lng,
                int blockStart,int blockEnd)
{
  QCString lang = lng;
  if (!lang.isEmpty() && lang.at(0)=='.') lang=lang.mid(1);
  out.addStr("@code");
  if (!lang.isEmpty())
  {
    out.addStr("{"+lang+"}");
  }
  out.addStr(data+blockStart,blockEnd-blockStart);
  out.addStr("\n");
  out.addStr("@endcode");
}

static QCString processQuotations(const QCString &s,int refIndent)
{
  GrowBuf out;
  const char *data = s.data();
  int size = s.length();
  int i=0,end=0,pi=-1;
  int blockStart,blockEnd,blockOffset;
  QCString lang;
  while (i<size)
  {
    findEndOfLine(out,data,size,pi,i,end);
    // line is now found at [i..end)

    if (pi!=-1)
    {
      if (isFencedCodeBlock(data+pi,size-pi,refIndent,lang,blockStart,blockEnd,blockOffset))
      {
        writeFencedCodeBlock(out,data+pi,lang,blockStart,blockEnd);
        i=pi+blockOffset;
        pi=-1;
        end=i+1;
        continue;
      }
      else if (isBlockQuote(data+pi,i-pi,refIndent))
      {
        i = pi+writeBlockQuote(out,data+pi,size-pi);
        pi=-1;
        end=i+1;
        continue;
      }
      else
      {
        //printf("quote out={%s}\n",QCString(data+pi).left(i-pi).data());
        out.addStr(data+pi,i-pi);
      }
    }
    pi=i;
    i=end;
  }
  if (pi!=-1 && pi<size) // deal with the last line
  {
    if (isBlockQuote(data+pi,size-pi,refIndent))
    {
      writeBlockQuote(out,data+pi,size-pi);
    }
    else
    {
      out.addStr(data+pi,size-pi);
    }
  }
  out.addChar(0);

  //printf("Process quotations\n---- input ----\n%s\n---- output ----\n%s\n------------\n",
  //    s.data(),out.get());

  return out.get();
}

static QCString processBlocks(const QCString &s,int indent)
{
  GrowBuf out;
  const char *data = s.data();
  int size = s.length();
  int i=0,end=0,pi=-1,ref,level;
  QCString id,link,title;
  int blockIndent = indent;

  // get indent for the first line
  end = i+1;
  int sp=0;
  while (end<=size && data[end-1]!='\n') 
  {
    if (data[end-1]==' ') sp++;
    end++;
  }

#if 0 // commented out, since starting with a comment block is probably a usage error
      // see also http://stackoverflow.com/q/20478611/784672

  // special case when the documentation starts with a code block
  // since the first line is skipped when looking for a code block later on.
  if (end>codeBlockIndent && isCodeBlock(data,0,end,blockIndent))
  {
    i=writeCodeBlock(out,data,size,blockIndent);
    end=i+1;
    pi=-1;
  }
#endif

  // process each line
  while (i<size)
  {
    findEndOfLine(out,data,size,pi,i,end);
    // line is now found at [i..end)

    //printf("findEndOfLine: pi=%d i=%d end=%d\n",pi,i,end);

    if (pi!=-1)
    {
      int blockStart,blockEnd,blockOffset;
      QCString lang;
      blockIndent = indent;
      //printf("isHeaderLine(%s)=%d\n",QCString(data+i).left(size-i).data(),level);
      if ((level=isHeaderline(data+i,size-i))>0)
      {
        //if (level==1) g_correctSectionLevel=FALSE;
        //if (g_correctSectionLevel) level--;
        //printf("Found header at %d-%d\n",i,end);
        while (pi<size && data[pi]==' ') pi++;
        QCString header,id;
        convertStringFragment(header,data+pi,i-pi-1);
        id = extractTitleId(header);
        //printf("header='%s' is='%s'\n",header.data(),id.data());
        if (!header.isEmpty())
        {
          if (!id.isEmpty())
          {
            out.addStr(level==1?"@section ":"@subsection ");
            out.addStr(id);
            out.addStr(" ");
            out.addStr(header);
            out.addStr("\n\n");
            SectionInfo *si = Doxygen::sectionDict->find(id);
            if (si)
            {
              if (si->lineNr != -1)
              {
                warn(g_fileName,g_lineNr,"multiple use of section label '%s', (first occurrence: %s, line %d)",header.data(),si->fileName.data(),si->lineNr);
              }
              else
              {
                warn(g_fileName,g_lineNr,"multiple use of section label '%s', (first occurrence: %s)",header.data(),si->fileName.data());
              }
            }
            else
            {
              si = new SectionInfo(g_fileName,g_lineNr,id,header,
                      level==1 ? SectionInfo::Section : SectionInfo::Subsection,level);
              if (g_current)
              {
                g_current->anchors->append(si);
              }
              Doxygen::sectionDict->append(id,si);
            }
          }
          else
          {
            out.addStr(level==1?"<h1>":"<h2>");
            out.addStr(header);
            out.addStr(level==1?"\n</h1>\n":"\n</h2>\n");
          }
        }
        else
        {
          out.addStr("<hr>\n");
        }
        pi=-1;
        i=end;
        end=i+1;
        continue;
      }
      else if ((ref=isLinkRef(data+pi,size-pi,id,link,title)))
      {
        //printf("found link ref: id='%s' link='%s' title='%s'\n",
        //       id.data(),link.data(),title.data());
        g_linkRefs.insert(id.lower(),new LinkRef(link,title));
        i=ref+pi;
        pi=-1;
        end=i+1;
      }
      else if (isFencedCodeBlock(data+pi,size-pi,indent,lang,blockStart,blockEnd,blockOffset))
      {
        //printf("Found FencedCodeBlock lang='%s' start=%d end=%d code={%s}\n",
        //       lang.data(),blockStart,blockEnd,QCString(data+pi+blockStart).left(blockEnd-blockStart).data());
        writeFencedCodeBlock(out,data+pi,lang,blockStart,blockEnd);
        i=pi+blockOffset;
        pi=-1;
        end=i+1;
        continue;
      }
      else if (isCodeBlock(data+i,i,end-i,blockIndent))
      {
        // skip previous line (it is empty anyway)
        i+=writeCodeBlock(out,data+i,size-i,blockIndent);
        pi=-1;
        end=i+1;
        continue;
      }
      else if (isTableBlock(data+pi,size-pi))
      {
        i=pi+writeTableBlock(out,data+pi,size-pi);
        pi=-1;
        end=i+1;
        continue;
      }
      else
      {
        writeOneLineHeaderOrRuler(out,data+pi,i-pi);
      }
    }
    pi=i;
    i=end;
  }
  //printf("last line %d size=%d\n",i,size);
  if (pi!=-1 && pi<size) // deal with the last line
  {
    if (isLinkRef(data+pi,size-pi,id,link,title))
    {
      //printf("found link ref: id='%s' link='%s' title='%s'\n",
      //    id.data(),link.data(),title.data());
      g_linkRefs.insert(id.lower(),new LinkRef(link,title));
    }
    else
    {
      writeOneLineHeaderOrRuler(out,data+pi,size-pi);
    }
  }

  out.addChar(0);
  return out.get();
}

static QCString extractPageTitle(QCString &docs,QCString &id)
{
  int ln=0;
  // first first non-empty line
  QCString title;
  const char *data = docs.data();
  int i=0;
  int size=docs.size();
  while (i<size && (data[i]==' ' || data[i]=='\n')) 
  {
    if (data[i]=='\n') ln++;
    i++;
  }
  if (i>=size) return "";
  int end1=i+1;
  while (end1<size && data[end1-1]!='\n') end1++;
  //printf("i=%d end1=%d size=%d line='%s'\n",i,end1,size,docs.mid(i,end1-i).data());
  // first line from i..end1
  if (end1<size)
  {
    ln++;
    // second line form end1..end2
    int end2=end1+1;
    while (end2<size && data[end2-1]!='\n') end2++;
    if (isHeaderline(data+end1,size-end1))
    {
      convertStringFragment(title,data+i,end1-i-1);
      QCString lns;
      lns.fill('\n',ln);
      docs=lns+docs.mid(end2);
      id = extractTitleId(title);
      //printf("extractPageTitle(title='%s' docs='%s' id='%s')\n",title.data(),docs.data(),id.data());
      return title;
    }
  }
  if (i<end1 && isAtxHeader(data+i,end1-i,title,id)>0)
  {
    docs=docs.mid(end1);
  }
  //printf("extractPageTitle(title='%s' docs='%s' id='%s')\n",title.data(),docs.data(),id.data());
  return title;
}

static QCString detab(const QCString &s,int &refIndent)
{
  static int tabSize = Config_getInt("TAB_SIZE");
  GrowBuf out;
  int size = s.length();
  const char *data = s.data();
  int i=0;
  int col=0;
  const int maxIndent=1000000; // value representing infinity
  int minIndent=maxIndent;
  while (i<size)
  {
    char c = data[i++];
    switch(c)
    {
      case '\t': // expand tab
        {
          int stop = tabSize - (col%tabSize);
          //printf("expand at %d stop=%d\n",col,stop);
          col+=stop;
          while (stop--) out.addChar(' '); 
        }
        break;
      case '\n': // reset colomn counter
        out.addChar(c);
        col=0;
        break;
      case ' ': // increment column counter
        out.addChar(c);
        col++;
        break;
      default: // non-whitespace => update minIndent
        out.addChar(c);
        if (c<0 && i<size) // multibyte sequence
        {
          out.addChar(data[i++]); // >= 2 bytes
          if (((uchar)c&0xE0)==0xE0 && i<size)
          {
            out.addChar(data[i++]); // 3 bytes
          }
          if (((uchar)c&0xF0)==0xF0 && i<size)
          {
            out.addChar(data[i++]); // 4 byres
          }
        }
        if (col<minIndent) minIndent=col;
        col++;
    }
  }
  if (minIndent!=maxIndent) refIndent=minIndent; else refIndent=0;
  out.addChar(0);
  //printf("detab refIndent=%d\n",refIndent);
  return out.get();
}

//---------------------------------------------------------------------------

QCString processMarkdown(const QCString &fileName,const int lineNr,Entry *e,const QCString &input)
{
  static bool init=FALSE;
  if (!init)
  {
    // setup callback table for special characters
    g_actions[(unsigned int)'_']=processEmphasis;
    g_actions[(unsigned int)'*']=processEmphasis;
    g_actions[(unsigned int)'`']=processCodeSpan;
    g_actions[(unsigned int)'\\']=processSpecialCommand;
    g_actions[(unsigned int)'@']=processSpecialCommand;
    g_actions[(unsigned int)'[']=processLink;
    g_actions[(unsigned int)'!']=processLink;
    g_actions[(unsigned int)'<']=processHtmlTag;
    g_actions[(unsigned int)'-']=processNmdash;
    g_actions[(unsigned int)'"']=processQuoted;
    init=TRUE;
  }

  g_linkRefs.setAutoDelete(TRUE);
  g_linkRefs.clear();
  g_current = e;
  g_fileName = fileName;
  g_lineNr   = lineNr;
  static GrowBuf out;
  if (input.isEmpty()) return input;
  out.clear();
  int refIndent;
  // for replace tabs by spaces
  QCString s = detab(input,refIndent);
  //printf("======== DeTab =========\n---- output -----\n%s\n---------\n",s.data());
  // then process quotation blocks (as these may contain other blocks)
  s = processQuotations(s,refIndent);
  //printf("======== Quotations =========\n---- output -----\n%s\n---------\n",s.data());
  // then process block items (headers, rules, and code blocks, references)
  s = processBlocks(s,refIndent);
  //printf("======== Blocks =========\n---- output -----\n%s\n---------\n",s.data());
  // finally process the inline markup (links, emphasis and code spans)
  processInline(out,s,s.length());
  out.addChar(0);
  Debug::print(Debug::Markdown,0,"======== Markdown =========\n---- input ------- \n%s\n---- output -----\n%s\n---------\n",input.data(),out.get());
  return out.get();
}

//---------------------------------------------------------------------------

QCString markdownFileNameToId(const QCString &fileName)
{
  QCString baseFn  = stripFromPath(QFileInfo(fileName).absFilePath().utf8());
  int i = baseFn.findRev('.');
  if (i!=-1) baseFn = baseFn.left(i);
  QCString baseName = substitute(substitute(baseFn," ","_"),"/","_");
  return "md_"+baseName;
}

void MarkdownFileParser::parseInput(const char *fileName, 
                const char *fileBuf, 
                Entry *root,
                bool /*sameTranslationUnit*/,
                QStrList & /*filesInSameTranslationUnit*/)
{
  Entry *current = new Entry;
  current->lang = SrcLangExt_Markdown;
  current->fileName = fileName;
  current->docFile  = fileName;
  current->docLine  = 1;
  QCString docs = fileBuf;
  QCString id;
  QCString title=extractPageTitle(docs,id).stripWhiteSpace();
  QCString titleFn = QFileInfo(fileName).baseName().utf8();
  QCString fn      = QFileInfo(fileName).fileName().utf8();
  static QCString mdfileAsMainPage = Config_getString("USE_MDFILE_AS_MAINPAGE");
  if (id.isEmpty()) id = markdownFileNameToId(fileName);
  if (title.isEmpty()) title = titleFn;
  if (!mdfileAsMainPage.isEmpty() &&
      (fn==mdfileAsMainPage || // name reference
       QFileInfo(fileName).absFilePath()==
       QFileInfo(mdfileAsMainPage).absFilePath()) // file reference with path
     )
  {
    docs.prepend("@mainpage\n");
  }
  else if (id=="mainpage" || id=="index")
  {
    docs.prepend("@mainpage "+title+"\n");
  }
  else
  {
    docs.prepend("@page "+id+" "+title+"\n");
  }
  int lineNr=1;
  int position=0;

  // even without markdown support enabled, we still 
  // parse markdown files as such
  bool markdownEnabled = Doxygen::markdownSupport;
  Doxygen::markdownSupport = TRUE;

  bool needsEntry = FALSE;
  Protection prot=Public;
  while (parseCommentBlock(
        this,
        current,
        docs,
        fileName,
        lineNr,
        FALSE,     // isBrief
        FALSE,     // javadoc autobrief
        FALSE,     // inBodyDocs
        prot,      // protection
        position,
        needsEntry))
  {
    if (needsEntry)
    {
      QCString docFile = current->docFile;
      root->addSubEntry(current);
      current = new Entry;
      current->lang = SrcLangExt_Markdown;
      current->docFile = docFile;
      current->docLine = lineNr;
    }
  }
  if (needsEntry)
  {
    root->addSubEntry(current);
  }

  // restore setting
  Doxygen::markdownSupport = markdownEnabled;
  //g_correctSectionLevel = FALSE;
}

void MarkdownFileParser::parseCode(CodeOutputInterface &codeOutIntf,
               const char *scopeName,
               const QCString &input,
               SrcLangExt lang,
               bool isExampleBlock,
               const char *exampleName,
               FileDef *fileDef,
               int startLine,
               int endLine,
               bool inlineFragment,
               MemberDef *memberDef,
               bool showLineNumbers,
               Definition *searchCtx,
               bool collectXRefs
              )
{
  ParserInterface *pIntf = Doxygen::parserManager->getParser("*.cpp");
  if (pIntf!=this)
  {
    pIntf->parseCode(
       codeOutIntf,scopeName,input,lang,isExampleBlock,exampleName,
       fileDef,startLine,endLine,inlineFragment,memberDef,showLineNumbers,
       searchCtx,collectXRefs);
  }
}

void MarkdownFileParser::resetCodeParserState()
{
  ParserInterface *pIntf = Doxygen::parserManager->getParser("*.cpp");
  if (pIntf!=this)
  {
    pIntf->resetCodeParserState();
  }
}

void MarkdownFileParser::parsePrototype(const char *text)
{
  ParserInterface *pIntf = Doxygen::parserManager->getParser("*.cpp");
  if (pIntf!=this)
  {
    pIntf->parsePrototype(text);
  }
}