From 424d46d3365e5d53fd4e91eed1b19aeb2fe77d0c Mon Sep 17 00:00:00 2001
From: Alex 'AdUser' Z <ad_user@runbox.com>
Date: Tue, 7 Feb 2017 22:49:13 +1000
Subject: [PATCH] + group.[ch]

---
 src/group.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/group.h | 35 +++++++++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 src/group.c
 create mode 100644 src/group.h

diff --git a/src/group.c b/src/group.c
new file mode 100644
index 0000000..721bd99
--- /dev/null
+++ b/src/group.c
@@ -0,0 +1,96 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor Boston, MA 02110-1301,  USA
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "group.h"
+
+#define FREE(x) free((x)), (x) = NULL;
+
+static const int grow_step = 10;
+
+static bool
+group_grow(group_t *group, int size) {
+  int *p = NULL;
+
+  assert(group != NULL);
+
+  if (size <= 0)
+    return false;
+  if (size <= group->caps)
+    return false;
+
+  if ((p = realloc(group->ids, size * sizeof(int))) == NULL)
+    return false;
+
+  group->ids  = p,
+  group->caps = size;
+
+  return true;
+}
+
+group_t *
+group_create(int num, int size) {
+  group_t *tmp = NULL;
+
+  if ((tmp = calloc(1, sizeof(group_t))) == NULL)
+    return NULL;
+  tmp->num = num;
+
+  if (size == 0)
+    return tmp;
+
+  if (!group_grow(tmp, size))
+    FREE(tmp);
+
+  return tmp;
+}
+
+bool
+group_append(group_t *group, int id) {
+  assert(group != NULL);
+
+  for (int i = 0; i < group->size; i++) {
+    if (group->ids[i] == id)
+      return true;
+  }
+
+  if (group->size >= group->caps) {
+    int newcaps = group->caps ? group->caps * 2 : grow_step;
+    if (!group_grow(group, newcaps))
+      return false;
+  }
+
+  group->ids[group->size] = id,
+  group->size++;
+
+  return true;
+}
+
+void
+group_free(group_t *group) {
+  assert(group != NULL);
+
+  FREE(group->ids);
+  group->size = 0,
+  group->caps = 0;
+}
diff --git a/src/group.h b/src/group.h
new file mode 100644
index 0000000..fdd0450
--- /dev/null
+++ b/src/group.h
@@ -0,0 +1,35 @@
+#ifndef GROUP_H_
+#define GROUP_H_ 1
+
+/** group of similar images */
+typedef struct group_t {
+  struct group_t *next; /**< pointer to next group in list */
+  int num;  /**< group number */
+  int size; /**< images count in this group */
+  int caps; /**< allocated slots for images */
+  int *ids; /**< images ids */
+} group_t;
+
+/**
+ * @brief Creates new image group
+ * @param num  Group number
+ * @param size Initial preallocated slots
+ * @returns Pointer to new group of NULL on error
+ */
+group_t * group_create(int num, int size);
+
+/**
+ * @brief Append new image id to given group
+ * @param group Pointer to group struct
+ * @param id Image id to add (dublicates will be ignored)
+ * @returns true on success, false on error
+ */
+bool group_append(group_t *group, int id);
+
+/**
+ * @brief Remove all group members and free allocated memory
+ * @param group Pointer to group struct
+ */
+void group_free(group_t *group);
+
+#endif /* GROUP_H_ */