src/ui/history.c

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