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/** 
* name         fxu -- function extract utility 
* 
* usage        fxu filename function 
* 
*              where "filename" is the name of a file containing 
*              several C functions, and "function" is the name of 
*              the particular function to be extracted.  If the 
*              named function is found, then (1) standard input is 
*              copied to the standard output until EOF, and (2) the 
*              text of the named function is written to the standard 
*              output.  The first option allows header information 
*              to be prepended to the output file. 
* 
**/ 
 
#include "stdio.h" 
#include "ctype.h" 
 
#define MAX 16        /* maximum characters in function name */ 
#define MAXBUF 2000   /* maximum characters buffered between functions */ 
 
main(argc, argv) 
int argc; 
char *argv[]; 
{ 
int c, brace, cnest, nc; 
int i, ns, copy, inlit, delim, pc; 
FILE *sfp; 
char symbol[MAX+1]; 
char text[MAXBUF]; 
 
if (argc != 3) 
   { 
   fputs("Usage: fxu filename function\n", stderr); 
   exit(1); 
   } 
if ((sfp = fopen(argv[1], "r")) == NULL) 
   { 
   fputs("Can't open source file\n", stderr); 
   exit(1); 
   } 
brace = cnest = nc = ns = copy = inlit = pc = 0; 
c = getc(sfp);        /* get first char */ 
while (c != EOF) 
   {                 /* scan through source file */ 
   if (ns == MAXBUF) 
       { 
       fputs("Maximum buffer size exceeded\n", stderr); 
       exit(1); 
       } 
   if (copy == 0) 
       { 
       if (brace == 0) text[ns++] = c;  /* save chars between functions */ 
       } 
   else 
       if (putchar(c) == EOF) 
           { 
           fputs("Copy error\n", stderr); 
           exit(1); 
           } 
   if (c == '/') 
       {             /* possible comment */ 
       nc = 0; 
       if ((c = getc(sfp)) == '*') 
           { 
           ++cnest;   /* bump nesting level */ 
           if (copy) putchar(c); 
           else if (brace == 0) text[ns++] = c; 
           c = getc(sfp); 
           } 
       continue; 
       } 
   if (cnest != 0) 
       {             /* inside comment */ 
       if (c == '*') 
           { 
           if ((c = getc(sfp)) == '/') 
              { 
              --cnest;       /* reduce nesting level */ 
              if (copy) putchar(c); 
              else if (brace == 0) text[ns++] = c; 
              c = getc(sfp); 
              } 
           continue; 
           } 
       nc = 0; 
       } 
   else if (inlit) 
       {               /* inside literal string */ 
       if (c == '\\' && pc == '\\') c = 0; 
       if (c == delim && pc != '\\') inlit = 0; 
       pc = c;         /* save previous character */ 
       } 
   else if (c == '\'' || c == '\"') 
       {               /* enter literal string */ 
       inlit = 1; 
       pc = 0; 
       delim = c; 
       } 
   else if (c == '{') ++brace; 
   else if (c == '}') 
       {             /* right brace */ 
       nc = 0; 
       if (--brace == 0) 
           if (copy == 0) ns = 0;      /* reset save index if not found */ 
           else 
               {               /* copy complete */ 
               putchar('\n'); 
               exit(0); 
               } 
       } 
   else if (brace == 0) 
       { 
       if (nc == 0) 
           {             /* symbol not started yet */ 
           if (iscsymf(c)) 
               symbol[nc++] = c;  /* start new symbol */ 
           } 
       else if (iscsym(c) || c == '$') 
                     /* continue symbol */ 
           if (nc < MAX) symbol[nc++] = c; 
           else symbol[0] = '\0'; 
       else if (nc != 0) 
           {             /* end of current symbol */ 
           symbol[nc++] = '\0'; 
           if (strcmp(symbol,argv[2]) == 0) 
               {               /* named function has been found */ 
               while ((c = getchar()) != EOF) 
                   putchar(c);         /* copy standard input to output */ 
               for (i = 0; i < ns; i++) 
                   putchar(text[i]);           /* copy saved characters */ 
               copy = 1;       /* turn on copy flag */ 
               } 
           nc = 0; 
           } 
       } 
   c = getc(sfp);      /* get next char */ 
   } 
 
fputs("Named function not found\n", stderr); 
exit(1); 
}