history.cpp

   1 #include "stdafx.h"
   2
   3 #include <stdlib.h>
   4 #include <string.h>
   5
   6 extern char *get_curr_cmd(void);
   7 extern void update_curr_cmd(char *);
   8 //extern char *get_cmd_str(int);
   9
  10 #define N 21
  11
  12 static char *buf[N];
  13 static int i, j, k;
  14
  15 void
  16 update_cmd_history(char *s)
  17 {
  18         // reset history pointer
  19
  20         k = i;
  21
  22         // blank string?
  23
  24         if (*s == 0)
  25                 return;
  26
  27         // no duplicates
  28
  29         if (i != j && strcmp(s, buf[(i + N - 1) % N]) == 0)
  30                 return;
  31
  32         buf[i] = strdup(s);
  33
  34         i = (i + 1) % N;
  35
  36         if (i == j) {
  37                 free(buf[j]);
  38                 buf[j] = 0;
  39                 j = (j + 1) % N;
  40         }
  41
  42         k = i;
  43 }
  44
  45 // k != i indicates curr cmd is historical
  46
  47 void
  48 do_up_arrow(void)
  49 {
  50         char *s;
  51
  52         // save curr cmd if new input or change to historical input
  53
  54         s = get_curr_cmd();
  55
  56         if (*s) {
  57                 if (k == i || strcmp(s, buf[k]) != 0) {
  58                         update_cmd_history(s);
  59                         k = (i + N - 1) % N;
  60                 }
  61         }
  62
  63         free(s);
  64
  65         // retard history pointer
  66
  67         if (k != j)
  68                 k = (k + N - 1) % N;
  69
  70         if (buf[k])
  71                 update_curr_cmd(buf[k]);
  72         else
  73                 update_curr_cmd("");
  74 }
  75
  76 void
  77 do_down_arrow(void)
  78 {
  79         char *s;
  80
  81         // save curr cmd if new input or change to historical input
  82
  83         s = get_curr_cmd();
  84
  85         if (*s) {
  86                 if (k == i || strcmp(s, buf[k]) != 0) {
  87                         update_cmd_history(s);
  88                         k = (i + N - 1) % N;
  89                 }
  90         }
  91
  92         free(s);
  93
  94         // advance history pointer
  95
  96         if (k != i)
  97                 k = (k + 1) % N;
  98
  99         if (buf[k])
 100                 update_curr_cmd(buf[k]);
 101         else
 102                 update_curr_cmd("");
 103 }
 104
 105 char *
 106 get_cmd_history(void)
 107 {
 108         int k, n;
 109         char *s, *t;
 110
 111         // measure
 112
 113         n = 0;
 114         k = j;
 115         while (k != i) {
 116                 n += (int) strlen(buf[k]) + 2;
 117                 k = (k + 1) % N;
 118         }
 119
 120         s = (char *) malloc(n + 1);
 121
 122         if (s == NULL)
 123                 return NULL;
 124
 125         // copy
 126
 127         t = s;
 128         k = j;
 129         while (k != i) {
 130                 strcpy(t, buf[k]);
 131                 k = (k + 1) % N;
 132                 t += strlen(t);
 133                 //*t++ = '\r';
 134                 //*t++ = ' ';
 135         }
 136
 137         *t = 0;
 138
 139         return s;
 140 }