src/ui/history.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <assert.h>
   4
   5 #include "history.h"
   6 #include "str.h"
   7 #include "system/lt.h"
   8 #include "system/nth_alloc.h"
   9
  10 struct History
  11 {
  12     Lt *lt;
  13
  14     char **buffer;
  15     size_t begin;
  16     size_t capacity;
  17     size_t cursor;
  18 };
  19
  20 History *create_history(size_t capacity)
  21 {
  22     Lt *lt = create_lt();
  23     if (lt == NULL) {
  24         return NULL;
  25     }
  26
  27     History *history = PUSH_LT(
  28         lt,
  29         nth_alloc(sizeof(History)),
  30         free);
  31     if (history == NULL) {
  32         RETURN_LT(lt, NULL);
  33     }
  34     history->lt = lt;
  35
  36     history->capacity = capacity;
  37     history->begin = 0;
  38     history->cursor = 0;
  39
  40     history->buffer = PUSH_LT(lt, nth_calloc(capacity, sizeof(char*)), free);
  41     if (history->buffer == NULL) {
  42         RETURN_LT(lt, NULL);
  43     }
  44
  45     return history;
  46 }
  47
  48 void destroy_history(History *history)
  49 {
  50     assert(history);
  51
  52     for (size_t i = 0; i < history->capacity; ++i) {
  53         if (history->buffer[i] != NULL) {
  54             free(history->buffer[i]);
  55         }
  56     }
  57
  58     RETURN_LT0(history->lt);
  59 }
  60
  61 int history_push(History *history, const char *command)
  62 {
  63     assert(history);
  64     assert(command);
  65
  66     const size_t next_begin = (history->begin + 1) % history->capacity;
  67
  68     if (history->buffer[history->begin] != NULL) {
  69         free(history->buffer[history->begin]);
  70     }
  71
  72     history->buffer[history->begin] = string_duplicate(command, NULL);
  73
  74     if (history->buffer[history->begin] == NULL) {
  75         return -1;
  76     }
  77
  78     history->begin = next_begin;
  79     history->cursor = next_begin;
  80
  81     return 0;
  82 }
  83
  84 const char *history_current(History *history)
  85 {
  86     assert(history);
  87     return history->buffer[history->cursor];
  88 }
  89
  90 void history_prev(History *history)
  91 {
  92     assert(history);
  93     if (history->cursor == 0) {
  94         history->cursor = history->capacity - 1;
  95     } else {
  96         history->cursor--;
  97     }
  98 }
  99
 100 void history_next(History *history)
 101 {
 102     assert(history);
 103     history->cursor = (history->cursor + 1) % history->capacity;
 104 }