BString: rename SetCharAt to SetByteAt

Makes it clear that it operates on bytes, not unicode codepoints.
Thanks to mmlr for remembering me of this subtlety.

headers/os/support/String.h

@@ -309,7 +309,7 @@ public:
 			// Fast low-level manipulation
 			char*			LockBuffer(int32 maxLength);
 			BString&		UnlockBuffer(int32 length = -1);
-			BString&		SetCharAt(int32 pos, char to);
+			BString&		SetByteAt(int32 pos, char to);
 
 			// Upercase <-> Lowercase
 			BString&		ToLower();

src/apps/deskcalc/ExpressionTextView.cpp

@@ -288,13 +288,13 @@ ExpressionTextView::SetValue(BString value)
 				if (digit != 10)
 					break;
 
-				value.SetCharAt(offset, '0');
+				value.SetByteAt(offset, '0');
 			}
 			if (digit == 10) {
 				// carry over, shift the result
 				if (value[firstDigit + 1] == '.') {
-					value.SetCharAt(firstDigit + 1, '0');
+					value.SetByteAt(firstDigit + 1, '0');
-					value.SetCharAt(firstDigit, '.');
+					value.SetByteAt(firstDigit, '.');
 				}
 				value.Insert('1', 1, firstDigit);
 
@@ -311,7 +311,7 @@ ExpressionTextView::SetValue(BString value)
 				value << 'E' << exponent;
 			} else {
 				// increase the current digit value with one
-				value.SetCharAt(offset, char(digit + 48));
+				value.SetByteAt(offset, char(digit + 48));
 
 				// set offset to last digit
 				offset = value.FindFirst('E');

src/apps/webpositive/BrowserWindow.cpp

@@ -2435,7 +2435,7 @@ BrowserWindow::_EncodeURIComponent(const BString& search)
 	for (int32 i = 0; i < result.Length(); i++) {
 		if (escCharList.FindFirst(result[i]) != B_ERROR) {
 			sprintf(hexcode, "%02X", (unsigned int)result[i]);
-			result.SetCharAt(i, '%');
+			result.SetByteAt(i, '%');
 			result.Insert(hexcode, i + 1);
 			i += 2;
 		}

src/kits/mail/HaikuMailFormatFilter.cpp

@@ -247,7 +247,7 @@ HaikuMailFormatFilter::_RemoveExtraWhitespace(BString& name)
 			if (i == remove + 1 || i == name.Length())
 				remove++;
 			else
-				name.SetCharAt(i - spaces, ' ');
+				name.SetByteAt(i - spaces, ' ');
 			name.Remove(i - remove, remove);
 			i -= remove;
 			spaces = 0;

src/kits/support/String.cpp

@@ -1904,7 +1904,7 @@ BString::UnlockBuffer(int32 length)
 
 
 BString&
-BString::SetCharAt(int32 pos, char to)
+BString::SetByteAt(int32 pos, char to)
 {
 	if (pos < Length() && _MakeWritable() == B_OK)
 		fPrivateData[pos] = to;

src/preferences/mail/DNSQuery.cpp

@@ -229,14 +229,14 @@ DNSTools::ConvertToDNSName(const BString& string)
 
 			// set a counts to the dot
 			diff =  dot - 1 - lastDot;
-			outString.SetCharAt(lastDot, (char)diff);
+			outString.SetByteAt(lastDot, (char)diff);
 			lastDot = dot;
 		}
 	} else
 		lastDot = 0;
 
 	diff = outString.CountChars() - 1 - lastDot;
-	outString.SetCharAt(lastDot, (char)diff);
+	outString.SetByteAt(lastDot, (char)diff);
 
 	return outString;
 }
@@ -259,7 +259,7 @@ DNSTools::ConvertFromDNSName(const BString& string)
 		if (dot == 0)
 			break;
 		// set a "."
-		outString.SetCharAt(nextDot, '.');
+		outString.SetByteAt(nextDot, '.');
 		nextDot+= dot + 1;
 	}
 	return outString;

src/tests/kits/support/bstring/StringCharAccessTest.cpp

@@ -27,7 +27,7 @@ StringCharAccessTest::PerformTest(void)
 
 	//&operator[]
 	NextSubTest();
-	string.SetCharAt(0, 'a');
+	string.SetByteAt(0, 'a');
 	CPPUNIT_ASSERT(strcmp(string.String(), "a simple string") == 0);
 	
 	//ByteAt(int32)