Fossil

TCLSH = @TCLSH@

CFLAGS = @CFLAGS@
CFLAGS_INCLUDE = @CFLAGS_INCLUDE@
LIB =	@LDFLAGS@ @EXTRA_LDFLAGS@ @LIBS@
BCCFLAGS =	@CPPFLAGS@ $(CFLAGS)
TCCFLAGS =	@EXTRA_CFLAGS@ @CPPFLAGS@ $(CFLAGS) -DHAVE_AUTOCONFIG_H -D_HAVE_SQLITE_CONFIG_H
#
# Fuzzing may be enable by appending -fsanitize=fuzzer -DFOSSIL_FUZZ
# to the TCCFLAGS variable.
# For more thorouth (but also slower) investigation
#      -fsanitize=fuzzer,undefined,address
# might be more useful.

INSTALLDIR = $(DESTDIR)@prefix@/bin
USE_SYSTEM_SQLITE = @USE_SYSTEM_SQLITE@
SQLITE3_SRC.2 = @SQLITE3_SRC.2@
SQLITE3_OBJ.2 = @SQLITE3_OBJ.2@
SQLITE3_SHELL_SRC.2 = @SQLITE3_SHELL_SRC.2@
SQLITE3_ORIGIN = @SQLITE3_ORIGIN@
# SQLITE3_ORIGIN changes...
#  SQLITE3_SRC:
#   0=src/sqlite3.c, 1=src/sqlite3-see.c, 2=$(SQLITE3_SRC.2)
#  SQLITE3_SHELL_SRC:
#   0=src/shell.c, 1=src/shell-see.c, 2=$(SQLITE3_SHELL_SRC.2)
USE_LINENOISE = @USE_LINENOISE@
USE_MMAN_H = @USE_MMAN_H@
USE_SEE = @USE_SEE@
APPNAME = fossil
#
# APPNAME = fossil-fuzz
# may be more appropriate for fuzzing.

.PHONY: all tags

include $(SRCDIR)/main.mk

distclean: clean
	-rm -f autoconfig.h config.log Makefile

void markdown_extract_links(
  char *zInputText,
  Backlink *p
){
  struct mkd_renderer html_renderer = {
    /* prolog     */ (void(*)(Blob*,void*))mkdn_noop0,
    /* epilog     */ (void(*)(Blob*,void*))mkdn_noop0,
    /* footnotes  */ (void(*)(Blob*,const Blob*, void*))mkdn_noop0,

    /* blockcode  */ (void(*)(Blob*,Blob*,void*))mkdn_noop0,
    /* blockquote */ (void(*)(Blob*,Blob*,void*))mkdn_noop0,
    /* blockhtml  */ (void(*)(Blob*,Blob*,void*))mkdn_noop0,
    /* header     */ (void(*)(Blob*,Blob*,int,void*))mkdn_noop0,
    /* hrule      */ (void(*)(Blob*,void*))mkdn_noop0,
    /* list       */ (void(*)(Blob*,Blob*,int,void*))mkdn_noop0,
    /* listitem   */ (void(*)(Blob*,Blob*,int,void*))mkdn_noop0,
    /* paragraph  */ (void(*)(Blob*,Blob*,void*))mkdn_noop0,
    /* table      */ (void(*)(Blob*,Blob*,Blob*,void*))mkdn_noop0,
    /* table_cell */ (void(*)(Blob*,Blob*,int,void*))mkdn_noop0,
    /* table_row  */ (void(*)(Blob*,Blob*,int,void*))mkdn_noop0,
    /* footnoteitm*/ (void(*)(Blob*,const Blob*,int,int,void*))mkdn_noop0,

    /* autolink   */ (int(*)(Blob*,Blob*,enum mkd_autolink,void*))mkdn_noop1,
    /* codespan   */ (int(*)(Blob*,Blob*,int,void*))mkdn_noop1,
    /* dbl_emphas */ (int(*)(Blob*,Blob*,char,void*))mkdn_noop1,
    /* emphasis   */ (int(*)(Blob*,Blob*,char,void*))mkdn_noop1,
    /* image      */ (int(*)(Blob*,Blob*,Blob*,Blob*,void*))mkdn_noop1,
    /* linebreak  */ (int(*)(Blob*,void*))mkdn_noop1,
    /* link       */ backlink_md_link,
    /* r_html_tag */ (int(*)(Blob*,Blob*,void*))mkdn_noop1,
    /* tri_emphas */ (int(*)(Blob*,Blob*,char,void*))mkdn_noop1,
    /* footnoteref*/ (int(*)(Blob*,const Blob*,const Blob*,int,int,void*))mkdn_noop1,

    0,  /* entity */
    0,  /* normal_text */
    "*_", /* emphasis characters */
    0   /* client data */
  };
  Blob out, in;
  html_renderer.opaque = (void*)p;

#define blob_size(X)  ((X)->nUsed)

/*
** The buffer holding the blob data
*/
#define blob_buffer(X)  ((X)->aData)

/*
** Append blob contents to another
*/
#define blob_appendb(dest, src) \
  blob_append((dest), blob_buffer(src), blob_size(src))

/*
** Append a string literal to a blob
** TODO: Consider renaming to blob_appendl()
*/
#define blob_append_literal(blob, literal) \
  blob_append((blob), "" literal, (sizeof literal)-1)
  /*
   * The empty string in the second argument leads to a syntax error
   * when the macro is not used with a string literal. Unfortunately
   * the error is not overly explicit.
   */

/*
** TODO: Suggested for removal because the name seems misleading.
*/
#define blob_append_string blob_append_literal

/*
** Seek whence parameter values
*/
#define BLOB_SEEK_SET 1
#define BLOB_SEEK_CUR 2

#endif /* INTERFACE */

  }
  nUsed = pBlob->nUsed;
  pBlob->nUsed += nData;
  pBlob->aData[pBlob->nUsed] = 0;
  memcpy(&pBlob->aData[nUsed], aData, nData);
}








/*
** Append a single character to the blob.  If pBlob is zero then the
** character is written directly to stdout.
*/
void blob_append_char(Blob *pBlob, char c){
  if( pBlob==0 || pBlob->nUsed+1 >= pBlob->nAlloc ){
    blob_append_full(pBlob, &c, 1);

  return p->aData;
}

/*
** Compare two blobs.  Return negative, zero, or positive if the first
** blob is less then, equal to, or greater than the second.
*/
int blob_compare(const Blob *pA, const Blob *pB){
  int szA, szB, sz, rc;
  blob_is_init(pA);
  blob_is_init(pB);
  szA = blob_size(pA);
  szB = blob_size(pB);
  sz = szA<szB ? szA : szB;
  rc = memcmp(blob_buffer(pA), blob_buffer(pB), sz);

body.branch .submenu > a.timeline-link.selected {
  display: inline;
}

.monospace {
  font-family: monospace;
}

div.markdown > ol.footnotes {
  font-size: 90%;
}
div.markdown > ol.footnotes > li {
  margin-bottom: 0.5em;
}
div.markdown ol.footnotes > li.fn-joined > sup.fn-joined {
  color: gray;
  font-family: monospace;
}
div.markdown ol.footnotes > li.fn-joined > sup.fn-joined::after {
  content: "(joined from multiple locations) ";
}
div.markdown ol.footnotes > li.fn-misreference {
  margin-top:    0.75em;
  margin-bottom: 0.75em;
}
div.markdown ol.footnotes > li.fn-toodeep > i,
div.markdown ol.footnotes > li.fn-misreference,
div.markdown ol.footnotes > li.fn-unreferenced {
  color: gray;
}
div.markdown ol.footnotes > li.fn-misreference > span {
  color: red;
}
div.markdown ol.footnotes > li.fn-misreference > span::after {
  content: " (use of undefined label).";
}
div.markdown ol.footnotes > li.fn-unreferenced {
  padding-left: 0.5em;
}
div.markdown ol.footnotes > li.fn-unreferenced > code {
  color: red;
}
div.markdown ol.footnotes > li.fn-unreferenced > i::after {
  content: " was defined but is not referenced";
}
div.markdown ol.footnotes > li.fn-toodeep > i::after {
  content: " depth of nesting of inline footnotes exceeded the limit";
}
div.markdown ol.footnotes > li.fn-toodeep > pre,
div.markdown ol.footnotes > li.fn-unreferenced > pre {
  color: gray;
  font-size: 85%;
  padding-left: 0.5em;
  margin-top:  0.25em;
  border-left: 2px solid red;
}
div.markdown ol.footnotes > li.fn-toodeep > pre {
  margin-left: 0.5em;
}
div.markdown > ol.footnotes > li > .fn-backrefs {
  margin-right: 0.5em;
  font-weight: bold;
}
div.markdown > ol.footnotes > li > .fn-backrefs > a,
div.markdown sup.noteref > a {
  padding-left:  2px;
  padding-right: 2px;
}
div.markdown sup.noteref.misref,
div.markdown sup.noteref.misref > a {
  color: red;
  font-size: 90%;
}
div.markdown sup.noteref > a:target,
div.markdown span.notescope:target > sup.noteref > a,
div.markdown span.notescope:hover  > sup.noteref > a,
div.markdown > ol.footnotes > li > .fn-backrefs > a:target {
  background: gold;
}
div.markdown span.notescope:hover,
div.markdown span.notescope:target {
  border-bottom: 2px solid gold;
}

/* Objects in the "desktoponly" class are invisible on mobile */
@media screen and (max-width: 600px) {
  .desktoponly {
    display: none;
  }
}

** characters are encoded as "%HH" where HH is a two-digit hexidecimal
** representation of the character.  The "/" character is not encoded
** by this routine.
*/
char *urlize(const char *z, int n){
  return EncodeHttp(z, n, 0);
}

/*
** If input string does not contain quotes (niether ' nor ")
** then return the argument itself. Otherwise return a newly allocated
** copy of input with all quotes %-escaped.
*/
const char* escape_quotes(const char *zIn){
  char *zRet, *zOut;
  size_t i, n = 0;
  for(i=0; zIn[i]; i++){
    if( zIn[i]== '"' || zIn[i]== '\'' ) n++;
  }
  if( !n ) return zIn;
  zRet = zOut = fossil_malloc( i + 2*n + 1 );
  for(i=0; zIn[i]; i++){
    if( zIn[i]=='"' ){
      *(zOut++) = '%';
      *(zOut++) = '2';
      *(zOut++) = '2';
    }else if( zIn[i]=='\'' ){
      *(zOut++) = '%';
      *(zOut++) = '2';
      *(zOut++) = '7';
    }else{
      *(zOut++) = zIn[i];
    }
  }
  *zOut = 0;
  return zRet;
}

/*
** Convert a single HEX digit to an integer
*/
static int AsciiToHex(int c){
  if( c>='a' && c<='f' ){
    c += 10 - 'a';

      cson_value *v;
      cson_object *o;
    } reqPayload;              /* request payload object (if any) */
    cson_array *warnings;      /* response warnings */
    int timerId;               /* fetched from fossil_timer_start() */
  } json;
#endif /* FOSSIL_ENABLE_JSON */
  int ftntsIssues[4];     /* Counts for misref, strayed, joined, overnested */
  int diffCnt[3];         /* Counts for DIFF_NUMSTAT: files, ins, del */
};

/*
** Macro for debugging:
*/
#define CGIDEBUG(X)  if( g.fDebug ) cgi_debug X

};

/* mkd_renderer -- functions for rendering parsed data */
struct mkd_renderer {
  /* document level callbacks */
  void (*prolog)(struct Blob *ob, void *opaque);
  void (*epilog)(struct Blob *ob, void *opaque);
  void (*footnotes)(struct Blob *ob, const struct Blob *items, void *opaque);

  /* block level callbacks - NULL skips the block */
  void (*blockcode)(struct Blob *ob, struct Blob *text, void *opaque);
  void (*blockquote)(struct Blob *ob, struct Blob *text, void *opaque);
  void (*blockhtml)(struct Blob *ob, struct Blob *text, void *opaque);
  void (*header)(struct Blob *ob, struct Blob *text,
            int level, void *opaque);
  void (*hrule)(struct Blob *ob, void *opaque);
  void (*list)(struct Blob *ob, struct Blob *text, int flags, void *opaque);
  void (*listitem)(struct Blob *ob, struct Blob *text,
            int flags, void *opaque);
  void (*paragraph)(struct Blob *ob, struct Blob *text, void *opaque);
  void (*table)(struct Blob *ob, struct Blob *head_row, struct Blob *rows,
              void *opaque);
  void (*table_cell)(struct Blob *ob, struct Blob *text, int flags,
              void *opaque);
  void (*table_row)(struct Blob *ob, struct Blob *cells, int flags,
              void *opaque);
  void (*footnote_item)(struct Blob *ob, const struct Blob *text, 
              int index, int nUsed, void *opaque);

  /* span level callbacks - NULL or return 0 prints the span verbatim */
  int (*autolink)(struct Blob *ob, struct Blob *link,
          enum mkd_autolink type, void *opaque);
  int (*codespan)(struct Blob *ob, struct Blob *text, int nSep, void *opaque);
  int (*double_emphasis)(struct Blob *ob, struct Blob *text,
            char c, void *opaque);
  int (*emphasis)(struct Blob *ob, struct Blob *text, char c,void*opaque);
  int (*image)(struct Blob *ob, struct Blob *link, struct Blob *title,
            struct Blob *alt, void *opaque);
  int (*linebreak)(struct Blob *ob, void *opaque);
  int (*link)(struct Blob *ob, struct Blob *link, struct Blob *title,
          struct Blob *content, void *opaque);
  int (*raw_html_tag)(struct Blob *ob, struct Blob *tag, void *opaque);
  int (*triple_emphasis)(struct Blob *ob, struct Blob *text,
            char c, void *opaque);
  int (*footnote_ref)(struct Blob *ob, const struct Blob *span,
              const struct Blob *upc, int index, int locus, void *opaque);

  /* low level callbacks - NULL copies input directly into the output */
  void (*entity)(struct Blob *ob, struct Blob *entity, void *opaque);
  void (*normal_text)(struct Blob *ob, struct Blob *text, void *opaque);

  /* renderer data */
  const char *emph_chars; /* chars that trigger emphasis rendering */

/**********************
 * EXPORTED FUNCTIONS *
 **********************/

/*
** markdown -- parses the input buffer and renders it into the output buffer.
*/
void markdown(
  struct Blob *ob,
  const struct Blob *ib,
  const struct mkd_renderer *rndr);


#endif /* INTERFACE */

#define BLOB_COUNT(pBlob,el_type) (blob_size(pBlob)/sizeof(el_type))
#define COUNT_FOOTNOTES(pBlob) BLOB_COUNT(pBlob,struct footnote)
#define CAST_AS_FOOTNOTES(pBlob) ((struct footnote*)blob_buffer(pBlob))

/***************
 * LOCAL TYPES *
 ***************/

/*
** link_ref -- reference to a link.
*/
struct link_ref {
  struct Blob id;     /* must be the first field as in footnote struct */
  struct Blob link;
  struct Blob title;
};

/*
** A footnote's data.
** id, text, and upc fields must be in that particular order.
*/
struct footnote {
  struct Blob id;      /* must be the first field as in link_ref struct  */
  struct Blob text;    /* footnote's content that is rendered at the end */
  struct Blob upc;     /* user-provided classes  .ASCII-alnum.or-hypen:  */
  int bRndred;         /* indicates if `text` holds a rendered content   */

  int defno;  /* serial number of definition, set during the first pass  */
  int index;  /* set to the index within array after ordering by id      */
  int iMark;  /* user-visible numeric marker, assigned upon the first use*/
  int nUsed;  /* counts references to this note, increments upon each use*/
};
#define FOOTNOTE_INITIALIZER {empty_blob,empty_blob,empty_blob, 0,0,0,0,0}

/* char_trigger -- function pointer to render active chars */
/*   returns the number of chars taken care of */
/*   data is the pointer of the beginning of the span */
/*   offset is the number of valid chars before data */
struct render;
typedef size_t (*char_trigger)(

struct render {
  struct mkd_renderer make;
  struct Blob refs;
  char_trigger active_char[256];
  int iDepth;                    /* Depth of recursion */
  int nBlobCache;                /* Number of entries in aBlobCache */
  struct Blob *aBlobCache[20];   /* Cache of Blobs available for reuse */


  struct {
    Blob all;    /* Buffer that holds array of footnotes. Its underline
                    memory may be reallocated when a new footnote is added. */
    int nLbled;  /* number of labeled footnotes found during the first pass */
    int nMarks;  /* counts distinct indices found during the second pass    */
    struct footnote misref; /* nUsed counts misreferences, iMark must be -1 */
  } notes;
};

/* html_tag -- structure for quick HTML tag search (inspired from discount) */
struct html_tag {
  const char *text;
  int size;
};

*/
static const struct html_tag block_tags[] = {
  { "html",         4 },
  { "pre",          3 },
  { "script",       6 },
};


/***************************
 * STATIC HELPER FUNCTIONS *
 ***************************/

/*
** build_ref_id -- collapse whitespace from input text to make it a ref id.
** Potential TODO: maybe also handle CR+LF line endings?
*/
static int build_ref_id(struct Blob *id, const char *data, size_t size){
  size_t beg, i;
  char *id_data;

  /* skip leading whitespace */
  while( size>0 && (data[0]==' ' || data[0]=='\t' || data[0]=='\n') ){
    data++;

/* cmp_link_ref_sort -- comparison function for link_ref qsort */
static int cmp_link_ref_sort(const void *a, const void *b){
  struct link_ref *lra = (void *)a;
  struct link_ref *lrb = (void *)b;
  return blob_compare(&lra->id, &lrb->id);
}

/*
** cmp_footnote_id -- comparison function for footnotes qsort.
** Empty IDs sort last (in undetermined order).
** Equal IDs are sorted in the order of definition in the source.
*/
static int cmp_footnote_id(const void *fna, const void *fnb){
  const struct footnote *a = fna, *b = fnb;
  const int szA = blob_size(&a->id), szB = blob_size(&b->id);
  if( szA ){
    if( szB ){
      int cmp = blob_compare(&a->id, &b->id);
      if( cmp ) return cmp;
    }else return -1;
  }else return szB ? 1 : 0;
  /* IDs are equal and non-empty */
  if( a->defno < b->defno ) return -1;
  if( a->defno > b->defno ) return  1;
  assert(!"reachable");
  return 0; /* should never reach here */
}

/*
** cmp_footnote_sort -- comparison function for footnotes qsort.
** Unreferenced footnotes (when nUsed == 0) sort last and
** are sorted in the order of definition in the source.
*/
static int cmp_footnote_sort(const void *fna, const void *fnb){
  const struct footnote *a = fna, *b = fnb;
  int i, j;
  assert( a->nUsed >= 0 );
  assert( b->nUsed >= 0 );
  assert( a->defno >= 0 );
  assert( b->defno >= 0 );
  if( a->nUsed ){
    assert( a->iMark >  0 );
    if( !b->nUsed ) return -1;
    assert( b->iMark >  0 );
    i = a->iMark;
    j = b->iMark;
  }else{
    if( b->nUsed )  return  1;
    i = a->defno;
    j = b->defno;
  }
  if( i < j ) return -1;
  if( i > j ) return  1;
  return 0;
}

/* cmp_html_tag -- comparison function for bsearch() (stolen from discount) */
static int cmp_html_tag(const void *a, const void *b){
  const struct html_tag *hta = a;
  const struct html_tag *htb = b;
  int sz = hta->size;
  int c;

  if( fossil_isspace(before) ) return 0;
  if( fossil_isalnum(before) ) return 1;
  if( fossil_isalnum(after) ) return 0;
  return 1;
}


/*
** parse_emph1 -- parsing single emphasis.
** closed by a symbol not preceded by whitespace and not followed by symbol.
*/
static size_t parse_emph1(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t size,
  char c
){

      release_work_buffer(rndr, work);
      return r ? i+1 : 0;
    }
  }
  return 0;
}

/*
** parse_emph2 -- parsing single emphasis.
*/
static size_t parse_emph2(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t size,
  char c
){

      return r ? i+2 : 0;
    }
    i++;
  }
  return 0;
}

/*
** parse_emph3 -- parsing single emphasis.
** finds the first closing tag, and delegates to the other emph.
*/
static size_t parse_emph3(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t size,
  char c
){

      len = parse_emph2(ob, rndr, data-1, size+1, c);
      return len ? len-1 : 0;
    }
  }
  return 0;
}

/*
** char_emphasis -- single and double emphasis parsing.
*/
static size_t char_emphasis(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){

      return 0;
    }
    return ret+3;
  }
  return 0;
}

/*
** char_linebreak -- '\n' preceded by two spaces (assuming linebreak != 0).
*/
static size_t char_linebreak(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){
  if( offset<2 || data[-1]!=' ' || data[-2]!=' ' ) return 0;
  /* removing the last space from ob and rendering */
  if( blob_size(ob)>0 && blob_buffer(ob)[blob_size(ob)-1]==' ' ) ob->nUsed--;
  return rndr->make.linebreak(ob, rndr->make.opaque) ? 1 : 0;
}

/*
** char_codespan -- '`' parsing a code span (assuming codespan != 0).
*/
static size_t char_codespan(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){

  }else{
    if( !rndr->make.codespan(ob, 0, nb, rndr->make.opaque) ) end = 0;
  }
  return end;
}


/*
** char_escape -- '\\' backslash escape.
*/
static size_t char_escape(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){
  struct Blob work = BLOB_INITIALIZER;
  if( size>1 ){
    if( rndr->make.normal_text ){
      blob_init(&work, data+1,1);
      rndr->make.normal_text(ob, &work, rndr->make.opaque);
    }else{
      blob_append(ob, data+1, 1);
    }
  }
  return 2;
}

/*
** char_entity -- '&' escaped when it doesn't belong to an entity.
** valid entities are assumed to be anything matching &#?[A-Za-z0-9]+;
*/
static size_t char_entity(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){

    rndr->make.entity(ob, &work, rndr->make.opaque);
  }else{
    blob_append(ob, data, end);
  }
  return end;
}

/*
** char_langle_tag -- '<' when tags or autolinks are allowed.
*/
static size_t char_langle_tag(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){

  if( !ret ){
    return 0;
  }else{
    return end;
  }
}

/*
** get_link_inline -- extract inline-style link and title from
** parenthesed data
*/
static int get_link_inline(
  struct Blob *link,
  struct Blob *title,
  char *data,
  size_t size

       || data[link_e-1]=='\n')
  ){
    link_e--;
  }

  /* remove optional angle brackets around the link */
  if( data[link_b]=='<' ) link_b += 1;
  if( link_e && data[link_e-1]=='>' ) link_e -= 1;

  /* escape backslashed character from link */
  blob_reset(link);
  i = link_b;
  while( i<link_e ){
    mark = i;
    while( i<link_e && data[i]!='\\' ){ i++; }
    blob_append(link, data+mark, i-mark);
    while( i<link_e && data[i]=='\\' ){ i++; }
  }

  /* handing back title */
  blob_reset(title);
  if( title_e>title_b ) blob_append(title, data+title_b, title_e-title_b);

  /* this function always succeed */
  return 0;
}


/*
** get_link_ref -- extract referenced link and title from id.
*/
static int get_link_ref(
  struct render *rndr,
  struct Blob *link,
  struct Blob *title,
  char *data,
  size_t size
){
  struct link_ref *lr;
  const size_t sz = blob_size(&rndr->refs);

  /* find the link from its id (stored temporarily in link) */
  blob_reset(link);
  if( !sz || build_ref_id(link, data, size)<0 ) return -1;
  lr = bsearch(link,
               blob_buffer(&rndr->refs),
               sz/sizeof(struct link_ref),
               sizeof (struct link_ref),
               cmp_link_ref);
  if( !lr ) return -1;

  /* fill the output buffers */
  blob_reset(link);
  blob_reset(title);
  blob_appendb(link, &lr->link);
  blob_appendb(title, &lr->title);
  return 0;
}

/*
** get_footnote() -- find a footnote by label, invoked during the 2nd pass.
** If found then return a shallow copy of the corresponding footnote;
** otherwise return a shallow copy of rndr->notes.misref.
** In both cases corresponding `nUsed` field is incremented before return.
*/
static struct footnote get_footnote(
  struct render *rndr,
  const char *data,
  size_t size
){
  struct footnote *fn = 0;
  struct Blob *id;
  if( !rndr->notes.nLbled ) goto fallback;
  id = new_work_buffer(rndr);
  if( build_ref_id(id, data, size)<0 ) goto cleanup;
  fn = bsearch(id, blob_buffer(&rndr->notes.all),
               rndr->notes.nLbled,
               sizeof (struct footnote),
               cmp_link_ref);
  if( !fn ) goto cleanup;

  if( fn->nUsed == 0 ){  /* the first reference to the footnote */
    assert( fn->iMark == 0 );
    fn->iMark = ++(rndr->notes.nMarks);
  }
  assert( fn->iMark > 0 );
cleanup:
  release_work_buffer( rndr, id );
fallback:
  if( !fn ) fn = &rndr->notes.misref;
  fn->nUsed++;
  assert( fn->nUsed > 0 );
  return *fn;
}

/*
** Counts characters in the blank prefix within at most nHalfLines.
** A sequence of spaces and tabs counts as odd halfline,
** a newline counts as even halfline.
** If nHalfLines < 0 then proceed without constraints.
*/
static inline size_t sizeof_blank_prefix(
  const char *data, size_t size, int nHalfLines
){
  const char *p = data;
  const char * const end = data+size;
  if( nHalfLines < 0 ){
    while( p!=end && fossil_isspace(*p) ){
      p++;
    }
  }else while( nHalfLines > 0 ){
    while( p!=end && (*p==' ' || *p=='\t' ) ){ p++; }
    if( p==end || --nHalfLines == 0 ) break;
    if( *p=='\n' || *p=='\r' ){
      p++;
      if( p==end ) break;
      if( *p=='\n' && p[-1]=='\r' ){
        p++;
      }
    }
    nHalfLines--;
  }
  return p-data;
}

/*
** Check if the data starts with a classlist token of the special form.
** If so then return the length of that token, otherwise return 0.
**
** The token must start with a dot and must end with a colon;
** in between of these it must be a dot-separated list of words;
** each word may contain only alphanumeric characters and hyphens.
**
** If `bBlank` is non-zero then a blank character must follow
** the token's ending colon: otherwise function returns 0
** despite the well-formed token.
*/
static size_t is_footnote_classlist(const char * const data, size_t size,
                                    int bBlank){
  const char *p;
  const char * const end = data+size;
  if( data==end || *data != '.' ) return 0;
  for(p=data+1; p!=end; p++){
    if( fossil_isalnum(*p) || *p=='-' ) continue;
    if( p[-1]=='.' ) break;
    if( *p==':' ){
      p++;
      if( bBlank ){
        if( p==end || !fossil_isspace(*p) ) break;
      }
      return p-data;
    }
    if( *p!='.' ) break;
  }
  return 0;
}

/*
** Adds unlabeled footnote to the rndr->notes.all.
** On success puts a shallow copy of the constructed footnote into pFN
** and returns 1, otherwise pFN is unchanged and 0 is returned.
*/
static inline int add_inline_footnote(
  struct render *rndr,
  const char *text,
  size_t size,
  struct footnote* pFN
){
  struct footnote fn = FOOTNOTE_INITIALIZER, *last;
  const char *zUPC = 0;
  size_t nUPC = 0, n = sizeof_blank_prefix(text, size, 3);
  if( n >= size ) return 0;
  text += n;
  size -= n;
  nUPC = is_footnote_classlist(text, size, 1);
  if( nUPC ){
    assert( nUPC<size );
    zUPC = text;
    text += nUPC;
    size -= nUPC;
  }
  if( sizeof_blank_prefix(text,size,-1)==size ){
    if( !nUPC ) return 0; /* empty inline footnote */
    text = zUPC;
    size = nUPC;          /* bare classlist is treated */
    nUPC = 0;             /* as plain text */
  }
  fn.iMark = ++(rndr->notes.nMarks);
  fn.nUsed  = 1;
  fn.index  = COUNT_FOOTNOTES(&rndr->notes.all);
  assert( fn.iMark > 0 );
  blob_append(&fn.text, text, size);
  if(nUPC) blob_append(&fn.upc, zUPC, nUPC);
  blob_append(&rndr->notes.all, (char *)&fn, sizeof fn);
  last = (struct footnote*)( blob_buffer(&rndr->notes.all)
                            +( blob_size(&rndr->notes.all)-sizeof fn ));
  assert( pFN );
  memcpy( pFN, last, sizeof fn );
  return 1;
}

/*
** Return the byte offset of the matching closing bracket or 0 if not
** found.  begin[0] must be either '[' or '('.
**
** TODO: It seems that things like "\\(" are not handled correctly.
**       That is historical behavior for a corner-case,
**       so it's left as it is until somebody complains.
*/
static inline size_t matching_bracket_offset(
  const char* begin,
  const char* end
){
  const char *i;
  int level;
  const char bra = *begin;
  const char ket = bra=='[' ? ']' : ')';
  assert( bra=='[' || bra=='(' );
  for(i=begin+1,level=1; i!=end; i++){
    if( *i=='\n' )        /* do nothing */;
    else if( i[-1]=='\\' ) continue;
    else if( *i==bra )     level++;
    else if( *i==ket ){
      if( --level<=0 ) return i-begin;
    }
  }
  return 0;
}

/*
** char_footnote -- '(': parsing a standalone inline footnote.
*/
static size_t char_footnote(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size
){
  size_t end;
  struct footnote fn;

  if( size<4 || data[1]!='^' ) return 0;
  end = matching_bracket_offset(data, data+size);
  if( !end ) return 0;
  if( !add_inline_footnote(rndr, data+2, end-2, &fn) ) return 0;
  if( rndr->make.footnote_ref ){
    rndr->make.footnote_ref(ob,0,&fn.upc,fn.iMark,1,rndr->make.opaque);
  }
  return end+1;
}

/*
** char_link -- '[': parsing a link or an image.
*/
static size_t char_link(
  struct Blob *ob,
  struct render *rndr,
  char *data,
  size_t offset,
  size_t size     /* parse_inline() ensures that size > 0 */
){
  const int is_img = (offset && data[-1] == '!');
  size_t i = 1, txt_e;
  struct Blob *content = 0;
  struct Blob *link = 0;
  struct Blob *title = 0;
  struct footnote fn;
  int ret;

  /* checking whether the correct renderer exists */
  if( (is_img && !rndr->make.image) || (!is_img && !rndr->make.link) ){
    return 0;
  }

  /* looking for the matching closing bracket */
  txt_e = matching_bracket_offset(data, data+size);








  if( !txt_e ) return 0;
  i = txt_e + 1;










  ret = 0; /* error if we don't get to the callback */
  fn.nUsed = 0;

  /* free-standing footnote refernece */
  if(!is_img && size>3 && data[1]=='^'){
    fn = get_footnote(rndr, data+2, txt_e-2);
  }else{

    /* skip "inter-bracket-whitespace" - any amount of whitespace or newline */
    /* (this is much more lax than original markdown syntax) */
    while( i<size && (data[i]==' ' || data[i]=='\t' || data[i]=='\n') ){ i++; }

    /* allocate temporary buffers to store content, link and title */
    title = new_work_buffer(rndr);
    content = new_work_buffer(rndr);
    link = new_work_buffer(rndr);

    if( i<size && data[i]=='(' ){

      if( i+2<size && data[i+1]=='^' ){  /* span-bounded inline footnote */

        const size_t k = matching_bracket_offset(data+i, data+size);

        if( !k ) goto char_link_cleanup;

        add_inline_footnote(rndr, data+(i+2), k-2, &fn);
        i += k+1;
      }else{                             /* inline style link  */
        size_t span_end = i;
        while( span_end<size
               && !(data[span_end]==')'
                    && (span_end==i || data[span_end-1]!='\\')) ){
          span_end++;
        }
        if( span_end>=size
            || get_link_inline(link, title, data+i+1, span_end-(i+1))<0 ){
          goto char_link_cleanup;
        }
        i = span_end+1;
      }
    /* reference style link or span-bounded footnote reference */
    }else if( i<size && data[i]=='[' ){
      char *id_data;
      size_t id_size, id_end = i;
      int bFootnote;

      while( id_end<size && data[id_end]!=']' ){ id_end++; }

      if( id_end>=size ) goto char_link_cleanup;
      bFootnote = data[i+1]=='^';
      if( i+1==id_end || (bFootnote && i+2==id_end) ){
        /* implicit id - use the contents */
        id_data = data+1;
        id_size = txt_e-1;
      }else{
        /* explicit id - between brackets */
        id_data = data+i+1;
        id_size = id_end-(i+1);
        if( bFootnote ){
          id_data++;
          id_size--;
        }
      }
      if( bFootnote ){
        fn = get_footnote(rndr, id_data, id_size);
      }else if( get_link_ref(rndr, link, title, id_data, id_size)<0 ){
        goto char_link_cleanup;
      }

      i = id_end+1;

    /* shortcut reference style link */
    }else{
      if( get_link_ref(rndr, link, title, data+1, txt_e-1)<0 ){
        goto char_link_cleanup;
      }

      /* rewinding an "inter-bracket-whitespace" */
      i = txt_e+1;
    }
  }
  /* building content: img alt is escaped, link content is parsed */
  if( txt_e>1 && content ){
    if( is_img ) blob_append(content, data+1, txt_e-1);
    else parse_inline(content, rndr, data+1, txt_e-1);
  }

  /* calling the relevant rendering function */
  if( is_img ){
    if( blob_size(ob)>0 && blob_buffer(ob)[blob_size(ob)-1]=='!' ){
      ob->nUsed--;
    }
    ret = rndr->make.image(ob, link, title, content, rndr->make.opaque);
  }else if( fn.nUsed ){
    if( rndr->make.footnote_ref ){
      ret = rndr->make.footnote_ref(ob, content, &fn.upc, fn.iMark,
                                    fn.nUsed, rndr->make.opaque);
    }
  }else{
    ret = rndr->make.link(ob, link, title, content, rndr->make.opaque);
  }

  /* cleanup */
char_link_cleanup:
  release_work_buffer(rndr, title);
  release_work_buffer(rndr, link);
  release_work_buffer(rndr, content);
  return ret ? i : 0;
}



/*********************************
 * BLOCK-LEVEL PARSING FUNCTIONS *
 *********************************/

/* is_empty -- returns the line length when it is empty, 0 otherwise */

  if( !found ) return 0;

  /* the end of the block has been found */
  if( strcmp(curtag->text,"html")==0 ){
    /* Omit <html> tags */
    enum mkd_autolink dummy;
    int k = tag_length(data, size, &dummy);
    int sz = i - (j+k);
    if( sz>0 ) blob_init(&work, data+k, sz);
  }else{
    blob_init(&work, data, i);
  }
  if( rndr->make.blockhtml ){
    rndr->make.blockhtml(ob, &work, rndr->make.opaque);
  }
  return i;

  struct Blob *ob,        /* output blob */
  struct render *rndr,    /* renderer internal state */
  char *data,             /* input text */
  size_t size             /* input text size */
){
  size_t beg, end, i;
  char *txt_data;
  int has_table;
  if( !size ) return;
  has_table = (rndr->make.table
    && rndr->make.table_row
    && rndr->make.table_cell
    && memchr(data, '|', size)!=0);

  beg = 0;
  while( beg<size ){
    txt_data = data+beg;

/*********************
 * REFERENCE PARSING *
 *********************/

/* is_ref -- returns whether a line is a reference or not */
static int is_ref(
  const char *data,   /* input text */
  size_t beg,         /* offset of the beginning of the line */
  size_t end,         /* offset of the end of the text */
  size_t *last,       /* last character of the link */
  struct Blob *refs   /* array of link references */
){
  size_t i = 0;
  size_t id_offset, id_end;

    }
  }
  i += beg;

  /* id part: anything but a newline between brackets */
  if( data[i]!='[' ) return 0;
  i++;
  if( i>=end || data[i]=='^' ) return 0;  /* see is_footnote() */

  id_offset = i;
  while( i<end && data[i]!='\n' && data[i]!='\r' && data[i]!=']' ){ i++; }
  if( i>=end || data[i]!=']' ) return 0;
  id_end = i;

  /* spacer: colon (space | tab)* newline? (space | tab)* */
  i++;

   && data[i]!=' '
   && data[i]!='\t'
   && data[i]!='\n'
   && data[i]!='\r'
  ){
    i += 1;
  }
  /* TODO: maybe require both data[i-1]=='>' && data[link_offset-1]=='<' ? */
  if( data[i-1]=='>' ) link_end = i-1; else link_end = i;

  /* optional spacer: (space | tab)* (newline | '\'' | '"' | '(' ) */
  while( i<end && (data[i]==' ' || data[i]=='\t') ){ i++; }
  if( i<end
   && data[i]!='\n'
   && data[i]!='\r'

  if( title_end>title_offset ){
    blob_append(&lr.title, data+title_offset, title_end-title_offset);
  }
  blob_append(refs, (char *)&lr, sizeof lr);
  return 1;
}

/*********************
 * FOOTNOTE PARSING  *
 *********************/

/* is_footnote -- check if data holds a definition of a labeled footnote.
 * If so then append the corresponding element to `footnotes` array */
static int is_footnote(
  const char *data,   /* input text */
  size_t beg,         /* offset of the beginning of the line */
  size_t end,         /* offset of the end of the text */
  size_t *last,       /* last character of the link */
  struct Blob * footnotes
){
  size_t i, id_offset, id_end, upc_offset, upc_size;
  struct footnote fn = FOOTNOTE_INITIALIZER;

  /* failfast if data is too short */
  if( beg+5>=end ) return 0;
  i = beg;

  /* footnote definition must start at the begining of a line */
  if( data[i]!='[' ) return 0;
  i++;
  if( data[i]!='^' ) return 0;
  id_offset = ++i;

  /* id part: anything but a newline between brackets */
  while( i<end && data[i]!=']' && data[i]!='\n' && data[i]!='\r' ){ i++; }
  if( i>=end || data[i]!=']' ) return 0;
  id_end = i++;

  /* spacer: colon (space | tab)* */
  if( i>=end || data[i]!=':' ) return 0;
  i++;
  while( i<end && (data[i]==' ' || data[i]=='\t') ){ i++; }

  /* passthrough truncated footnote definition */
  if( i>=end ) return 0;

  if( build_ref_id(&fn.id, data+id_offset, id_end-id_offset)<0 ) return 0;

  /* footnote's text may start on the same line after [^id]: */
  upc_offset = upc_size = 0;
  if( data[i]!='\n' && data[i]!='\r' ){
    size_t j;
    upc_size = is_footnote_classlist(data+i, end-i, 1);
    upc_offset = i; /* prevent further checks for a classlist */
    i += upc_size;
    j = i;
    while( i<end && data[i]!='\n' && data[i]!='\r' ){ i++; };
    if( i!=j )blob_append(&fn.text, data+j, i-j);
    if( i<end ){
      blob_append_char(&fn.text, data[i]);
      i++;
      if( i<end && data[i]=='\n' && data[i-1]=='\r' ){
        blob_append_char(&fn.text, data[i]);
        i++;
      }
    }
  }else{
    i++;
    if( i<end && data[i]=='\n' && data[i-1]=='\r' ) i++;
  }
  if( i<end ){

    /* compute the indentation from the 2nd line  */
    size_t indent = i;
    const char *spaces = data+i;
    while( indent<end && data[indent]==' ' ){ indent++; }
    if( indent>=end ) goto footnote_finish;
    indent -= i;
    if( indent<2 ) goto footnote_finish;

    /* process the 2nd and subsequent lines */
    while( i+indent<end && memcmp(data+i,spaces,indent)==0 ){
      size_t j;
      i += indent;
      if( !upc_offset ){
        /* a classlist must be provided no later than at the 2nd line */
        upc_offset = i + sizeof_blank_prefix(data+i, end-i, 1);
        upc_size = is_footnote_classlist(data+upc_offset,
                                         end-upc_offset, 1);
        if( upc_size ){
          i = upc_offset + upc_size;
        }
      }
      j = i;
      while( i<end && data[i]!='\n' && data[i]!='\r' ){ i++; }
      if( i!=j ) blob_append(&fn.text, data+j, i-j);
      if( i>=end ) break;
      blob_append_char(&fn.text, data[i]);
      i++;
      if( i<end && data[i]=='\n' && data[i-1]=='\r' ){
        blob_append_char(&fn.text, data[i]);
        i++;
      }
    }
  }
footnote_finish:
  if( !blob_size(&fn.text) ){
    blob_reset(&fn.id);
    return 0;
  }
  if( !blob_trim(&fn.text) ){  /* if the content is all-blank */
    if( upc_size ){            /* interpret UPC as plain text */
      blob_append(&fn.text, data+upc_offset, upc_size);
      upc_size = 0;
    }else{
      blob_reset(&fn.id);      /* or clean up and fail */
      blob_reset(&fn.text);
      return 0;
    }
  }
  /* a valid note has been found */
  if( last ) *last = i;
  if( footnotes ){
    fn.defno = COUNT_FOOTNOTES( footnotes );
    if( upc_size ){
      assert( upc_offset && upc_offset+upc_size<end );
      blob_append(&fn.upc, data+upc_offset, upc_size);
    }
    blob_append(footnotes, (char *)&fn, sizeof fn);
  }
  return 1;
}

/**********************
 * EXPORTED FUNCTIONS *
 **********************/

/* markdown -- parses the input buffer and renders it into the output buffer */
void markdown(
  struct Blob *ob,                   /* output blob for rendered text */
  const struct Blob *ib,             /* input blob in markdown */
  const struct mkd_renderer *rndrer  /* renderer descriptor (callbacks) */
){
  struct link_ref *lr;
  struct footnote *fn;
  size_t i, beg, end = 0;
  struct render rndr;

  Blob text = BLOB_INITIALIZER;        /* input after the first pass  */
  Blob * const allNotes = &rndr.notes.all;

  /* filling the render structure */
  if( !rndrer ) return;
  rndr.make = *rndrer;
  rndr.nBlobCache = 0;
  rndr.iDepth = 0;
  rndr.refs  = empty_blob;
  rndr.notes.all = empty_blob;
  rndr.notes.nMarks = 0;
  rndr.notes.misref.id    = empty_blob;
  rndr.notes.misref.text  = empty_blob;
  rndr.notes.misref.upc   = empty_blob;
  rndr.notes.misref.bRndred = 0;
  rndr.notes.misref.nUsed =  0;
  rndr.notes.misref.iMark = -1;

  for(i=0; i<256; i++) rndr.active_char[i] = 0;
  if( (rndr.make.emphasis
    || rndr.make.double_emphasis
    || rndr.make.triple_emphasis)
   && rndr.make.emph_chars
  ){
    for(i=0; rndr.make.emph_chars[i]; i++){
      rndr.active_char[(unsigned char)rndr.make.emph_chars[i]] = char_emphasis;
    }
  }
  if( rndr.make.codespan ) rndr.active_char['`'] = char_codespan;
  if( rndr.make.linebreak ) rndr.active_char['\n'] = char_linebreak;
  if( rndr.make.image || rndr.make.link ) rndr.active_char['['] = char_link;
  if( rndr.make.footnote_ref ) rndr.active_char['('] = char_footnote;
  rndr.active_char['<'] = char_langle_tag;
  rndr.active_char['\\'] = char_escape;
  rndr.active_char['&'] = char_entity;

  /* first pass: iterate over lines looking for references,
   * copying everything else into "text" */
  beg = 0;
  for(const size_t size = blob_size(ib); beg<size ;){
    const char* const data = blob_buffer(ib);

    if( is_ref(data, beg, size, &end, &rndr.refs) ){
      beg = end;
    }else if(is_footnote(data, beg, size, &end, &rndr.notes.all)){
      beg = end;
    }else{ /* skipping to the next line */
      end = beg;
      while( end<size && data[end]!='\n' && data[end]!='\r' ){
        end += 1;
      }
      /* adding the line body if present */
      if( end>beg ) blob_append(&text, data + beg, end - beg);
      while( end<size && (data[end]=='\n' || data[end]=='\r') ){
        /* add one \n per newline */
        if( data[end]=='\n' || (end+1<size && data[end+1]!='\n') ){


          blob_append_char(&text, '\n');
        }
        end += 1;
      }
      beg = end;
    }
  }

  /* sorting the reference array */
  if( blob_size(&rndr.refs) ){
    qsort(blob_buffer(&rndr.refs),
          blob_size(&rndr.refs)/sizeof(struct link_ref),
          sizeof(struct link_ref),
          cmp_link_ref_sort);
  }
  rndr.notes.nLbled = COUNT_FOOTNOTES( allNotes );

  /* sort footnotes by ID and join duplicates */
  if( rndr.notes.nLbled > 1 ){
    int nDups = 0;
    fn = CAST_AS_FOOTNOTES( allNotes );
    qsort(fn, rndr.notes.nLbled, sizeof(struct footnote), cmp_footnote_id);

    /* concatenate footnotes with equal labels */
    for(i=0; i<rndr.notes.nLbled ;){
      struct footnote *x = fn + i;
      size_t j = i+1, k = blob_size(&x->text) + 64 + blob_size(&x->upc);
      while(j<rndr.notes.nLbled && !blob_compare(&x->id, &fn[j].id)){
        k += blob_size(&fn[j].text) + 10 + blob_size(&fn[j].upc);
        j++;
        nDups++;
      }
      if( i+1<j ){
        Blob list = empty_blob;
        blob_reserve(&list, k);
        /* must match _joined_footnote_indicator in html_footnote_item() */
        blob_append_literal(&list, "<ul class='fn-joined'>\n");
        for(k=i; k<j; k++){
          struct footnote *y = fn + k;
          blob_append_literal(&list, "<li>");
          if( blob_size(&y->upc) ){
            blob_appendb(&list, &y->upc);
            blob_reset(&y->upc);
          }
          blob_appendb(&list, &y->text);
          blob_append_literal(&list, "</li>\n");

          /* free memory buffer */
          blob_reset(&y->text);
          if( k!=i ) blob_reset(&y->id);
        }
        blob_append_literal(&list, "</ul>\n");
        x->text = list;
        g.ftntsIssues[2]++;
      }
      i = j;
    }
    if( nDups ){  /* clean rndr.notes.all from invalidated footnotes */
      const int n = rndr.notes.nLbled - nDups;
      struct Blob filtered = empty_blob;
      blob_reserve(&filtered, n*sizeof(struct footnote));
      for(i=0; i<rndr.notes.nLbled; i++){
        if( blob_size(&fn[i].id) ){
          blob_append(&filtered, (char*)(fn+i), sizeof(struct footnote));
        }
      }
      blob_reset( allNotes );
      rndr.notes.all = filtered;
      rndr.notes.nLbled = n;
      assert( COUNT_FOOTNOTES(allNotes) == rndr.notes.nLbled );
    }
  }
  fn = CAST_AS_FOOTNOTES( allNotes );
  for(i=0; i<rndr.notes.nLbled; i++){
    fn[i].index = i;
  }
  assert( rndr.notes.nMarks==0 );

  /* second pass: actual rendering */
  if( rndr.make.prolog ) rndr.make.prolog(ob, rndr.make.opaque);
  parse_block(ob, &rndr, blob_buffer(&text), blob_size(&text));

  if( blob_size(allNotes) || rndr.notes.misref.nUsed ){

    /* Footnotes must be parsed for the correct discovery of (back)links */
    Blob *notes = new_work_buffer( &rndr );
    if( blob_size(allNotes) ){
      Blob *tmp   = new_work_buffer( &rndr );
      int nMarks = -1, maxDepth = 5;

      /* inline notes may get appended to rndr.notes.all while rendering */
      while(1){
        struct footnote *aNotes;
        const int N = COUNT_FOOTNOTES( allNotes );

        /* make a shallow copy of `allNotes` */
        blob_truncate(notes,0);
        blob_appendb(notes, allNotes);
        aNotes = CAST_AS_FOOTNOTES(notes);
        qsort(aNotes, N, sizeof(struct footnote), cmp_footnote_sort);

        if( --maxDepth < 0 || nMarks == rndr.notes.nMarks ) break;
        nMarks = rndr.notes.nMarks;

        for(i=0; i<N; i++){
          const int j = aNotes[i].index;
          struct footnote *x = CAST_AS_FOOTNOTES(allNotes) + j;
          assert( 0<=j && j<N );
          if( x->bRndred || !x->nUsed ) continue;
          assert( x->iMark > 0 );
          assert( blob_size(&x->text) );
          blob_truncate(tmp,0);

          /* `allNotes` may be altered and extended through this call */
          parse_inline(tmp, &rndr, blob_buffer(&x->text), blob_size(&x->text));

          x = CAST_AS_FOOTNOTES(allNotes) + j;
          blob_truncate(&x->text,0);
          blob_appendb(&x->text, tmp);
          x->bRndred = 1;
        }
      }
      release_work_buffer(&rndr,tmp);
    }

    /* footnotes rendering */
    if( rndr.make.footnote_item && rndr.make.footnotes ){
      Blob *all_items = new_work_buffer(&rndr);
      int j = -1;

      /* Assert that the in-memory layout of id, text and upc within
      ** footnote struct matches the expectations of html_footnote_item()
      ** If it doesn't then a compiler has done something very weird.
      */
      assert( &(rndr.notes.misref.id)  == &(rndr.notes.misref.text) - 1 );
      assert( &(rndr.notes.misref.upc) == &(rndr.notes.misref.text) + 1 );

      for(i=0; i<COUNT_FOOTNOTES(notes); i++){
        const struct footnote* x = CAST_AS_FOOTNOTES(notes) + i;
        const int xUsed = x->bRndred ? x->nUsed : 0;
        if( !x->iMark ) break;
        assert( x->nUsed );
        rndr.make.footnote_item(all_items, &x->text, x->iMark,
                                     xUsed, rndr.make.opaque);
        if( !xUsed ) g.ftntsIssues[3]++;  /* an overnested footnote */
        j = i;
      }
      if( rndr.notes.misref.nUsed ){
        rndr.make.footnote_item(all_items, 0, -1,
                    rndr.notes.misref.nUsed, rndr.make.opaque);
        g.ftntsIssues[0] += rndr.notes.misref.nUsed;
      }
      while( ++j < COUNT_FOOTNOTES(notes) ){
        const struct footnote* x = CAST_AS_FOOTNOTES(notes) + j;
        assert( !x->iMark );
        assert( !x->nUsed );
        assert( !x->bRndred );
        rndr.make.footnote_item(all_items,&x->text,0,0,rndr.make.opaque);
        g.ftntsIssues[1]++;
      }
      rndr.make.footnotes(ob, all_items, rndr.make.opaque);
      release_work_buffer(&rndr, all_items);
    }
    release_work_buffer(&rndr, notes);
  }
  if( rndr.make.epilog ) rndr.make.epilog(ob, rndr.make.opaque);

  /* clean-up */
  assert( rndr.iDepth==0 );
  blob_reset(&text);
  lr = (struct link_ref *)blob_buffer(&rndr.refs);
  end = blob_size(&rndr.refs)/sizeof(struct link_ref);
  for(i=0; i<end; i++){
    blob_reset(&lr[i].id);
    blob_reset(&lr[i].link);
    blob_reset(&lr[i].title);
  }
  blob_reset(&rndr.refs);
  fn = CAST_AS_FOOTNOTES( allNotes );
  end = COUNT_FOOTNOTES( allNotes );
  for(i=0; i<end; i++){
    if(blob_size(&fn[i].id)) blob_reset(&fn[i].id);
    if(blob_size(&fn[i].upc)) blob_reset(&fn[i].upc);
    blob_reset(&fn[i].text);
  }
  blob_reset(&rndr.notes.all);
  for(i=0; i<rndr.nBlobCache; i++){
    fossil_free(rndr.aBlobCache[i]);
  }
}

> Formatted using [Pikchr](https://pikchr.org/home), resulting in:

>
~~~ pikchr
oval "Start" fit; arrow; box "Hello, World!" fit; arrow; oval "Done" fit
~~~

<a id="ftnts"></a>
## Footnotes ##

> Footnotes (or "endnotes") is a Fossil's extention of classical Markdown.
> Fossil's syntax for footnotes is similar to links and
> is distinguished by the use of character **^**
> that *immediately* follows an opening bracket.

> 1. **\(^** footnote's text **)**
> 2. **\[** fragment of text **]\(^** a comment about that fragment **\)**
> 3. **\[^**&nbsp;label&nbsp;**\]**
> 4. **\[** fragment of text **\]\[^**&nbsp;label&nbsp;**\]**
> 5. **\[** fragment of text **\]\[^\]**

> With formats 1 and 2 ("inline footnotes") text of a footnote is provided
> in the place where the corresponding numeric mark will be rendered.
> With formats 3, 4, and 5 ("reference footnotes") text of a footnote
> is supplied elsewhere in the document, as shown below.
> Formats 2, 4 and 5 ("span-specific footnotes") mark a specific fragment
> that is being commented in the footnote.
> Format 5 reuses a fragment of text as a label.
> Labels are case-insensitive.

> ```
> [^label]: Footnote definition must start on the first column.
>      The second line (if any) must be indented by two or more spaces.
>      Definition continues until indentation drops below that of the 2nd line.
>```
> Character **^** is not part of a label, it is part of the syntax.
> Both a footnote's text and a fragment to which a footnote applies
> are subject to further interpretation as Markdown sources.

## Miscellaneous ##

> *   In-line images are made using **\!\[alt-text\]\(image-URL\)**.
> *   Use HTML for advanced formatting such as forms.
> *   **\<!--** HTML-style comments **-->** are supported.
> *   Escape special characters (ex: **\[** **\(** **\|** **\***)
>     using backslash (ex: **\\\[** **\\\(** **\\\|** **\\\***).

void markdown_to_html(
  struct Blob *input_markdown,
  struct Blob *output_title,
  struct Blob *output_body);

#endif /* INTERFACE */

/*
** Markdown-internal helper for generating unique link reference IDs.
** Fields provide typed interpretation of the underline memory buffer.
*/
typedef union bitfield64_t bitfield64_t;
union bitfield64_t{
  char c[8];           /* interpret as the array of  signed  characters */
  unsigned char b[8];  /* interpret as the array of unsigned characters */
};

/*
** An instance of the following structure is passed through the
** "opaque" pointer.
*/
typedef struct MarkdownToHtml MarkdownToHtml;
struct MarkdownToHtml {
  Blob *output_title;     /* Store the title here */
  bitfield64_t unique;    /* Enables construction of unique #id elements */

  #ifndef FOOTNOTES_WITHOUT_URI
  Blob reqURI;            /* REQUEST_URI with escaped quotes */
  #endif
};


/* INTER_BLOCK -- skip a line between block level elements */
#define INTER_BLOCK(ob) \
  do { if( blob_size(ob)>0 ) blob_append_char(ob, '\n'); } while (0)




/*
** FOOTNOTES_WITHOUT_URI macro was introduced by [2c1f8f3592ef00e0]
** to enable flexibility in rendering of footnote-specific hyperlinks.
** It may be defined for a particular build in order to omit
** full REQUEST_URIs within footnote-specific (and page-local) hyperlinks.
** This *is* used for the builds that incorporate 'base-href-fix' branch
** (which in turn fixes footnotes on the preview tab of /wikiedit page).
*/
#ifndef FOOTNOTES_WITHOUT_URI
  #define BLOB_APPEND_URI(dest,ctx) blob_appendb(dest,&((ctx)->reqURI))
#else
  #define BLOB_APPEND_URI(dest,ctx)
#endif

/* Converts an integer to a textual base26 representation
** with proper null-termination.
 * Return empty string if that integer is negative.   */
static bitfield64_t to_base26(int i, int uppercase){
  bitfield64_t x;
  int j;
  memset( &x, 0, sizeof(x) );
  if( i >= 0 ){
    for(j=7; j >= 0; j--){
      x.b[j] = (unsigned char)(uppercase?'A':'a') + i%26;
      if( (i /= 26) == 0 ) break;
    }
    assert( j > 0 );    /* because 2^32 < 26^7 */
    for(i=0; i<8-j; i++)  x.b[i] = x.b[i+j];
    for(   ; i<8  ; i++)  x.b[i] = 0;
  }
  assert( x.c[7] == 0 );
  return x;
}

/* HTML escapes
**
** html_escape() converts < to &lt;, > to &gt;, and & to &amp;.
** html_quote() goes further and converts " into &quot; and ' in &#39;.
*/
static void html_quote(struct Blob *ob, const char *data, size_t size){

     && data[i]!='\''
    ){
      i++;
    }
    blob_append(ob, data+beg, i-beg);
    while( i<size ){
      if( data[i]=='<' ){
        blob_append_literal(ob, "&lt;");
      }else if( data[i]=='>' ){
        blob_append_literal(ob, "&gt;");
      }else if( data[i]=='&' ){
        blob_append_literal(ob, "&amp;");
      }else if( data[i]=='"' ){
        blob_append_literal(ob, "&quot;");
      }else if( data[i]=='\'' ){
        blob_append_literal(ob, "&#39;");
      }else{
        break;
      }
      i++;
    }
  }
}

     && data[i]!='&'
    ){
      i++;
    }
    blob_append(ob, data+beg, i-beg);
    while( i<size ){
      if( data[i]=='<' ){
        blob_append_literal(ob, "&lt;");
      }else if( data[i]=='>' ){
        blob_append_literal(ob, "&gt;");
      }else if( data[i]=='&' ){
        blob_append_literal(ob, "&amp;");
      }else{
        break;
      }
      i++;
    }
  }
}


/* HTML block tags */

/* Size of the prolog: "<div class='markdown'>\n" */
#define PROLOG_SIZE 23

static void html_prolog(struct Blob *ob, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<div class=\"markdown\">\n");
  assert( blob_size(ob)==PROLOG_SIZE );
}

static void html_epilog(struct Blob *ob, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "</div>\n");
}

static void html_blockhtml(struct Blob *ob, struct Blob *text, void *opaque){
  char *data = blob_buffer(text);
  size_t size = blob_size(text);
  Blob *title = ((MarkdownToHtml*)opaque)->output_title;
  while( size>0 && fossil_isspace(data[0]) ){ data++; size--; }

  ){
    int nTag = html_tag_length(data);
    blob_append(title, data+nTag, size - nTag - 5);
    return;
  }
  INTER_BLOCK(ob);
  blob_append(ob, data, size);
  blob_append_literal(ob, "\n");
}

static void html_blockcode(struct Blob *ob, struct Blob *text, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<pre><code>");
  html_escape(ob, blob_buffer(text), blob_size(text));
  blob_append_literal(ob, "</code></pre>\n");
}

static void html_blockquote(struct Blob *ob, struct Blob *text, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<blockquote>\n");
  blob_appendb(ob, text);
  blob_append_literal(ob, "</blockquote>\n");
}

static void html_header(
  struct Blob *ob,
  struct Blob *text,
  int level,
  void *opaque
){
  struct Blob *title = ((MarkdownToHtml*)opaque)->output_title;
  /* The first header at the beginning of a text is considered as
   * a title and not output. */
  if( blob_size(ob)<=PROLOG_SIZE && title!=0 && blob_size(title)==0 ){
    blob_appendb(title, text);
    return;
  }
  INTER_BLOCK(ob);
  blob_appendf(ob, "<h%d>", level);
  blob_appendb(ob, text);
  blob_appendf(ob, "</h%d>", level);
}

static void html_hrule(struct Blob *ob, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<hr />\n");
}


static void html_list(
  struct Blob *ob,
  struct Blob *text,
  int flags,
  void *opaque
){
  char ol[] = "ol";
  char ul[] = "ul";
  char *tag = (flags & MKD_LIST_ORDERED) ? ol : ul;
  INTER_BLOCK(ob);
  blob_appendf(ob, "<%s>\n", tag);
  blob_appendb(ob, text);
  blob_appendf(ob, "</%s>\n", tag);
}

static void html_list_item(
  struct Blob *ob,
  struct Blob *text,
  int flags,
  void *opaque
){
  char *text_data = blob_buffer(text);
  size_t text_size = blob_size(text);
  while( text_size>0 && text_data[text_size-1]=='\n' ) text_size--;
  blob_append_literal(ob, "<li>");
  blob_append(ob, text_data, text_size);
  blob_append_literal(ob, "</li>\n");
}

static void html_paragraph(struct Blob *ob, struct Blob *text, void *opaque){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<p>");
  blob_appendb(ob, text);
  blob_append_literal(ob, "</p>\n");
}


static void html_table(
  struct Blob *ob,
  struct Blob *head_row,
  struct Blob *rows,
  void *opaque
){
  INTER_BLOCK(ob);
  blob_append_literal(ob, "<table>\n");
  if( head_row && blob_size(head_row)>0 ){
    blob_append_literal(ob, "<thead>\n");
    blob_appendb(ob, head_row);
    blob_append_literal(ob, "</thead>\n<tbody>\n");
  }
  if( rows ){
    blob_appendb(ob, rows);
  }
  if( head_row && blob_size(head_row)>0 ){
    blob_append_literal(ob, "</tbody>\n");
  }
  blob_append_literal(ob, "</table>\n");
}

static void html_table_cell(
  struct Blob *ob,
  struct Blob *text,
  int flags,
  void *opaque
){
  if( flags & MKD_CELL_HEAD ){
    blob_append_literal(ob, "    <th");
  }else{
    blob_append_literal(ob, "    <td");
  }
  switch( flags & MKD_CELL_ALIGN_MASK ){
    case MKD_CELL_ALIGN_LEFT: {
      blob_append_literal(ob, " align=\"left\"");
      break;
    }
    case MKD_CELL_ALIGN_RIGHT: {
      blob_append_literal(ob, " align=\"right\"");
      break;
    }
    case MKD_CELL_ALIGN_CENTER: {
      blob_append_literal(ob, " align=\"center\"");
      break;
    }
  }
  blob_append_literal(ob, ">");
  blob_appendb(ob, text);
  if( flags & MKD_CELL_HEAD ){
    blob_append_literal(ob, "</th>\n");
  }else{
    blob_append_literal(ob, "</td>\n");
  }
}

static void html_table_row(
  struct Blob *ob,
  struct Blob *cells,
  int flags,
  void *opaque
){
  blob_append_literal(ob, "  <tr>\n");
  blob_appendb(ob, cells);
  blob_append_literal(ob, "  </tr>\n");
}

/*
** Render a token of user provided classes.
** If bHTML is true then render HTML for (presumably) visible text,
** otherwise just a space-separated list of the derived classes.
*/
static void append_footnote_upc(
  struct Blob *ob,
  const struct Blob *upc,  /* token of user-provided classes */
  int bHTML
){
  const char *z = blob_buffer(upc);
  int i, n = blob_size(upc);

  if( n<3 ) return;
  assert( z[0]=='.' && z[n-1] == ':' );
  if( bHTML ){
    blob_append_literal(ob, "<span class='fn-upc'>"
                            "<span class='fn-upcDot'>.</span>");
  }
  n = 0;
  do{
    z++;
    if( *z!='.' && *z!=':' ){
      assert( fossil_isalnum(*z) || *z=='-' );
      n++;
      continue;
    }
    assert( n );
    if(  bHTML ) blob_append_literal(ob, "<span class='");
    blob_append_literal(ob, "fn-upc-");

    for(i=-n; i<0; i++){
      blob_append_char(ob, fossil_tolower(z[i]) );
    }
    if( bHTML ){
      blob_append_literal(ob, "'>");
      blob_append(ob, z-n, n);
      blob_append_literal(ob, "</span>");
    }else{
      blob_append_char(ob, ' ');
    }
    n = 0;
    if( bHTML ){
      if( *z==':' ){
        blob_append_literal(ob,"<span class='fn-upcColon'>:</span>");
      }else{
        blob_append_literal(ob,"<span class='fn-upcDot'>.</span>");
      }
    }
  }while( *z != ':' );
  if( bHTML ) blob_append_literal(ob,"</span>\n");
}

static int html_footnote_ref(
  struct Blob *ob, const struct Blob *span, const struct Blob *upc,
  int iMark, int locus, void *opaque
){
  const struct MarkdownToHtml* ctx = (struct MarkdownToHtml*)opaque;
  const bitfield64_t l = to_base26(locus-1,0);
  char pos[32];
  memset(pos,0,32);
  assert( locus > 0 );
  /* expect BUGs if the following yields compiler warnings */
  if( iMark > 0 ){      /* a regular reference to a footnote */
    sprintf(pos, "%s-%d-%s", ctx->unique.c, iMark, l.c);
    if(span && blob_size(span)) {
      blob_append_literal(ob,"<span class='");
      append_footnote_upc(ob, upc, 0);
      blob_append_literal(ob,"notescope' id='noteref");
      blob_appendf(ob,"%s'>",pos);
      blob_appendb(ob, span);
      blob_trim(ob);
      blob_append_literal(ob,"<sup class='noteref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#footnote%s'>%d</a></sup></span>", pos, iMark);
    }else{
      blob_trim(ob);
      blob_append_literal(ob,"<sup class='");
      append_footnote_upc(ob, upc, 0);
      blob_append_literal(ob,"noteref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#footnote%s' id='noteref%s'>%d</a></sup>",
                      pos,           pos,  iMark);
    }
  }else{              /* misreference */
    assert( iMark == -1 );

    sprintf(pos, "%s-%s", ctx->unique.c, l.c);
    if(span && blob_size(span)) {
      blob_appendf(ob, "<span class='notescope' id='misref%s'>", pos);
      blob_appendb(ob, span);
      blob_trim(ob);
      blob_append_literal(ob, "<sup class='noteref misref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob, "#misreference%s'>misref</a></sup></span>", pos);
    }else{
      blob_trim(ob);
      blob_append_literal(ob, "<sup class='noteref misref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob, "#misreference%s' id='misref%s'>", pos, pos);
      blob_append_literal(ob, "misref</a></sup>");
    }
  }
  return 1;
}

/* Render a single item of the footnotes list.
 * Each backref gets a unique id to enable dynamic styling. */
static void html_footnote_item(
  struct Blob *ob, const struct Blob *text, int iMark, int nUsed, void *opaque
){
  const struct MarkdownToHtml* ctx = (struct MarkdownToHtml*)opaque;
  const char * const unique = ctx->unique.c;
  assert( nUsed >= 0 );
  /* expect BUGs if the following yields compiler warnings */

  if( iMark < 0 ){                     /* misreferences */
    assert( iMark == -1 );
    assert( nUsed );
    blob_append_literal(ob,"<li class='fn-misreference'>"
                              "<sup class='fn-backrefs'>");
    if( nUsed == 1 ){
      blob_appendf(ob,"<a id='misreference%s-a' href='", unique);
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#misref%s-a'>^</a>", unique);
    }else{
      int i;
      blob_append_char(ob, '^');
      for(i=0; i<nUsed && i<26; i++){
        const int c = i + (unsigned)'a';
        blob_appendf(ob," <a id='misreference%s-%c' href='", unique,c);
        BLOB_APPEND_URI(ob, ctx);
        blob_appendf(ob,"#misref%s-%c'>%c</a>", unique,c, c);
      }
      if( i < nUsed ) blob_append_literal(ob," &hellip;");
    }
    blob_append_literal(ob,"</sup>\n<span>Misreference</span>");
  }else if( iMark > 0 ){  /* regular, joined and overnested footnotes */
    char pos[24];
    int bJoin = 0;
    #define _joined_footnote_indicator "<ul class='fn-joined'>"
    #define _jfi_sz (sizeof(_joined_footnote_indicator)-1)
    /* make.footnote_item() invocations should pass args accordingly */
    const struct Blob *upc = text+1;
    assert( text );
    /* allow blob_size(text)==0 for constructs like  [...](^ [] ())  */
    memset(pos,0,24);
    sprintf(pos, "%s-%d", unique, iMark);
    blob_appendf(ob, "<li id='footnote%s' class='", pos);
    if( nUsed ){
      if( blob_size(text)>=_jfi_sz &&
         !memcmp(blob_buffer(text),_joined_footnote_indicator,_jfi_sz)){
        bJoin = 1;
        blob_append_literal(ob, "fn-joined ");
      }
      append_footnote_upc(ob, upc, 0);
    }else{
      blob_append_literal(ob, "fn-toodeep ");
    }
    if( nUsed <= 1 ){
      blob_append_literal(ob, "fn-monoref'><sup class='fn-backrefs'>");
      blob_appendf(ob,"<a id='footnote%s-a' href='", pos);
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#noteref%s-a'>^</a>", pos);
    }else{
      int i;
      blob_append_literal(ob, "fn-polyref'><sup class='fn-backrefs'>^");
      for(i=0; i<nUsed && i<26; i++){
        const int c = i + (unsigned)'a';
        blob_appendf(ob," <a id='footnote%s-%c' href='", pos,c);
        BLOB_APPEND_URI(ob, ctx);
        blob_appendf(ob,"#noteref%s-%c'>%c</a>", pos,c, c);
      }
      /* It's unlikely that so many backrefs will be usefull */
      /* but maybe for some machine generated documents... */
      for(; i<nUsed && i<676; i++){
        const bitfield64_t l = to_base26(i,0);
        blob_appendf(ob," <a id='footnote%s-%s' href='", pos, l.c);
        BLOB_APPEND_URI(ob, ctx);
        blob_appendf(ob,"#noteref%s-%s'>%s</a>", pos,l.c, l.c);
      }
      if( i < nUsed ) blob_append_literal(ob," &hellip;");
    }
    blob_append_literal(ob,"</sup>\n");
    if( bJoin ){
      blob_append_literal(ob,"<sup class='fn-joined'></sup><ul>");
      blob_append(ob,blob_buffer(text)+_jfi_sz,blob_size(text)-_jfi_sz);
    }else if( nUsed ){
      append_footnote_upc(ob, upc, 1);
      blob_appendb(ob, text);
    }else{
      blob_append_literal(ob,"<i></i>\n"
          "<pre><code class='language-markdown'>");
      if( blob_size(upc) ){
        blob_appendb(ob, upc);
      }
      html_escape(ob, blob_buffer(text), blob_size(text));
      blob_append_literal(ob,"</code></pre>");
    }
    #undef _joined_footnote_indicator
    #undef _jfi_sz
  }else{             /* a footnote was defined but wasn't referenced */
    /* make.footnote_item() invocations should pass args accordingly */
    const struct Blob *id = text-1, *upc = text+1;
    assert( !nUsed );
    assert( text );
    assert( blob_size(text) );
    assert( blob_size(id) );
    blob_append_literal(ob,"<li class='fn-unreferenced'>\n[^&nbsp;<code>");
    html_escape(ob, blob_buffer(id), blob_size(id));
    blob_append_literal(ob, "</code>&nbsp;]<i></i>\n"
        "<pre><code class='language-markdown'>");
    if( blob_size(upc) ){
      blob_appendb(ob, upc);
    }
    html_escape(ob, blob_buffer(text), blob_size(text));
    blob_append_literal(ob,"</code></pre>");
  }
  blob_append_literal(ob, "\n</li>\n");
}

static void html_footnotes(
  struct Blob *ob, const struct Blob *items, void *opaque
){
  if( items && blob_size(items) ){
    blob_append_literal(ob,
      "\n<hr class='footnotes-separator'/>\n<ol class='footnotes'>\n");
    blob_appendb(ob, items);
    blob_append_literal(ob, "</ol>\n");
  }
}

/* HTML span tags */

static int html_raw_html_tag(struct Blob *ob, struct Blob *text, void *opaque){
  blob_append(ob, blob_buffer(text), blob_size(text));
  return 1;
}

static int html_autolink(
  struct Blob *ob,
  struct Blob *link,
  enum mkd_autolink type,
  void *opaque
){
  if( !link || blob_size(link)<=0 ) return 0;
  blob_append_literal(ob, "<a href=\"");
  if( type==MKDA_IMPLICIT_EMAIL ) blob_append_literal(ob, "mailto:");
  html_quote(ob, blob_buffer(link), blob_size(link));
  blob_append_literal(ob, "\">");
  if( type==MKDA_EXPLICIT_EMAIL && blob_size(link)>7 ){
    /* remove "mailto:" from displayed text */
    html_escape(ob, blob_buffer(link)+7, blob_size(link)-7);
  }else{
    html_escape(ob, blob_buffer(link), blob_size(link));
  }
  blob_append_literal(ob, "</a>");
  return 1;
}

/*
** The nSrc bytes at zSrc[] are Pikchr input text (allegedly).  Process that
** text and insert the result in place of the original.
*/

  int nSep,           /* Number of grave accents marks as delimiters */
  void *opaque
){
  if( text==0 ){
    /* no-op */
  }else if( nSep<=2 ){
    /* One or two graves: an in-line code span */
    blob_append_literal(ob, "<code>");
    html_escape(ob, blob_buffer(text), blob_size(text));
    blob_append_literal(ob, "</code>");
  }else{
    /* Three or more graves: a fenced code block */
    int n = blob_size(text);
    const char *z = blob_buffer(text);
    int i;
    for(i=0; i<n && z[i]!='\n'; i++){}
    if( i>=n ){

static int html_double_emphasis(
  struct Blob *ob,
  struct Blob *text,
  char c,
  void *opaque
){
  blob_append_literal(ob, "<strong>");
  blob_appendb(ob, text);
  blob_append_literal(ob, "</strong>");
  return 1;
}

static int html_emphasis(
  struct Blob *ob,
  struct Blob *text,
  char c,
  void *opaque
){
  blob_append_literal(ob, "<em>");
  blob_appendb(ob, text);
  blob_append_literal(ob, "</em>");
  return 1;
}

static int html_image(
  struct Blob *ob,
  struct Blob *link,
  struct Blob *title,
  struct Blob *alt,
  void *opaque
){
  blob_append_literal(ob, "<img src=\"");
  html_quote(ob, blob_buffer(link), blob_size(link));
  blob_append_literal(ob, "\" alt=\"");
  html_quote(ob, blob_buffer(alt), blob_size(alt));
  if( title && blob_size(title)>0 ){
    blob_append_literal(ob, "\" title=\"");
    html_quote(ob, blob_buffer(title), blob_size(title));
  }
  blob_append_literal(ob, "\" />");
  return 1;
}

static int html_linebreak(struct Blob *ob, void *opaque){
  blob_append_literal(ob, "<br />\n");
  return 1;
}

static int html_link(
  struct Blob *ob,
  struct Blob *link,
  struct Blob *title,

    static const int flags = 
       WIKI_NOBADLINKS |
       WIKI_MARKDOWNLINKS
    ;
    wiki_resolve_hyperlink(ob, flags, zLink, zClose, sizeof(zClose), 0, zTitle);
  }
  if( blob_size(content)==0 ){
    if( link ) blob_appendb(ob, link);
  }else{
    blob_appendb(ob, content);
  }
  blob_append(ob, zClose, -1);
  return 1;
}

static int html_triple_emphasis(
  struct Blob *ob,
  struct Blob *text,
  char c,
  void *opaque
){
  blob_append_literal(ob, "<strong><em>");
  blob_appendb(ob, text);
  blob_append_literal(ob, "</em></strong>");
  return 1;
}


static void html_normal_text(struct Blob *ob, struct Blob *text, void *opaque){
  html_escape(ob, blob_buffer(text), blob_size(text));
}

  struct Blob *output_title,     /* Put title here.  May be NULL */
  struct Blob *output_body       /* Put document body here. */
){
  struct mkd_renderer html_renderer = {
    /* prolog and epilog */
    html_prolog,
    html_epilog,
    html_footnotes,

    /* block level elements */
    html_blockcode,
    html_blockquote,
    html_blockhtml,
    html_header,
    html_hrule,
    html_list,
    html_list_item,
    html_paragraph,
    html_table,
    html_table_cell,
    html_table_row,
    html_footnote_item,

    /* span level elements */
    html_autolink,
    html_codespan,
    html_double_emphasis,
    html_emphasis,
    html_image,
    html_linebreak,
    html_link,
    html_raw_html_tag,
    html_triple_emphasis,
    html_footnote_ref,

    /* low level elements */
    0,    /* entity */
    html_normal_text,

    /* misc. parameters */
    "*_", /* emph_chars */
    0     /* opaque */
  };
  static int invocation = -1; /* no marker for the first document */
  static const char* zRU = 0; /* REQUEST_URI with escaped quotes  */
  MarkdownToHtml context;
  memset(&context, 0, sizeof(context));
  context.output_title = output_title;
  context.unique = to_base26(invocation++,1);
  if( !zRU ) zRU = escape_quotes(PD("REQUEST_URI",""));
  #ifndef FOOTNOTES_WITHOUT_URI
    blob_set( &context.reqURI, zRU );
  #endif
  html_renderer.opaque = &context;
  if( output_title ) blob_reset(output_title);
  blob_reset(output_body);
  markdown(output_body, input_markdown, &html_renderer);
}

  stylesheet_url_var();
  image_url_var("logo");
  image_url_var("background");
  if( !login_is_nobody() ){
    Th_Store("login", g.zLogin);
  }
  Th_MaybeStore("current_feature", feature_from_page_path(local_zCurrentPage) );
  if( g.ftntsIssues[0] || g.ftntsIssues[1] ||
      g.ftntsIssues[2] || g.ftntsIssues[3] ){
    char buf[80];
    sprintf(&buf[0],"%i %i %i %i",g.ftntsIssues[0],g.ftntsIssues[1],
                                  g.ftntsIssues[2],g.ftntsIssues[3]);
    Th_Store("footnotes_issues_counters", buf);
  }
}

/*
** Draw the header.
*/
void style_header(const char *zTitleFormat, ...){
  va_list ap;

** COMMAND: test-markdown-render
**
** Usage: %fossil test-markdown-render FILE ...
**
** Render markdown in FILE as HTML on stdout.
** Options:
**
**    --safe            Restrict the output to use only "safe" HTML
**    --lint-footnotes  Print stats for footnotes-related issues
*/
void test_markdown_render(void){
  Blob in, out;
  int i;
  int bSafe = 0, bFnLint = 0;
  db_find_and_open_repository(OPEN_OK_NOT_FOUND|OPEN_SUBSTITUTE,0);
  bSafe = find_option("safe",0,0)!=0;
  bFnLint = find_option("lint-footnotes",0,0)!=0;
  verify_all_options();
  for(i=2; i<g.argc; i++){
    blob_zero(&out);
    blob_read_from_file(&in, g.argv[i], ExtFILE);
    if( g.argc>3 ){
      fossil_print("<!------ %h ------->\n", g.argv[i]);
    }
    markdown_to_html(&in, 0, &out);
    safe_html_context( bSafe ? DOCSRC_UNTRUSTED : DOCSRC_TRUSTED );
    safe_html(&out);
    blob_write_to_file(&out, "-");
    blob_reset(&in);
    blob_reset(&out);
  }
  if( bFnLint && (g.ftntsIssues[0] || g.ftntsIssues[1]
      || g.ftntsIssues[2] || g.ftntsIssues[3] )){
    fossil_fatal("There were issues with footnotes:\n"
                  " %8d misreference%s\n"
                  " %8d unreferenced\n"
                  " %8d splitted\n"
                  " %8d overnested",
                  g.ftntsIssues[0], g.ftntsIssues[0]==1?"":"s",
                  g.ftntsIssues[1], g.ftntsIssues[2], g.ftntsIssues[3]);
  }
}

/*
** Search for a <title>...</title> at the beginning of a wiki page.
** Return true (nonzero) if a title is found.  Return zero if there is
** not title.
**

Markdown Footnotes Test Document
================================

**This document** should help with testing of footnotes support that
is introduced by the ["`markdown-footnotes`"][branch] branch.
It **might look pretty misformatted unless rendered by the proper Fossil
executable** that incorporates the abovementioned branch.[^1]  
That is also a humble attempt to explore the robustness of the Markdown parser.
So please excuse for the mess in the [source code of this document][src].
By no means the normal use of footnotes should look that scarry.

Developers are invited to add test cases here[^here].
It is suggested that the more simple is a test case the earlier it should
appear in this document.[^ if glitch occurs	]


[^lost3]: This note was defined at the begining of the document.

[^duplicate]: This came from the begining of the document.

A footnote's label should be case insensitive[^ case INSENSITIVE ],
it is whitespace-savvy and can even contain newlines.[^ a
multiline
label]

A labeled footnote may be [referenced several times][^many-refs].

A footnote's text should support Markdown [markup][^].  
Markup within [a [text fragment](https://en.wikipedia.org/wiki/Lorem_ipsum)
of a *span-bounded footnote*][^markup] should also be rendered.

Another reference[^many-refs] to the preveously used footnote.

[^lost2]: This note was defined in the middle of the document.
   It references [its previous][^lost3] 
   and [the forthcoming][^lost1] siblings.

[^i am strayed]:
  This should be presented **verbatim** (without any [markup][^])
  in the end of the footnotes.
  
  Default skin renders label in red font and the main text in gray.
  Other styling may also apply.

Inline footnotes are supported.(^These may be usefull for adding
<s>small</s> comments.)

This is a corner case that is rendered as [an empty footnote](^  []  ()).

If [undefined label is used][^] then red "`misref`" is emited instead of
a numeric marker.[^ see it yourself ]
This can be overridden by the skin though.

The refenrence at the end of this sentence is the sole reason of
rendering of <s>`lost1` and</s> [lost2][^].

If several labeled footnote definitions have the same equal label then texts
from all these definitions are joined.[^duplicate]

Several references should be recognized as several distinct numbers.
(^There should be an interval between numbers.) [^many-refs]

If markup is ambigous between a span-bounded footnote and
a "free-standing" footnote followed by another footnote
then interpret as the later case.
This facilitates the usage in the usual case
when several footnotes are refenrenced at the end
of a phrase.[^scipub][^many-refs](^All these four should
be parsed as "free-standing" footnotes)[^Coelurosauria]

A footnote may not be empty(^)
or consist just of blank characters.(^        
              )

The same holds for labeled footnotes. If definition of a labeled footnote
is blank then it is not accepted by the first pass of the parser and
is recognized during the second pass as misreference.
[^ This definition consists of just blanks ]:     
     
     
<style>
  li.fn-upc-example span.fn-upc {
    border: solid 2px lightgreen;
    border-radius: 0.25em;
    padding-left: 2px;
    padding-right: 2px;
    margin-bottom: 0.2em;
  }
  li.fn-upc-example span.fn-upcDot:first-child {
    font-weight: bold;
  }
  sup.noteref.fn-upc-example,
  span.notescope.fn-upc-example sup.noteref {
    border: solid 2px lightgreen;
[^duplicate]:
      Labeled footnote definition may appear anywhere.
      That part came from inside of an inline style definition.
    border-radius: 0.4em;
    padding: 2px;
  }
  sup.noteref.fn-upc-example::after,
  span.notescope.fn-upc-example sup.noteref::after {
    content: " ⛄";
  }
  sup.noteref.fn-upc-example:hover::after,
  span.notescope.fn-upc-example sup.noteref:hover::after {
    content: " 👻";
  }
  li.fn-upc-l span.fn-upc  {
    font-size: 60%;
    color: orange;
  }
  li.fn-upc-l span.fn-upc span.fn-upcDot {
    display: none;
  }
</style>

It is possible to provide a list of classes for a particular footnote and
all its references. This is achieved by prepending a footnote's text with
a special token that starts with dot and ends with colon.
(^
   .alpha-Numeric123.EXAMPLE:
   This token defines a dot-separated list of CSS classes
   which are added to that particular footnote and also to the
   corresponding reference(s). Hypens ('-') are also allowed.
   Classes from the token are tranformed to lowercase and are prepended
   with `"fn-upc-"` to avoid collisions.
)  
This feature is "*opt-in*": there is nothing wrong in starting a footnote's
text with a token of that form while not defining any corresponding classes
in the stylesheet.[^nostyle]
If a footnote consists just of a valid userclass token then this token
is not interpreted as such, instead it is emitted as plain text.
(^  
   .bare.classlist.inside.inline.footnote:  
)[^bare1]
[^bare2]

[^duplicate]: .with.UPC.token:   
   When duplicates are joined their UPC tokens are treated as plain-text.
   Blank characters between token and main text must be preserved.

<html>
  Click
  <a href="?a=B&quote='&nonASCII=😂&script=<script>alert('Broken!');</script>">
  here</a> and
  <a href='?a=B&quote="&nonASCII=😂&script=<script>alert("Broken!");</script>'>
  here</a>
  to test escaping of REQUEST_URI in the generated footnote markers.
</html>

A depth of nesting must be limited.
(^
 .L.1: A long chain of nested inline footnotes...
 (^
  .L.2: is a rather unusual thing...
  (^
   .L.3: and requires extra CPU cycles for processing.
   (^
    .L.4: Theoretically speaking O(n<sup>2</sup>).
    (^
     .L.5: Thus it is worth dismissing those footnotes...
     (^
      .L.6: that are nested deeper than on a certain level.
      (^
       .L.7: A particular value for that limit...
       (^
        is hard-coded in src/markdown.c ...
        (^
         in function `markdown()` ...
         (^
          in variable named `maxDepth`.
          (^
           For the time being, its value is **5**
          )
         )
        )
       )
      )
     )
    )
   )
  )
 )
)

## Footnotes

[branch]: /timeline?r=markdown-footnotes&nowiki

[^ 1]:  Footnotes is a Fossil' extention of
        Markdown. Your other tools may have limited support for these.

[^here]: [History of test/markdown-test3.md](/finfo/test/markdown-test3.md)

[src]: /file/test/markdown-test3.md?ci=markdown-footnotes&txt&ln

[^if glitch occurs]:
        So that simple cases are processed even if
        a glitch happens for more tricky cases.

[^	CASE	 insensitive  	]: And also tolerate whitespaces.

[^ a multiline label ]: But at a footnote's definition it should still
    be written within square brackets
             on a single line.

[^duplicate]: And that came from the end of the document.

[^many-refs]:
   Each letter on the left is a back-reference to the place of use.
   Highlighted back-reference indicates a place from which navigation
   occurred[^lost1].

[^lost1]: This note was defined at the end of the document.
   It defines an inline note.
   
   (^This is inline note defined inside of [a labeled note][^lost1].)

[^markup]:   E.g. *emphasis*, and [so on](/md_rules).
   BTW, this note may not have a backreference to the "stray".

[^undefined label is used]: For example due to a typo.

[^another stray]: Just to verify the correctness of ordering and styling.

[^scipub]: Which is common in the scientific publications.

[^bare1]:  .at.the.1st.line.of.labeled.footnote.definition:
     

[^bare2]:  
           .at.the.2nd.line.of.labeled.footnote.definition:
           
[^stray with UPC]: .UPC-token:
    A token of user-provided classes must be rendered within strays.
    Aslo: this and the previous line may not have extra indentation.

[^nostyle]:
  .unused.classes:
  In that case text of the footnote just looks like as if
  no special processing occured.


[^ <script>alert("You have been pwned!");</script> ]: Labels are escaped

[^ <textarea>"Last words here...' ]:
  <textarea>Content is also escaped</textarea>