/// <summary>
/// Attempts to parse a reference e.g. "[example]: http://www.reddit.com 'title'".
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="start"> The location to start parsing. </param>
/// <param name="end"> The location to stop parsing. </param>
/// <returns> A parsed markdown link, or <c>null</c> if this is not a markdown link. </returns>
internal static LinkReferenceBlock Parse(string markdown, int start, int end)
{
// Expect a '[' character.
if (start >= end || markdown[start] != '[')
{
return(null);
}
// Find the ']' character
int pos = start + 1;
while (pos < end)
{
if (markdown[pos] == ']')
{
break;
}
pos++;
}
if (pos == end)
{
return(null);
}
// Extract the ID.
string id = markdown.Substring(start + 1, pos - (start + 1));
// Expect the ':' character.
pos++;
if (pos == end || markdown[pos] != ':')
{
return(null);
}
// Skip whitespace
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
{
pos++;
}
if (pos == end)
{
return(null);
}
// Extract the URL.
int urlStart = pos;
while (pos < end && !Common.IsWhiteSpace(markdown[pos]))
{
pos++;
}
string url = TextRunInline.ResolveEscapeSequences(markdown, urlStart, pos);
// Ignore leading '<' and trailing '>'.
url = url.TrimStart('<').TrimEnd('>');
// Skip whitespace.
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
{
pos++;
}
string tooltip = null;
if (pos < end)
{
// Extract the tooltip.
char tooltipEndChar;
switch (markdown[pos])
{
case '(':
tooltipEndChar = ')';
break;
case '"':
case '\'':
tooltipEndChar = markdown[pos];
break;
default:
return(null);
}
pos++;
int tooltipStart = pos;
while (pos < end && markdown[pos] != tooltipEndChar)
{
pos++;
}
if (pos == end)
{
return(null); // No end character.
}
tooltip = markdown.Substring(tooltipStart, pos - tooltipStart);
// Check there isn't any trailing text.
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
{
pos++;
}
if (pos < end)
{
return(null);
}
}
// We found something!
var result = new LinkReferenceBlock();
result.Id = id;
result.Url = url;
result.Tooltip = tooltip;
return(result);
}
/// <summary>
/// Attempts to parse a reference e.g. "[example]: http://www.reddit.com 'title'".
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="start"> The location to start parsing. </param>
/// <param name="end"> The location to stop parsing. </param>
/// <returns> A parsed markdown link, or <c>null</c> if this is not a markdown link. </returns>
internal static LinkReferenceBlock Parse(string markdown, int start, int end)
{
// Expect a '[' character.
if (start >= end || markdown[start] != '[')
return null;
// Find the ']' character
int pos = start + 1;
while (pos < end)
{
if (markdown[pos] == ']')
break;
pos++;
}
if (pos == end)
return null;
// Extract the ID.
string id = markdown.Substring(start + 1, pos - (start + 1));
// Expect the ':' character.
pos++;
if (pos == end || markdown[pos] != ':')
return null;
// Skip whitespace
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
pos++;
if (pos == end)
return null;
// Extract the URL.
int urlStart = pos;
while (pos < end && !Common.IsWhiteSpace(markdown[pos]))
pos++;
string url = TextRunInline.ResolveEscapeSequences(markdown, urlStart, pos);
// Ignore leading '<' and trailing '>'.
url = url.TrimStart('<').TrimEnd('>');
// Skip whitespace.
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
pos++;
string tooltip = null;
if (pos < end)
{
// Extract the tooltip.
char tooltipEndChar;
switch (markdown[pos])
{
case '(':
tooltipEndChar = ')';
break;
case '"':
case '\'':
tooltipEndChar = markdown[pos];
break;
default:
return null;
}
pos++;
int tooltipStart = pos;
while (pos < end && markdown[pos] != tooltipEndChar)
pos++;
if (pos == end)
return null; // No end character.
tooltip = markdown.Substring(tooltipStart, pos - tooltipStart);
// Check there isn't any trailing text.
pos++;
while (pos < end && Common.IsWhiteSpace(markdown[pos]))
pos++;
if (pos < end)
return null;
}
// We found something!
var result = new LinkReferenceBlock();
result.Id = id;
result.Url = url;
result.Tooltip = tooltip;
return result;
}
