src/process1.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5 /** If buffer is too small to hold entire string, it is incremented by this value */
   6 #define BUFFER_STEP 16
   7
   8 /**
   9  * Program reads entire lines of text from the standard input and returns them
  10  * on the standard output without changing anything.
  11  */
  12 int main(void) {
  13         /** Currently fetched from stdin character */
  14         int c;
  15
  16         /** Buffer used to store line of characters */
  17         char * buffer = NULL;
  18
  19         /** Current buffer length*/
  20         int buffer_length = 0;
  21
  22         /* Index of the current character */
  23         int i = 0;
  24
  25         /** Temporary buffer used as a proxy between
  26          * checking memory allocation and copying data to real buffer
  27          */
  28         char *tmp = NULL;
  29
  30         do {
  31                 c = fgetc(stdin);
  32
  33                 /*
  34                  * Check if current index is bigger than current buffer size.
  35                  * If so increment buffer size. On error release memory, and set
  36                  * appropriate flags.
  37                  */
  38                 if (i >= buffer_length) {
  39                         tmp = NULL;
  40                         buffer_length += BUFFER_STEP;
  41                         tmp = (char*) realloc(buffer, buffer_length);
  42                         if (tmp == NULL) {
  43                                 fprintf(stderr, "[%s] Memory allocation problem on read!\n", "process1");
  44                                 free(buffer);
  45                                 buffer = NULL;
  46                                 c = EOF;
  47                         }
  48                 }
  49
  50                 /*
  51                  * If there were no errors parse data.
  52                  */
  53                 if (c != EOF) {
  54                         /* If newline has been found
  55                          * return entire string and release the memory
  56                          */
  57                         if (c == 10) {
  58                                 fprintf(stdout, "%s\n", buffer);
  59
  60                                 buffer_length = 0;
  61                                 i = 0;
  62
  63                                 free(buffer);
  64                                 buffer = NULL;
  65                                 tmp = NULL;
  66                         }
  67                         /*
  68                          * Normal character, add it to the buffer
  69                          */
  70                         else {
  71                                 buffer = tmp;
  72                                 buffer[i] = c;
  73
  74                                 /* Used for debug..*/
  75                                 /*
  76                                 printf("c: %c/%d, i: %d, bl: %d\n", c, c, i, buffer_length);
  77                                 */
  78                                 i++;
  79                         }
  80                 }
  81         } while(c != EOF);
  82
  83         if (buffer) {
  84                 free(buffer);
  85                 buffer = NULL;
  86         }
  87
  88         return 0;
  89 }