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2017-06-07 回答

网上很多关于websocket发送数据大于大于0xFFFF(65535)的处理都是一句话“暂不处理”！！！！！所以特写此文。

int WSSession::safeSendFrame(uint8_t *buffer, size_t bufferSize, enum wsFrameType frameType)

{

// 发数据到浏览器需要封装一个websocket的头，但wsMakeFrame()函数e5a48de588b6e79fa5e9819331333363383935存在内存拷贝，会消耗性能，

// 所以这里分两步发：1、发websocket头，2、发实际数据。

// 构造websocket头

uint8_t wsMakeFrameHead[20] = {0};

size_t FrameHeadLen = 0;

assert(frameType < 0x10);

if (bufferSize > 0)

assert(buffer);

wsMakeFrameHead[0] = 0x80 | frameType;

if (bufferSize <= 125) {

wsMakeFrameHead[1] = bufferSize;

FrameHeadLen = 2;

} else if (bufferSize <= 0xFFFF) {

wsMakeFrameHead[1] = 126;

uint16_t payloadLength16b = htons(bufferSize);

memcpy(&wsMakeFrameHead[2], &payloadLength16b, 2);

FrameHeadLen = 4;

} else {

// assert(dataLength <= 0xFFFF);

//implementation for 64bit systems

/*wsMakeFrameHead[1] = 127;

uint64_t lenHigh32b = htonl((bufferSize>>32)& 0xFFFFFFFF);

uint64_t lenLow32b = ((uint64_t)htonl(bufferSize&0xFFFFFFFF)) << 32;

uint64_t payloadLength64b = lenHigh32b | lenLow32b;

memcpy(&wsMakeFrameHead[2], &payloadLength64b, 8);

FrameHeadLen = 10;*/

wsMakeFrameHead[1] = 127;

wsMakeFrameHead[2] = 0;

wsMakeFrameHead[3] = 0;

wsMakeFrameHead[4] = 0;

wsMakeFrameHead[5] = 0;

wsMakeFrameHead[6] = (byte)(bufferSize >>24);

wsMakeFrameHead[7] = (byte)(bufferSize >>16);

wsMakeFrameHead[8] = (byte)(bufferSize >>8);

wsMakeFrameHead[9] = (byte)(bufferSize & 0xFF);

FrameHeadLen = 10;

}

// 发websocket头

int nRetH = safeSend(wsMakeFrameHead, FrameHeadLen);

// 发实际数据

int nRetD = safeSend(buffer, bufferSize);

if (nRetH != EXIT_SUCCESS || nRetD != EXIT_SUCCESS)

return EXIT_FAILURE;

return EXIT_SUCCESS;

}