wmcalc/readln.c

   1 /* readln.c - Edward H. Flora - ehflora@ksu.edu */
   2 /* Last Modified: 2/24/98 */
   3 /*
   4  *      This function reads a string from a file pointed to by fp until a
   5  *   new line (EOLN) or an end of file is encountered.  It returns a pointer
   6  *   to the string.  The new line character is included in the string returned
   7  *   by the function.
   8  */
   9
  10 /* EXTERNALS:
  11  ******************
  12  * Functions Called:
  13  *      Standard Libraries.
  14  *
  15  * Header Files Included:
  16  *      Standard Includes only.
  17  */
  18
  19 /* PORTABILITY:
  20  ******************
  21  * Coded in ANSI C, using ANSI prototypes.
  22  */
  23
  24 /******  Include Files  *************************************************/
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28
  29 #define EOLN '\n'               /* Defines the new line character */
  30 #define SIZE1 10                /* Defines the increment to increase the */
  31                                 /*  string by until a newline of EOF is found */
  32
  33 /******  Function to Read a Line from fp  *******************************/
  34 char *readln(FILE *fp){
  35   char *tmp, *t1, *t2;
  36   int count = 0, s1 = SIZE1;
  37
  38   if((tmp = malloc(SIZE1*sizeof(char))) == NULL)return NULL;
  39                                 /* If cannot allocate memory */
  40   if((t1 = fgets(tmp, SIZE1, fp)) == NULL){
  41     free(tmp);
  42     return NULL;
  43   }                             /* If there is no string to be read */
  44   while(strchr(t1,EOLN) == NULL){ /* Loop while EOLN is not in the string */
  45     count += strlen(t1);
  46     if((s1 - count) > 1)break;
  47     s1 +=SIZE1;
  48     if((t2 = realloc(tmp, s1*sizeof(char))) == NULL){
  49       free(tmp);
  50       return NULL;
  51     }                           /* If cannot allocate more memory */
  52     else tmp = t2;
  53     if((t1 = fgets((tmp+count),((s1 - count)),fp)) == NULL)break;
  54   }                             /* End of While Loop */
  55   if((t2 = realloc(tmp,strlen(tmp)+1)) == NULL)free(tmp);
  56   return (t2);
  57 }
  58 /******  End of Function readln  ****************************************/
  59