live.2012.02.29.tar.gz_live555_音视频处理_音频传输协议

#ifndef _NET_COMMON_H #include "NetCommon.h" #endif #include <stdio.h> #ifdef VXWORKS #include <inetLib.h> #endif /* Some systems (e.g., SunOS) have header files that erroneously declare inet_addr() as taking no arguments. * This confuses C++. To overcome this, we use our own routine, implemented in C. */ unsigned our_inet_addr(cp) char const* cp; { return inet_addr(cp); } #if defined(__WIN32__) || defined(_WIN32) #ifndef IMN_PIM #define WS_VERSION_CHOICE1 0x202/*MAKEWORD(2,2)*/ #define WS_VERSION_CHOICE2 0x101/*MAKEWORD(1,1)*/ int initializeWinsockIfNecessary(void) { /* We need to call an initialization routine before * we can do anything with winsock. (How fucking lame!): */ static int _haveInitializedWinsock = 0; WSADATA wsadata; if (!_haveInitializedWinsock) { if ((WSAStartup(WS_VERSION_CHOICE1, &wsadata) != 0) && ((WSAStartup(WS_VERSION_CHOICE2, &wsadata)) != 0)) { return 0; /* error in initialization */ } if ((wsadata.wVersion != WS_VERSION_CHOICE1) && (wsadata.wVersion != WS_VERSION_CHOICE2)) { WSACleanup(); return 0; /* desired Winsock version was not available */ } _haveInitializedWinsock = 1; } return 1; } #else int initializeWinsockIfNecessary(void) { return 1; } #endif #else #define initializeWinsockIfNecessary() 1 #endif #ifndef NULL #define NULL 0 #endif #ifdef USE_SYSTEM_RANDOM /* Use the system-supplied "random()" and "srandom()" functions */ #include <stdlib.h> long our_random() { #if defined(__WIN32__) || defined(_WIN32) return rand(); #else return random(); #endif } void our_srandom(unsigned int x) { #if defined(__WIN32__) || defined(_WIN32) srand(x); #else srandom(x); #endif } #else /* Use our own implementation of the "random()" and "srandom()" functions */ /* * random.c: * * An improved random number generation package. In addition to the standard * rand()/srand() like interface, this package also has a special state info * interface. The our_initstate() routine is called with a seed, an array of * bytes, and a count of how many bytes are being passed in; this array is * then initialized to contain information for random number generation with * that much state information. Good sizes for the amount of state * information are 32, 64, 128, and 256 bytes. The state can be switched by * calling the our_setstate() routine with the same array as was initiallized * with our_initstate(). By default, the package runs with 128 bytes of state * information and generates far better random numbers than a linear * congruential generator. If the amount of state information is less than * 32 bytes, a simple linear congruential R.N.G. is used. * * Internally, the state information is treated as an array of longs; the * zeroeth element of the array is the type of R.N.G. being used (small * integer); the remainder of the array is the state information for the * R.N.G. Thus, 32 bytes of state information will give 7 longs worth of * state information, which will allow a degree seven polynomial. (Note: * the zeroeth word of state information also has some other information * stored in it -- see our_setstate() for details). * * The random number generation technique is a linear feedback shift register * approach, employing trinomials (since there are fewer terms to sum up that * way). In this approach, the least significant bit of all the numbers in * the state table will act as a linear feedback shift register, and will * have period 2^deg - 1 (where deg is the degree of the polynomial being * used, assuming that the polynomial is irreducible and primitive). The * higher order bits will have longer periods, since their values are also * influenced by pseudo-random carries out of the lower bits. The total * period of the generator is approximately deg*(2**deg - 1); thus doubling * the amount of state information has a vast influence on the period of the * generator. Note: the deg*(2**deg - 1) is an approximation only good for * large deg, when the period of the shift register is the dominant factor. * With deg equal to seven, the period is actually much longer than the * 7*(2**7 - 1) predicted by this formula. */ /* * For each of the currently supported random number generators, we have a * break value on the amount of state information (you need at least this * many bytes of state info to support this random number generator), a degree * for the polynomial (actually a trinomial) that the R.N.G. is based on, and * the separation between the two lower order coefficients of the trinomial. */ #define TYPE_0 0 /* linear congruential */ #define BREAK_0 8 #define DEG_0 0 #define SEP_0 0 #define TYPE_1 1 /* x**7 + x**3 + 1 */ #define BREAK_1 32 #define DEG_1 7 #define SEP_1 3 #define TYPE_2 2 /* x**15 + x + 1 */ #define BREAK_2 64 #define DEG_2 15 #define SEP_2 1 #define TYPE_3 3 /* x**31 + x**3 + 1 */ #define BREAK_3 128 #define DEG_3 31 #define SEP_3 3 #define TYPE_4 4 /* x**63 + x + 1 */ #define BREAK_4 256 #define DEG_4 63 #define SEP_4 1 /* * Array versions of the above information to make code run faster -- * relies on fact that TYPE_i == i. */ #define MAX_TYPES 5 /* max number of types above */ static int const degrees[MAX_TYPES] = { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 }; static int const seps [MAX_TYPES] = { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 }; /* * Initially, everything is set up as if from: * * our_initstate(1, &randtbl, 128); * * Note that this initialization takes advantage of the fact that srandom() * advances the front and rear pointers 10*rand_deg times, and hence the * rear pointer which starts at 0 will also end up at zero; thus the zeroeth * element of the state information, which contains info about the current * position of the rear pointer is just * * MAX_TYPES * (rptr - state) + TYPE_3 == TYPE_3. */ static long randtbl[DEG_3 + 1] = { TYPE_3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342, 0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b, 0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f, 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d, 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc, 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e, 0x8999220b, 0x27fb47b9, }; /* * fptr and rptr are two pointers into the state info, a front and a rear * pointer. These two pointers are always rand_sep places aparts, as they * cycle cyclically through the state information. (Yes, this does mean we * could get away with just one pointer, but the code for random() is more * efficient this way). The pointers are left positioned as they would be * from the call * * our_initstate(1, randtbl, 128); * * (The position of the rear pointer, rptr, is really 0 (as explained above * in the initialization of randtbl) because the state table pointer is set * to point to randtbl[1] (as explained below). */ static long* fptr = &randtbl[SEP_3 + 1]; static long* rptr = &randtbl[1]; /* * The following things are the pointer to the state information table, the * type of the current generator, the degree of the current polynomial being * used, and the separation between the two pointers. Note that for efficiency * of random(), we remember the first location of the state information, not * the zeroeth. Hence it is valid to access state[-1], which is used to * store the type of the R.N.G. Also, we remember the last location, since * this is more efficient than indexing every time to find the address of * the last element to see if the front and rear pointers have wrapped. */ static long *state = &randtbl[1]; static int rand_type = TYPE_3; static int rand_deg = DEG_3; static int rand_sep = SEP_3; static long* end_ptr = &randtbl[DEG_3 + 1]; /* * srandom: * * Initialize the random number generator based on the given seed. If the * type is the trivial no-state-information type, just remember the seed. * O