RTMPdump 源代码分析 3： AMF编码
之前分析了RTMPDump解析RTMP的URL的源代码，在这里简单分析一下其AMF编码方面的源码。
AMF编码广泛用于Adobe公司的Flash以及Flex系统中。由于RTMP协议也是Adobe公司的，所以它也使用AMF进行通信。具体AMF是怎么使用的在这里就不做详细讨论了。RTMPDump如果想实现RTMP协议的流媒体的下载保存，就必须可以编码和解码AMF格式的数据。
amf.c是RTMPDump解析RTMP协议的函数存放的地方，在这里贴上其源代码。先不做详细解释了，以后有机会再补充。
#include "stdafx.h"/*本文件主要包含了对AMF对象的操作 *------------------------------------- *AMF数据类型： *TypeByte code *Number0x00 *Boolean0x01 *String0x02 *Object0x03 *MovieClip0x04 *Null0x05 *Undefined0x06 *Reference0x07 *MixedArray0x08 *EndOfObject0x09 *Array0x0a *Date0x0b *LongString0x0c *Unsupported0x0d *Recordset0x0e *XML0x0f *TypedObject (Class instance)0x10 *AMF3 data0×11 *-------------------------------------- *应用举例： *0.Number这里指的是double类型，数据用8字节表示，比如十六进制00 40 10 00 00 00 00 00 00就表示的是一个double数4.0 *1.Boolean对应的是.net中的bool类型，数据使用1字节表示，和C语言差不多，使用00表示false，使用01表示true。比如十六进制01 01就表示true。 *2.String相当于.net中的string类型，String所占用的空间有1个类型标识字节和2个表示字符串UTF8长度的字节加上字符串UTF8格式的内容组成。 * 比如十六进制03 00 08 73 68 61 6E 67 67 75 61表示的就是字符串，该字符串长8字节，字符串内容为73 68 61 6E 67 67 75 61，对应的就是“shanggua”。 *3.Object在对应的就是Hashtable，内容由UTF8字符串作为Key，其他AMF类型作为Value，该对象由3个字节：00 00 09来表示结束。 *5.Null就是空对象，该对象只占用一个字节，那就是Null对象标识0x05。 *6.Undefined 也是只占用一个字节0x06。 *8.MixedArray相当于Hashtable，与3不同的是该对象定义了Hashtable的大小。 */#include <string.h>#include <assert.h>#include <stdlib.h>#include "rtmp_sys.h"#include "amf.h"#include "log.h"#include "bytes.h"static const AMFObjectProperty AMFProp_Invalid = { {0, 0}, AMF_INVALID };static const AVal AV_empty = { 0, 0 };//大端Big-Endian//低地址存放最高有效位（MSB），既高位字节排放在内存的低地址端，低位字节排放在内存的高地址端。//符合人脑逻辑，与计算机逻辑不同//网络字节序 Network Order:TCP/IP各层协议将字节序定义为Big-Endian，因此TCP/IP协议中使//用的字节序通常称之为网络字节序。//主机序 Host Orader:它遵循Little-Endian规则。所以当两台主机之间要通过TCP/IP协议进行通//信的时候就需要调用相应的函数进行主机序（Little-Endian）和网络序（Big-Endian）的转换。/*AMF数据采用 Big-Endian（大端模式），主机采用Little-Endian（小端模式） */unsigned shortAMF_DecodeInt16(const char *data){ unsigned char *c = (unsigned char *) data; unsigned short val; val = (c[0] << 8) | c[1];//转换 return val;}unsigned intAMF_DecodeInt24(const char *data){ unsigned char *c = (unsigned char *) data; unsigned int val; val = (c[0] << 16) | (c[1] << 8) | c[2]; return val;}unsigned intAMF_DecodeInt32(const char *data){ unsigned char *c = (unsigned char *)data; unsigned int val; val = (c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]; return val;}voidAMF_DecodeString(const char *data, AVal *bv){ bv->av_len = AMF_DecodeInt16(data); bv->av_val = (bv->av_len > 0) ? (char *)data + 2 : NULL;}voidAMF_DecodeLongString(const char *data, AVal *bv){ bv->av_len = AMF_DecodeInt32(data); bv->av_val = (bv->av_len > 0) ? (char *)data + 4 : NULL;}doubleAMF_DecodeNumber(const char *data){ double dVal;#if __FLOAT_WORD_ORDER == __BYTE_ORDER#if __BYTE_ORDER == __BIG_ENDIAN memcpy(&dVal, data, 8);#elif __BYTE_ORDER == __LITTLE_ENDIAN unsigned char *ci, *co; ci = (unsigned char *)data; co = (unsigned char *)&dVal; co[0] = ci[7]; co[1] = ci[6]; co[2] = ci[5]; co[3] = ci[4]; co[4] = ci[3]; co[5] = ci[2]; co[6] = ci[1]; co[7] = ci[0];#endif#else#if __BYTE_ORDER == __LITTLE_ENDIAN/* __FLOAT_WORD_ORER == __BIG_ENDIAN */ unsigned char *ci, *co; ci = (unsigned char *)data; co = (unsigned char *)&dVal; co[0] = ci[3]; co[1] = ci[2]; co[2] = ci[1]; co[3] = ci[0]; co[4] = ci[7]; co[5] = ci[6]; co[6] = ci[5]; co[7] = ci[4];#else /* __BYTE_ORDER == __BIG_ENDIAN && __FLOAT_WORD_ORER == __LITTLE_ENDIAN */ unsigned char *ci, *co; ci = (unsigned char *)data; co = (unsigned char *)&dVal; co[0] = ci[4]; co[1] = ci[5]; co[2] = ci[6]; co[3] = ci[7]; co[4] = ci[0]; co[5] = ci[1]; co[6] = ci[2]; co[7] = ci[3];#endif#endif return dVal;}intAMF_DecodeBoolean(const char *data){ return *data != 0;}char *AMF_EncodeInt16(char *output, char *outend, short nVal){ if (output+2 > outend) return NULL; output[1] = nVal & 0xff; output[0] = nVal >> 8; return output+2;}//3字节的int数据进行AMF编码，AMF采用大端模式char *AMF_EncodeInt24(char *output, char *outend, int nVal){ if (output+3 > outend) return NULL; //倒过来 output[2] = nVal & 0xff; output[1] = nVal >> 8; output[0] = nVal >> 16; //返回指针指向编码后数据的尾部 return output+3;}char *AMF_EncodeInt32(char *output, char *outend, int nVal){ if (output+4 > outend) return NULL; output[3] = nVal & 0xff; output[2] = nVal >> 8; output[1] = nVal >> 16; output[0] = nVal >> 24; return output+4;}char *AMF_EncodeString(char *output, char *outend, const AVal *bv){ if ((bv->av_len < 65536 && output + 1 + 2 + bv->av_len > outend) ||output + 1 + 4 + bv->av_len > outend) return NULL; if (bv->av_len < 65536) { *output++ = AMF_STRING; output = AMF_EncodeInt16(output, outend, bv->av_len); } else { *output++ = AMF_LONG_STRING; output = AMF_EncodeInt32(output, outend, bv->av_len); } memcpy(output, bv->av_val, bv->av_len); output += bv->av_len; return output;}char *AMF_EncodeNumber(char *output, char *outend, double dVal){ if (output+1+8 > outend) return NULL; *output++ = AMF_NUMBER;/* type: Number */#if __FLOAT_WORD_ORDER == __BYTE_ORDER#if __BYTE_ORDER == __BIG_ENDIAN memcpy(output, &dVal, 8);#elif __BYTE_ORDER == __LITTLE_ENDIAN { unsigned char *ci, *co; ci = (unsigned char *)&dVal; co = (unsigned char *)output; co[0] = ci[7]; co[1] = ci[6]; co[2] = ci[5]; co[3] = ci[4]; co[4] = ci[3]; co[5] = ci[2]; co[6] = ci[1]; co[7] = ci[0]; }#endif#else#if __BYTE_ORDER == __LITTLE_ENDIAN/* __FLOAT_WORD_ORER == __BIG_ENDIAN */ { unsigned char *ci, *co; ci = (unsigned char *)&dVal; co = (unsigned char *)output; co[0] = ci[3]; co[1] = ci[2]; co[2] = ci[1]; co[3] = ci[0]; co[4] = ci[7]; co[5] = ci[6]; co[6] = ci[5]; co[7] = ci[4]; }#else /* __BYTE_ORDER == __BIG_ENDIAN && __FLOAT_WORD_ORER == __LITTLE_ENDIAN */ { unsigned char *ci, *co; ci = (unsigned char *)&dVal; co = (unsigned char *)output; co[0] = ci[4]; co[1] = ci[5]; co[2] = ci[6]; co[3] = ci[7]; co[4] = ci[0]; co[5] = ci[1]; co[6] = ci[2]; co[7] = ci[3]; }#endif#endif return output+8;}char *AMF_EncodeBoolean(char *output, char *outend, int bVal){ if (output+2 > outend) return NULL; *output++ = AMF_BOOLEAN; *output++ = bVal ? 0x01 : 0x00; return output;}char *AMF_EncodeNamedString(char *output, char *outend, const AVal *strName, const AVal *strValue){ if (output+2+strName->av_len > outend) return NULL; output = AMF_EncodeInt16(output, outend, strName->av_len); memcpy(output, strName->av_val, strName->av_len); output += strName->av_len; return AMF_EncodeString(output, outend, strValue);}char *AMF_EncodeNamedNumber(char *output, char *outend, const AVal *strName, double dVal){ if (output+2+strName->av_len > outend) return NULL; output = AMF_EncodeInt16(output, outend, strName->av_len); memcpy(output, strName->av_val, strName->av_len); output += strName->av_len; return AMF_EncodeNumber(output, outend, dVal);}char *AMF_EncodeNamedBoolean(char *output, char *outend, const AVal *strName, int bVal){ if (output+2+strName->av_len > outend) return NULL; output = AMF_EncodeInt16(output, outend, strName->av_len); memcpy(output, strName->av_val, strName->av_len); output += strName->av_len; return AMF_EncodeBoolean(output, outend, bVal);}voidAMFProp_GetName(AMFObjectProperty *prop, AVal *name){ *name = prop->p_name;}voidAMFProp_SetName(AMFObjectProperty *prop, AVal *name){ prop->p_name = *name;}AMFDataTypeAMFProp_GetType(AMFObjectProperty *prop){ return prop->p_type;}doubleAMFProp_GetNumber(AMFObjectProperty *prop){ return prop->p_vu.p_number;}intAMFProp_GetBoolean(AMFObjectProperty *prop){ return prop->p_vu.p_number != 0;}voidAMFProp_GetString(AMFObjectProperty *prop, AVal *str){ *str = prop->p_vu.p_aval;}voidAMFProp_GetObject(AMFObjectProperty *prop, AMFObject *obj){ *obj = prop->p_vu.p_object;}intAMFProp_IsValid(AMFObjectProperty *prop){ return prop->p_type != AMF_INVALID;}char *AMFProp_Encode(AMFObjectProperty *prop, char *pBuffer, char *pBufEnd){ if (prop->p_type == AMF_INVALID) return NULL; if (prop->p_type != AMF_NULL && pBuffer + prop->p_name.av_len + 2 + 1 >= pBufEnd) return NULL; if (prop->p_type != AMF_NULL && prop->p_name.av_len) { *pBuffer++ = prop->p_name.av_len >> 8; *pBuffer++ = prop->p_name.av_len & 0xff; memcpy(pBuffer, prop->p_name.av_val, prop->p_name.av_len); pBuffer += prop->p_name.av_len; } switch (prop->p_type) { case AMF_NUMBER: pBuffer = AMF_EncodeNumber(pBuffer, pBufEnd, prop->p_vu.p_number); break; case AMF_BOOLEAN: pBuffer = AMF_EncodeBoolean(pBuffer, pBufEnd, prop->p_vu.p_number != 0); break; case AMF_STRING: pBuffer = AMF_EncodeString(pBuffer, pBufEnd, &prop->p_vu.p_aval); break; case AMF_NULL: if (pBuffer+1 >= pBufEnd) return NULL; *pBuffer++ = AMF_NULL; break; case AMF_OBJECT: pBuffer = AMF_Encode(&prop->p_vu.p_object, pBuffer, pBufEnd); break; default: RTMP_Log(RTMP_LOGERROR, "%s, invalid type. %d", __FUNCTION__, prop->p_type); pBuffer = NULL; }; return pBuffer;}#define AMF3_INTEGER_MAX268435455#define AMF3_INTEGER_MIN-268435456intAMF3ReadInteger(const char *data, int32_t *valp){ int i = 0; int32_t val = 0; while (i <= 2) {/* handle first 3 bytes */ if (data[i] & 0x80){/* byte used */ val <<= 7;/* shift up */ val |= (data[i] & 0x7f);/* add bits */ i++;} else{ break;} } if (i > 2) {/* use 4th byte, all 8bits */ val <<= 8; val |= data[3]; /* range check */ if (val > AMF3_INTEGER_MAX)val -= (1 << 29); } else {/* use 7bits of last unparsed byte (0xxxxxxx) */ val <<= 7; val |= data[i]; } *valp = val; return i > 2 ? 4 : i + 1;}intAMF3ReadString(const char *data, AVal *str){ int32_t ref = 0; int len; assert(str != 0); len = AMF3ReadInteger(data, &ref); data += len; if ((ref & 0x1) == 0) {/* reference: 0xxx */ uint32_t refIndex = (ref >> 1); RTMP_Log(RTMP_LOGDEBUG, "%s, string reference, index: %d, not supported, ignoring!", __FUNCTION__, refIndex); return len; } else { uint32_t nSize = (ref >> 1); str->av_val = (char *)data; str->av_len = nSize; return len + nSize; } return len;}intAMF3Prop_Decode(AMFObjectProperty *prop, const char *pBuffer, int nSize,int bDecodeName){ int nOriginalSize = nSize; AMF3DataType type; prop->p_name.av_len = 0; prop->p_name.av_val = NULL; if (nSize == 0 || !pBuffer) { RTMP_Log(RTMP_LOGDEBUG, "empty buffer/no buffer pointer!"); return -1; } /* decode name */ if (bDecodeName) { AVal name; int nRes = AMF3ReadString(pBuffer, &name); if (name.av_len <= 0)return nRes; prop->p_name = name; pBuffer += nRes; nSize -= nRes; } /* decode */ type = (AMF3DataType) *pBuffer++; nSize--; switch (type) { case AMF3_UNDEFINED: case AMF3_NULL: prop->p_type = AMF_NULL; break; case AMF3_FALSE: prop->p_type = AMF_BOOLEAN; prop->p_vu.p_number = 0.0; break; case AMF3_TRUE: prop->p_type = AMF_BOOLEAN; prop->p_vu.p_number = 1.0; break; case AMF3_INTEGER: {int32_t res = 0;int len = AMF3ReadInteger(pBuffer, &res);prop->p_vu.p_number = (double)res;prop->p_type = AMF_NUMBER;nSize -= len;break; } case AMF3_DOUBLE: if (nSize < 8)return -1; prop->p_vu.p_number = AMF_DecodeNumber(pBuffer); prop->p_type = AMF_NUMBER; nSize -= 8; break; case AMF3_STRING: case AMF3_XML_DOC: case AMF3_XML: {int len = AMF3ReadString(pBuffer, &prop->p_vu.p_aval);prop->p_type = AMF_STRING;nSize -= len;break; } case AMF3_DATE: {int32_t res = 0;int len = AMF3ReadInteger(pBuffer, &res);nSize -= len;pBuffer += len;if ((res & 0x1) == 0) {/* reference */ uint32_t nIndex = (res >> 1); RTMP_Log(RTMP_LOGDEBUG, "AMF3_DATE reference: %d, not supported!", nIndex); }else { if (nSize < 8) return -1; prop->p_vu.p_number = AMF_DecodeNumber(pBuffer); nSize -= 8; prop->p_type = AMF_NUMBER; }break; } case AMF3_OBJECT: {int nRes = AMF3_Decode(&prop->p_vu.p_object, pBuffer, nSize, TRUE);if (nRes == -1) return -1;nSize -= nRes;prop->p_type = AMF_OBJECT;break; } case AMF3_ARRAY: case AMF3_BYTE_ARRAY: default: RTMP_Log(RTMP_LOGDEBUG, "%s - AMF3 unknown/unsupported datatype 0x%02x, @0x%08X", __FUNCTION__, (unsigned char)(*pBuffer), pBuffer); return -1; } return nOriginalSize - nSize;}//对AMF数据类型解析intAMFProp_Decode(AMFObjectProperty *prop, const char *pBuffer, int nSize, int bDecodeName){ int nOriginalSize = nSize; int nRes; prop->p_name.av_len = 0; prop->p_name.av_val = NULL; if (nSize == 0 || !pBuffer) { RTMP_Log(RTMP_LOGDEBUG, "%s: Empty buffer/no buffer pointer!", __FUNCTION__); return -1; } if (bDecodeName && nSize < 4) {/* at least name (length + at least 1 byte) and 1 byte of data */ RTMP_Log(RTMP_LOGDEBUG, "%s: Not enough data for decoding with name, less than 4 bytes!", __FUNCTION__); return -1; } if (bDecodeName) { unsigned short nNameSize = AMF_DecodeInt16(pBuffer); if (nNameSize > nSize - 2){ RTMP_Log(RTMP_LOGDEBUG, "%s: Name size out of range: namesize (%d) > len (%d) - 2", __FUNCTION__, nNameSize, nSize); return -1;} AMF_DecodeString(pBuffer, &prop->p_name); nSize -= 2 + nNameSize; pBuffer += 2 + nNameSize; } if (nSize == 0) { return -1; } nSize--; prop->p_type = (AMFDataType) *pBuffer++; switch (prop->p_type) {//Number数据类型 case AMF_NUMBER: if (nSize < 8)return -1; prop->p_vu.p_number = AMF_DecodeNumber(pBuffer); nSize -= 8; break; //Boolean数据类型 case AMF_BOOLEAN: if (nSize < 1)return -1; prop->p_vu.p_number = (double)AMF_DecodeBoolean(pBuffer); nSize--; break; //String数据类型 case AMF_STRING: {unsigned short nStringSize = AMF_DecodeInt16(pBuffer);if (nSize < (long)nStringSize + 2) return -1;AMF_DecodeString(pBuffer, &prop->p_vu.p_aval);nSize -= (2 + nStringSize);break; } //Object数据类型 case AMF_OBJECT: {int nRes = AMF_Decode(&prop->p_vu.p_object, pBuffer, nSize, TRUE);if (nRes == -1) return -1;nSize -= nRes;break; } case AMF_MOVIECLIP: {RTMP_Log(RTMP_LOGERROR, "AMF_MOVIECLIP reserved!");return -1;break; } case AMF_NULL: case AMF_UNDEFINED: case AMF_UNSUPPORTED: prop->p_type = AMF_NULL; break; case AMF_REFERENCE: {RTMP_Log(RTMP_LOGERROR, "AMF_REFERENCE not supported!");return -1;break; } case AMF_ECMA_ARRAY: {nSize -= 4;/* next comes the rest, mixed array has a final 0x000009 mark and names, so its an object */nRes = AMF_Decode(&prop->p_vu.p_object, pBuffer + 4, nSize, TRUE);if (nRes == -1) return -1;nSize -= nRes;prop->p_type = AMF_OBJECT;break; } case AMF_OBJECT_END: {return -1;break; } case AMF_STRICT_ARRAY: {unsigned int nArrayLen = AMF_DecodeInt32(pBuffer);nSize -= 4;nRes = AMF_DecodeArray(&prop->p_vu.p_object, pBuffer + 4, nSize, nArrayLen, FALSE);if (nRes == -1) return -1;nSize -= nRes;prop->p_type = AMF_OBJECT;break; } case AMF_DATE: {RTMP_Log(RTMP_LOGDEBUG, "AMF_DATE");if (nSize < 10) return -1;prop->p_vu.p_number = AMF_DecodeNumber(pBuffer);prop->p_UTCoffset = AMF_DecodeInt16(pBuffer + 8);nSize -= 10;break; } case AMF_LONG_STRING: {unsigned int nStringSize = AMF_DecodeInt32(pBuffer);if (nSize < (long)nStringSize + 4) return -1;AMF_DecodeLongString(pBuffer, &prop->p_vu.p_aval);nSize -= (4 + nStringSize);prop->p_type = AMF_STRING;break; } case AMF_RECORDSET: {RTMP_Log(RTMP_LOGERROR, "AMF_RECORDSET reserved!");return -1;break; } case AMF_XML_DOC: {RTMP_Log(RTMP_LOGERROR, "AMF_XML_DOC not supported!");return -1;break; } case AMF_TYPED_OBJECT: {RTMP_Log(RTMP_LOGERROR, "AMF_TYPED_OBJECT not supported!");return -1;break; } case AMF_AVMPLUS: {int nRes = AMF3_Decode(&prop->p_vu.p_object, pBuffer, nSize, TRUE);if (nRes == -1) return -1;nSize -= nRes;prop->p_type = AMF_OBJECT;break; } default: RTMP_Log(RTMP_LOGDEBUG, "%s - unknown datatype 0x%02x, @0x%08X", __FUNCTION__, prop->p_type, pBuffer - 1); return -1; } return nOriginalSize - nSize;}voidAMFProp_Dump(AMFObjectProperty *prop){ char strRes[256]; char str[256]; AVal name; if (prop->p_type == AMF_INVALID) { RTMP_Log(RTMP_LOGDEBUG, "Property: INVALID"); return; } if (prop->p_type == AMF_NULL) { RTMP_Log(RTMP_LOGDEBUG, "Property: NULL"); return; } if (prop->p_name.av_len) { name = prop->p_name; } else { name.av_val = "no-name."; name.av_len = sizeof("no-name.") - 1; } if (name.av_len > 18) name.av_len = 18; snprintf(strRes, 255, "Name: %18.*s, ", name.av_len, name.av_val); if (prop->p_type == AMF_OBJECT) { RTMP_Log(RTMP_LOGDEBUG, "Property: <%sOBJECT>", strRes); AMF_Dump(&prop->p_vu.p_object); return; } switch (prop->p_type) { case AMF_NUMBER: snprintf(str, 255, "NUMBER:\t%.2f", prop->p_vu.p_number); break; case AMF_BOOLEAN: snprintf(str, 255, "BOOLEAN:\t%s", prop->p_vu.p_number != 0.0 ? "TRUE" : "FALSE"); break; case AMF_STRING: snprintf(str, 255, "STRING:\t%.*s", prop->p_vu.p_aval.av_len, prop->p_vu.p_aval.av_val); break; case AMF_DATE: snprintf(str, 255, "DATE:\ttimestamp: %.2f, UTC offset: %d", prop->p_vu.p_number, prop->p_UTCoffset); break; default: snprintf(str, 255, "INVALID TYPE 0x%02x", (unsigned char)prop->p_type); } RTMP_Log(RTMP_LOGDEBUG, "Property: <%s%s>", strRes, str);}voidAMFProp_Reset(AMFObjectProperty *prop){ if (prop->p_type == AMF_OBJECT) AMF_Reset(&prop->p_vu.p_object); else { prop->p_vu.p_aval.av_len = 0; prop->p_vu.p_aval.av_val = NULL; } prop->p_type = AMF_INVALID;}/* AMFObject */char *AMF_Encode(AMFObject *obj, char *pBuffer, char *pBufEnd){ int i; if (pBuffer+4 >= pBufEnd) return NULL; *pBuffer++ = AMF_OBJECT; for (i = 0; i < obj->o_num; i++) { char *res = AMFProp_Encode(&obj->o_props[i], pBuffer, pBufEnd); if (res == NULL){ RTMP_Log(RTMP_LOGERROR, "AMF_Encode - failed to encode property in index %d", i); break;} else{ pBuffer = res;} } if (pBuffer + 3 >= pBufEnd) return NULL;/* no room for the end marker */ pBuffer = AMF_EncodeInt24(pBuffer, pBufEnd, AMF_OBJECT_END); return pBuffer;}intAMF_DecodeArray(AMFObject *obj, const char *pBuffer, int nSize,int nArrayLen, int bDecodeName){ int nOriginalSize = nSize; int bError = FALSE; obj->o_num = 0; obj->o_props = NULL; while (nArrayLen > 0) { AMFObjectProperty prop; int nRes; nArrayLen--; nRes = AMFProp_Decode(&prop, pBuffer, nSize, bDecodeName); if (nRes == -1)bError = TRUE; else{ nSize -= nRes; pBuffer += nRes; AMF_AddProp(obj, &prop);} } if (bError) return -1; return nOriginalSize - nSize;}intAMF3_Decode(AMFObject *obj, const char *pBuffer, int nSize, int bAMFData){ int nOriginalSize = nSize; int32_t ref; int len; obj->o_num = 0; obj->o_props = NULL; if (bAMFData) { if (*pBuffer != AMF3_OBJECT)RTMP_Log(RTMP_LOGERROR, "AMF3 Object encapsulated in AMF stream does not start with AMF3_OBJECT!"); pBuffer++; nSize--; } ref = 0; len = AMF3ReadInteger(pBuffer, &ref); pBuffer += len; nSize -= len; if ((ref & 1) == 0) {/* object reference, 0xxx */ uint32_t objectIndex = (ref >> 1); RTMP_Log(RTMP_LOGDEBUG, "Object reference, index: %d", objectIndex); } else/* object instance */ { int32_t classRef = (ref >> 1); AMF3ClassDef cd = { {0, 0} }; AMFObjectProperty prop; if ((classRef & 0x1) == 0){/* class reference */ uint32_t classIndex = (classRef >> 1); RTMP_Log(RTMP_LOGDEBUG, "Class reference: %d", classIndex);} else{ int32_t classExtRef = (classRef >> 1); int i; cd.cd_externalizable = (classExtRef & 0x1) == 1; cd.cd_dynamic = ((classExtRef >> 1) & 0x1) == 1; cd.cd_num = classExtRef >> 2; /* class name */ len = AMF3ReadString(pBuffer, &cd.cd_name); nSize -= len; pBuffer += len; /*std::string str = className; */ RTMP_Log(RTMP_LOGDEBUG, "Class name: %s, externalizable: %d, dynamic: %d, classMembers: %d", cd.cd_name.av_val, cd.cd_externalizable, cd.cd_dynamic, cd.cd_num); for (i = 0; i < cd.cd_num; i++) { AVal memberName; len = AMF3ReadString(pBuffer, &memberName); RTMP_Log(RTMP_LOGDEBUG, "Member: %s", memberName.av_val); AMF3CD_AddProp(&cd, &memberName); nSize -= len; pBuffer += len; }} /* add as referencable object */ if (cd.cd_externalizable){ int nRes; AVal name = AVC("DEFAULT_ATTRIBUTE"); RTMP_Log(RTMP_LOGDEBUG, "Externalizable, TODO check"); nRes = AMF3Prop_Decode(&prop, pBuffer, nSize, FALSE); if (nRes == -1) RTMP_Log(RTMP_LOGDEBUG, "%s, failed to decode AMF3 property!",__FUNCTION__); else { nSize -= nRes; pBuffer += nRes; } AMFProp_SetName(&prop, &name); AMF_AddProp(obj, &prop);} else{ int nRes, i; for (i = 0; i < cd.cd_num; i++)/* non-dynamic */ { nRes = AMF3Prop_Decode(&prop, pBuffer, nSize, FALSE); if (nRes == -1)RTMP_Log(RTMP_LOGDEBUG, "%s, failed to decode AMF3 property!", __FUNCTION__); AMFProp_SetName(&prop, AMF3CD_GetProp(&cd, i)); AMF_AddProp(obj, &prop); pBuffer += nRes; nSize -= nRes; } if (cd.cd_dynamic) { int len = 0; do{ nRes = AMF3Prop_Decode(&prop, pBuffer, nSize, TRUE); AMF_AddProp(obj, &prop); pBuffer += nRes; nSize -= nRes; len = prop.p_name.av_len;} while (len > 0); }} RTMP_Log(RTMP_LOGDEBUG, "class object!"); } return nOriginalSize - nSize;}//解AMF编码的Object数据类型intAMF_Decode(AMFObject *obj, const char *pBuffer, int nSize, int bDecodeName){ int nOriginalSize = nSize; int bError = FALSE;/* if there is an error while decoding - try to at least find the end mark AMF_OBJECT_END */ obj->o_num = 0; obj->o_props = NULL; while (nSize > 0) { AMFObjectProperty prop; int nRes; if (nSize >=3 && AMF_DecodeInt24(pBuffer) == AMF_OBJECT_END){ nSize -= 3; bError = FALSE; break;} if (bError){ RTMP_Log(RTMP_LOGERROR, "DECODING ERROR, IGNORING BYTES UNTIL NEXT KNOWN PATTERN!"); nSize--; pBuffer++; continue;} //解Object里的Property nRes = AMFProp_Decode(&prop, pBuffer, nSize, bDecodeName); if (nRes == -1)bError = TRUE; else{ nSize -= nRes; pBuffer += nRes; AMF_AddProp(obj, &prop);} } if (bError) return -1; return nOriginalSize - nSize;}voidAMF_AddProp(AMFObject *obj, const AMFObjectProperty *prop){ if (!(obj->o_num & 0x0f)) obj->o_props = (AMFObjectProperty *) realloc(obj->o_props, (obj->o_num + 16) * sizeof(AMFObjectProperty)); obj->o_props[obj->o_num++] = *prop;}intAMF_CountProp(AMFObject *obj){ return obj->o_num;}AMFObjectProperty *AMF_GetProp(AMFObject *obj, const AVal *name, int nIndex){ if (nIndex >= 0) { if (nIndex <= obj->o_num)return &obj->o_props[nIndex]; } else { int n; for (n = 0; n < obj->o_num; n++){ if (AVMATCH(&obj->o_props[n].p_name, name)) return &obj->o_props[n];} } return (AMFObjectProperty *)&AMFProp_Invalid;}voidAMF_Dump(AMFObject *obj){ int n; RTMP_Log(RTMP_LOGDEBUG, "(object begin)"); for (n = 0; n < obj->o_num; n++) { AMFProp_Dump(&obj->o_props[n]); } RTMP_Log(RTMP_LOGDEBUG, "(object end)");}voidAMF_Reset(AMFObject *obj){ int n; for (n = 0; n < obj->o_num; n++) { AMFProp_Reset(&obj->o_props[n]); } free(obj->o_props); obj->o_props = NULL; obj->o_num = 0;}/* AMF3ClassDefinition */voidAMF3CD_AddProp(AMF3ClassDef *cd, AVal *prop){ if (!(cd->cd_num & 0x0f)) cd->cd_props = (AVal *)realloc(cd->cd_props, (cd->cd_num + 16) * sizeof(AVal)); cd->cd_props[cd->cd_num++] = *prop;}AVal *AMF3CD_GetProp(AMF3ClassDef *cd, int nIndex){ if (nIndex >= cd->cd_num) return (AVal *)&AV_empty; return &cd->cd_props[nIndex];}可参考文件：
AMF3 中文版介绍：http://download.csdn.net/detail/leixiaohua1020/6389977