--- /dev/null
+/**************************************************************************
+ *
+ * Copyright 2017 Valve Corporation
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * @file
+ * A simple allocator that allocates and release "numbers".
+ *
+ * @author Samuel Pitoiset <samuel.pitoiset@gmail.com>
+ */
+
+#include "util/u_idalloc.h"
+#include "util/u_math.h"
+#include "util/u_memory.h"
+
+void
+util_idalloc_init(struct util_idalloc *buf)
+{
+ memset(buf, 0, sizeof(*buf));
+}
+
+void
+util_idalloc_fini(struct util_idalloc *buf)
+{
+ if (buf->data)
+ free(buf->data);
+}
+
+void
+util_idalloc_resize(struct util_idalloc *buf, unsigned new_num_elements)
+{
+ new_num_elements = align(new_num_elements, 32);
+
+ if (new_num_elements > buf->num_elements) {
+ unsigned i;
+
+ buf->data = realloc(buf->data,
+ (new_num_elements / 32) * sizeof(*buf->data));
+
+ for (i = buf->num_elements / 32; i < new_num_elements / 32; i++)
+ buf->data[i] = 0;
+ buf->num_elements = new_num_elements;
+ }
+}
+
+unsigned
+util_idalloc_alloc(struct util_idalloc *buf)
+{
+ unsigned num_elements = buf->num_elements;
+
+ for (unsigned i = 0; i < num_elements / 32; i++) {
+ if (buf->data[i] == 0xffffffff)
+ continue;
+
+ unsigned bit = ffs(~buf->data[i]) - 1;
+ buf->data[i] |= 1u << bit;
+ return i * 32 + bit;
+ }
+
+ /* No slots available, resize and return the first free. */
+ util_idalloc_resize(buf, num_elements * 2);
+
+ buf->data[num_elements / 32] |= 1 << (num_elements % 32);
+
+ return num_elements;
+}
+
+void
+util_idalloc_free(struct util_idalloc *buf, unsigned id)
+{
+ assert(id < buf->num_elements);
+ buf->data[id / 32] &= ~(1 << (id % 32));
+}
--- /dev/null
+/**************************************************************************
+ *
+ * Copyright 2017 Valve Corporation
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#ifndef U_IDALLOC_H
+#define U_IDALLOC_H
+
+#include <inttypes.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct util_idalloc
+{
+ uint32_t *data;
+ unsigned num_elements;
+};
+
+void
+util_idalloc_init(struct util_idalloc *buf);
+
+void
+util_idalloc_fini(struct util_idalloc *buf);
+
+void
+util_idalloc_resize(struct util_idalloc *buf, unsigned new_num_elements);
+
+unsigned
+util_idalloc_alloc(struct util_idalloc *buf);
+
+void
+util_idalloc_free(struct util_idalloc *buf, unsigned id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* U_IDALLOC_H */