data/buffer.[ch]: Fix buffer_remove().

mity · Dec 11, 2023 · 1826062 · 1826062
1 parent 018ad60
commit 1826062
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Showing 2 changed files with 45 additions and 11 deletions.
diff --git a/data/buffer.c b/data/buffer.c
@@ -137,7 +137,7 @@ void
 buffer_remove(BUFFER* buf, size_t off, size_t n)
 {
     if(off + n < buf->size) {
-        memmove((uint8_t*)buf->data + off, (uint8_t*)buf->data + off + n, n);
+        memmove((uint8_t*)buf->data + off, (uint8_t*)buf->data + off + n, buf->size - off - n);
         buf->size -= n;
     } else {
         buf->size = off;
@@ -148,9 +148,12 @@ buffer_remove(BUFFER* buf, size_t off, size_t n)
         buf->data = NULL;
         buf->alloc = 0;
     } else if(buf->size < buf->alloc / 4) {
-        /* No error checking here: If the realloc fails, we still have valid
-         * albeit bloated buffer. */
-        buffer_realloc(buf, buffer_good_alloc_size(buf->size * 2));
+        size_t new_alloc = buffer_good_alloc_size(buf->size * 2);
+        if(new_alloc < buf->alloc / 2) {
+            /* No error checking here: If the realloc fails, we still have valid
+             * albeit bloated buffer. */
+            buffer_realloc(buf, new_alloc);
+        }
     }
 }
 
diff --git a/tests/test-buffer.c b/tests/test-buffer.c
@@ -2,7 +2,7 @@
  * C Reusables
  * <http://github.com/mity/c-reusables>
  *
- * Copyright (c) 2018 Martin Mitas
+ * Copyright (c) 2018-2023 Martin Mitas
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -129,13 +129,44 @@ test_remove(void)
     buffer_fini(&buf);
 }
 
+static void
+test_remove_most(void)
+{
+    BUFFER buf = BUFFER_INITIALIZER;
+    int i;
+
+    for(i = 0; i < 1000; i++)
+        buffer_append(&buf, "1234567890", 10);
+    buffer_remove(&buf, 1, 10*1000 - 3);
+    TEST_CHECK(buffer_size(&buf) == 3);
+    TEST_CHECK(buf.alloc < 100);
+
+    buffer_fini(&buf);
+}
+
+static void
+test_remove_all(void)
+{
+    BUFFER buf = BUFFER_INITIALIZER;
+
+    buffer_append(&buf, "1234567890", 10);
+    buffer_remove(&buf, 0, 10);
+    TEST_CHECK(buffer_size(&buf) == 0);
+    TEST_CHECK(buf.alloc == 0);
+    TEST_CHECK(buf.data == NULL);
+
+    buffer_fini(&buf);
+}
+
 
 TEST_LIST = {
-    { "init",       test_init },
-    { "grow",       test_grow },
-    { "reserve",    test_reserve },
-    { "shrink",     test_shrink },
-    { "insert",     test_insert },
-    { "remove",     test_remove },
+    { "init",           test_init },
+    { "grow",           test_grow },
+    { "reserve",        test_reserve },
+    { "shrink",         test_shrink },
+    { "insert",         test_insert },
+    { "remove",         test_remove },
+    { "remove-most",    test_remove_most },
+    { "remove-all",     test_remove_all },
     { 0 }
 };