src/process1.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5 /* open/read/write/close */
   6 #include <fcntl.h>
   7
   8 /** If buffer is too small to hold entire string, it is incremented by this value */
   9 #define BUFFER_STEP 16
  10
  11 /**
  12  * Program reads entire lines of text from the standard input and pass them
  13  * to the process2 using created pipe.
  14  */
  15 int main(void) {
  16         /** Currently fetched from stdin character */
  17         int c;
  18
  19         /** Buffer used to store line of characters */
  20         char * buffer = NULL;
  21
  22         /** Current buffer length*/
  23         int buffer_length = 0;
  24
  25         /** Index of the current character */
  26         int i = 0;
  27
  28         /**
  29          * Temporary buffer used as a proxy between
  30          * checking memory allocation and copying data to real buffer
  31          */
  32         char * tmp = NULL;
  33
  34         /** Named pipe used to communnicate with process2 */
  35         char * fifo = "/tmp/process1fifo";
  36
  37         /** File descriptor of pipe */
  38         int file_descriptor;
  39
  40         mkfifo(fifo, 0666);
  41
  42         file_descriptor = open(fifo, O_WRONLY);
  43
  44         do {
  45                 c = fgetc(stdin);
  46
  47                 /*
  48                  * Check if current index is bigger than current buffer size.
  49                  * If so increment buffer size. On error release memory, and set
  50                  * appropriate flags.
  51                  */
  52                 if (i >= buffer_length) {
  53                         tmp = NULL;
  54                         buffer_length += BUFFER_STEP;
  55                         tmp = (char*) realloc(buffer, buffer_length);
  56                         if (tmp == NULL) {
  57                                 fprintf(stderr, "[%s] Memory allocation problem on read!\n", "process1");
  58                                 free(buffer);
  59                                 buffer = NULL;
  60                                 c = EOF;
  61                         }
  62                 }
  63
  64                 /*
  65                  * If there were no errors parse data.
  66                  */
  67                 if (c != EOF) {
  68                         /* If newline has been found
  69                          * return entire string and release the memory
  70                          */
  71                         if (c == 10) {
  72                                 buffer[i] = '\n';
  73                                 write(file_descriptor, buffer, ++buffer_length);
  74                                 /*fprintf(stdout, "%s\n", buffer);*/
  75
  76                                 buffer_length = 0;
  77                                 i = 0;
  78
  79                                 free(buffer);
  80                                 buffer = NULL;
  81                                 tmp = NULL;
  82                         }
  83                         /*
  84                          * Normal character, add it to the buffer
  85                          */
  86                         else {
  87                                 buffer = tmp;
  88                                 buffer[i] = c;
  89
  90                                 /* Used for debug..*/
  91                                 /*
  92                                 printf("c: %c/%d, i: %d, bl: %d\n", c, c, i, buffer_length);
  93                                 */
  94                                 i++;
  95                         }
  96                 }
  97         } while(c != EOF);
  98
  99         close(fifo);
 100         unlink(fifo);
 101
 102         if (buffer) {
 103                 free(buffer);
 104                 buffer = NULL;
 105         }
 106
 107         return 0;
 108 }