ObjFW  Check-in [566d4df603]

#import "OFStdIOStream.h"

OF_ASSUME_NONNULL_BEGIN

@interface OFStdIOStream_Win32Console: OFStdIOStream
{
	HANDLE _handle;
	of_char16_t _incompleteSurrogate;
}
@end

OF_ASSUME_NONNULL_END

 * file.
 */

/*
 * This file tries to make writing UTF-8 strings to the console "just work" on
 * Windows.
 *
 * While Windows does provide a way to change the codepage of the console to
 * UTF-8, unfortunately, different Windows versions handle that differently.
 * For example, on Windows XP, when using Windows XP's console, changing the
 * codepage to UTF-8 mostly breaks write() and completely breaks read():
 * write() suddenly returns the number of characters - instead of bytes -
 * written and read() just returns 0 as soon as a Unicode character is being
 * read.
 *
 * Therefore, instead of just using the UTF-8 codepage, this captures all reads
 * and writes to of_std{in,out,err} on the lowlevel, interprets the buffer as
 * UTF-8 and converts to / from UTF-16 to use ReadConsoleW() / WriteConsoleW().

 * Doing so is safe, as the console only supports text anyway and thus it does
 * not matter if binary gets garbled by the conversion.
 *
 * In order to not do this when redirecting input / output to a file (as the
 * file would then be read / written in the wrong encoding and break reading /
 * writing binary), it checks that the handle is indeed a console.


 */

#define OF_STDIO_STREAM_WIN32_CONSOLE_M

#include "config.h"

#import "OFStdIOStream_Win32Console.h"

- (size_t)lowlevelReadIntoBuffer: (void*)buffer_
			  length: (size_t)length
{
	void *pool = objc_autoreleasePoolPush();
	char *buffer = buffer_;
	of_char16_t *UTF16;
	size_t j = 0;


	UTF16 = [self allocMemoryWithSize: sizeof(of_char16_t)
				    count: length];
	@try {
		DWORD UTF16Len;
		OFDataArray *rest = nil;

		if (!ReadConsoleW(_handle, UTF16, length, &UTF16Len, NULL))
			@throw [OFReadFailedException
			    exceptionWithObject: self
				requestedLength: length];

		if (UTF16Len > 0 && _incompleteSurrogate != 0) {
			of_unichar_t c =
			    (((_incompleteSurrogate & 0x3FF) << 10) |
			    (UTF16[0] & 0x3FF)) + 0x10000;
			char UTF8[4];
			size_t UTF8Len;

			if ((UTF8Len = of_string_utf8_encode(c, UTF8)) == 0)
				@throw [OFInvalidEncodingException exception];

			if (UTF8Len <= length) {
				memcpy(buffer, UTF8, UTF8Len);
				j += UTF8Len;
			} else {
				if (rest == nil)
					rest = [OFDataArray dataArray];

				[rest addItems: UTF8
					 count: UTF8Len];
			}

			_incompleteSurrogate = 0;
		}

		for (size_t i = 0; i < UTF16Len; i++) {
			of_unichar_t c = UTF16[i];
			char UTF8[4];
			size_t UTF8Len;

			/* Missing high surrogate */
			if ((c & 0xFC00) == 0xDC00)
				@throw [OFInvalidEncodingException exception];

			if ((c & 0xFC00) == 0xD800) {
				of_char16_t next;

				if (UTF16Len <= i + 1) {
					_incompleteSurrogate = c;

					if (rest != nil) {
						char *items = [rest items];
						size_t count = [rest count];

						[self unreadFromBuffer: items
								length: count];
					}

					objc_autoreleasePoolPop(pool);

					return j;
				}

				next = UTF16[i + 1];

				if ((next & 0xFC00) != 0xDC00)
					@throw [OFInvalidEncodingException
					    exception];