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/error.h"
   8 #include "system/lt.h"
   9 #include "system/nth_alloc.h"
  10
  11 struct History
  12 {
  13     Lt *lt;
  14
  15     char **buffer;
  16     size_t begin;
  17     size_t capacity;
  18     size_t cursor;
  19 };
  20
  21 History *create_history(size_t capacity)
  22 {
  23     Lt *lt = create_lt();
  24     if (lt == NULL) {
  25         return NULL;
  26     }
  27
  28     History *history = PUSH_LT(
  29         lt,
  30         nth_alloc(sizeof(History)),
  31         free);
  32     if (history == NULL) {
  33         throw_error(ERROR_TYPE_LIBC);
  34         RETURN_LT(lt, NULL);
  35     }
  36     history->lt = lt;
  37
  38     history->capacity = capacity;
  39     history->begin = 0;
  40     history->cursor = 0;
  41
  42     history->buffer = PUSH_LT(lt, nth_calloc(capacity, sizeof(char*)), free);
  43     if (history->buffer == NULL) {
  44         throw_error(ERROR_TYPE_LIBC);
  45         RETURN_LT(lt, NULL);
  46     }
  47
  48     return history;
  49 }
  50
  51 void destroy_history(History *history)
  52 {
  53     assert(history);
  54
  55     for (size_t i = 0; i < history->capacity; ++i) {
  56         if (history->buffer[i] != NULL) {
  57             free(history->buffer[i]);
  58         }
  59     }
  60
  61     RETURN_LT0(history->lt);
  62 }
  63
  64 int history_push(History *history, const char *command)
  65 {
  66     assert(history);
  67     assert(command);
  68
  69     const size_t next_begin = (history->begin + 1) % history->capacity;
  70
  71     if (history->buffer[history->begin] != NULL) {
  72         free(history->buffer[history->begin]);
  73     }
  74
  75     history->buffer[history->begin] = string_duplicate(command, NULL);
  76
  77     if (history->buffer[history->begin] == NULL) {
  78         return -1;
  79     }
  80
  81     history->begin = next_begin;
  82     history->cursor = next_begin;
  83
  84     return 0;
  85 }
  86
  87 const char *history_current(History *history)
  88 {
  89     assert(history);
  90     return history->buffer[history->cursor];
  91 }
  92
  93 void history_prev(History *history)
  94 {
  95     assert(history);
  96     if (history->cursor == 0) {
  97         history->cursor = history->capacity - 1;
  98     } else {
  99         history->cursor--;
 100     }
 101 }
 102
 103 void history_next(History *history)
 104 {
 105     assert(history);
 106     history->cursor = (history->cursor + 1) % history->capacity;
 107 }