/// <summary>
/// Parses a header that starts with a hash.
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="start"> The location of the first hash character. </param>
/// <param name="end"> The location of the end of the line. </param>
/// <returns> A parsed header block, or <c>null</c> if this is not a header. </returns>
internal static HeaderBlock ParseHashPrefixedHeader(string markdown, int start, int end)
{
// This type of header starts with one or more '#' characters, followed by the header
// text, optionally followed by any number of hash characters.
var result = new HeaderBlock();
// Figure out how many consecutive hash characters there are.
int pos = start;
while (pos < end && markdown[pos] == '#' && pos - start < 6)
{
pos++;
}
result.HeaderLevel = pos - start;
if (result.HeaderLevel == 0)
{
return(null);
}
// Ignore any hashes at the end of the line.
while (pos < end && markdown[end - 1] == '#')
{
end--;
}
// Parse the inline content.
result.Inlines = Common.ParseInlineChildren(markdown, pos, end);
return(result);
}
/// <summary>
/// Parses a two-line header.
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="firstLineStart"> The location of the start of the first line. </param>
/// <param name="firstLineEnd"> The location of the end of the first line. </param>
/// <param name="secondLineStart"> The location of the start of the second line. </param>
/// <param name="secondLineEnd"> The location of the end of the second line. </param>
/// <returns> A parsed header block, or <c>null</c> if this is not a header. </returns>
internal static HeaderBlock ParseUnderlineStyleHeader(string markdown, int firstLineStart, int firstLineEnd, int secondLineStart, int secondLineEnd)
{
// This type of header starts with some text on the first line, followed by one or more
// underline characters ('=' or '-') on the second line.
// The second line can have whitespace after the underline characters, but not before
// or between each character.
// Check the second line is valid.
if (secondLineEnd <= secondLineStart)
{
return(null);
}
// Figure out what the underline character is ('=' or '-').
char underlineChar = markdown[secondLineStart];
if (underlineChar != '=' && underlineChar != '-')
{
return(null);
}
// Read past consecutive underline characters.
int pos = secondLineStart + 1;
for (; pos < secondLineEnd; pos++)
{
char c = markdown[pos];
if (c != underlineChar)
{
break;
}
pos++;
}
// The rest of the line must be whitespace.
for (; pos < secondLineEnd; pos++)
{
char c = markdown[pos];
if (c != ' ' && c != '\t')
{
return(null);
}
pos++;
}
var result = new HeaderBlock();
result.HeaderLevel = underlineChar == '=' ? 1 : 2;
// Parse the inline content.
result.Inlines = Common.ParseInlineChildren(markdown, firstLineStart, firstLineEnd);
return(result);
}
