Thanks Mr. Krugler. It was very helpful and cleared up all my confusions regarding characeter encoding in Palm OS.
Regards, Jenni ----- Original Message ----- From: "Ken Krugler" <[EMAIL PROTECTED]> To: "Palm Developer Forum" <[EMAIL PROTECTED]> Sent: Thursday, August 19, 2004 10:32 AM Subject: Re: Strings are always maintained in UTF-8 format while characters are always in 2 bytes? > >I read the following on Text Manager and just wondering if this means that > >"strings are always mainteained in UTF-8 format while characters are always > >in 2 bytes". > > No. The encoding for characters in a string is based on the device's > character encoding. Currently no device is based on UTF-8 - the set > of officially supported character encodings is Latin, Shift-JIS, and > EUC-CN (aka GB). > > >"Character variables are always two bytes long. However, when you add a > >character to a string, the operating system may shrink it down to a single > >byte if it's a low ASCII character. Thus, any string that you work with may > >contain a mix of single-byte and multi-byte characters, up to four bytes." > > Here's an example from what happens on a Japanese device that uses > the Shift-JIS character encoding, first using the character 'A' > (0x41): > > WChar myChar = 0x0041; // sizeof(myChar) == 2. > UInt16 charSize = TxtSetNextChar(buffer, 0, myChar); // charSize = 1 > > After the call to TxtSetNextChar, buffer[0] will contain 0x41. > > Now an example (also using Japanese) of what happens when you set the > first character in the buffer string to be a full-width (double-byte) > space (0x8140): > > WChar myChar = 0x8140; // sizeof(myChar) == 2. > UInt16 charSize = TxtSetNextChar(buffer, 0, myChar); // charSize = 2 > > After this call, buffer[0] will contain 0x81, and buffer[1] will contain 0x40. > > So in a string, a single "character" can occupy one or two bytes when > the device's character encoding is Shift-JIS. If and when a device is > released that uses UTF-8, each character will occupy between one and > four bytes in the string. > > -- Ken > -- > Ken Krugler > TransPac Software, Inc. > <http://www.transpac.com> > +1 530-470-9200 > > -- > For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/ > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
