private static int GetContentRangeLength(string input, int startIndex, out ContentRangeHeaderValue parsedValue)
{
Contract.Requires(startIndex >= 0);
parsedValue = null;
if (string.IsNullOrEmpty(input) || (startIndex >= input.Length))
{
return(0);
}
// Parse the unit string: <unit> in '<unit> <from>-<to>/<length>'
var unitLength = HttpRuleParser.GetTokenLength(input, startIndex);
if (unitLength == 0)
{
return(0);
}
var unit = input.Substring(startIndex, unitLength);
var current = startIndex + unitLength;
var separatorLength = HttpRuleParser.GetWhitespaceLength(input, current);
if (separatorLength == 0)
{
return(0);
}
current = current + separatorLength;
if (current == input.Length)
{
return(0);
}
// Read range values <from> and <to> in '<unit> <from>-<to>/<length>'
var fromStartIndex = current;
var fromLength = 0;
var toStartIndex = 0;
var toLength = 0;
if (!TryGetRangeLength(input, ref current, out fromLength, out toStartIndex, out toLength))
{
return(0);
}
// After the range is read we expect the length separator '/'
if ((current == input.Length) || (input[current] != '/'))
{
return(0);
}
current++; // Skip '/' separator
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
if (current == input.Length)
{
return(0);
}
// We may not have a length (e.g. 'bytes 1-2/*'). But if we do, parse the length now.
var lengthStartIndex = current;
var lengthLength = 0;
if (!TryGetLengthLength(input, ref current, out lengthLength))
{
return(0);
}
if (!TryCreateContentRange(input, unit, fromStartIndex, fromLength, toStartIndex, toLength,
lengthStartIndex, lengthLength, out parsedValue))
{
return(0);
}
return(current - startIndex);
}
private static bool TryCreateContentRange(
string input,
string unit,
int fromStartIndex,
int fromLength,
int toStartIndex,
int toLength,
int lengthStartIndex,
int lengthLength,
out ContentRangeHeaderValue parsedValue)
{
parsedValue = null;
long from = 0;
if ((fromLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(fromStartIndex, fromLength), out from))
{
return(false);
}
long to = 0;
if ((toLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(toStartIndex, toLength), out to))
{
return(false);
}
// 'from' must not be greater than 'to'
if ((fromLength > 0) && (toLength > 0) && (from > to))
{
return(false);
}
long length = 0;
if ((lengthLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(lengthStartIndex, lengthLength),
out length))
{
return(false);
}
// 'from' and 'to' must be less than 'length'
if ((toLength > 0) && (lengthLength > 0) && (to >= length))
{
return(false);
}
var result = new ContentRangeHeaderValue();
result._unit = unit;
if (fromLength > 0)
{
result._from = from;
result._to = to;
}
if (lengthLength > 0)
{
result._length = length;
}
parsedValue = result;
return(true);
}
public static bool TryParse(string input, out ContentRangeHeaderValue parsedValue)
{
var index = 0;
return(Parser.TryParseValue(input, ref index, out parsedValue));
}
