COMMON: Add encoding conversion using iconv

common/encoding.cpp

@@ -0,0 +1,154 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "common/encoding.h"
+#include "common/debug.h"
+#include "common/textconsole.h"
+#include <cerrno>
+
+namespace Common {
+
+Encoding::Encoding(const String &to, const String &from) 
+	: _to(to)
+	, _from(from) {
+#ifdef USE_ICONV
+		String toTranslit = to + "//TRANSLIT";
+		_iconvHandle = iconv_open(toTranslit.c_str(), from.c_str());
+#endif // USE_ICONV
+}
+
+Encoding::~Encoding() {
+#ifdef USE_ICONV
+	if (_iconvHandle != (iconv_t) -1)
+		iconv_close(_iconvHandle);
+#endif // USE_ICONV
+}
+
+char *Encoding::convert(const char *string, size_t size) {
+#ifndef USE_ICONV
+	_iconvHandle = 0;
+#endif
+	return doConversion(_iconvHandle, _to, _from, string, size);
+}
+
+char *Encoding::convert(const String &to, const String &from, const char *string, size_t size) {
+#ifdef USE_ICONV
+	String toTranslit = to + "//TRANSLIT";
+	iconv_t iconvHandle = iconv_open(toTranslit.c_str(), from.c_str());
+#else
+	iconv_t iconvHandle = 0;
+#endif // USE_ICONV
+
+	char *result =  doConversion(iconvHandle, to, from, string, size);
+
+#ifdef USE_ICONV
+	if (iconvHandle != (iconv_t) -1)
+		iconv_close(iconvHandle);
+#endif // USE_ICONV
+	return result;
+}
+
+char *Encoding::doConversion(iconv_t iconvHandle, const String &to, const String &from, const char *string, size_t length) {
+	char *result = nullptr;
+#ifdef USE_ICONV
+	if (iconvHandle != (iconv_t) -1)
+		result = convertIconv(iconvHandle, string, length);
+	else
+		debug("Could not convert from %s to %s using iconv", from.c_str(), to.c_str());
+	if (result == nullptr)
+		debug("Error while converting with iconv");
+#else
+	debug("Iconv is not available");
+#endif // USE_ICONV
+
+	return result;
+}
+
+char *Encoding::convertIconv(iconv_t iconvHandle, const char *string, size_t length) {
+#ifdef USE_ICONV
+	debug("Trying iconv...");
+
+	size_t inSize = length;
+	size_t outSize = inSize;
+	size_t stringSize = inSize > 4 ? inSize : outSize;
+
+
+#ifdef ICONV_USES_CONST
+	const char *src = string;
+#else
+	char *src = new char[length];
+	char *originalSrc = src;
+	memcpy(src, string, length);
+#endif // ICONV_USES_CONST
+
+	char *buffer = (char *) malloc(sizeof(char) * stringSize);
+	if (!buffer) {
+		warning ("Cannot allocate memory for converting string");
+		return nullptr;
+	}
+	memset(buffer, 0, stringSize);
+	char *dst = buffer;
+	bool error = false;
+
+	while (inSize > 0) {
+		if (iconv(iconvHandle, &src, &inSize, &dst, &outSize) == ((size_t)-1)) {
+			// from SDLs implementation of SDL_iconv_string (slightly altered)
+			if (errno == E2BIG) {
+				char *oldString = buffer;
+				stringSize *= 2;
+				buffer = (char *) realloc(buffer, stringSize);
+				if (!buffer) {
+					warning ("Cannot allocate memory for converting string");
+					error = true;
+					break;
+				}
+				dst = buffer + (dst - oldString);
+				outSize = stringSize - (dst - buffer);
+				memset(dst, 0, stringSize / 2);
+			} else {
+				error = true;
+				debug("iconv failed");
+				break;
+			}
+		}
+	}
+	// Add a zero character to the end. Hopefuly UTF32 uses the most bytes from
+	// all possible encodings, so add 4 zero bytes.
+	buffer = (char *) realloc(buffer, stringSize + 4);
+	memset(buffer + stringSize, 0, 4);
+
+#ifndef ICONV_USES_CONST
+	delete[] originalSrc;
+#endif // ICONV_USES_CONST
+
+	if (error)
+		return nullptr;
+	debug("Size: %d", stringSize);
+
+	return buffer;
+#else
+	debug("Iconv isn't available");
+	return nullptr;
+#endif //USE_ICONV
+}
+
+}