AMF
AMF是Action Message Format(动作消息格式)的简写，它是一种二进制的数据格式。它的设计是为了把actionscript里面的数据(包括Object, Array, Boolean, Number等)序列化成二进制数据，然后把这段数据随意发送给其他接收方程序，比如发给远程的服务器，在远程服务器那边，可以把这段数据给还原出来，以此达到一个数据传输的作用。
为什么要用AMF
通常情况下我们使用JSON或者XML来做数据的传输，他们的好处是文本数据易读、容易修改，坏处在于文本数据体积较大，而且数据的组织有其局限性。那么二进制协议是不是只有AMF一个呢？ 答案明显是否定的，你完全可以自定义自己的二进制数据格式，用AMF只是由于它是现成的，拿来即可用，不用重新去发明轮子。
AMFObject详解
AMF分成两种： 1. AMF0，基本的数据转换规则； 2. AMF3，是AMF0的扩展。
// AMF0数据类型;
typedef enum
{
AMF_NUMBER = 0, // 数字(double);
AMF_BOOLEAN, // 布尔;
AMF_STRING, // 字符串;
AMF_OBJECT, // 对象;
AMF_MOVIECLIP, // 保留,未使用;
AMF_NULL, // null;
AMF_UNDEFINED, // 未定义;
AMF_REFERENCE, // 引用;
AMF_ECMA_ARRAY, // 数组;
AMF_OBJECT_END, // 对象结束;
AMF_STRICT_ARRAY, // 严格的数组;
AMF_DATE, // 日期;
AMF_LONG_STRING, // 长字符串;
AMF_UNSUPPORTED, // 未支持;
AMF_RECORDSET, // 保留,未使用;
AMF_XML_DOC, // xml文档;
AMF_TYPED_OBJECT, // 有类型的对象;
AMF_AVMPLUS, // 需要扩展到AMF3;
AMF_INVALID = 0xff // 无效的;
}AMFDataType;
// AMF3数据类型;
typedef enum
{
AMF3_UNDEFINED = 0, // 未定义;
AMF3_NULL, // null;
AMF3_FALSE, // false;
AMF3_TRUE, // true;
AMF3_INTEGER, // 数字int;
AMF3_DOUBLE, // double;
AMF3_STRING, // 字符串;
AMF3_XML_DOC, // xml文档;
AMF3_DATE, // 日期;
AMF3_ARRAY, // 数组;
AMF3_OBJECT, // 对象;
AMF3_XML, // xml;
AMF3_BYTE_ARRAY // 字节数组;
} AMF3DataType;
AMF定义了自己的字符串类型：
// AMF自定义的字符串;
typedef struct AVal
{
char *av_val;
int av_len;
} AVal;
// AVal的快速初始化;
#define AVC(str) {str, sizeof(str)-1}
// 比较AVal字符串;
#define AVMATCH(a1,a2) ((a1)->av_len == (a2)->av_len && !memcmp((a1)->av_val,(a2)->av_val,(a1)->av_len))
AMFObject表示AMF对象，o_num 代表 o_props的个数， 一个对象内部可以包含N个对象属性;
// AMF对象, 就是由一系列的属性构成的;
typedef struct AMFObject
{
int o_num; // 属性数目;
struct AMFObjectProperty *o_props; // 属性数组;
} AMFObject;
AMFObject表示AMF对象属性，即key-value键值对。p_name表示key；p_type表示value的类型；p_vu表示value的数值。
// AMF对象的属性;
typedef struct AMFObjectProperty
{
AVal p_name; // 属性名称;
AMFDataType p_type; // 属性类型;
union
{
double p_number;
AVal p_aval;
AMFObject p_object;
} p_vu; // 属性数值;
int16_t p_UTCoffset; // UTC偏移;
} AMFObjectProperty;
p_vu设置为联合体的目的：
当p_type为number时, m_vu取值double类型 p_number;
当p_type为string时, m_vu取值AVal类型 p_aval;
当p_type为object时, m_vu取值AMFObject类型 p_object。
AMF编码、解码的具体实现
#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 };
/* Data is Big-Endian */
/************************************************************************************************************
* 解码int16(这个整数占用两个字节);
*
* c[0]左移8位(就是乘以256)+c[1];
************************************************************************************************************/
unsigned short AMF_DecodeInt16(const char* data)
{
unsigned char* c = (unsigned char* ) data;
unsigned short val;
val = (c[0] << 8) | c[1];
return val;
}
/************************************************************************************************************
* 解码int24(这个整数占用三个字节);
*
* c[0]左移16位+c[1]左移8位+c[2];
************************************************************************************************************/
unsigned int AMF_DecodeInt24(const char* data)
{
unsigned char* c = (unsigned char* ) data;
unsigned int val;
val = (c[0] << 16) | (c[1] << 8) | c[2];
return val;
}
/************************************************************************************************************
* 解码int32(这个整数占用四个字节);
*
* c[0]左移24位+c[1]左移16位+c[2]左移8位+c[3];
************************************************************************************************************/
unsigned int AMF_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;
}
/************************************************************************************************************
* 解码String;
*
* 前两个字节是长度,后面是内容;
************************************************************************************************************/
void AMF_DecodeString(const char* data, AVal* bv)
{
bv->av_len = AMF_DecodeInt16(data);
bv->av_val = (bv->av_len > 0) ? (char* )data + 2 : NULL;
}
/************************************************************************************************************
* 解码LongString;
*
* 前四个字节是长度,后面是内容;
************************************************************************************************************/
void AMF_DecodeLongString(const char* data, AVal* bv)
{
bv->av_len = AMF_DecodeInt32(data);
bv->av_val = (bv->av_len > 0) ? (char* )data + 4 : NULL;
}
/************************************************************************************************************
* 解码数值double;
*
* float字的存储顺序等于字节顺序;
* 大端字节顺序,直接赋值; 小端字节顺序,反转赋值;
*
* float字的存储顺序不等字节顺序;
* 大端字节顺序,反转赋值; 小端字节顺序,直接赋值;
************************************************************************************************************/
double AMF_DecodeNumber(const char* data)
{
double dVal;
#if __FLOAT_WORD_ORDER == __BYTE_ORDER // 如果float字的存储顺序等于字节顺序;
#if __BYTE_ORDER == __BIG_ENDIAN // 如果是大端字节顺序;
memcpy(&dVal, data, 8); // 直接复制;
#elif __BYTE_ORDER == __LITTLE_ENDIAN // 如果是小端字节顺序;
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;
}
/************************************************************************************************************
* 解码布尔;
*
* 判断内容是否为0;
************************************************************************************************************/
int AMF_DecodeBoolean(const char* data)
{
return *data != 0;
}
/************************************************************************************************************
* 编码int16(这个整数占用两个字节);
*
* 依次截取1个字节进行赋值;
************************************************************************************************************/
char* AMF_EncodeInt16(char* output, char* outend, short nVal)
{
if (output + 2 > outend)
{
return NULL;
}
output[1] = nVal & 0xff; // output[1] = nVal; 两者等价;
output[0] = nVal >> 8;
return output+2;
}
/************************************************************************************************************
* 编码int24(这个整数占用三个字节);
*
* 依次截取1个字节进行赋值;
************************************************************************************************************/
char* AMF_EncodeInt24(char* output, char* outend, int nVal)
{
if (output+3 > outend)
return NULL;
output[2] = nVal & 0xff;
output[1] = nVal >> 8;
output[0] = nVal >> 16;
return output+3;
}
/************************************************************************************************************
* 编码int32(这个整数占用四个字节);
*
* 依次截取1个字节进行赋值;
************************************************************************************************************/
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;
}
/************************************************************************************************************
* 编码字符串bv;
*
* 第一个字节存字符串类型;
* 若字节小于65536,用两个字节存储长度; 否则用4个字节存储长度;
************************************************************************************************************/
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;
}
// 第一个字节存字符串类型;
// 若字节小于65536, 用两个字节存储长度; 否则用4个字节存储长度;
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);
}
// 然后将avl内容赋值即可;
memcpy(output, bv->av_val, bv->av_len);
output += bv->av_len;
return output;
}
/************************************************************************************************************
* 编码数值double;
*
* float字的存储顺序等于字节顺序;
* 大端字节顺序,直接赋值; 小端字节顺序,反转赋值;
*
* float字的存储顺序不等字节顺序;
* 大端字节顺序,反转赋值; 小端字节顺序,直接赋值;
************************************************************************************************************/
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;
}
/************************************************************************************************************
* 编码布尔;
*
* 第一个字节存字符串类型;
* 若二个字节： bVal若为真存1 为假存0;
************************************************************************************************************/
char* AMF_EncodeBoolean(char* output, char* outend, int bVal)
{
if (output + 2 > outend)
{
return NULL;
}
*output++ = AMF_BOOLEAN;
*output++ = bVal ? 0x01 : 0x00;
return output;
}
/************************************************************************************************************
* 编码strName+strValue;
*
* name : 长度+内容;
: value: string编码;
************************************************************************************************************/
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);
}
/************************************************************************************************************
* 编码strName+dVal;
*
* name : 长度+内容;
: value: double编码;
************************************************************************************************************/
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);
}
/************************************************************************************************************
* 编码strName+dVal;
*
* name : 长度+内容;
: value: bool编码;
************************************************************************************************************/
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);
}
/************************************************************************************************************
* 获取对象属性的name;
*
************************************************************************************************************/
void AMFProp_GetName(AMFObjectProperty* prop, AVal* name)
{
*name = prop->p_name;
}
/************************************************************************************************************
* 设置对象属性的name;
*
************************************************************************************************************/
void AMFProp_SetName(AMFObjectProperty* prop, AVal* name)
{
prop->p_name = *name;
}
/************************************************************************************************************
* 获取对象属性的type;
*
************************************************************************************************************/
AMFDataType AMFProp_GetType(AMFObjectProperty* prop)
{
return prop->p_type;
}
/************************************************************************************************************
* 设置对象属性的数值(double);
*
************************************************************************************************************/
double AMFProp_GetNumber(AMFObjectProperty* prop)
{
return prop->p_vu.p_number;
}
/************************************************************************************************************
* 获取对象属性的数值(bool);
*
************************************************************************************************************/
int AMFProp_GetBoolean(AMFObjectProperty* prop)
{
return prop->p_vu.p_number != 0;
}
/************************************************************************************************************
* 获取对象属性的数值(string);
*
************************************************************************************************************/
void AMFProp_GetString(AMFObjectProperty* prop, AVal* str)
{
*str = prop->p_vu.p_aval;
}
/************************************************************************************************************
* 获取对象属性的数值(object);
*
************************************************************************************************************/
void AMFProp_GetObject(AMFObjectProperty* prop, AMFObject* obj)
{
*obj = prop->p_vu.p_object;
}
/************************************************************************************************************
* 判断对象属性的类型是否有效;
*
************************************************************************************************************/
int AMFProp_IsValid(AMFObjectProperty* prop)
{
return prop->p_type != AMF_INVALID;
}
/************************************************************************************************************
* 编码： 对象的属性prop;
*
************************************************************************************************************/
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;
}
// 编码对象的name,两个字节存长度;
// 之所以不直接调用AMF_EncodeString 是因为会多存一个字节(表示数据类型);
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;
}
// 编码对象的value, 不同类型不同处理;
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;
case AMF_ECMA_ARRAY:
{
pBuffer = AMF_EncodeEcmaArray(&prop->p_vu.p_object, pBuffer, pBufEnd);
}
break;
case AMF_STRICT_ARRAY:
{
pBuffer = AMF_EncodeArray(&prop->p_vu.p_object, pBuffer, pBufEnd);
}
break;
default:
{
RTMP_Log(RTMP_LOGERROR, "%s, invalid type. %d", __FUNCTION__, prop->p_type);
pBuffer = NULL;
}
break;
};
return pBuffer;
}
#define AMF3_INTEGER_MAX 268435455
#define AMF3_INTEGER_MIN -268435456
/************************************************************************************************************
* AMF读取数值;
*
************************************************************************************************************/
int AMF3ReadInteger(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;
}
int AMF3ReadString(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;
}
int AMF3Prop_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 = AV_empty;
int nRes = AMF3ReadString(pBuffer, &name);
if (name.av_len <= 0)
return nRes;
prop->p_name = name;
pBuffer += nRes;
nSize -= nRes;
}
/* decode */
type = *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, @%p",
__FUNCTION__, (unsigned char)(*pBuffer), pBuffer);
return -1;
}
return nOriginalSize - nSize;
}
/************************************************************************************************************
* 解码： pBuffer->prop;
*
************************************************************************************************************/
int AMFProp_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)
{
// 解码对象属性的name;
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;
}
// 获取属性类型;
nSize--;
prop->p_type = *pBuffer++;
switch (prop->p_type)
{
case AMF_NUMBER:
{
if (nSize < 8)
{
return -1;
}
prop->p_vu.p_number = AMF_DecodeNumber(pBuffer);
nSize -= 8;
}
break;
case AMF_BOOLEAN:
{
if (nSize < 1)
{
return -1;
}
prop->p_vu.p_number = (double)AMF_DecodeBoolean(pBuffer);
nSize--;
}
break;
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;
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;
}
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;
}
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:
case AMF_XML_DOC:
{
unsigned int nStringSize = AMF_DecodeInt32(pBuffer);
if (nSize < (long)nStringSize + 4)
{
return -1;
}
AMF_DecodeLongString(pBuffer, &prop->p_vu.p_aval);
nSize -= (4 + nStringSize);
if (prop->p_type == AMF_LONG_STRING)
{
prop->p_type = AMF_STRING;
}
}
break;
case AMF_RECORDSET:
{
RTMP_Log(RTMP_LOGERROR, "AMF_RECORDSET reserved!");
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, @%p", __FUNCTION__, prop->p_type, pBuffer - 1);
return -1;
}
break;
}
return nOriginalSize - nSize;
}
/************************************************************************************************************
* 对属性prop进行输出显示,用于调试;
*
************************************************************************************************************/
void AMFProp_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);
switch (prop->p_type)
{
case AMF_OBJECT:
{
RTMP_Log(RTMP_LOGDEBUG, "Property: <%sOBJECT>", strRes);
AMF_Dump(&prop->p_vu.p_object);
return;
}
break;
case AMF_ECMA_ARRAY:
{
RTMP_Log(RTMP_LOGDEBUG, "Property: <%sECMA_ARRAY>", strRes);
AMF_Dump(&prop->p_vu.p_object);
return;
}
break;
case AMF_STRICT_ARRAY:
{
RTMP_Log(RTMP_LOGDEBUG, "Property: <%sSTRICT_ARRAY>", strRes);
AMF_Dump(&prop->p_vu.p_object);
return;
}
break;
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);
break;
}
RTMP_Log(RTMP_LOGDEBUG, "Property: <%s%s>", strRes, str);
}
/************************************************************************************************************
* 属性prop的重置;
*
************************************************************************************************************/
void AMFProp_Reset(AMFObjectProperty* prop)
{
if (prop->p_type == AMF_OBJECT || prop->p_type == AMF_ECMA_ARRAY || prop->p_type == AMF_STRICT_ARRAY)
{
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;
}
/************************************************************************************************************
* 编码: obj->pBuffer;
*
************************************************************************************************************/
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++)
{
// 各个属性依次编码;
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 */
}
// oject的对象需要以009结尾标识;
pBuffer = AMF_EncodeInt24(pBuffer, pBufEnd, AMF_OBJECT_END);
return pBuffer;
}
/************************************************************************************************************
* 编码: obj->pBuffer;
*
************************************************************************************************************/
char* AMF_EncodeEcmaArray(AMFObject* obj, char* pBuffer, char* pBufEnd)
{
int i;
if (pBuffer + 4 >= pBufEnd)
{
return NULL;
}
*pBuffer++ = AMF_ECMA_ARRAY;
// 数组需要把个数编码进去;
pBuffer = AMF_EncodeInt32(pBuffer, pBufEnd, obj->o_num);
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 */
}
// oject的对象需要以009结尾标识;
pBuffer = AMF_EncodeInt24(pBuffer, pBufEnd, AMF_OBJECT_END);
return pBuffer;
}
/************************************************************************************************************
* 编码: obj->pBuffer;
*
************************************************************************************************************/
char* AMF_EncodeArray(AMFObject* obj, char* pBuffer, char* pBufEnd)
{
int i;
if (pBuffer + 4 >= pBufEnd)
{
return NULL;
}
*pBuffer++ = AMF_STRICT_ARRAY;
// 数组需要把个数编码进去;
pBuffer = AMF_EncodeInt32(pBuffer, pBufEnd, obj->o_num);
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;
}
}
// 此处oject的对象不需要以009结尾标识;
//if (pBuffer + 3 >= pBufEnd)
// return NULL; /* no room for the end marker */
//pBuffer = AMF_EncodeInt24(pBuffer, pBufEnd, AMF_OBJECT_END);
return pBuffer;
}
/************************************************************************************************************
* 解码: pBuffer->obj;
*
************************************************************************************************************/
int AMF_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
{
// 解码出来的属性追加到obj上;
nSize -= nRes;
pBuffer += nRes;
AMF_AddProp(obj, &prop);
}
}
if (bError)
{
return -1;
}
return nOriginalSize - nSize;
}
int AMF3_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 = AV_empty;
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;
}
/************************************************************************************************************
* 解码: pBuffer->obj;
*
************************************************************************************************************/
int AMF_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 */
// 如果解码出错,会尝试查找009结束标识符;
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;
}
nRes = AMFProp_Decode(&prop, pBuffer, nSize, bDecodeName);
if (nRes == -1)
{
bError = TRUE;
}
else
{
// 解码出来的属性追加到obj上;
nSize -= nRes;
pBuffer += nRes;
AMF_AddProp(obj, &prop);
}
}
if (bError)
{
return -1;
}
return nOriginalSize - nSize;
}
/************************************************************************************************************
* 将属性prop追加到obj上(深拷贝实现);
*
************************************************************************************************************/
void AMF_AddProp(AMFObject* obj, const AMFObjectProperty* prop)
{
if (!(obj->o_num & 0x0f))
{
// 此处的意思每次一次性申请16块内存, 若第17个属性追加时还会触发再申请16块内存;
obj->o_props = realloc(obj->o_props, (obj->o_num + 16) * sizeof(AMFObjectProperty));
}
memcpy(&obj->o_props[obj->o_num++], prop, sizeof(AMFObjectProperty));
}
/************************************************************************************************************
* 获取obj内的属性数量;
*
************************************************************************************************************/
int AMF_CountProp(AMFObject* obj)
{
return obj->o_num;
}
/************************************************************************************************************
* 获取obj内的某个属性;
*
* 优先以nIndex进行返回, 若nIndex<0 会根据name进行筛选;
************************************************************************************************************/
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;
}
/************************************************************************************************************
* 对obj内的所有属性进行输出显示,用于调试;
*
************************************************************************************************************/
void AMF_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)");
}
/************************************************************************************************************
* 对obj内的所有属性进行重置,最后并释放属性数组;
*
************************************************************************************************************/
void AMF_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 */
/************************************************************************************************************
* 将字符串prop追加到cd内的字符串数组中(深拷贝);
*
************************************************************************************************************/
void AMF3CD_AddProp(AMF3ClassDef* cd, AVal* prop)
{
if (!(cd->cd_num & 0x0f))
{
cd->cd_props = realloc(cd->cd_props, (cd->cd_num + 16) * sizeof(AVal));
}
cd->cd_props[cd->cd_num++] = *prop;
}
/************************************************************************************************************
* 获取cd对象内的字符串数组内的第nIndex个字符串;
*
************************************************************************************************************/
AVal* AMF3CD_GetProp(AMF3ClassDef* cd, int nIndex)
{
if (nIndex >= cd->cd_num)
{
return (AVal* )&AV_empty;
}
return &cd->cd_props[nIndex];
}