diff --git a/.gitignore b/.gitignore
index 24f31d8..319a48e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 /*.a
 /*.ok
 /*_test
+/build/*
+/cmake-build-*
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..ee14399
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,70 @@
+cmake_minimum_required(VERSION 3.5)
+project(json_cpp)
+
+# options
+
+set(JART_JSON_CPP_LIBRARY_NAME ${CMAKE_PROJECT_NAME} CACHE STRING "CMake target name and library name of json.cpp, default to 'json_cpp' (project name)")
+option(JART_JSON_CPP_ENABLE_TEST "enable json.cpp test" ON)
+option(JART_JSON_CPP_ENABLE_TEST_JSON_TEST_SUITE "enable json.cpp json test suite" ON)
+
+# library: double conversion
+
+set(DOUBLE_CONVERSION_LIBRARY_NAME "${JART_JSON_CPP_LIBRARY_NAME}_double_conversion")
+add_library(${DOUBLE_CONVERSION_LIBRARY_NAME} STATIC)
+target_compile_features(${DOUBLE_CONVERSION_LIBRARY_NAME} PRIVATE cxx_std_17)
+target_include_directories(${DOUBLE_CONVERSION_LIBRARY_NAME} PUBLIC double-conversion)
+target_sources(${DOUBLE_CONVERSION_LIBRARY_NAME} PRIVATE
+    double-conversion/bignum-dtoa.cc
+    double-conversion/bignum-dtoa.h
+    double-conversion/bignum.cc
+    double-conversion/bignum.h
+    double-conversion/cached-powers.cc
+    double-conversion/cached-powers.h
+    double-conversion/diy-fp.h
+    double-conversion/double-conversion.h
+    double-conversion/double-to-string.cc
+    double-conversion/double-to-string.h
+    double-conversion/fast-dtoa.cc
+    double-conversion/fast-dtoa.h
+    double-conversion/fixed-dtoa.cc
+    double-conversion/fixed-dtoa.h
+    double-conversion/ieee.h
+    double-conversion/string-to-double.cc
+    double-conversion/string-to-double.h
+    double-conversion/strtod.cc
+    double-conversion/strtod.h
+    double-conversion/utils.h
+)
+
+# library: json.cpp
+
+set(LIBRARY_NAME ${JART_JSON_CPP_LIBRARY_NAME})
+add_library(${LIBRARY_NAME} STATIC)
+target_compile_features(${LIBRARY_NAME} PRIVATE cxx_std_17)
+target_include_directories(${LIBRARY_NAME} PUBLIC .)
+target_sources(${LIBRARY_NAME} PRIVATE
+    jtckdint.h
+    json.h
+    json.cpp
+)
+target_link_libraries(${LIBRARY_NAME} INTERFACE ${DOUBLE_CONVERSION_LIBRARY_NAME})
+
+# test: benchmark
+
+if (JART_JSON_CPP_ENABLE_TEST)
+    set(TEST_NAME "${JART_JSON_CPP_LIBRARY_NAME}_test")
+    add_executable(${TEST_NAME})
+    target_compile_features(${TEST_NAME} PRIVATE cxx_std_17)
+    target_sources(${TEST_NAME} PRIVATE json_test.cpp)
+    target_link_libraries(${TEST_NAME} PRIVATE ${LIBRARY_NAME})
+endif ()
+
+# test: json test suite
+
+if (JART_JSON_CPP_ENABLE_TEST_JSON_TEST_SUITE)
+    set(TEST_JSON_TEST_SUITE_NAME "${JART_JSON_CPP_LIBRARY_NAME}_test_json_test_suite")
+    add_executable(${TEST_JSON_TEST_SUITE_NAME})
+    target_compile_features(${TEST_JSON_TEST_SUITE_NAME} PRIVATE cxx_std_17)
+    target_sources(${TEST_JSON_TEST_SUITE_NAME} PRIVATE jsontestsuite_test.cpp)
+    target_link_libraries(${TEST_JSON_TEST_SUITE_NAME} PRIVATE ${LIBRARY_NAME})
+endif ()
diff --git a/json.cpp b/json.cpp
index 420b2c9..56f86b7 100644
--- a/json.cpp
+++ b/json.cpp
@@ -881,7 +881,15 @@ Json::parse(Json& json, const char*& p, const char* e, int context, int depth)
                 json.setLong(0);
                 return success;
 
-            case '1' ... '9': // integer
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9': // integer
                 if (context & (COLON | COMMA | KEY))
                     goto OnColonCommaKey;
                 for (x = (c - '0') * d; p < e; ++p) {
diff --git a/json_test.cpp b/json_test.cpp
index e222ada..f56c65b 100644
--- a/json_test.cpp
+++ b/json_test.cpp
@@ -101,7 +101,7 @@ struct timespec
 now(void)
 {
     struct timespec ts;
-    clock_gettime(CLOCK_REALTIME, &ts);
+    timespec_get(&ts, TIME_UTC);
     return ts;
 }
 
diff --git a/jsontestsuite_test.cpp b/jsontestsuite_test.cpp
index b5fe16e..719eeed 100644
--- a/jsontestsuite_test.cpp
+++ b/jsontestsuite_test.cpp
@@ -19,7 +19,6 @@
 
 #include <cstdio>
 #include <cstdlib>
-#include <unistd.h>
 
 #define HI_RESET "\033[0m" // green
 #define HI_GOOD "\033[32m" // green