自学教程：C++ AString类代码示例

void ARTSPConnection::onSendRequest(const sp<AMessage> &msg) {    sp<AMessage> reply;    CHECK(msg->findMessage("reply", &reply));    if (mState != CONNECTED) {        reply->setInt32("result", -ENOTCONN);        reply->post();        return;    }    AString request;    CHECK(msg->findString("request", &request));    // Just in case we need to re-issue the request with proper authentication    // later, stash it away.    reply->setString("original-request", request.c_str(), request.size());    addAuthentication(&request);    addUserAgent(&request);    // Find the boundary between headers and the body.    ssize_t i = request.find("/r/n/r/n");    CHECK_GE(i, 0);    int32_t cseq = mNextCSeq++;    AString cseqHeader = "CSeq: ";    cseqHeader.append(cseq);    cseqHeader.append("/r/n");    request.insert(cseqHeader, i + 2);    LOGV("request: '%s'", request.c_str());    size_t numBytesSent = 0;    while (numBytesSent < request.size()) {        ssize_t n =            send(mSocket, request.c_str() + numBytesSent,                 request.size() - numBytesSent, 0);        if (n < 0 && errno == EINTR) {            continue;        }        if (n <= 0) {            performDisconnect();            if (n == 0) {                // Server closed the connection.                LOGE("Server unexpectedly closed the connection.");                reply->setInt32("result", ERROR_IO);                reply->post();            } else {                LOGE("Error sending rtsp request. (%s)", strerror(errno));                reply->setInt32("result", -errno);                reply->post();            }            return;        }        numBytesSent += (size_t)n;    }    mPendingRequests.add(cseq, reply);}

bool ARTSPConnection::receiveRTSPReponse() {    AString statusLine;    if (!receiveLine(&statusLine)) {        return false;    }    if (statusLine == "$") {        sp<ABuffer> buffer = receiveBinaryData();        if (buffer == NULL) {            return false;        }        if (mObserveBinaryMessage != NULL) {            sp<AMessage> notify = mObserveBinaryMessage->dup();            notify->setObject("buffer", buffer);            notify->post();        } else {            LOGW("received binary data, but no one cares.");        }        return true;    }    sp<ARTSPResponse> response = new ARTSPResponse;    response->mStatusLine = statusLine;    LOGI("status: %s", response->mStatusLine.c_str());    ssize_t space1 = response->mStatusLine.find(" ");    if (space1 < 0) {        return false;    }    ssize_t space2 = response->mStatusLine.find(" ", space1 + 1);    if (space2 < 0) {        return false;    }    bool isRequest = false;    if (!IsRTSPVersion(AString(response->mStatusLine, 0, space1))) {        CHECK(IsRTSPVersion(                    AString(                        response->mStatusLine,                        space2 + 1,                        response->mStatusLine.size() - space2 - 1)));        isRequest = true;        response->mStatusCode = 0;    } else {        AString statusCodeStr(                response->mStatusLine, space1 + 1, space2 - space1 - 1);        if (!ParseSingleUnsignedLong(                    statusCodeStr.c_str(), &response->mStatusCode)                || response->mStatusCode < 100 || response->mStatusCode > 999) {            return false;        }    }    AString line;    ssize_t lastDictIndex = -1;    for (;;) {        if (!receiveLine(&line)) {            break;        }        if (line.empty()) {            break;        }        LOGV("line: '%s'", line.c_str());        if (line.c_str()[0] == ' ' || line.c_str()[0] == '/t') {            // Support for folded header values.            if (lastDictIndex < 0) {                // First line cannot be a continuation of the previous one.                return false;            }            AString &value = response->mHeaders.editValueAt(lastDictIndex);            value.append(line);            continue;        }        ssize_t colonPos = line.find(":");        if (colonPos < 0) {            // Malformed header line.            return false;        }        AString key(line, 0, colonPos);        key.trim();        key.tolower();        line.erase(0, colonPos + 1);//.........这里部分代码省略.........

	virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override	{		LOGD("Error while connecting HTTP: %d (%s)", a_ErrorCode, a_ErrorMsg.c_str());		m_Event.Set();	}

void ARTSPConnection::onConnect(const sp<AMessage> &msg) {    ++mConnectionID;    if (mState != DISCONNECTED) {        if (mUIDValid) {            HTTPBase::UnRegisterSocketUserTag(mSocket);        }        close(mSocket);        mSocket = -1;        flushPendingRequests();    }    mState = CONNECTING;    AString url;    CHECK(msg->findString("url", &url));    sp<AMessage> reply;    CHECK(msg->findMessage("reply", &reply));    AString host, path;    unsigned port;    if (!ParseURL(url.c_str(), &host, &port, &path, &mUser, &mPass)            || (mUser.size() > 0 && mPass.size() == 0)) {        // If we have a user name but no password we have to give up        // right here, since we currently have no way of asking the user        // for this information.        LOGE("Malformed rtsp url %s", url.c_str());        reply->setInt32("result", ERROR_MALFORMED);        reply->post();        mState = DISCONNECTED;        return;    }    if (mUser.size() > 0) {        LOGV("user = '%s', pass = '%s'", mUser.c_str(), mPass.c_str());    }    struct hostent *ent = gethostbyname(host.c_str());    if (ent == NULL) {        LOGE("Unknown host %s", host.c_str());        reply->setInt32("result", -ENOENT);        reply->post();        mState = DISCONNECTED;        return;    }    mSocket = socket(AF_INET, SOCK_STREAM, 0);    if (mUIDValid) {        HTTPBase::RegisterSocketUserTag(mSocket, mUID,                                        (uint32_t)*(uint32_t*) "RTSP");    }    MakeSocketBlocking(mSocket, false);    union {        struct sockaddr_in remote;        struct sockaddr remote_generic;    };    memset(remote.sin_zero, 0, sizeof(remote.sin_zero));    remote.sin_family = AF_INET;    remote.sin_addr.s_addr = *(in_addr_t *)ent->h_addr;    remote.sin_port = htons(port);    int err = ::connect(            mSocket, &remote_generic, sizeof(remote));    reply->setInt32("server-ip", ntohl(remote.sin_addr.s_addr));    if (err < 0) {        if (errno == EINPROGRESS) {            sp<AMessage> msg = new AMessage(kWhatCompleteConnection, id());            msg->setMessage("reply", reply);            msg->setInt32("connection-id", mConnectionID);            msg->post();            return;        }        reply->setInt32("result", -errno);        mState = DISCONNECTED;        if (mUIDValid) {            HTTPBase::UnRegisterSocketUserTag(mSocket);        }        close(mSocket);        mSocket = -1;    } else {        reply->setInt32("result", OK);        mState = CONNECTED;        mNextCSeq = 1;        postReceiveReponseEvent();    }//.........这里部分代码省略.........

bool ASessionDescription::getDurationUs(int64_t *durationUs) const {    *durationUs = 0;    CHECK(mIsValid);    AString value;    if (!findAttribute(0, "a=range", &value)) {        return false;    }#ifndef ANDROID_DEFAULT_CODE     if (strncmp(value.c_str(), "npt=", 4) && strncmp(value.c_str(), "npt:", 4)) {#else    if (strncmp(value.c_str(), "npt=", 4)) {#endif // #ifndef ANDROID_DEFAULT_CODE        return false;    }    float from, to;    if (!parseNTPRange(value.c_str() + 4, &from, &to)) {        return false;    }    *durationUs = (int64_t)((to - from) * 1E6);    return true;}// staticvoid ASessionDescription::ParseFormatDesc(        const char *desc, int32_t *timescale, int32_t *numChannels) {    const char *slash1 = strchr(desc, '/');    CHECK(slash1 != NULL);    const char *s = slash1 + 1;    char *end;    unsigned long x = strtoul(s, &end, 10);    CHECK_GT(end, s);    CHECK(*end == '/0' || *end == '/');    *timescale = x;    *numChannels = 1;    if (*end == '/') {        s = end + 1;        unsigned long x = strtoul(s, &end, 10);        CHECK_GT(end, s);        CHECK_EQ(*end, '/0');        *numChannels = x;    }}// staticbool ASessionDescription::parseNTPRange(        const char *s, float *npt1, float *npt2) {    if (s[0] == '-') {        return false;  // no start time available.    }    if (!strncmp("now", s, 3)) {        return false;  // no absolute start time available    }    char *end;    *npt1 = strtof(s, &end);    if (end == s || *end != '-') {        // Failed to parse float or trailing "dash".        return false;    }    s = end + 1;  // skip the dash.    if (!strncmp("now", s, 3)) {        return false;  // no absolute end time available    }    *npt2 = strtof(s, &end);	#ifndef ANDROID_DEFAULT_CODE	//We support range string as "Range: npt=1.0000-"	return true;#else	if (end == s || *end != '/0') {		return false;	}	return *npt2 > *npt1;#endif}#ifndef ANDROID_DEFAULT_CODE bool ASessionDescription::getBitrate(size_t index, int32_t* bitrate) const {    char key[] = "b=AS";    AString value;    if (!findAttribute(index, key, &value))        return false;    int32_t b = atoi(value.c_str());    b *= 1000;    if (b < 0)//.........这里部分代码省略.........

bool ASessionDescription::parse(const void *data, size_t size) {    mTracks.clear();    mFormats.clear();    mTracks.push(Attribs());    mFormats.push(AString("[root]"));    AString desc((const char *)data, size);#ifndef ANDROID_DEFAULT_CODE     int rtpmapNum = 0;    bool unsupported = false;#endif // #ifndef ANDROID_DEFAULT_CODE    size_t i = 0;    for (;;) {#ifndef ANDROID_DEFAULT_CODE         if (i >= desc.size()) {            break;        }#endif // #ifndef ANDROID_DEFAULT_CODE        ssize_t eolPos = desc.find("/n", i);        if (eolPos < 0) {#ifndef ANDROID_DEFAULT_CODE             eolPos = desc.size();#else            break;#endif // #ifndef ANDROID_DEFAULT_CODE        }        AString line;        if ((size_t)eolPos > i && desc.c_str()[eolPos - 1] == '/r') {            // We accept both '/n' and '/r/n' line endings, if it's            // the latter, strip the '/r' as well.            line.setTo(desc, i, eolPos - i - 1);        } else {            line.setTo(desc, i, eolPos - i);        }        if (line.empty()) {            i = eolPos + 1;            continue;        }        if (line.size() < 2 || line.c_str()[1] != '=') {            return false;        }#ifndef ANDROID_DEFAULT_CODE         if (unsupported && line.c_str()[0] != 'm') {            ALOGI("skip %s in unsupported media description", line.c_str());            i = eolPos + 1;            continue;        } else#endif // #ifndef ANDROID_DEFAULT_CODE        ALOGI("%s", line.c_str());        switch (line.c_str()[0]) {            case 'v':            {                if (strcmp(line.c_str(), "v=0")) {                    return false;                }                break;            }            case 'a':            case 'b':            {                AString key, value;                ssize_t colonPos = line.find(":", 2);                if (colonPos < 0) {                    key = line;                } else {                    key.setTo(line, 0, colonPos);                    if (key == "a=fmtp" || key == "a=rtpmap"                            || key == "a=framesize") {                        ssize_t spacePos = line.find(" ", colonPos + 1);                        if (spacePos < 0) {                            return false;                        }#ifndef ANDROID_DEFAULT_CODE                         if (key == "a=rtpmap") {                            if (rtpmapNum > 0) {                                mTracks.pop();                                mFormats.pop();                                unsupported = true;                                ALOGW("ASessionDescription: multiple rtpmap"                                        " for one media is not supported yet");                                break;                            } else {                                rtpmapNum++;                            }                        }#endif // #ifndef ANDROID_DEFAULT_CODE                        key.setTo(line, 0, spacePos);//.........这里部分代码省略.........

bool ASessionDescription::getDimensions(        size_t index, unsigned long PT,        int32_t *width, int32_t *height) const {    *width = 0;    *height = 0;    char key[20];    sprintf(key, "a=framesize:%lu", PT);    AString value;    if (!findAttribute(index, key, &value)) {#ifndef ANDROID_DEFAULT_CODE         // try to get dimensions from cliprect if no framesize        strcpy(key, "a=cliprect");        if (!findAttribute(index, key, &value)) {            ALOGW("no framesize and cliprect, try Width/Height");            strcpy(key, "a=Width");            if (!findAttribute(index, key, &value)) {                return false;            }            int w = parseString(value.c_str());            strcpy(key, "a=Height");            if (!findAttribute(index, key, &value)) {                return false;            }            int h = parseString(value.c_str());            if (w > 0 && h > 0) {                *width = w;                *height = h;                return true;            }            return false;        }        const char *s = value.c_str();        int a = -1, b = -1, c = -1, d = -1;        sscanf(s, "%d,%d,%d,%d", &a, &b, &c, &d);        if (a == -1 || b == -1 || c == -1 || d == -1)            return false;        *height = c - a;        *width = d - b;        return true;#else        return false;#endif // #ifndef ANDROID_DEFAULT_CODE    }    const char *s = value.c_str();    char *end;    *width = strtoul(s, &end, 10);    CHECK_GT(end, s);    CHECK_EQ(*end, '-');    s = end + 1;    *height = strtoul(s, &end, 10);    CHECK_GT(end, s);    CHECK_EQ(*end, '/0');    return true;}

// StoreVariableToVariable//------------------------------------------------------------------------------bool BFFParser::StoreVariableToVariable( const AString & dstName, BFFIterator & varNameSrcStart, const BFFIterator & operatorIter, BFFStackFrame * dstFrame ){	AStackString< MAX_VARIABLE_NAME_LENGTH > srcName;	bool srcParentScope = false;	if ( ParseVariableName( varNameSrcStart, srcName, srcParentScope ) == false )	{		return false;	}	// find src var	const BFFVariable * varSrc = nullptr;	BFFStackFrame * const srcFrame = ( srcParentScope )		? BFFStackFrame::GetParentDeclaration( srcName, nullptr, varSrc )		: nullptr;	if ( !srcParentScope )	{		varSrc = BFFStackFrame::GetVar( srcName, nullptr );	}	if ( ( srcParentScope && nullptr == srcFrame ) || ( nullptr == varSrc ) )    {    	Error::Error_1009_UnknownVariable( varNameSrcStart, nullptr );    	return false;    }	// find dst var	const BFFVariable * varDst = BFFStackFrame::GetVar( dstName, dstFrame );	const bool concat = ( *operatorIter == BFF_VARIABLE_CONCATENATION );	// concatenation?	if ( concat )	{		// can only concatenate to existing vars		if ( varDst == nullptr )		{			Error::Error_1026_VariableNotFoundForConcatenation( operatorIter, dstName );			return false;		}	}	// if dst exists, types must match	BFFVariable::VarType srcType = varSrc->GetType(); 	BFFVariable::VarType dstType = BFFVariable::VAR_ANY; 	if ( varDst )	{		dstType = varDst->GetType();	}	else 	{		ASSERT( concat == false );		dstType = srcType;	}	// handle supported types	if ( srcType != dstType )	{		// Mismatched - is there a supported conversion?		// String to ArrayOfStrings		if ( ( dstType == BFFVariable::VAR_ARRAY_OF_STRINGS ) && 			 ( srcType == BFFVariable::VAR_STRING ) )		{			uint32_t num = (uint32_t)( 1 + ( concat ? varDst->GetArrayOfStrings().GetSize() : 0 ) );			Array< AString > values( num, false );			if ( concat )			{				values.Append( varDst->GetArrayOfStrings() );			}			values.Append( varSrc->GetString() );			BFFStackFrame::SetVarArrayOfStrings( dstName, values, dstFrame );			FLOG_INFO( "Registered <ArrayOfStrings> variable '%s' with %u elements", dstName.Get(), num );			return true;		}		// Struct to ArrayOfStructs		if ( ( dstType == BFFVariable::VAR_ARRAY_OF_STRUCTS ) && 			 ( srcType == BFFVariable::VAR_STRUCT ) )		{			uint32_t num = (uint32_t)( 1 + ( concat ? varDst->GetArrayOfStructs().GetSize() : 0 ) );			Array< const BFFVariable * > values( num, false );			if ( concat )			{				values.Append( varDst->GetArrayOfStructs() );			}			values.Append( varSrc );			BFFStackFrame::SetVarArrayOfStructs( dstName, values, dstFrame );			FLOG_INFO( "Registered <ArrayOfStructs> variable '%s' with %u elements", dstName.Get(), num );			return true;		}	}	else//.........这里部分代码省略.........

// StoreVariableArray//------------------------------------------------------------------------------bool BFFParser::StoreVariableArray( const AString & name,									const BFFIterator & valueStart, const BFFIterator & valueEnd,									const BFFIterator & operatorIter,									BFFStackFrame * frame ){	Array< AString > values( 32, true );	Array< const BFFVariable * > structValues( 32, true );	// are we concatenating?	if ( *operatorIter == BFF_VARIABLE_CONCATENATION )	{		// find existing		const BFFVariable * var = BFFStackFrame::GetVar( name, frame );		if ( var == nullptr )		{			Error::Error_1026_VariableNotFoundForConcatenation( operatorIter, name );			return false;		}		// make sure existing is an array		if ( var->IsArrayOfStrings() )		{			// get values to start with			values = var->GetArrayOfStrings();		}		else if ( var->IsArrayOfStructs() )		{			// get values to start with			structValues = var->GetArrayOfStructs();		}		else		{			// TODO:B Improve this error to handle ArrayOfStructs case			Error::Error_1027_CannotConcatenate( operatorIter, name, var->GetType(), BFFVariable::VAR_ARRAY_OF_STRINGS );			return false;		}	}	// Parse array of variables	BFFIterator iter( valueStart );	for (;;)	{		iter.SkipWhiteSpaceAndComments();		// end?		if ( iter.GetCurrent() == valueEnd.GetCurrent() )		{			break;		}		const char c = *iter;		if ( ( c == '"' ) || ( c == '/'' ) )		{			// a quoted string			// detect mistmatches			if ( structValues.IsEmpty() == false )			{				// Mixed types in vector				Error::Error_1034_OperationNotSupported( iter, 														 BFFVariable::VAR_ARRAY_OF_STRUCTS,														 BFFVariable::VAR_STRING,														 operatorIter );				return false;			}			// a string			BFFIterator elementValueStart( iter );			iter.SkipString( c );			ASSERT( iter.GetCurrent() <= valueEnd.GetCurrent() ); // should not be in this function if string is not terminated			elementValueStart++; // move to start of actual content			AStackString< 2048 > elementValue;			// unescape and subsitute embedded variables			if ( PerformVariableSubstitutions( elementValueStart, iter, elementValue ) == false )			{				return false;			}			values.Append( elementValue );			iter++; // pass closing quote		}		else if ( c == BFF_DECLARE_VAR_INTERNAL ||				  c == BFF_DECLARE_VAR_PARENT )		{			const BFFIterator elementStartValue = iter;			// a variable			AStackString< MAX_VARIABLE_NAME_LENGTH > varName;			bool parentScope = false; // ignored, the behavior is the same			if ( ParseVariableName( iter, varName, parentScope ) == false )			{				return false;			}			// get the variable			const BFFVariable * var = BFFStackFrame::GetVar( varName, frame );//.........这里部分代码省略.........

int cProtocol132::ParseItemMetadata(cItem & a_Item, const AString & a_Metadata){	// Uncompress the GZIPped data:	AString Uncompressed;	if (UncompressStringGZIP(a_Metadata.data(), a_Metadata.size(), Uncompressed) != Z_OK)	{		AString HexDump;		CreateHexDump(HexDump, a_Metadata.data(), a_Metadata.size(), 16);		LOG("Cannot unGZIP item metadata:/n%s", HexDump.c_str());		return PARSE_ERROR;	}		// Parse into NBT:	cParsedNBT NBT(Uncompressed.data(), Uncompressed.size());	if (!NBT.IsValid())	{		AString HexDump;		CreateHexDump(HexDump, Uncompressed.data(), Uncompressed.size(), 16);		LOG("Cannot parse NBT item metadata:/n%s", HexDump.c_str());		return PARSE_ERROR;	}		// Load enchantments from the NBT:	for (int tag = NBT.GetFirstChild(NBT.GetRoot()); tag >= 0; tag = NBT.GetNextSibling(tag))	{		if (			(NBT.GetType(tag) == TAG_List) &&			(				(NBT.GetName(tag) == "ench") ||				(NBT.GetName(tag) == "StoredEnchantments")			)		)		{			EnchantmentSerializer::ParseFromNBT(a_Item.m_Enchantments, NBT, tag);		}	}		return PARSE_OK;}

bool ARTSPConnection::receiveRTSPRequest() {    AString requestLine;	LOGI(LOG_TAG,"start receiveLine ....../n");    if (!receiveLine(&requestLine)) {        return false;    }//	LOGI(LOG_TAG,"receiveLine OK/n");    sp<AMessage>  request = new AMessage(kWhatRequest,mhandlerID);	request->setInt32("SessionID",mSessionID);	LOGI(LOG_TAG,"request->setInt32 SessionID %d/n",mSessionID);    LOGI(LOG_TAG,"request: %s/n", requestLine.c_str());    ssize_t space1 = requestLine.find(" ");//寻找空格    if (space1 < 0) {        return false;    }    ssize_t space2 = requestLine.find(" ", space1 + 1);    if (space2 < 0) {        return false;    }    AString Method(requestLine.c_str(), space1);	request->setString("Method",Method.c_str());	AString URI(requestLine,space1+1,space2-space1-1);	request->setString("URI",URI.c_str());    AString line;    for (;;) {        if (!receiveLine(&line)) {            break;        }        if (line.empty()) {            break;        }        ssize_t colonPos = line.find(":");        if (colonPos < 0) {            // Malformed header line.            return false;        }        AString key(line, 0, colonPos);        key.trim();       // key.tolower();        line.erase(0, colonPos + 1);        line.trim();		        LOGI(LOG_TAG,"line: %s:%s/n", key.c_str(),line.c_str());	    request->setString(key.c_str(),line.c_str());	    }	LOGI(LOG_TAG,"Post the request to handler/n");    request->post();//将请求消息发送给uplayer 处理	return OK;}