使用不规则数组(ragged array)和agetline()将整个文件读入内存

  
    

   
      1 
   
     #include 
   
     <
   
     stdio.h
   
     >
   
     

   
      2 
   
     #include 
   
     <
   
     stdlib.h
   
     >
   
     

   
      3 
   
     
   
     extern
   
      
   
     char
   
      
   
     *
   
     agetline(FILE 
   
     *
   
     );

   
      4 
   
     FILE 
   
     *
   
     ifp;

   
      5 
   
     

   
      6 
   
     
   
     /*
   
      assume ifp is open on input file 
   
     */
   
     

   
      7 
   
     

   
      8 
   
     
   
     char
   
     **
   
      lines 
   
     =
   
      NULL;

   
      9 
   
     size_t nalloc 
   
     =
   
      
   
     0
   
     ;

   
     10 
   
     size_t nlines 
   
     =
   
      
   
     0
   
     ;

   
     11 
   
     
   
     char
   
      
   
     *
   
     p;

   
     12 
   
     

   
     13 
   
     
   
     while
   
     ((p 
   
     =
   
      agetline(ifp)) 
   
     !=
   
      NULL) {

   
     14 
   
      
   
     if
   
      (nlines 
   
     >=
   
      nalloc) {

   
     15 
   
      nalloc 
   
     +=
   
      
   
     50
   
     ;

   
     16 
   
     #ifdef SAFEREALLOC

   
     17 
   
      lines 
   
     =
   
      realloc(lines, nalloc 
   
     *
   
      
   
     sizeof
   
     (
   
     char
   
     *
   
     ));

   
     18 
   
     
   
     #else
   
     

   
     19 
   
      
   
     if
   
     (lines 
   
     ==
   
      NULL) 
   
     /*
   
      in case pre - ANSI realloc 
   
     */
   
     

   
     20 
   
      lines 
   
     =
   
      malloc(lines, nalloc 
   
     *
   
      
   
     sizeof
   
     (
   
     char
   
     *
   
     ));

   
     21 
   
      
   
     else
   
     

   
     22 
   
      lines 
   
     =
   
      realloc(lines, nalloc 
   
     *
   
      
   
     sizeof
   
     (
   
     char
   
     *
   
     ));

   
     23 
   
     
   
     #endif
   
     

   
     24 
   
      
   
     if
   
     (lines 
   
     ==
   
      NULL) {

   
     25 
   
      fprintf(stderr, 
   
     "
   
     out of memeory
   
     "
   
     );

   
     26 
   
      exit(
   
     1
   
     );

   
     27 
   
      }

   
     28 
   
      }

   
     29 
   
      lines[nlines
   
     ++
   
     ] 
   
     =
   
      p;

   
     30 
   
     }