C语言中函数的套嵌定义？

graydream

看OpenQ的代码，在qq_crypt.c中发现这样的一个函数，严重不明白。其中似乎套嵌定义了一个函数

1. 
   
2. void qq_encrypt (
   
3.     unsigned char*  instr,
   
4.     int             instrlen,
   
5.     unsigned char*  key,
   
6.     unsigned char*  outstr,
   
7.     int*            outstrlen_prt)
   
8. {
   
9.   unsigned char
   
10.     plain[8],         // plain text buffer
    
11.     plain_pre_8[8],   // plain text buffer, previous 8 bytes
    
12.     * crypted,        // crypted text
    
13.     * crypted_pre_8,  // crypted test, previous 8 bytes
    
14.     * inp;            // current position in instr
    
15.   int
    
16.     pos_in_byte = 1,  // loop in the byte
    
17.     is_header=1,      // header is one byte
    
18.     count=0,          // number of bytes being crypted
    
19.     padding = 0;      // number of padding stuff
    
20. 
    
21.   int rand(void) {    // it can be the real random seed function
    
22.     return 0xdead; }  // override with number, convenient for debug
    
23. 
    
24.   /*** we encrypt every eight byte ***/
    
25. [color=crimson]void encrypt_every_8_byte (void) {[/color]
    
26.     for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {
    
27.       if(is_header) { plain[pos_in_byte] ^= plain_pre_8[pos_in_byte]; }
    
28.       else { plain[pos_in_byte] ^= crypted_pre_8[pos_in_byte]; }
    
29.     } // prepare plain text
    
30.     qq_encipher( (unsigned long *) plain,
    
31.                        (unsigned long *) key,
    
32.                              (unsigned long *) crypted);   // encrypt it
    
33. 
    
34.     for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {
    
35.       crypted[pos_in_byte] ^= plain_pre_8[pos_in_byte];
    
36.     }
    
37.     memcpy(plain_pre_8, plain, 8);     // prepare next
    
38. 
    
39.     crypted_pre_8   =   crypted;       // store position of previous 8 byte
    
40.     crypted         +=  8;             // prepare next output
    
41.     count           +=  8;             // outstrlen increase by 8
    
42.     pos_in_byte     =   0;             // back to start
    
43.     is_header       =   0;             // and exit header
    
44.   }// encrypt_every_8_byte
    
45.   pos_in_byte = (instrlen + 0x0a) % 8; // header padding decided by instrlen
    
46.   if (pos_in_byte) {
    
47.     pos_in_byte = 8 - pos_in_byte;
    
48.   }
    
49.   plain[0] = (rand() & 0xf8) | pos_in_byte;
    
50. 
    
51.   memset(plain+1, rand()&0xff, pos_in_byte++);
    
52.   memset(plain_pre_8, 0x00, sizeof(plain_pre_8));
    
53. 
    
54.   crypted = crypted_pre_8 = outstr;
    
55. 
    
56.   padding = 1; // pad some stuff in header
    
57.   while (padding <= 2) { // at most two byte
    
58.     if(pos_in_byte < 8) { plain[pos_in_byte++] = rand() & 0xff; padding ++; }
    
59.     if(pos_in_byte == 8){ encrypt_every_8_byte(); }
    
60.   }
    
61. 
    
62.   inp = instr;
    
63.   while (instrlen > 0) {
    
64.     if (pos_in_byte < 8) { plain[pos_in_byte++] = *(inp++); instrlen --; }
    
65.     if (pos_in_byte == 8){ encrypt_every_8_byte(); }
    
66.   }
    
67. 
    
68.   padding = 1; // pad some stuff in tailer
    
69.   while (padding <= 7) { // at most sever byte
    
70.     if (pos_in_byte < 8) { plain[pos_in_byte++] = 0x00; padding ++; }
    
71.     if (pos_in_byte == 8){ encrypt_every_8_byte(); }
    
72.   }
    
73. 
    
74.   *outstrlen_prt = count;
    
75. }// qq_encrypt
    
76. 
    
77. 
    
78. 
    

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pupilzeng

具体的看gcc的手册,nested functions

graydream

我在手册上之找到了这样的东东
-mfast-indirect-calls
Generates code that assumes calls never cross space boundaries.
   This allows the compiler to generate code that performs faster indirect calls. This
option will not work in the presence of shared libraries or nested functions.

想问一下，我尝试编译这个文件，编译到内嵌函数的时候，pos_in_byte变成未定义了，正常来说应该是这样的，但是编译OpenQ的时候似乎并没有这样的错误，应该怎样解决这样的问题？

kj501

看看少了什么头文件吧。