Search/trunk/HttpHandler.cpp

/* ============================================================================
 * Douglas Thrift's Search Engine License
 *
 * Copyright (C) 2002, Douglas Thrift. All Rights Reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment:
 *
 *       "This product includes software developed by Douglas Thrift
 *       (http://computers.douglasthrift.net/searchengine/)."
 *
 *    Alternately, this acknowledgment may appear in the software itself, if
 *    and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Douglas Thrift" and "Douglas Thrift's Search Engine" must not
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.  For written permission, please visit
 *    http://www.douglasthrift.net/contact.cgi for contact information.
 *
 * 5. Products derived from this software may not be called "Douglas Thrift's
 *    Search Engine", nor may "Douglas Thrift's Search Engine" appear in their
 *    name, without prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ============================================================================
 */
// Douglas Thrift's Search Engine HTTP Handler
//
// Douglas Thrift
//
// HttpHandler.cpp

#include "HttpHandler.h"

HttpHandler::HttpHandler()
{
        buffer = new char[BUFSIZ + 1];

#ifdef _WIN32
        if (WSAStartup(MAKEWORD(2, 0), &data) != 0)
        {
                error(program + ": WSAStartup");
                exit(1);
        }
#endif // _WIN32

        begin = 0;
}

HttpHandler::~HttpHandler()
{
        delete [] buffer;

#ifdef _WIN32
        WSACleanup();
#endif // _WIN32
}

bool HttpHandler::handle(URL &url, bool head)
{
        bool answer = false;

        if ((http = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
        {
                error(program + ": Socket");
                exit(1);
        }

        sockaddr_in address;
        hostent* host;

        address.sin_family = AF_INET;

        if ((host = gethostbyname(url.getAddress().c_str())) == NULL)
        {
                error(program + ": Host: " + url.getAddress(), true);
                return answer;
        }

        address.sin_addr = *((in_addr*)*host->h_addr_list);
        address.sin_port = htons(url.getPort());

        if (connect(http, (sockaddr*)&address, sizeof(sockaddr_in)) ==
                SOCKET_ERROR)
        {
                error(program + ": Connect");
                return answer;
        }

        if (head)
        {
                putline("HEAD " + url.getPath() + " HTTP/1.1");
        }
        else
        {
                putline("GET " + url.getPath() + " HTTP/1.1");
        }

        putline("Accept: text/html; text/plain");
        putline("User-Agent: " + agent(true) + ' ' + platform());

        if (url.getPort() == 80)
        {
                putline("Host: " + url.getAddress());
        }
        else
        {
                char* port = new char[1024];
                sprintf(port, "%u", url.getPort());

                putline("Host: " + url.getAddress() + ':' + port);

                delete [] port;
        }

        putline();

        string line = getline();

        if (line.find("HTTP/") != 0)
        {
                return answer;
        }

        unsigned dot = line.find('.');
        unsigned space = line.find(' ');

        unsigned major = strtoul(line.substr(5, dot - 5).c_str(), 0, 0);
        unsigned minor = strtoul(line.substr(dot + 1, space - dot - 1).c_str(), 0,
                0);

        if (major > 1 || minor < 1)
        {
                cerr << program << ": Potentially Incompatible Server: HTTP/" << major
                        << "." << minor << "\n";

                return answer;
        }

        code response = code(strtoul(line.substr(space + 1).c_str(), 0, 0));

        do
        {
                line = getline();
        }
        while (line != "");

        switch (response)
        {
        case ok:
                answer = true;
                break;
        case choices: 
                break;
        case moved:
                break;
        case found:
                break;
        case notfound:
                break;
        case internal:
                break;
        default:
                break;
        }

        return answer;
}

HttpHandler& HttpHandler::getline(string& line, char endline)
{
        int end = page.find(endline, begin);
        int newline = page.find('\n', begin);

        if (newline < end || end == string::npos)
        {
                end = newline;
        }

        line = page.substr(begin, end - begin);

        if (end == string::npos)
        {
                begin = end;
        }
        else
        {
                begin = end + 1;
        }

        return *this;
}

bool HttpHandler::good()
{
        bool answer = true;

        if (begin >= page.length())
        {
                answer = false;
        }
        else if (begin == string::npos)
        {
                answer = false;
        }

        return answer;
}

void HttpHandler::clear()
{
        type = "";
        length = 0;
        location = "";
        begin = 0;
        page = "";
}

void HttpHandler::putline(const string line)
{
        sprintf(buffer, "%s\r\n", line.c_str());
        if (send(http, buffer, strlen(buffer), 0) == SOCKET_ERROR)
        {
                error(program + ": Send");
                exit(1);
        }
}

string HttpHandler::getline()
{
        string line;
        char byte;

        do
        {
                if (recv(http, &byte, 1, 0) == SOCKET_ERROR)
                {
                        error(program + ": Recv");
                }

                if (byte != '\r' && byte != '\n')
                {
                        line += byte;
                }
        }
        while (byte != '\n');

        return line;
}

void HttpHandler::error(const string prefix, bool host)
{
#ifdef _WIN32
        string error;

        switch (WSAGetLastError())
        {
        case WSAEACCES:
                error = "Permission denied.";
                break;
        case WSAEADDRINUSE:
                error = "Address already in use.";
                break;
        case WSAEADDRNOTAVAIL:
                error = "Cannot assign requested address.";
                break;
        case WSAEAFNOSUPPORT:
                error = "Address family not supported by protocol family.";
                break;
        case WSAEALREADY:
                error = "Operation already in progress.";
                break;
        case WSAECONNABORTED:
                error = "Software caused connection abort.";
                break;
        case WSAECONNREFUSED:
                error = "Connection refused.";
                break;
        case WSAECONNRESET:
                error = "Connection reset by peer.";
                break;
        case WSAEDESTADDRREQ:
                error = "Destination address required.";
                break;
        case WSAEFAULT:
                error = "Bad address.";
                break;
        case WSAEHOSTDOWN:
                error = "Host is down.";
                break;
        case WSAEHOSTUNREACH:
                error = "No route to host.";
                break;
        case WSAEINPROGRESS:
                error = "Operation now in progress.";
                break;
        case WSAEINTR:
                error = "Interrupted function call.";
                break;
        case WSAEINVAL:
                error = "Invalid argument.";
                break;
        case WSAEISCONN:
                error = "Socket is already connected.";
                break;
        case WSAEMFILE:
                error = "Too many open files.";
                break;
        case WSAEMSGSIZE:
                error = "Message too long.";
                break;
        case WSAENETDOWN:
                error = "Network is down.";
                break;
        case WSAENETRESET:
                error = "Network dropped connection on reset.";
                break;
        case WSAENETUNREACH:
                error = "Network is unreachable.";
                break;
        case WSAENOBUFS:
                error = "No buffer space available.";
                break;
        case WSAENOPROTOOPT:
                error = "Bad protocol option.";
                break;
        case WSAENOTCONN:
                error = "Socket is not connected.";
                break;
        case WSAENOTSOCK:
                error = "Socket operation on non-socket.";
                break;
        case WSAEOPNOTSUPP:
                error = "Operation not supported.";
                break;
        case WSAEPFNOSUPPORT:
                error = "Protocol family not supported.";
                break;
        case WSAEPROCLIM:
                error = "Too many processes.";
                break;
        case WSAEPROTONOSUPPORT:
                error = "Protocol not supported.";
                break;
        case WSAEPROTOTYPE:
                error = "Protocol wrong type for socket.";
                break;
        case WSAESHUTDOWN:
                error = "Cannot send after socket shutdown.";
                break;
        case WSAESOCKTNOSUPPORT:
                error = "Socket type not supported.";
                break;
        case WSAETIMEDOUT:
                error = "Connection timed out.";
                break;
        case WSATYPE_NOT_FOUND:
                error = "Class type not found.";
                break;
        case WSAEWOULDBLOCK:
                error = "Resource temporarily unavailable.";
                break;
        case WSAHOST_NOT_FOUND:
                error = "Host not found.";
                break;
        case WSA_INVALID_HANDLE:
                error = "Specified event object handle is invalid.";
                break;
        case WSA_INVALID_PARAMETER:
                error = "One or more parameters are invalid.";
                break;
//      case WSAINVALIDPROCTABLE:
//              error = "Invalid procedure table from service provider.";
//              break;
//      case WSAINVALIDPROVIDER:
//              error = "Invalid service provider version number.";
//              break;
        case WSA_IO_INCOMPLETE:
                error = "Overlapped I/O event object not in signaled state.";
                break;
        case WSA_IO_PENDING:
                error = "Overlapped operations will complete later.";
                break;
        case WSA_NOT_ENOUGH_MEMORY:
                error = "Insufficient memory available.";
                break;
        case WSANOTINITIALISED:
                error = "Successful WSAStartup not yet performed.";
                break;
        case WSANO_DATA:
                error = "Valid name, no data record of requested type.";
                break;
        case WSANO_RECOVERY:
                error = "This is a non-recoverable error.";
                break;
//      case WSAPROVIDERFAILEDINIT:
//              error = "Unable to initialize a service provider.";
//              break;
        case WSASYSCALLFAILURE:
                error = "System call failure.";
                break;
        case WSASYSNOTREADY:
                error = "Network subsystem is unavailable.";
                break;
        case WSATRY_AGAIN:
                error = "Non-authoritative host not found.";
                break;
        case WSAVERNOTSUPPORTED:
                error = "WINSOCK.DLL version out of range.";
                break;
        case WSAEDISCON:
                error = "Graceful shutdown in progress.";
                break;
        case WSA_OPERATION_ABORTED:
                error = "Overlapped operation aborted.";
                break;
        default:
                error = "Unknown error.";
                break;
        }

        cerr << prefix << ": " << error << "\n";
#else
        if (host)
        {
                herror(prefix.c_str());
        }
        else
        {
                perror(prefix.c_str());
        }
#endif // _WIN32
}
Revision:	17
Committed:	2002-12-09T18:31:11-08:00 (22 years, 6 months ago) by douglas
Original Path:	*trunk/Search/HttpHandler.cpp*
File size:	10082 byte(s)
Log Message:	Started reimplementing HttpHandler, moved Processor.getLink() to be global and included in URL.h and implemented in URL.cpp.
#	User	Rev	Content
1	douglas	1	/* ============================================================================
2			* Douglas Thrift's Search Engine License
3			*
4			* Copyright (C) 2002, Douglas Thrift. All Rights Reserved.
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions are met:
7			*
8			* 1. Redistributions of source code must retain the above copyright notice,
9			* this list of conditions and the following disclaimer.
10			*
11			* 2. Redistributions in binary form must reproduce the above copyright notice,
12			* this list of conditions and the following disclaimer in the documentation
13			* and/or other materials provided with the distribution.
14			*
15			* 3. The end-user documentation included with the redistribution, if any, must
16			* include the following acknowledgment:
17			*
18			* "This product includes software developed by Douglas Thrift
19			* (http://computers.douglasthrift.net/searchengine/)."
20			*
21			* Alternately, this acknowledgment may appear in the software itself, if
22			* and wherever such third-party acknowledgments normally appear.
23			*
24			* 4. The names "Douglas Thrift" and "Douglas Thrift's Search Engine" must not
25			* be used to endorse or promote products derived from this software without
26			* specific prior written permission. For written permission, please visit
27			* http://www.douglasthrift.net/contact.cgi for contact information.
28			*
29			* 5. Products derived from this software may not be called "Douglas Thrift's
30			* Search Engine", nor may "Douglas Thrift's Search Engine" appear in their
31			* name, without prior written permission.
32			*
33			* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
34			* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35			* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
36			* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
37			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
38			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
39			* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
40			* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
41			* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
42			* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43			* ============================================================================
44			*/
45			// Douglas Thrift's Search Engine HTTP Handler
46			//
47			// Douglas Thrift
48			//
49			// HttpHandler.cpp
50
51			#include "HttpHandler.h"
52
53			HttpHandler::HttpHandler()
54			{
55	douglas	14	buffer = new char[BUFSIZ + 1];
56
57	douglas	13	#ifdef _WIN32
58	douglas	14	if (WSAStartup(MAKEWORD(2, 0), &data) != 0)
59	douglas	13	{
60	douglas	17	error(program + ": WSAStartup");
61	douglas	13	exit(1);
62			}
63			#endif // _WIN32
64	douglas	1
65			begin = 0;
66			}
67
68			HttpHandler::~HttpHandler()
69			{
70	douglas	14	delete [] buffer;
71
72	douglas	13	#ifdef _WIN32
73			WSACleanup();
74			#endif // _WIN32
75	douglas	1	}
76
77	douglas	14	bool HttpHandler::handle(URL &url, bool head)
78	douglas	1	{
79			bool answer = false;
80
81	douglas	14	if ((http = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
82			{
83			error(program + ": Socket");
84			exit(1);
85			}
86	douglas	1
87	douglas	14	sockaddr_in address;
88			hostent* host;
89	douglas	1
90	douglas	14	address.sin_family = AF_INET;
91	douglas	1
92	douglas	14	if ((host = gethostbyname(url.getAddress().c_str())) == NULL)
93			{
94			error(program + ": Host: " + url.getAddress(), true);
95			return answer;
96			}
97	douglas	1
98	douglas	14	address.sin_addr = ((in_addr)*host->h_addr_list);
99			address.sin_port = htons(url.getPort());
100
101			if (connect(http, (sockaddr*)&address, sizeof(sockaddr_in)) ==
102			SOCKET_ERROR)
103			{
104			error(program + ": Connect");
105			return answer;
106			}
107
108			if (head)
109			{
110			putline("HEAD " + url.getPath() + " HTTP/1.1");
111			}
112			else
113			{
114			putline("GET " + url.getPath() + " HTTP/1.1");
115			}
116
117			putline("Accept: text/html; text/plain");
118			putline("User-Agent: " + agent(true) + ' ' + platform());
119
120			if (url.getPort() == 80)
121			{
122			putline("Host: " + url.getAddress());
123			}
124			else
125			{
126			char* port = new char[1024];
127			sprintf(port, "%u", url.getPort());
128
129			putline("Host: " + url.getAddress() + ':' + port);
130
131			delete [] port;
132			}
133
134			putline();
135
136	douglas	17	string line = getline();
137
138			if (line.find("HTTP/") != 0)
139			{
140			return answer;
141			}
142
143			unsigned dot = line.find('.');
144			unsigned space = line.find(' ');
145
146			unsigned major = strtoul(line.substr(5, dot - 5).c_str(), 0, 0);
147			unsigned minor = strtoul(line.substr(dot + 1, space - dot - 1).c_str(), 0,
148			0);
149
150			if (major > 1 \|\| minor < 1)
151			{
152			cerr << program << ": Potentially Incompatible Server: HTTP/" << major
153			<< "." << minor << "\n";
154
155			return answer;
156			}
157
158			code response = code(strtoul(line.substr(space + 1).c_str(), 0, 0));
159
160			do
161			{
162			line = getline();
163			}
164			while (line != "");
165
166			switch (response)
167			{
168			case ok:
169			answer = true;
170			break;
171			case choices:
172			break;
173			case moved:
174			break;
175			case found:
176			break;
177			case notfound:
178			break;
179			case internal:
180			break;
181			default:
182			break;
183			}
184
185	douglas	1	return answer;
186			}
187
188			HttpHandler& HttpHandler::getline(string& line, char endline)
189			{
190			int end = page.find(endline, begin);
191			int newline = page.find('\n', begin);
192
193			if (newline < end \|\| end == string::npos)
194			{
195			end = newline;
196			}
197
198			line = page.substr(begin, end - begin);
199
200			if (end == string::npos)
201			{
202			begin = end;
203			}
204			else
205			{
206			begin = end + 1;
207			}
208
209			return *this;
210			}
211
212			bool HttpHandler::good()
213			{
214			bool answer = true;
215
216			if (begin >= page.length())
217			{
218			answer = false;
219			}
220			else if (begin == string::npos)
221			{
222			answer = false;
223			}
224
225			return answer;
226			}
227
228			void HttpHandler::clear()
229			{
230	douglas	17	type = "";
231			length = 0;
232			location = "";
233	douglas	1	begin = 0;
234			page = "";
235			}
236
237	douglas	14	void HttpHandler::putline(const string line)
238			{
239			sprintf(buffer, "%s\r\n", line.c_str());
240			if (send(http, buffer, strlen(buffer), 0) == SOCKET_ERROR)
241			{
242			error(program + ": Send");
243			exit(1);
244			}
245			}
246
247	douglas	17	string HttpHandler::getline()
248			{
249			string line;
250			char byte;
251
252			do
253			{
254			if (recv(http, &byte, 1, 0) == SOCKET_ERROR)
255			{
256			error(program + ": Recv");
257			}
258
259			if (byte != '\r' && byte != '\n')
260			{
261			line += byte;
262			}
263			}
264			while (byte != '\n');
265
266			return line;
267			}
268
269	douglas	13	void HttpHandler::error(const string prefix, bool host)
270	douglas	1	{
271	douglas	13	#ifdef _WIN32
272			string error;
273	douglas	1
274	douglas	13	switch (WSAGetLastError())
275	douglas	1	{
276	douglas	13	case WSAEACCES:
277			error = "Permission denied.";
278			break;
279			case WSAEADDRINUSE:
280			error = "Address already in use.";
281			break;
282			case WSAEADDRNOTAVAIL:
283			error = "Cannot assign requested address.";
284			break;
285			case WSAEAFNOSUPPORT:
286			error = "Address family not supported by protocol family.";
287			break;
288			case WSAEALREADY:
289			error = "Operation already in progress.";
290			break;
291			case WSAECONNABORTED:
292			error = "Software caused connection abort.";
293			break;
294			case WSAECONNREFUSED:
295			error = "Connection refused.";
296			break;
297			case WSAECONNRESET:
298			error = "Connection reset by peer.";
299			break;
300			case WSAEDESTADDRREQ:
301			error = "Destination address required.";
302			break;
303			case WSAEFAULT:
304			error = "Bad address.";
305			break;
306			case WSAEHOSTDOWN:
307			error = "Host is down.";
308			break;
309			case WSAEHOSTUNREACH:
310			error = "No route to host.";
311			break;
312			case WSAEINPROGRESS:
313			error = "Operation now in progress.";
314			break;
315			case WSAEINTR:
316			error = "Interrupted function call.";
317			break;
318			case WSAEINVAL:
319			error = "Invalid argument.";
320			break;
321			case WSAEISCONN:
322			error = "Socket is already connected.";
323			break;
324			case WSAEMFILE:
325			error = "Too many open files.";
326			break;
327			case WSAEMSGSIZE:
328			error = "Message too long.";
329			break;
330			case WSAENETDOWN:
331			error = "Network is down.";
332			break;
333			case WSAENETRESET:
334			error = "Network dropped connection on reset.";
335			break;
336			case WSAENETUNREACH:
337			error = "Network is unreachable.";
338			break;
339			case WSAENOBUFS:
340			error = "No buffer space available.";
341			break;
342			case WSAENOPROTOOPT:
343			error = "Bad protocol option.";
344			break;
345			case WSAENOTCONN:
346			error = "Socket is not connected.";
347			break;
348			case WSAENOTSOCK:
349			error = "Socket operation on non-socket.";
350			break;
351			case WSAEOPNOTSUPP:
352			error = "Operation not supported.";
353			break;
354			case WSAEPFNOSUPPORT:
355			error = "Protocol family not supported.";
356			break;
357			case WSAEPROCLIM:
358			error = "Too many processes.";
359			break;
360			case WSAEPROTONOSUPPORT:
361			error = "Protocol not supported.";
362			break;
363			case WSAEPROTOTYPE:
364			error = "Protocol wrong type for socket.";
365			break;
366			case WSAESHUTDOWN:
367			error = "Cannot send after socket shutdown.";
368			break;
369			case WSAESOCKTNOSUPPORT:
370			error = "Socket type not supported.";
371			break;
372			case WSAETIMEDOUT:
373			error = "Connection timed out.";
374			break;
375			case WSATYPE_NOT_FOUND:
376			error = "Class type not found.";
377			break;
378			case WSAEWOULDBLOCK:
379			error = "Resource temporarily unavailable.";
380			break;
381			case WSAHOST_NOT_FOUND:
382			error = "Host not found.";
383			break;
384			case WSA_INVALID_HANDLE:
385			error = "Specified event object handle is invalid.";
386			break;
387			case WSA_INVALID_PARAMETER:
388			error = "One or more parameters are invalid.";
389			break;
390			// case WSAINVALIDPROCTABLE:
391			// error = "Invalid procedure table from service provider.";
392			// break;
393			// case WSAINVALIDPROVIDER:
394			// error = "Invalid service provider version number.";
395			// break;
396			case WSA_IO_INCOMPLETE:
397			error = "Overlapped I/O event object not in signaled state.";
398			break;
399			case WSA_IO_PENDING:
400			error = "Overlapped operations will complete later.";
401			break;
402			case WSA_NOT_ENOUGH_MEMORY:
403			error = "Insufficient memory available.";
404			break;
405			case WSANOTINITIALISED:
406			error = "Successful WSAStartup not yet performed.";
407			break;
408			case WSANO_DATA:
409			error = "Valid name, no data record of requested type.";
410			break;
411			case WSANO_RECOVERY:
412			error = "This is a non-recoverable error.";
413			break;
414			// case WSAPROVIDERFAILEDINIT:
415			// error = "Unable to initialize a service provider.";
416			// break;
417			case WSASYSCALLFAILURE:
418			error = "System call failure.";
419			break;
420			case WSASYSNOTREADY:
421			error = "Network subsystem is unavailable.";
422			break;
423			case WSATRY_AGAIN:
424			error = "Non-authoritative host not found.";
425			break;
426			case WSAVERNOTSUPPORTED:
427			error = "WINSOCK.DLL version out of range.";
428			break;
429			case WSAEDISCON:
430			error = "Graceful shutdown in progress.";
431			break;
432			case WSA_OPERATION_ABORTED:
433			error = "Overlapped operation aborted.";
434			break;
435			default:
436			error = "Unknown error.";
437			break;
438			}
439	douglas	1
440	douglas	13	cerr << prefix << ": " << error << "\n";
441			#else
442			if (host)
443			{
444			herror(prefix.c_str());
445	douglas	1	}
446			else
447			{
448	douglas	13	perror(prefix.c_str());
449	douglas	1	}
450	douglas	13	#endif // _WIN32
451			}