static bool NextChunk(string oldText, ref int oldIndex, string newText, ref int newIndex, List<TextChange> changes) {
int oldLength = oldText.Length;
int newLength = newText.Length;
if (oldIndex >= oldLength && newIndex >= newLength)
return false;
if (oldIndex >= oldLength && newIndex < newLength) {
// new text is longer, this is the last chunk
var tc = new TextChange(oldLength, 0, newText.Substring(newIndex));
AddChange(tc, changes);
return false;
}
if (newIndex >= newLength && oldIndex < oldLength) {
// old text is longer, this is the last chunk
var tc = new TextChange(oldIndex, oldLength - oldIndex, string.Empty);
AddChange(tc, changes);
return false;
}
int oldChunkStart = oldIndex;
int newChunkStart = newIndex;
// collect whitespace in the old text - next time both indices will be at non-ws
while (oldIndex < oldLength && char.IsWhiteSpace(oldText[oldIndex]))
oldIndex++;
// collect whitespace in the new text - next time both indices will be at non-ws
while (newIndex < newLength && char.IsWhiteSpace(newText[newIndex]))
newIndex++;
if (oldIndex > oldChunkStart || newIndex > newChunkStart) {
// some ws collected
AddChange(oldText, oldChunkStart, oldIndex - oldChunkStart, newText, newChunkStart, newIndex - newChunkStart, changes);
return true;
}
bool oldStartsWithDelimiter = false;
bool newStartsWithDelimiter = false;
// collect non-whitespace in the old text - next time both indices will be at whitespace or a delimiter
while (oldIndex < oldLength) {
char oldChar = oldText[oldIndex];
if (char.IsWhiteSpace(oldChar))
break;
oldIndex++;
}
while (newIndex < newLength) {
char newChar = newText[newIndex];
if (char.IsWhiteSpace(newChar))
break;
newIndex++;
}
// If both start with a delimiter, then move them past it
if (oldStartsWithDelimiter && newStartsWithDelimiter) {
oldIndex += 1;
newIndex += 1;
}
AddChange(oldText, oldChunkStart, oldIndex - oldChunkStart, newText, newChunkStart, newIndex - newChunkStart, changes);
return true;
}
static void AddChange(TextChange tc, List<TextChange> changes) {
if (changes.Count > 0) {
TextChange lastChange = changes[changes.Count - 1];
// Check if new change can be merged with the last one
if (tc.Position == lastChange.Position + lastChange.Length) {
if (lastChange.NewText.Length == 0 && tc.NewText.Length == 0) // both delete
{
lastChange.Length += tc.Length;
return;
} else if (lastChange.NewText.Length > 0 && tc.NewText.Length > 0) // both insert or replace
{
lastChange.Length += tc.Length;
lastChange.NewText += tc.NewText;
return;
}
}
}
changes.Add(tc);
}
static bool NextChunk(string oldText, ref int oldIndex, string newText, ref int newIndex, List <TextChange> changes)
{
int oldLength = oldText.Length;
int newLength = newText.Length;
if (oldIndex >= oldLength && newIndex >= newLength)
{
return(false);
}
if (oldIndex >= oldLength && newIndex < newLength)
{
// new text is longer, this is the last chunk
var tc = new TextChange(oldLength, 0, newText.Substring(newIndex));
AddChange(tc, changes);
return(false);
}
if (newIndex >= newLength && oldIndex < oldLength)
{
// old text is longer, this is the last chunk
var tc = new TextChange(oldIndex, oldLength - oldIndex, string.Empty);
AddChange(tc, changes);
return(false);
}
int oldChunkStart = oldIndex;
int newChunkStart = newIndex;
// collect whitespace in the old text - next time both indices will be at non-ws
while (oldIndex < oldLength && char.IsWhiteSpace(oldText[oldIndex]))
{
oldIndex++;
}
// collect whitespace in the new text - next time both indices will be at non-ws
while (newIndex < newLength && char.IsWhiteSpace(newText[newIndex]))
{
newIndex++;
}
if (oldIndex > oldChunkStart || newIndex > newChunkStart)
{
// some ws collected
AddChange(oldText, oldChunkStart, oldIndex - oldChunkStart, newText, newChunkStart, newIndex - newChunkStart, changes);
return(true);
}
bool oldStartsWithDelimiter = false;
bool newStartsWithDelimiter = false;
// collect non-whitespace in the old text - next time both indices will be at whitespace or a delimiter
while (oldIndex < oldLength)
{
char oldChar = oldText[oldIndex];
if (char.IsWhiteSpace(oldChar))
{
break;
}
oldIndex++;
}
while (newIndex < newLength)
{
char newChar = newText[newIndex];
if (char.IsWhiteSpace(newChar))
{
break;
}
newIndex++;
}
// If both start with a delimiter, then move them past it
if (oldStartsWithDelimiter && newStartsWithDelimiter)
{
oldIndex += 1;
newIndex += 1;
}
AddChange(oldText, oldChunkStart, oldIndex - oldChunkStart, newText, newChunkStart, newIndex - newChunkStart, changes);
return(true);
}
static void AddChange(
string oldText,
int oldChunkStart,
int oldChunkLength,
string newText,
int newChunkStart,
int newChunkLength,
List<TextChange> changes) {
int maxCharsToTrim = Math.Min(oldChunkLength, newChunkLength);
int i;
// trim off matching characters from the start
for (i = 0; i < maxCharsToTrim; i++) {
if (oldText[oldChunkStart + i] != newText[newChunkStart + i])
break;
}
if (i > 0) {
oldChunkStart += i;
newChunkStart += i;
oldChunkLength -= i;
newChunkLength -= i;
maxCharsToTrim -= i;
}
// trim off matching characters from the end
int oldChunkLastIndex = oldChunkStart + oldChunkLength - 1;
int newChunkLastIndex = newChunkStart + newChunkLength - 1;
for (i = 0; i < maxCharsToTrim; i++) {
if (oldText[oldChunkLastIndex - i] != newText[newChunkLastIndex - i])
break;
}
if (i > 0) {
oldChunkLength -= i;
newChunkLength -= i;
}
if (oldChunkLength != 0 || newChunkLength != 0) {
if (newChunkLength > 0) {
// Dev12 933254: Don't allow a \r\n at the end to get broken apart
// At some point we may want to handle more of the \r\n splitting cases,
// but this is the only one that we know comes up (due to us converting
// a \n to a \r\n
newChunkLastIndex = newChunkStart + newChunkLength - 1;
if ((newText[newChunkLastIndex] == '\r') && (newChunkLastIndex + 1 < newText.Length) && (newText[newChunkLastIndex + 1] == '\n')) {
newChunkLength += 1;
oldChunkLength += 1;
}
}
string newChunkText = newText.Substring(newChunkStart, newChunkLength);
var tc = new TextChange(oldChunkStart, oldChunkLength, newChunkText);
AddChange(tc, changes);
}
}
static void AddChange(
string oldText,
int oldChunkStart,
int oldChunkLength,
string newText,
int newChunkStart,
int newChunkLength,
List <TextChange> changes)
{
int maxCharsToTrim = Math.Min(oldChunkLength, newChunkLength);
int i;
// trim off matching characters from the start
for (i = 0; i < maxCharsToTrim; i++)
{
if (oldText[oldChunkStart + i] != newText[newChunkStart + i])
{
break;
}
}
if (i > 0)
{
oldChunkStart += i;
newChunkStart += i;
oldChunkLength -= i;
newChunkLength -= i;
maxCharsToTrim -= i;
}
// trim off matching characters from the end
int oldChunkLastIndex = oldChunkStart + oldChunkLength - 1;
int newChunkLastIndex = newChunkStart + newChunkLength - 1;
for (i = 0; i < maxCharsToTrim; i++)
{
if (oldText[oldChunkLastIndex - i] != newText[newChunkLastIndex - i])
{
break;
}
}
if (i > 0)
{
oldChunkLength -= i;
newChunkLength -= i;
}
if (oldChunkLength != 0 || newChunkLength != 0)
{
if (newChunkLength > 0)
{
// Dev12 933254: Don't allow a \r\n at the end to get broken apart
// At some point we may want to handle more of the \r\n splitting cases,
// but this is the only one that we know comes up (due to us converting
// a \n to a \r\n
newChunkLastIndex = newChunkStart + newChunkLength - 1;
if ((newText[newChunkLastIndex] == '\r') && (newChunkLastIndex + 1 < newText.Length) && (newText[newChunkLastIndex + 1] == '\n'))
{
newChunkLength += 1;
oldChunkLength += 1;
}
}
string newChunkText = newText.Substring(newChunkStart, newChunkLength);
var tc = new TextChange(oldChunkStart, oldChunkLength, newChunkText);
AddChange(tc, changes);
}
}