calc.c

   1 /* depend: */
   2 /* cflags: */
   3 /* linker: */
   4
   5 #include <assert.h>
   6 #include <getopt.h>
   7 #include <malloc.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 /* constants */
  13
  14 //#define BUFFER_SIZE 4096
  15 #define BUFFER_SIZE 256
  16
  17 /* macros */
  18
  19 #define CEIL(x, y) (((x) + (y) - 1) / (y))
  20 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
  21 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
  22
  23 /* verbose */
  24
  25 #define ERROR 0
  26 #define WARNING 1
  27 #define INFO 2
  28 #define DEBUG 3
  29
  30 #define VERBOSE(level, statement...) do { if (level <= verbose) { statement; } } while(0)
  31
  32 /* gobal variables */
  33
  34 char *progname = NULL;
  35 int verbose = 0;
  36
  37 /* help function */
  38
  39 void usage (int ret)
  40 {
  41     FILE *fd = ret ? stderr : stdout;
  42     fprintf (fd, "usage: %s\n", progname);
  43     fprintf (fd, " -h : help message\n");
  44     fprintf (fd, " -v : verbose level (%d)\n", verbose);
  45
  46     exit (ret);
  47 }
  48
  49 /* main function */
  50
  51 int main (int argc, char *argv[])
  52 {
  53     char buffer[BUFFER_SIZE + 1] = {0};
  54     char *pt = buffer;
  55     int i, j = 0, n;
  56
  57     progname = argv[0];
  58
  59     int c;
  60     while ((c = getopt(argc, argv, "hv:")) != EOF) {
  61         switch (c) {
  62         case 'v':
  63             verbose = atoi (optarg);
  64             break;
  65         case 'h':
  66             VERBOSE (INFO, usage (0));
  67             break;
  68         default:
  69             VERBOSE (ERROR, usage (1));
  70         }
  71     }
  72     if (argc - optind != 0) {
  73         VERBOSE (ERROR, fprintf (stderr, "%s: invalid option -- %s\n", progname, argv[optind]));
  74         VERBOSE (ERROR, usage (1));
  75     }
  76
  77     /* read from input stream */
  78     while ((n = read (STDIN_FILENO, pt, BUFFER_SIZE - (pt - buffer))) != 0) {
  79         VERBOSE (DEBUG, fprintf (stdout, "read %d bytes\n", n));
  80         n += (pt - buffer);
  81
  82         /* look for end of line */
  83         for (i = 0, j = 0; i < n; i++) {
  84             if (buffer[i] == '\n') {
  85                 buffer[i] = 0;
  86                 VERBOSE (DEBUG, fprintf (stdout, "line(%d): %s\n", j, buffer + j));
  87                 j = i + 1;
  88             }
  89         }
  90
  91         /* keep remainding */
  92         if (j < n) {
  93             for (i = 0; i < n - j; i++) {
  94                 buffer[i] = buffer[i + j];
  95             }
  96             pt = buffer + n - j;
  97             for (i = n - j; i < BUFFER_SIZE; i++) {
  98                 buffer[i] = 0;
  99             }
 100         }
 101     }
 102
 103     /* check that nothing is left behind */
 104
 105     VERBOSE (DEBUG, fprintf (stdout, "last\n"));
 106     VERBOSE (DEBUG, fprintf (stdout, "line(%d): %s\n", j, buffer + j));
 107
 108     return 0;
 109 }
 110
 111 // test: calc.exe -h
 112 // test: calc.exe -h | awk '/usage:/ { rc=1 } END { exit (1-rc) }'
 113 // test: calc.exe -_ 2> /dev/null | awk 'END { if (NR == 0) { exit(0) } else exit (1) }'
 114 // test: calc.exe -_ 2>&1 | awk '/usage:/ { rc=1 } END { exit (1-rc) }'
 115 // test: echo "foo\nbar\nfoobar" | calc.exe -v3
 116
 117 /* vim: set ts=4 sw=4 et: */