Inside Macintosh: Programming With the Text Encoding Conversion Manager /

Chapter 2 - Basic Text Types Reference / Basic Text Structures and Other Types

/

TextEncodingRun

It is not always possible to convert text expressed in Unicode to another single encoding because no other single encoding encompasses the Unicode character encoding range. To adjust for this, you can create a Unicode mapping structure array that specifies the target encodings the Unicode text should be converted to when multiple encodings must be used.

If the kUnicodeTextRunMask flag is set, ConvertFromUnicodeToTextRun and ConvertFromUnicodeToScriptCodeRun may convert Unicode text to a string of text containing multiple text encoding runs. Each run contains text expressed in a different encoding from that of the preceding or following text segment. For each text encoding run in the string, a TextEncodingRun structure indicates the beginning offset and the text encoding for that run.

Functions that convert text from Unicode to a text run return the converted text in an array of text encoding run structures. A text encoding run structure is defined by the TextEncodingRun data type.

struct TextEncodingRun {
   ByteOffset     offset;  
   TextEncoding   textEncoding;
};
typedef struct TextEncodingRun TextEncodingRun;

Field Description

offset

The beginning character position of a run of text in the converted text string.

textEncoding

The encoding of the text run that begins at the position specified.

struct TextEncodingRun {
   ByteOffset offset;
   TextEncoding textEncoding;
};

Field Description

offset

The byte offset at which the given text encoding begins. The offset is from the beginning of the text buffer.

textEncoding

The text encoding that begins at the byte offset.