Use dtoa for double to string conversion

CMakeLists.txt

@@ -5,6 +5,7 @@ project(jansson C)
 option(JANSSON_BUILD_SHARED_LIBS "Build shared libraries." OFF)
 option(USE_URANDOM "Use /dev/urandom to seed the hash function." ON)
 option(USE_WINDOWS_CRYPTOAPI "Use CryptGenRandom to seed the hash function." ON)
+option(USE_DTOA "Use dtoa for optimal floating-point to string conversions." ON)
 
 if (MSVC)
    # This option must match the settings used in your program, in particular if you
@@ -93,6 +94,9 @@ check_function_exists (sched_yield HAVE_SCHED_YIELD)
 # Check for the int-type includes
 check_include_files (stdint.h HAVE_STDINT_H)
 
+include (TestBigEndian)
+TEST_BIG_ENDIAN(WORDS_BIGENDIAN)
+
 # Check our 64 bit integer sizes
 check_type_size (__int64 __INT64)
 check_type_size (int64_t INT64_T)
@@ -193,6 +197,8 @@ endif ()
 # detect what to use for the 64 bit type.
 # Note: I will prefer long long if I can get it, as that is what the automake system aimed for.
 if (NOT DEFINED JSON_INT_T)
+   set (JSON_INTEGER_IS_LONG_LONG 1)
+
    if (HAVE_LONG_LONG_INT AND (LONG_LONG_INT EQUAL 8))
       set (JSON_INT_T "long long")
    elseif (HAVE_INT64_T)
@@ -274,6 +280,9 @@ include_directories (${CMAKE_CURRENT_BINARY_DIR}/private_include)
 
 # Add the lib sources.
 file(GLOB JANSSON_SRC src/*.c)
+if (NOT USE_DTOA)
+   list(FILTER JANSSON_SRC EXCLUDE REGEX ".*dtoa\\.c$")
+endif()
 
 set(JANSSON_HDR_PRIVATE
    ${CMAKE_CURRENT_SOURCE_DIR}/src/hashtable.h

cmake/jansson_config.h.cmake

@@ -21,9 +21,10 @@
 #define JANSSON_USING_CMAKE
 #endif
 
-/* Note: when using cmake, JSON_INTEGER_IS_LONG_LONG is not defined nor used,
- * as we will also check for __int64 etc types.
- * (the definition was used in the automake system) */
+/* If your compiler supports the `long long` type and the strtoll()
+   library function, JSON_INTEGER_IS_LONG_LONG is defined to 1,
+   otherwise to 0. */
+#cmakedefine JSON_INTEGER_IS_LONG_LONG 1
 
 /* Bring in the cmake-detected defines */
 #cmakedefine HAVE_STDINT_H 1

cmake/jansson_private_config.h.cmake

@@ -21,6 +21,8 @@
 #cmakedefine HAVE_LOCALE_H 1
 #cmakedefine HAVE_SETLOCALE 1
 
+#cmakedefine WORDS_BIGENDIAN 1
+
 #cmakedefine HAVE_INT32_T 1
 #ifndef HAVE_INT32_T
 #  define int32_t @JSON_INT32@
@@ -50,4 +52,11 @@
 #cmakedefine USE_URANDOM 1
 #cmakedefine USE_WINDOWS_CRYPTOAPI 1
 
+#cmakedefine USE_DTOA 1
+#if USE_DTOA
+#  define DTOA_ENABLED 1
+#else
+#  define DTOA_ENABLED 0
+#endif
+
 #define INITIAL_HASHTABLE_ORDER @JANSSON_INITIAL_HASHTABLE_ORDER@

configure.ac

@@ -25,6 +25,8 @@ AC_TYPE_UINT16_T
 AC_TYPE_UINT8_T
 AC_TYPE_LONG_LONG_INT
 
+AC_C_BIGENDIAN
+
 AC_C_INLINE
 case $ac_cv_c_inline in
     yes) json_inline=inline;;
@@ -136,6 +138,19 @@ JSON_SYMVER_LDFLAGS=
 AC_CHECK_DECL([__GLIBC__], [JSON_SYMVER_LDFLAGS=-Wl,--default-symver])
 AC_SUBST([JSON_SYMVER_LDFLAGS])
 
+AC_ARG_ENABLE([dtoa],
+  [AS_HELP_STRING([--enable-dtoa], [Use dtoa for optimal floating point to string conversion])],
+  [case "$enableval" in
+    yes) dtoa=yes ;;
+    no)  dtoa=no ;;
+    *) AC_MSG_ERROR([bad value ${enableval} for --enable-dtoa]) ;;
+  esac], [dtoa=yes])
+if test "$dtoa" = "yes"; then
+  AC_DEFINE([DTOA_ENABLED], [1],
+      [Define to 1 to use dtoa to convert floating points to strings])
+fi
+AM_CONDITIONAL([DTOA_ENABLED], [test "$dtoa" = "yes"])
+
 AC_ARG_ENABLE([ossfuzzers],
   [AS_HELP_STRING([--enable-ossfuzzers],
     [Whether to generate the fuzzers for OSS-Fuzz])],

src/Makefile.am

@@ -1,4 +1,4 @@
-EXTRA_DIST = jansson.def
+EXTRA_DIST = jansson.def dtoa.c
 
 include_HEADERS = jansson.h
 nodist_include_HEADERS = jansson_config.h
@@ -22,6 +22,11 @@ libjansson_la_SOURCES = \
 	utf.h \
 	value.c \
 	version.c
+
+if DTOA_ENABLED
+libjansson_la_SOURCES += dtoa.c
+endif
+
 libjansson_la_LDFLAGS = \
 	-no-undefined \
 	-export-symbols-regex '^json_|^jansson_' \