// Parse a hard or soft linebreak, returning an inline.
// Assumes the subject has a newline at the current position.
static Syntax.Inline handle_newline(Subject subj)
{
int nlpos = subj.Position;
// skip over newline
advance(subj);
// skip spaces at beginning of line
while (peek_char(subj) == ' ')
{
advance(subj);
}
if (nlpos > 1 &&
BString.bchar(subj.Buffer, nlpos - 1) == ' ' &&
BString.bchar(subj.Buffer, nlpos - 2) == ' ')
{
return make_linebreak();
}
else
{
return make_softbreak();
}
}
// Parse an autolink or HTML tag.
// Assumes the subject has a '<' character at the current position.
static Inline handle_pointy_brace(Subject subj)
{
int matchlen;
string contents;
// advance past first <
subj.Position++;
// first try to match a URL autolink
matchlen = Scanner.scan_autolink_uri(subj.Buffer, subj.Position, subj.Length);
if (matchlen > 0)
{
contents = subj.Buffer.Substring(subj.Position, matchlen - 1);
var resultContents = ParseStringEntities(contents);
var result = Inline.CreateLink(resultContents, contents, string.Empty);
result.SourcePosition = subj.Position - 1;
resultContents.SourcePosition = subj.Position;
subj.Position += matchlen;
result.SourceLastPosition = subj.Position;
resultContents.SourceLastPosition = subj.Position - 1;
return result;
}
// next try to match an email autolink
matchlen = Scanner.scan_autolink_email(subj.Buffer, subj.Position, subj.Length);
if (matchlen > 0)
{
contents = subj.Buffer.Substring(subj.Position, matchlen - 1);
var resultContents = ParseStringEntities(contents);
var result = Inline.CreateLink(resultContents, "mailto:" + contents, string.Empty);
result.SourcePosition = subj.Position - 1;
resultContents.SourcePosition = subj.Position;
subj.Position += matchlen;
result.SourceLastPosition = subj.Position;
resultContents.SourceLastPosition = subj.Position - 1;
return result;
}
// finally, try to match an html tag
matchlen = Scanner.scan_html_tag(subj.Buffer, subj.Position, subj.Length);
if (matchlen > 0)
{
var result = new Inline(InlineTag.RawHtml, subj.Buffer, subj.Position - 1, matchlen + 1);
result.SourcePosition = subj.Position - 1;
subj.Position += matchlen;
result.SourceLastPosition = subj.Position;
return result;
}
else
{
// if nothing matches, just return the opening <:
return new Inline("<", subj.Position - 1, subj.Position);
}
}
public static void Finalize(Block b, LineInfo line)
{
// don't do anything if the block is already closed
if (!b.IsOpen)
return;
b.IsOpen = false;
if (line.IsTrackingPositions)
{
// (b.SourcePosition >= line.LineOffset) determines if the block started on this line.
if (b.SourcePosition >= line.LineOffset && line.Line != null)
b.SourceLastPosition = line.CalculateOrigin(line.Line.Length, false);
else
b.SourceLastPosition = line.CalculateOrigin(0, false);
}
#pragma warning disable 0618
b.EndLine = (line.LineNumber > b.StartLine) ? line.LineNumber - 1 : line.LineNumber;
#pragma warning restore 0618
switch (b.Tag)
{
case BlockTag.Paragraph:
var sc = b.StringContent;
if (!sc.StartsWith('['))
break;
var subj = new Subject(b.Top.ReferenceMap);
sc.FillSubject(subj);
var origPos = subj.Position;
while (subj.Position < subj.Buffer.Length
&& subj.Buffer[subj.Position] == '['
&& 0 != InlineMethods.ParseReference(subj))
{
}
if (subj.Position != origPos)
{
sc.Replace(subj.Buffer, subj.Position, subj.Buffer.Length - subj.Position);
if (sc.PositionTracker != null)
sc.PositionTracker.AddBlockOffset(subj.Position - origPos);
if (Utilities.IsFirstLineBlank(subj.Buffer, subj.Position))
b.Tag = BlockTag.ReferenceDefinition;
}
break;
case BlockTag.IndentedCode:
b.StringContent.RemoveTrailingBlankLines();
break;
case BlockTag.FencedCode:
// first line of contents becomes info
var firstlinelen = b.StringContent.IndexOf('\n') + 1;
b.FencedCodeData.Info = InlineMethods.Unescape(b.StringContent.TakeFromStart(firstlinelen, true).Trim());
break;
case BlockTag.List: // determine tight/loose status
b.ListData.IsTight = true; // tight by default
var item = b.FirstChild;
Block subitem;
while (item != null)
{
// check for non-final non-empty list item ending with blank line:
if (item.IsLastLineBlank && item.NextSibling != null)
{
b.ListData.IsTight = false;
break;
}
// recurse into children of list item, to see if there are spaces between them:
subitem = item.FirstChild;
while (subitem != null)
{
if (EndsWithBlankLine(subitem) && (item.NextSibling != null || subitem.NextSibling != null))
{
b.ListData.IsTight = false;
break;
}
subitem = subitem.NextSibling;
}
if (!b.ListData.IsTight)
break;
item = item.NextSibling;
}
break;
}
}
// Parse backslash-escape or just a backslash, returning an inline.
private static Inline handle_backslash(Subject subj)
{
subj.Position++;
if (subj.Position >= subj.Length)
return new Inline("\\", subj.Position - 1, subj.Position);
var nextChar = subj.Buffer[subj.Position];
if (Utilities.IsEscapableSymbol(nextChar))
{
// only ascii symbols and newline can be escaped
// the exception is the unicode bullet char since it can be used for defining list items
subj.Position++;
return new Inline(nextChar.ToString(), subj.Position - 2, subj.Position);
}
else if (nextChar == '\n')
{
subj.Position++;
return new Inline(InlineTag.LineBreak)
{
SourcePosition = subj.Position - 2,
SourceLastPosition = subj.Position
};
}
else
{
return new Inline("\\", subj.Position - 1, subj.Position);
}
}
/// <summary>
/// Parses the entity at the current position.
/// Assumes that there is a <c>&</c> at the current position.
/// </summary>
private static string ParseEntity(Subject subj)
{
int match;
string entity;
int numericEntity;
var origPos = subj.Position;
match = Scanner.scan_entity(subj.Buffer, subj.Position, subj.Length - subj.Position, out entity, out numericEntity);
if (match > 0)
{
subj.Position += match;
if (entity != null)
{
entity = EntityDecoder.DecodeEntity(entity);
if (entity != null)
return entity;
return subj.Buffer.Substring(origPos, match);
}
else if (numericEntity > 0)
{
entity = EntityDecoder.DecodeEntity(numericEntity);
if (entity != null)
return entity;
}
return "\uFFFD";
}
else
{
subj.Position++;
return "&";
}
}
private static Inline HandleLeftSquareBracket(Subject subj, CommonMarkSettings settings)
{
return HandleLeftSquareBracket(subj, false, settings);
}
internal static void MatchSquareBracketStack(InlineStack opener, Subject subj, Reference details, InlineParserParameters parameters)
{
if (details != null)
{
var inl = opener.StartingInline;
var isImage = 0 != (opener.Flags & InlineStack.InlineStackFlags.ImageLink);
inl.Tag = isImage ? InlineTag.Image : InlineTag.Link;
inl.FirstChild = inl.NextSibling;
inl.NextSibling = null;
inl.SourceLastPosition = subj.Position;
inl.TargetUrl = details.Url;
inl.LiteralContent = details.Title;
if (!isImage)
{
// since there cannot be nested links, remove any other link openers before this
var temp = opener.Previous;
while (temp != null && temp.Priority <= InlineStack.InlineStackPriority.Links)
{
if (temp.Delimeter == '[' && temp.Flags == opener.Flags)
{
// mark the previous entries as "inactive"
if (temp.DelimeterCount == -1)
break;
temp.DelimeterCount = -1;
}
temp = temp.Previous;
}
}
InlineStack.RemoveStackEntry(opener, subj, null, parameters);
subj.LastInline = inl;
}
else
{
// this looked like a link, but was not.
// remove the opener stack entry but leave the inbetween intact
InlineStack.RemoveStackEntry(opener, subj, opener, parameters);
var inl = new Inline("]", subj.Position - 1, subj.Position);
subj.LastInline.LastSibling.NextSibling = inl;
subj.LastInline = inl;
}
}
public static Inline parse_inlines(Subject subj, Dictionary<string, Reference> refmap, InlineParserParameters parameters)
{
var len = subj.Length;
if (len == 0)
return null;
var first = ParseInline(subj, parameters);
subj.LastInline = first.LastSibling;
Inline cur;
while (subj.Position < len)
{
cur = ParseInline(subj, parameters);
if (cur != null)
{
subj.LastInline.NextSibling = cur;
subj.LastInline = cur.LastSibling;
}
}
InlineStack.PostProcessInlineStack(subj, subj.FirstPendingInline, subj.LastPendingInline, InlineStack.InlineStackPriority.Maximum, parameters);
return first;
}
// Parse zero or more space characters, including at most one newline.
private static void spnl(Subject subj)
{
var seenNewline = false;
var len = subj.Length;
while (subj.Position < len)
{
var c = subj.Buffer[subj.Position];
if (c == ' ' || (!seenNewline && (seenNewline = c == '\n')))
subj.Position++;
else
return;
}
}
// Parse a hard or soft linebreak, returning an inline.
// Assumes the subject has a newline at the current position.
static Inline handle_newline(Subject subj)
{
int nlpos = subj.Position;
// skip over newline
subj.Position++;
// skip spaces at beginning of line
var len = subj.Length;
while (subj.Position < len && subj.Buffer[subj.Position] == ' ')
subj.Position++;
if (nlpos > 1 && subj.Buffer[nlpos - 1] == ' ' && subj.Buffer[nlpos - 2] == ' ')
return new Inline(InlineTag.LineBreak) { SourcePosition = nlpos - 2, SourceLastPosition = nlpos + 1 };
else
return new Inline(InlineTag.SoftBreak) { SourcePosition = nlpos, SourceLastPosition = nlpos + 1 };
}
/// <summary>
/// Parse an inline element from the subject. The subject position is updated to after the element.
/// </summary>
public static Inline ParseInline(Subject subj, InlineParserParameters parameters)
{
var parsers = parameters.Parsers;
var specialCharacters = parameters.SpecialCharacters;
var c = subj.Buffer[subj.Position];
var parser = c < parsers.Length ? parsers[c] : null;
if (parser != null)
return parser(subj);
var startpos = subj.Position;
// we read until we hit a special character
// +1 is so that any special character at the current position is ignored.
var endpos = subj.Buffer.IndexOfAny(specialCharacters, startpos + 1, subj.Length - startpos - 1);
if (endpos == -1)
endpos = subj.Length;
subj.Position = endpos;
// if we're at a newline, strip trailing spaces.
if (endpos < subj.Length && subj.Buffer[endpos] == '\n')
while (endpos > startpos && subj.Buffer[endpos - 1] == ' ')
endpos--;
return new Inline(subj.Buffer, startpos, endpos - startpos, startpos, endpos, c);
}
// Parse zero or more space characters, including at most one newline.
private static void spnl(Subject subj)
{
bool seen_newline = false;
while (peek_char(subj) == ' ' ||
(!seen_newline &&
(seen_newline = peek_char(subj) == '\n')))
{
advance(subj);
}
}
// Parse an inline, advancing subject, and add it to last element.
// Adjust tail to point to new last element of list.
// Return 0 if no inline can be parsed, 1 otherwise.
public static Syntax.Inline parse_inline(Subject subj)
{
Syntax.Inline inew = null;
string contents;
string special_chars;
char? c;
int endpos;
c = peek_char(subj);
if (c == null)
return null;
switch (c)
{
case '\n':
inew = handle_newline(subj);
break;
case '`':
inew = handle_backticks(subj);
break;
case '\\':
inew = handle_backslash(subj);
break;
case '&':
inew = handle_entity(subj);
break;
case '<':
inew = handle_pointy_brace(subj);
break;
case '_':
inew = HandleEmphasis(subj, '_');
break;
case '*':
inew = HandleEmphasis(subj, '*');
break;
case '[':
inew = handle_left_bracket(subj);
break;
case '!':
advance(subj);
if (peek_char(subj) == '[')
{
inew = handle_left_bracket(subj);
if (inew != null && inew.Tag == InlineTag.Link)
{
inew.Tag = InlineTag.Image;
}
else
{
inew = append_inlines(make_str("!"), inew);
}
}
else
{
inew = make_str("!");
}
break;
default:
// we read until we hit a special character
special_chars = "\n\\`&_*[]<!";
endpos = BString.binchr(subj.Buffer, subj.Position, special_chars);
if (endpos == subj.Position)
{
// current char is special: read a 1-character str
contents = take_one(subj);
}
else if (endpos == -1)
{
// special char not found, take whole rest of buffer:
endpos = subj.Buffer.Length;
contents = BString.bmidstr(subj.Buffer, subj.Position, endpos - subj.Position);
subj.Position = endpos;
}
else
{
// take buffer from subj.pos to endpos to str.
contents = BString.bmidstr(subj.Buffer, subj.Position, endpos - subj.Position);
subj.Position = endpos;
// if we're at a newline, strip trailing spaces.
if (peek_char(subj) == '\n')
contents = contents.TrimEnd();
}
inew = make_str(contents);
break;
}
return inew;
}
// Parse inlines while a predicate is satisfied. Return inlines.
public static Syntax.Inline parse_inlines_while(Subject subj)
{
Syntax.Inline first = null;
Syntax.Inline cur;
while (!is_eof(subj))
{
cur = parse_inline(subj);
if (first == null)
{
first = cur;
subj.LastInline = cur.LastSibling;
}
else
{
subj.LastInline.Next = cur;
subj.LastInline = cur.LastSibling;
}
}
return first;
}
private static Inline HandleOpenerCloser(Subject subj, InlineTag singleCharTag, InlineTag doubleCharTag, InlineParserParameters parameters)
{
bool canOpen, canClose;
var c = subj.Buffer[subj.Position];
var numdelims = ScanEmphasisDelimeters(subj, c, out canOpen, out canClose);
if (canClose)
{
// walk the stack and find a matching opener, if there is one
var istack = InlineStack.FindMatchingOpener(subj.LastPendingInline, InlineStack.InlineStackPriority.Emphasis, c, out canClose);
if (istack != null)
{
var useDelims = MatchInlineStack(istack, subj, numdelims, null, singleCharTag, doubleCharTag, parameters);
// if the closer was not fully used, move back a char or two and try again.
if (useDelims < numdelims)
{
subj.Position = subj.Position - numdelims + useDelims;
// use recursion only if it will not be very deep.
if (numdelims < 10)
return HandleOpenerCloser(subj, singleCharTag, doubleCharTag, parameters);
}
return null;
}
}
var inlText = new Inline(subj.Buffer, subj.Position - numdelims, numdelims, subj.Position - numdelims, subj.Position, c);
if (canOpen || canClose)
{
var istack = new InlineStack();
istack.DelimeterCount = numdelims;
istack.Delimeter = c;
istack.StartingInline = inlText;
istack.Priority = InlineStack.InlineStackPriority.Emphasis;
istack.Flags = (canOpen ? InlineStack.InlineStackFlags.Opener : 0)
| (canClose ? InlineStack.InlineStackFlags.Closer : 0);
InlineStack.AppendStackEntry(istack, subj);
}
return inlText;
}
/// <summary>
/// Parses the contents of [..] for a reference label. Only used for parsing
/// reference definition labels for use with the reference dictionary because
/// it does not properly parse nested inlines.
///
/// Assumes the source starts with '[' character or spaces before '['.
/// Returns null and does not advance if no matching ] is found.
/// Note the precedence: code backticks have precedence over label bracket
/// markers, which have precedence over *, _, and other inline formatting
/// markers. So, 2 below contains a link while 1 does not:
/// 1. [a link `with a ](/url)` character
/// 2. [a link *with emphasized ](/url) text* /// </summary>
private static StringPart? ParseReferenceLabel(Subject subj)
{
var startPos = subj.Position;
var source = subj.Buffer;
var len = subj.Length;
while (subj.Position < len)
{
var c = subj.Buffer[subj.Position];
if (c == ' ' || c == '\n')
{
subj.Position++;
continue;
}
else if (c == '[')
{
subj.Position++;
break;
}
else
{
subj.Position = startPos;
return null;
}
}
var labelStartPos = subj.Position;
len = subj.Position + Reference.MaximumReferenceLabelLength;
if (len > source.Length)
len = source.Length;
subj.Position = source.IndexOfAny(BracketSpecialCharacters, subj.Position, len - subj.Position);
while (subj.Position > -1)
{
var c = source[subj.Position];
if (c == '\\')
{
subj.Position += 2;
if (subj.Position >= len)
break;
subj.Position = source.IndexOfAny(BracketSpecialCharacters, subj.Position, len - subj.Position);
}
else if (c == '[')
{
break;
}
else
{
var label = new StringPart(source, labelStartPos, subj.Position - labelStartPos);
subj.Position++;
return label;
}
}
subj.Position = startPos;
return null;
}
private static Inline HandleExclamation(Subject subj, CommonMarkSettings settings)
{
subj.Position++;
if (peek_char(subj) == '[')
return HandleLeftSquareBracket(subj, true, settings);
else
return new Inline("!", subj.Position - 1, subj.Position);
}
// Parse reference. Assumes string begins with '[' character.
// Modify refmap if a reference is encountered.
// Return 0 if no reference found, otherwise position of subject
// after reference is parsed.
public static int ParseReference(Subject subj, CommonMarkSettings settings)
{
string title;
var startPos = subj.Position;
// parse label:
var lab = ParseReferenceLabel(subj);
if (lab == null || lab.Value.Length > Reference.MaximumReferenceLabelLength)
goto INVALID;
if (!Scanner.HasNonWhitespace(lab.Value))
goto INVALID;
// colon:
if (peek_char(subj) == ':')
subj.Position++;
else
goto INVALID;
// parse link url:
spnl(subj);
var matchlen = Scanner.scan_link_url(subj.Buffer, subj.Position, subj.Length);
if (matchlen == 0)
goto INVALID;
var url = subj.Buffer.Substring(subj.Position, matchlen);
url = CleanUrl(url);
subj.Position += matchlen;
// parse optional link_title
var beforetitle = subj.Position;
spnl(subj);
matchlen = Scanner.scan_link_title(subj.Buffer, subj.Position, subj.Length);
if (matchlen > 0)
{
title = subj.Buffer.Substring(subj.Position, matchlen);
title = CleanTitle(title);
subj.Position += matchlen;
}
else
{
subj.Position = beforetitle;
title = string.Empty;
}
char c;
// parse final spaces and newline:
while ((c = peek_char(subj)) == ' ') subj.Position++;
if (c == '\n')
{
subj.Position++;
}
else if (c != '\0')
{
if (matchlen > 0)
{ // try rewinding before title
subj.Position = beforetitle;
while ((c = peek_char(subj)) == ' ') subj.Position++;
if (c == '\n')
subj.Position++;
else if (c != '\0')
goto INVALID;
}
else
{
goto INVALID;
}
}
// insert reference into refmap
AddReference(subj.ReferenceMap, lab.Value, url, title, settings);
return subj.Position;
INVALID:
subj.Position = startPos;
return 0;
}
private static Inline HandleLeftSquareBracket(Subject subj, bool isImage, CommonMarkSettings settings)
{
Inline inlText;
if (isImage)
{
inlText = new Inline("![", subj.Position - 1, subj.Position + 1);
}
else
{
inlText = new Inline("[", subj.Position, subj.Position + 1);
}
// move past the '['
subj.Position++;
var istack = new InlineStack();
istack.Delimeter = '[';
istack.StartingInline = inlText;
istack.StartPosition = subj.Position;
istack.Priority = InlineStack.InlineStackPriority.Links;
istack.Flags = InlineStack.InlineStackFlags.Opener | (isImage ? InlineStack.InlineStackFlags.ImageLink : InlineStack.InlineStackFlags.None);
InlineStack.AppendStackEntry(istack, subj);
return inlText;
}
private static char peek_char(Subject subj)
{
return subj.Length <= subj.Position ? '\0' : subj.Buffer[subj.Position];
}
private static Inline HandleRightSquareBracket(Subject subj, CommonMarkSettings settings)
{
// move past ']'
subj.Position++;
bool canClose;
var istack = InlineStack.FindMatchingOpener(subj.LastPendingInline, InlineStack.InlineStackPriority.Links, '[', out canClose);
if (istack != null)
{
// if the opener is "inactive" then it means that there was a nested link
if (istack.DelimeterCount == -1)
{
InlineStack.RemoveStackEntry(istack, subj, istack, settings.InlineParserParameters);
return new Inline("]", subj.Position - 1, subj.Position);
}
var endpos = subj.Position;
// try parsing details for '[foo](/url "title")' or '[foo][bar]'
var details = ParseLinkDetails(subj, settings);
// try lookup of the brackets themselves
if (details == null || details == Reference.SelfReference)
{
var startpos = istack.StartPosition;
var label = new StringPart(subj.Buffer, startpos, endpos - startpos - 1);
details = LookupReference(subj.ReferenceMap, label, settings);
}
if (details == Reference.InvalidReference)
details = null;
MatchSquareBracketStack(istack, subj, details, settings.InlineParserParameters);
return null;
}
var inlText = new Inline("]", subj.Position - 1, subj.Position);
if (canClose)
{
// note that the current implementation will not work if there are other inlines with priority
// higher than Links.
// to fix this the parsed link details should be added to the closer element in the stack.
throw new NotSupportedException("It is not supported to have inline stack priority higher than Links.");
////istack = new InlineStack();
////istack.Delimeter = '[';
////istack.StartingInline = inlText;
////istack.StartPosition = subj.Position;
////istack.Priority = InlineStack.InlineStackPriority.Links;
////istack.Flags = InlineStack.InlineStackFlags.Closer;
////InlineStack.AppendStackEntry(istack, subj);
}
return inlText;
}
/// <summary>
/// Searches the subject for a span of backticks that matches the given length.
/// Returns <c>0</c> if the closing backticks cannot be found, otherwise returns
/// the position in the subject after the closing backticks.
/// Also updates the position on the subject itself.
/// </summary>
private static int ScanToClosingBackticks(Subject subj, int openticklength)
{
// note - attempt to optimize by using string.IndexOf("````",...) proved to
// be ~2x times slower than the current implementation.
// but - buf.IndexOf('`') gives ~1.5x better performance than iterating over
// every char in the loop.
var buf = subj.Buffer;
var len = buf.Length;
var cc = 0;
for (var i = subj.Position; i < len; i++)
{
if (buf[i] == '`')
{
cc++;
}
else
{
if (cc == openticklength)
return subj.Position = i;
i = buf.IndexOf('`', i, len - i) - 1;
if (i == -2)
return 0;
cc = 0;
}
}
if (cc == openticklength)
return subj.Position = len;
return 0;
}
/// <summary>
/// Parses the entity at the current position. Returns a new string inline.
/// Assumes that there is a <c>&</c> at the current position.
/// </summary>
private static Inline HandleEntity(Subject subj)
{
var origPos = subj.Position;
return new Inline(ParseEntity(subj), origPos, subj.Position);
}
// Parse backtick code section or raw backticks, return an inline.
// Assumes that the subject has a backtick at the current position.
static Inline handle_backticks(Subject subj)
{
int ticklength = 0;
var bl = subj.Length;
while (subj.Position < bl && (subj.Buffer[subj.Position] == '`'))
{
ticklength++;
subj.Position++;
}
int startpos = subj.Position;
int endpos = ScanToClosingBackticks(subj, ticklength);
if (endpos == 0)
{
// closing not found
subj.Position = startpos; // rewind to right after the opening ticks
return new Inline(new string('`', ticklength), startpos - ticklength, startpos);
}
else
{
return new Inline(InlineTag.Code, NormalizeWhitespace(subj.Buffer, startpos, endpos - startpos - ticklength))
{
SourcePosition = startpos - ticklength,
SourceLastPosition = endpos
};
}
}
/// <summary>
/// Creates a new <see cref="Inline"/> element that represents string content but the given content
/// is processed to decode any HTML entities in it.
/// This method is guaranteed to return just one Inline, without nested elements.
/// </summary>
private static Inline ParseStringEntities(string s)
{
string result = null;
StringBuilder builder = null;
int searchpos;
char c;
var subj = new Subject(s, null);
while ('\0' != (c = peek_char(subj)))
{
if (result != null)
{
if (builder == null)
builder = new StringBuilder(result, s.Length);
else
builder.Append(result);
}
if (c == '&')
{
result = ParseEntity(subj);
}
else
{
searchpos = subj.Buffer.IndexOf('&', subj.Position);
if (searchpos == -1)
searchpos = subj.Length;
result = subj.Buffer.Substring(subj.Position, searchpos - subj.Position);
subj.Position = searchpos;
}
}
if (builder == null)
return new Inline(result);
builder.Append(result);
return new Inline(builder.ToString());
}
/// <summary>
/// Scans the subject for a series of the given emphasis character, testing if they could open and/or close
/// an emphasis element.
/// </summary>
private static int ScanEmphasisDelimeters(Subject subj, char delimeter, out bool canOpen, out bool canClose)
{
int numdelims = 0;
int startpos = subj.Position;
int len = subj.Length;
while (startpos + numdelims < len && subj.Buffer[startpos + numdelims] == delimeter)
numdelims++;
if (numdelims == 0)
{
canOpen = false;
canClose = false;
return numdelims;
}
char charBefore, charAfter;
bool beforeIsSpace, beforeIsPunctuation, afterIsSpace, afterIsPunctuation;
charBefore = startpos == 0 ? '\n' : subj.Buffer[startpos - 1];
subj.Position = (startpos += numdelims);
charAfter = len == startpos ? '\n' : subj.Buffer[startpos];
Utilities.CheckUnicodeCategory(charBefore, out beforeIsSpace, out beforeIsPunctuation);
Utilities.CheckUnicodeCategory(charAfter, out afterIsSpace, out afterIsPunctuation);
canOpen = !afterIsSpace && !(afterIsPunctuation && !beforeIsSpace && !beforeIsPunctuation);
canClose = !beforeIsSpace && !(beforeIsPunctuation && !afterIsSpace && !afterIsPunctuation);
if (delimeter == '_')
{
var temp = canOpen;
canOpen &= (!canClose || beforeIsPunctuation);
canClose &= (!temp || afterIsPunctuation);
}
if (delimeter == '$')
{
canOpen &= !char.IsDigit(charAfter);
}
return numdelims;
}
// Parse a link or the link portion of an image, or return a fallback.
static Reference ParseLinkDetails(Subject subj, CommonMarkSettings settings)
{
int n;
int sps;
int endlabel, starturl, endurl, starttitle, endtitle, endall;
string url, title;
endlabel = subj.Position;
var c = peek_char(subj);
if (c == '(' &&
((sps = Scanner.scan_spacechars(subj.Buffer, subj.Position + 1, subj.Length)) > -1) &&
((n = Scanner.scan_link_url(subj.Buffer, subj.Position + 1 + sps, subj.Length)) > -1))
{
// try to parse an explicit link:
starturl = subj.Position + 1 + sps; // after (
endurl = starturl + n;
starttitle = endurl + Scanner.scan_spacechars(subj.Buffer, endurl, subj.Length);
// ensure there are spaces btw url and title
endtitle = (starttitle == endurl) ? starttitle :
starttitle + Scanner.scan_link_title(subj.Buffer, starttitle, subj.Length);
endall = endtitle + Scanner.scan_spacechars(subj.Buffer, endtitle, subj.Length);
if (endall < subj.Length && subj.Buffer[endall] == ')')
{
subj.Position = endall + 1;
url = subj.Buffer.Substring(starturl, endurl - starturl);
url = CleanUrl(url);
title = subj.Buffer.Substring(starttitle, endtitle - starttitle);
title = CleanTitle(title);
return new Reference() { Title = title, Url = url };
}
}
else if (c == '[' || c == ' ' || c == '\n')
{
var label = ParseReferenceLabel(subj);
if (label != null)
{
if (label.Value.Length == 0)
return Reference.SelfReference;
var details = LookupReference(subj.ReferenceMap, label.Value, settings);
if (details != null)
return details;
// rollback the subject but return InvalidReference so that the caller knows not to
// parse 'foo' from [foo][bar].
subj.Position = endlabel;
return Reference.InvalidReference;
}
}
// rollback the subject position because didn't match anything.
subj.Position = endlabel;
return null;
}
internal static int MatchInlineStack(InlineStack opener, Subject subj, int closingDelimeterCount, InlineStack closer, InlineTag singleCharTag, InlineTag doubleCharTag, InlineParserParameters parameters)
{
// calculate the actual number of delimeters used from this closer
int useDelims;
var openerDelims = opener.DelimeterCount;
if (closingDelimeterCount < 3 || openerDelims < 3)
{
useDelims = closingDelimeterCount <= openerDelims ? closingDelimeterCount : openerDelims;
if (useDelims == 2 && doubleCharTag == 0)
useDelims = 1;
if (useDelims == 1 && singleCharTag == 0)
return 0;
}
else if (singleCharTag == 0)
useDelims = 2;
else if (doubleCharTag == 0)
useDelims = 1;
else
useDelims = closingDelimeterCount % 2 == 0 ? 2 : 1;
Inline inl = opener.StartingInline;
InlineTag tag = useDelims == 1 ? singleCharTag : doubleCharTag;
if (openerDelims == useDelims)
{
// the opener is completely used up - remove the stack entry and reuse the inline element
inl.Tag = tag;
inl.LiteralContent = null;
inl.FirstChild = inl.NextSibling;
inl.NextSibling = null;
InlineStack.RemoveStackEntry(opener, subj, closer?.Previous, parameters);
}
else
{
// the opener will only partially be used - stack entry remains (truncated) and a new inline is added.
opener.DelimeterCount -= useDelims;
inl.LiteralContent = inl.LiteralContent.Substring(0, opener.DelimeterCount);
inl.SourceLastPosition -= useDelims;
inl.NextSibling = new Inline(tag, inl.NextSibling);
inl = inl.NextSibling;
inl.SourcePosition = opener.StartingInline.SourcePosition + opener.DelimeterCount;
}
// there are two callers for this method, distinguished by the `closer` argument.
// if closer == null it means the method is called during the initial subject parsing and the closer
// characters are at the current position in the subject. The main benefit is that there is nothing
// parsed that is located after the matched inline element.
// if closer != null it means the method is called when the second pass for previously unmatched
// stack elements is done. The drawback is that there can be other elements after the closer.
if (closer != null)
{
var clInl = closer.StartingInline;
if ((closer.DelimeterCount -= useDelims) > 0)
{
// a new inline element must be created because the old one has to be the one that
// finalizes the children of the emphasis
var newCloserInline = new Inline(clInl.LiteralContent.Substring(useDelims));
newCloserInline.SourcePosition = inl.SourceLastPosition = clInl.SourcePosition + useDelims;
newCloserInline.SourceLength = closer.DelimeterCount;
newCloserInline.NextSibling = clInl.NextSibling;
clInl.LiteralContent = null;
clInl.NextSibling = null;
inl.NextSibling = closer.StartingInline = newCloserInline;
}
else
{
inl.SourceLastPosition = clInl.SourceLastPosition;
clInl.LiteralContent = null;
inl.NextSibling = clInl.NextSibling;
clInl.NextSibling = null;
}
}
else if (subj != null)
{
inl.SourceLastPosition = subj.Position - closingDelimeterCount + useDelims;
subj.LastInline = inl;
}
return useDelims;
}
/// <summary>
/// Walk through the block, its children and siblings, parsing string content into inline content where appropriate.
/// </summary>
/// <param name="block">The document level block from which to start the processing.</param>
/// <param name="refmap">The reference mapping used when parsing links.</param>
/// <param name="settings">The settings that influence how the inline parsing is performed.</param>
public static void ProcessInlines(Block block, Dictionary<string, Reference> refmap, CommonMarkSettings settings)
{
Stack<Inline> inlineStack = null;
var stack = new Stack<Block>();
var parsers = settings.InlineParsers;
var specialCharacters = settings.InlineParserSpecialCharacters;
var subj = new Subject(refmap);
StringContent sc;
int delta;
while (block != null)
{
var tag = block.Tag;
if (tag == BlockTag.Paragraph || tag == BlockTag.AtxHeader || tag == BlockTag.SETextHeader)
{
sc = block.StringContent;
if (sc != null)
{
sc.FillSubject(subj);
delta = subj.Position;
block.InlineContent = InlineMethods.parse_inlines(subj, refmap, parsers, specialCharacters);
block.StringContent = null;
if (sc.PositionTracker != null)
{
sc.PositionTracker.AddBlockOffset(-delta);
AdjustInlineSourcePosition(block.InlineContent, sc.PositionTracker, ref inlineStack);
}
}
}
if (block.FirstChild != null)
{
if (block.NextSibling != null)
stack.Push(block.NextSibling);
block = block.FirstChild;
}
else if (block.NextSibling != null)
{
block = block.NextSibling;
}
else if (stack.Count > 0)
{
block = stack.Pop();
}
else
{
block = null;
}
}
}
// Parse a link or the link portion of an image, or return a fallback.
static Syntax.Inline handle_left_bracket(Subject subj)
{
Syntax.Inline lab = null;
Syntax.Inline result = null;
Reference refer;
int n;
int sps;
bool found_label;
int endlabel, starturl, endurl, starttitle, endtitle, endall;
string url, title, reflabel;
string rawlabel = "";
string rawlabel2 = "";
found_label = link_label(subj, ref rawlabel);
endlabel = subj.Position;
if (found_label)
{
if (peek_char(subj) == '(' &&
((sps = Scanner.scan_spacechars(subj.Buffer, subj.Position + 1)) > -1) &&
((n = Scanner.scan_link_url(subj.Buffer, subj.Position + 1 + sps)) > -1))
{
// try to parse an explicit link:
starturl = subj.Position + 1 + sps; // after (
endurl = starturl + n;
starttitle = endurl + Scanner.scan_spacechars(subj.Buffer, endurl);
// ensure there are spaces btw url and title
endtitle = (starttitle == endurl) ? starttitle :
starttitle + Scanner.scan_link_title(subj.Buffer, starttitle);
endall = endtitle + Scanner.scan_spacechars(subj.Buffer, endtitle);
if (BString.bchar(subj.Buffer, endall) == ')')
{
subj.Position = endall + 1;
url = BString.bmidstr(subj.Buffer, starturl, endurl - starturl);
url = CleanUrl(url);
title = BString.bmidstr(subj.Buffer, starttitle, endtitle - starttitle);
title = CleanTitle(title);
lab = parse_inlines(rawlabel, null);
return make_link(lab, url, title);
}
else
{
// if we get here, we matched a label but didn't get further:
subj.Position = endlabel;
lab = parse_inlines(rawlabel, subj.ReferenceMap);
result = append_inlines(make_str("["),
append_inlines(lab, make_str("]")));
return result;
}
}
else
{
// Check for reference link.
// First, see if there's another label:
subj.Position = subj.Position + Scanner.scan_spacechars(subj.Buffer, endlabel);
reflabel = rawlabel;
// if followed by a nonempty link label, we change reflabel to it:
if (peek_char(subj) == '[' &&
link_label(subj, ref rawlabel2))
{
if (rawlabel2 != null && rawlabel2.Length > 0)
{
reflabel = rawlabel2;
}
}
else
{
subj.Position = endlabel;
}
// lookup rawlabel in subject.reference_map:
refer = lookup_reference(subj.ReferenceMap, reflabel);
if (refer != null)
{ // found
lab = parse_inlines(rawlabel, null);
result = make_link(lab, refer.Url, refer.Title);
}
else
{
subj.Position = endlabel;
lab = parse_inlines(rawlabel, subj.ReferenceMap);
result = append_inlines(make_str("["),
append_inlines(lab, make_str("]")));
}
return result;
}
}
// If we fall through to here, it means we didn't match a link:
advance(subj); // advance past [
return make_str("[");
}