delphi - Delphi C++ Indy UDP Server BytesToString 没有收到正确的字符串?
问题描述
我正在尝试从 TUIO 多模拟器接收 UDP 数据包。但是有些数据丢失了。
void __fastcall TMain::UDPServerUDPRead(TIdUDPListenerThread *AThread, const TIdBytes AData,
TIdSocketHandle *ABinding)
{
UDPData->Lines->Add(BytesToString(AData));
for (int i = 0; i < AData.Length; i++)
UDPData->Lines->Add((char)AData[i]);
}
当我使用时BytesToString()
,我只得到"#bundle"
一个字符串,但是当我使用第二个循环时,我得到了这个:
# 捆
/ t u i o / 2 D c u r , s i a l i v e 4 / t u i o / 2 D c u r , s i f f f f s e t ?
ホ 9 > ᅳ</p>
/ t u i o / 2 D c u r , s i f s e q # b u n d l e
/t u i o / 2 D o b j , s a l i v e
/ t u i o / 2 D o b j , s i f s e q # b u n d l e
/ t u i o / 2 D c u r , s a l i v e
/ t u i o / 2 D c u r , s i f s e q
当然,每个字符单独一行。
那么,当我不知道编码时,如何获得正确的数据呢?我在这里迷路了,需要真正的帮助。
另外,我怎样才能发送类似的捆绑数据TIdUDPClient
?
解决方案
您显示的 UDP 数据主要是二进制数据,其中包含一些文本元素。因此,您不应该使用 将整个 AData
字符串转换为单个字符串BytesToString()
,因为它不完全是以开头的文本(嗯,您可以使用BytesToStringRaw()
或BytesToString()
withIndyTextEncoding_8bit()
作为编码,但这对您没有太大帮助所以)。
您需要根据您链接到的协议规范(这又基于Open Sound Control协议)将数据分解为其单独的组件。只有这样,您才能根据需要处理组件。这意味着您需要逐个字节地循环AData
,根据协议在上下文中解析每个字节。
例如(到目前为止,这还不是一个完整的实现,但它应该让您了解所涉及的逻辑类型):
struct OSCArgument
{
char Type;
Variant Data;
}
struct OSCBundleElement
{
virtual ~OSCBundleElement() {}
};
struct OSCMessage : OSCBundleElement
{
String AddressPattern;
DynamicArray<OSCArgument> Arguments;
};
struct OSCBundle : OSCBundleElement
{
TDateTime TimeTag;
DynamicArray<OSCBundleElement*> Elements;
~OSCBundle()
{
int len = Elements.Length;
for (int i = 0; i < len; ++i)
delete Elements[i];
}
};
int32_t readInt32(const TIdBytes &Bytes, int &offset)
{
uint32_t ret = GStack->NetworkToHost(BytesToUInt32(Bytes, offset));
offet += 4;
return reinterpret_cast<int32_t&>(ret);
}
TDateTime readOSCTimeTag(const TIdBytes &Bytes, int &offset)
{
int32_t secondsSinceEpoch = readInt32(Bytes, offset); // since January 1 1900 00:00:00
int32_t fractionalSeconds = readInt32(Bytes, offset); // precision of about 200 picoseconds
// TODO: convert seconds to TDateTime...
TDateTime ret = ...;
return ret;
}
float readFloat32(const TIdBytes &Bytes, int &offset)
{
uint32_t ret = BytesToUInt32(Bytes, offset);
offet += 4;
return reinterpret_cast<float&>(ret);
}
String readOSCString(const TIdBytes &Bytes, int &offset)
{
int found = ByteIndex(0x00, Bytes, offset);
if (found == -1) throw ...; // error!
int len = found - offset;
String ret = BytesToString(Bytes, offset, len, IndyTextEncoding_ASCII());
len = ((len + 3) & ~3)); // round up to even multiple of 32 bits
offset += len;
return ret;
}
TIdBytes readOSCBlob(const TIdBytes &Bytes, int &offset)
{
int32_t size = readInt32(Bytes, offset);
TIdBytes ret;
ret.Length = size;
CopyTIdBytes(Bytes, offset, ret, 0, size);
size = ((size + 3) & ~3)); // round up to even multiple of 32 bits
offset += size;
return ret;
}
OSCMessage* readOSCMessage(const TIdBytes &Bytes, int &offset);
OSCBundle* readOSCBundle(const TIdBytes &Bytes, int &offset);
OSCBundleElement* readOSCBundleElement(const TIdBytes &Bytes, int &offset)
{
TIdBytes data = readOSCBlob(Bytes, offset);
int dataOffset = 0;
switch (data[0])
{
case '/': return readOSCMessage(data, dataOffset);
case '#': return readOSCBundle(data, dataOffset);
}
throw ...; // unknown data!
}
Variant readOSCArgumentData(char ArgType, const TIdBytes &Bytes, int &offset)
{
switch (ArgType)
{
case 'i': return readInt32(Bytes, offset);
case 'f': return readFloat32(Bytes, offset);
case 's': return readOSCString(Bytes, offset);
case 'b': return readOSCBlob(Bytes, offset);
// other types as needed ...
}
throw ...; // unknown data!
}
OSCMessage* readOSCMessage(const TIdBytes &Bytes, int &offset)
{
OSCMessage* ret = new OSCMessage;
try
{
ret->AddressPattern = readOSCString(Bytes, offset);
String ArgumentTypes = readOSCString(Bytes, offset);
if (ArgumentTypes[1] != ',') throw ...; // error!
for (int i = 2; i <= ret->ArgumentTypes.Length(); ++i)
{
OSCArgument arg;
arg.Type = ArgumentTypes[i];
arg.Data = readOSCArgumentData(arg.Type, Bytes, offset);
ret.Arguments.Length = ret.Arguments.Length + 1;
ret.Arguments[ret.Arguments.High] = arg;
}
}
catch (...)
{
delete ret;
throw;
}
return ret;
}
OSCBundle* readOSCBundle(const TIdBytes &Bytes, int &offset)
{
if (readOSCString(Bytes, offset) != "#bundle")
throw ...; // error!
OSCBundle *ret = new OSCBundle;
try
{
ret->TimeTag = readOSCTimeTag(Bytes, offset);
int len = Bytes.Length;
while (offset < len)
{
OSCBundleElement *element = readOSCBundleElement(Bytes, offset);
try
{
ret->Elements.Length = ret->Elements.Length + 1;
ret->Elements[ret->Elements.High] = element;
}
catch (...)
{
delete element;
throw;
}
}
}
catch (...)
{
delete ret;
throw;
}
return ret;
}
void __fastcall TMain::UDPServerUDPRead(TIdUDPListenerThread *AThread, const TIdBytes AData,
TIdSocketHandle *ABinding)
{
int offset = 0;
if (AData[0] == '/')
{
OSCMessage *msg = readOSCMessage(AData, offset);
// process msg as needed...
delete msg;
}
else if (AData[0] == '#')
{
OSCBundle *bundle = readOSCBundle(AData, offset);
// process bundle as needed...
delete bundle;
}
else
{
// unknown data!
}
}
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