sandbox: add util functions

sandbox/Makefile

@@ -6,7 +6,7 @@ BUILD_DIR := $(SANDBOX_BASE_DIR)/../build/sandbox
 
 include $(SANDBOX_BASE_DIR)/../tools/make/gcc-host.mk
 EXEC_NAME := sandbox
-DIR_LIST := memblock vm base queue btree
+DIR_LIST := memblock vm base queue btree util
 INCLUDE_DIRS := $(foreach dir,$(DIR_LIST),-I$(dir)/include)
 SRC := $(foreach dir,$(DIR_LIST),$(wildcard $(dir)/*.c))
 OBJ := $(addprefix $(BUILD_DIR)/,$(SRC:.c=.o))

sandbox/util/data_size.c

@@ -0,0 +1,66 @@
+#include <stddef.h>
+#include <stdio.h>
+
+struct magnitude {
+    size_t threshold;
+    const char *suffix;
+};
+
+#define USE_BASE2
+
+/* This list must be in decending order of threshold */
+#ifdef USE_BASE2
+static struct magnitude k_magnitudes[] = {
+    { 0x10000000000, "TiB" },
+    { 0x40000000, "GiB" },
+    { 0x100000, "MiB" },
+    { 0x400, "KiB" },
+    { 0x00, "B" },
+};
+#else
+static struct magnitude k_magnitudes[] = {
+    { 1000000000000, "TB" },
+    { 1000000000, "GB" },
+    { 1000000, "MB" },
+    { 1000, "KB" },
+    { 0, "B" },
+};
+#endif
+
+static void convert(size_t *big, size_t *small, size_t val, size_t threshold)
+{
+    if (!threshold) {
+        *big = val;
+        *small = 0;
+        return;
+    }
+
+    *big = val / threshold;
+    size_t rem = val % threshold;
+    *small = (10 * rem) / threshold;
+}
+
+void data_size_to_string(size_t value, char *out, size_t outsz)
+{
+    if (!value) {
+        snprintf(out, outsz, "0 B");
+        return;
+    }
+
+    size_t def_count = sizeof(k_magnitudes) / sizeof(struct magnitude);
+
+    for (size_t i = 0; i < def_count; i++) {
+        if (value > k_magnitudes[i].threshold) {
+            size_t big, small;
+            convert(&big, &small, value, k_magnitudes[i].threshold);
+            if (small) {
+                snprintf(out, outsz, "%zu.%zu %s", big, small, k_magnitudes[i].suffix);
+            } else {
+                snprintf(out, outsz, "%zu %s", big, k_magnitudes[i].suffix);
+            }
+            return;
+        }
+    }
+
+    *out = 0;
+}

sandbox/util/include/socks/util.h

@@ -0,0 +1,8 @@
+#ifndef SOCKS_UTIL_H_
+#define SOCKS_UTIL_H_
+
+#include <stddef.h>
+
+extern void data_size_to_string(size_t value, char *out, size_t outsz);
+
+#endif