seqset.c: add seqset_remove()

cyrusimap · Nov 18, 2022 · 53f739e · 53f739e
1 parent 6c95c13
commit 53f739e
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Showing 3 changed files with 73 additions and 2 deletions.
diff --git a/cunit/seqset.testc b/cunit/seqset.testc
@@ -519,4 +519,35 @@ static void test_simplify(void)
     seqset_free(&seq);
 }
 
+static void test_remove(void)
+{
+    seqset_t *seq;
+    char *s;
+
+    seq = seqset_parse("1:8,10,12:14,16:20", NULL, 0);
+    CU_ASSERT_PTR_NOT_NULL_FATAL(seq);
+
+    seqset_remove(seq, 18);
+    s = seqset_cstring(seq);
+    CU_ASSERT_STRING_EQUAL(s, "1:8,10,12:14,16:17,19:20");
+    free(s);
+
+    seqset_remove(seq, 1);
+    s = seqset_cstring(seq);
+    CU_ASSERT_STRING_EQUAL(s, "2:8,10,12:14,16:17,19:20");
+    free(s);
+
+    seqset_remove(seq, 14);
+    s = seqset_cstring(seq);
+    CU_ASSERT_STRING_EQUAL(s, "2:8,10,12:13,16:17,19:20");
+    free(s);
+
+    seqset_remove(seq, 10);
+    s = seqset_cstring(seq);
+    CU_ASSERT_STRING_EQUAL(s, "2:8,12:13,16:17,19:20");
+    free(s);
+
+    seqset_free(&seq);
+}
+
 /* vim: set ft=c: */
diff --git a/lib/seqset.c b/lib/seqset.c
@@ -57,6 +57,8 @@ struct seq_range {
     unsigned high;
 };
 
+#define RANGE_SIZE sizeof(struct seq_range)
+
 struct seqset {
     struct seq_range *set;
     size_t len;
@@ -128,8 +130,7 @@ EXPORTED void seqset_add(seqset_t *seq, unsigned num, int ismember)
     if (!seq->set || seq->set[seq->len-1].high < seq->prev || num <= seq->prev) {
         if (seq->len == seq->alloc) {
             seq->alloc += SETGROWSIZE;
-            seq->set =
-                xrealloc(seq->set, seq->alloc * sizeof(struct seq_range));
+            seq->set = xrealloc(seq->set, seq->alloc * RANGE_SIZE);
         }
         seq->set[seq->len].low = num;
         seq->len++;
@@ -139,6 +140,44 @@ EXPORTED void seqset_add(seqset_t *seq, unsigned num, int ismember)
     seq->prev = num;
 }
 
+/*
+ * Remove a number `num' from the sequence set `seq'.
+ */
+EXPORTED void seqset_remove(seqset_t *seq, unsigned num)
+{
+    if (!seqset_ismember(seq, num)) return;
+
+    struct seq_range *cur = &seq->set[seq->current];
+
+    if (cur->low == cur->high) {
+        /* Single value - remove from the set */
+        memmove(cur, cur+1, (seq->len - seq->current - 1) * RANGE_SIZE);
+        seq->len--;
+    }
+    else if (num == cur->low) {
+        /* Increment the low value */
+        cur->low = num + 1;
+    }
+    else if (num == cur->high) {
+        /* Decrement the high value */
+        cur->high = num - 1;
+    }
+    else {
+        /* Split the range - insert a new one after current */
+        if (seq->len == seq->alloc) {
+            seq->alloc += SETGROWSIZE;
+            seq->set = xrealloc(seq->set, seq->alloc * RANGE_SIZE);
+        }
+
+        cur = &seq->set[seq->current];  // xrealloc may have changed ptr location
+        memmove(cur+1, cur, (seq->len - seq->current) + RANGE_SIZE);
+        seq->len++;
+
+        cur->high = num - 1;
+        (cur+1)->low = num + 1;
+    }
+}
+
 
 /* read the final number from a sequence string and return it */
 EXPORTED unsigned seq_lastnum(const char *list)

diff --git a/lib/seqset.h b/lib/seqset.h
@@ -57,6 +57,7 @@ extern unsigned seq_lastnum(const char *list);
 /* for writing */
 extern seqset_t *seqset_init(unsigned maxval, int flags);
 void seqset_add(seqset_t *seq, unsigned num, int ismember);
+void seqset_remove(seqset_t *seq, unsigned num);
 
 extern seqset_t *seqset_parse(const char *sequence,
                               seqset_t *set,