internal static bool TryParse(string s, out DiffOp res)
{
if (string.IsNullOrEmpty(s))
{
res = null;
return(true);
}
char sign = s[0];
string line = Uri.UnescapeDataString(s.Substring(1).Replace("+", "%2b"));
if (sign == '-') // Deletion
{
res = new DiffOp(Operation.DELETE, line);
}
else if (sign == '+') // Insertion
{
res = new DiffOp(Operation.INSERT, line);
}
else if (sign == ' ') // minori equality
{
res = new DiffOp(Operation.EQUAL, line);
}
else if (sign == '@') // Start of next patch
{
res = null;
return(false);
}
else // ?? unrecognized sign.
{
throw new ArgumentException($"Invalid patch mode: '{sign}' in: {line}");
}
return(true);
}
public bool Equals(DiffOp obj)
{
// if parameter is null return false
if (obj == null)
{
return(false);
}
//Return true if the fields match
return(obj.Operation == Operation && obj.Text == Text);
}
/// <summary>
/// Parse a textual represenation of patches and return a List of PatchOp objects.
/// </summary>
/// <param name="textline">Text representation of patches</param>
/// <returns>List of PatchOp objects.</returns>
public static List <PatchOp> PatchFromText(this string textline)
{
List <PatchOp> res = new List <PatchOp>();
if (string.IsNullOrEmpty(textline) || textline == "<null>")
{
return(res);
}
string[] text = textline.Split('\n');
int pos = 0;
while (pos < text.Length)
{
if (!PatchOp.TryParse(text[pos], out PatchOp patch))
{
throw new ArgumentException($"Invalid path string: {text[pos]}");
}
res.Add(patch);
pos++;
while (pos < text.Length)
{
if (string.IsNullOrEmpty(text[pos]))
{
// Blank line; continue.
pos++;
continue;
}
if (text[pos].StartsWith("@")) // Start next patch.
{
break;
}
if (DiffOp.TryParse(text[pos], out DiffOp diff))
{
patch.Diffs.AddIfNotNull(diff);
pos++;
}
else
{
break;
}
}
}
return(res);
}
/// <summary>
/// Add some padding on text start and end so that edges can match something.
/// </summary>
/// <param name="patches">List of PatchOp objects</param>
/// <param name="margin">Chuck size for context length.</param>
/// <returns>The padding added to each side.</returns>
private static string AddPadding(this List <PatchOp> patches, short margin = 4)
{
string padding = string.Empty;
for (short x = 1; x <= margin; x++)
{
padding += (char)x;
}
// Bump all the patches forward.
foreach (var aPatch in patches)
{
aPatch.Start1 += margin;
aPatch.Start2 += margin;
}
// Add some padding on start of first diff.
PatchOp patch = patches.First();
if (patch.Diffs.Count == 0 || patch.Diffs.First().Operation != Operation.EQUAL)
{
// Add padding equality.
patch.Diffs.Insert(0, new DiffOp(Operation.EQUAL, padding));
patch.Start1 -= margin; // should be 0;
patch.Start2 -= margin; // should be 0;
patch.Length1 += margin;
patch.Length2 += margin;
}
else if (margin > patch.Diffs.First().Text.Length)
{
// Grow first equality.
DiffOp fDif = patch.Diffs.First();
int extraLen = margin - fDif.Text.Length;
fDif.Text = padding.Substring(fDif.Text.Length) + fDif.Text;
patch.Start1 -= extraLen;
patch.Start2 -= extraLen;
patch.Length1 += extraLen;
patch.Length2 += extraLen;
}
// Add some padding on end of last diff.
patch = patches.Last();
if (patch.Diffs.Count == 0 || patch.Diffs.Last().Operation != Operation.EQUAL)
{
// Add padding equality
patch.Diffs.Add(new DiffOp(Operation.EQUAL, padding));
patch.Length1 += margin;
patch.Length2 += margin;
}
else if (margin > patch.Diffs.Last().Text.Length)
{
// Grow last equality.
DiffOp lDif = patch.Diffs.Last();
int extaLen = margin - lDif.Text.Length;
lDif.Text += padding.Substring(0, extaLen);
patch.Length1 += extaLen;
patch.Length2 += extaLen;
}
return(padding);
}
