common: move bytecode utilities from filter to its own file

[lttng-tools.git] / src / common / bytecode / bytecode.c

diff --git a/src/common/bytecode/bytecode.c b/src/common/bytecode/bytecode.c
new file mode 100644 (file)
index 0000000..b8edd69
--- /dev/null
+++ b/src/common/bytecode/bytecode.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2020 EfficiOS, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include "bytecode.h"
+
+#include <errno.h>
+
+#include "common/align.h"
+
+#define INIT_ALLOC_SIZE 4
+
+static inline int get_count_order(unsigned int count)
+{
+       int order;
+
+       order = lttng_fls(count) - 1;
+       if (count & (count - 1))
+               order++;
+       return order;
+}
+
+LTTNG_HIDDEN
+int bytecode_init(struct lttng_filter_bytecode_alloc **fb)
+{
+       uint32_t alloc_len;
+
+       alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + INIT_ALLOC_SIZE;
+       *fb = calloc(alloc_len, 1);
+       if (!*fb) {
+               return -ENOMEM;
+       } else {
+               (*fb)->alloc_len = alloc_len;
+               return 0;
+       }
+}
+
+LTTNG_HIDDEN
+int32_t bytecode_reserve(struct lttng_filter_bytecode_alloc **fb, uint32_t align, uint32_t len)
+{
+       int32_t ret;
+       uint32_t padding = offset_align((*fb)->b.len, align);
+       uint32_t new_len = (*fb)->b.len + padding + len;
+       uint32_t new_alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + new_len;
+       uint32_t old_alloc_len = (*fb)->alloc_len;
+
+       if (new_len > LTTNG_FILTER_MAX_LEN)
+               return -EINVAL;
+
+       if (new_alloc_len > old_alloc_len) {
+               struct lttng_filter_bytecode_alloc *newptr;
+
+               new_alloc_len =
+                       max_t(uint32_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
+               newptr = realloc(*fb, new_alloc_len);
+               if (!newptr)
+                       return -ENOMEM;
+               *fb = newptr;
+               /* We zero directly the memory from start of allocation. */
+               memset(&((char *) *fb)[old_alloc_len], 0, new_alloc_len - old_alloc_len);
+               (*fb)->alloc_len = new_alloc_len;
+       }
+       (*fb)->b.len += padding;
+       ret = (*fb)->b.len;
+       (*fb)->b.len += len;
+       return ret;
+}
+
+LTTNG_HIDDEN
+int bytecode_push(struct lttng_filter_bytecode_alloc **fb, const void *data,
+               uint32_t align, uint32_t len)
+{
+       int32_t offset;
+
+       offset = bytecode_reserve(fb, align, len);
+       if (offset < 0)
+               return offset;
+       memcpy(&(*fb)->b.data[offset], data, len);
+       return 0;
+}
+
+LTTNG_HIDDEN
+int bytecode_push_logical(struct lttng_filter_bytecode_alloc **fb,
+               struct logical_op *data,
+               uint32_t align, uint32_t len,
+               uint16_t *skip_offset)
+{
+       int32_t offset;
+
+       offset = bytecode_reserve(fb, align, len);
+       if (offset < 0)
+               return offset;
+       memcpy(&(*fb)->b.data[offset], data, len);
+       *skip_offset =
+               (void *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset
+                       - (void *) &(*fb)->b.data[0];
+       return 0;
+}