148
edits
Jsctypes/api: Difference between revisions
→Converting strings
| Line 694: | Line 694: | ||
'''<code>''cdata''.writeString(''s'', ''[encoding[, length]]'')</code>''' - Determine the starting pointer ''p'' as above. If ''s'' is not a well-formed UTF-16 string, throw a <code>TypeError</code>. ''(Open issue: Error handling.)'' Otherwise convert ''s'' to bytes in the specified ''encoding'' (default: UTF-8) and write at most ''length'' - 1 bytes, or all the converted bytes, if ''length'' is <code>undefined</code> or omitted, to memory starting at ''p''. Write a converted null character after the data. Return the number of bytes of data written, not counting the terminating null character. | '''<code>''cdata''.writeString(''s'', ''[encoding[, length]]'')</code>''' - Determine the starting pointer ''p'' as above. If ''s'' is not a well-formed UTF-16 string, throw a <code>TypeError</code>. ''(Open issue: Error handling.)'' Otherwise convert ''s'' to bytes in the specified ''encoding'' (default: UTF-8) and write at most ''length'' - 1 bytes, or all the converted bytes, if ''length'' is <code>undefined</code> or omitted, to memory starting at ''p''. Write a converted null character after the data. Return the number of bytes of data written, not counting the terminating null character. | ||
''(Open issue: ''<code>''cdata''.writeString(...)</code>'' is awkward for the case where you want an autosized <code>ctypes.char.array()</code> to hold the converted data. If <code>''cdata''</code> happens to be too small for the resulting string, and you don't supply ''length'', you crash; and if you do supply ''length'', you don't know whether conversion was halted because the target array was of insufficient length.)'' | |||
''(Open issue: As proposed, these are not suitable for working with encodings where a zero byte might not indicate the end of text. For example, a string encoded in UTF-16 will typically contain a lot of zero bytes. Unfortunately, in the case of readString, the underlying library demands the length up front.)'' | ''(Open issue: As proposed, these are not suitable for working with encodings where a zero byte might not indicate the end of text. For example, a string encoded in UTF-16 will typically contain a lot of zero bytes. Unfortunately, in the case of readString, the underlying library demands the length up front.)'' | ||