lib: os: cbprintf: Add C++ support for static packaging

include/sys/cbprintf.h

@@ -16,17 +16,16 @@
 #include <stdio.h>
 #endif /* CONFIG_CBPRINTF_LIBC_SUBSTS */
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* Determine if _Generic is supported.
  * In general it's a C11 feature but it was added also in:
  * - GCC 4.9.0 https://gcc.gnu.org/gcc-4.9/changes.html
  * - Clang 3.0 https://releases.llvm.org/3.0/docs/ClangReleaseNotes.html
+ *
+ * @note Z_C_GENERIC is also set for C++ where functionality is implemented
+ * using overloading and templates.
  */
 #ifndef Z_C_GENERIC
-#if !defined(__cplusplus) && (((__STDC_VERSION__ >= 201112L) || \
+#if defined(__cplusplus) || (((__STDC_VERSION__ >= 201112L) || \
  ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) >= 40900) || \
  ((__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) >= 30000)))
 #define Z_C_GENERIC 1
@@ -38,6 +37,10 @@ extern "C" {
 /* Z_C_GENERIC is used there */
 #include <sys/cbprintf_internal.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * @defgroup cbprintf_apis Formatted Output APIs
  * @ingroup support_apis

include/sys/cbprintf_cxx.h

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_SYS_CBPRINTF_CXX_H_
+#define ZEPHYR_INCLUDE_SYS_CBPRINTF_CXX_H_
+#ifdef __cplusplus
+
+/* C++ version for detecting a pointer to a string. */
+static inline int z_cbprintf_cxx_is_pchar(char *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(const char *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(volatile char *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(const volatile char *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(wchar_t *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(const wchar_t *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(volatile wchar_t *)
+{
+ return 1;
+}
+
+static inline int z_cbprintf_cxx_is_pchar(const volatile wchar_t *)
+{
+ return 1;
+}
+
+template < typename T >
+static inline int z_cbprintf_cxx_is_pchar(T arg)
+{
+ return 0;
+}
+
+/* C++ version for calculating argument size. */
+static inline size_t z_cbprintf_cxx_arg_size(float f)
+{
+ return sizeof(double);
+}
+
+template < typename T >
+static inline size_t z_cbprintf_cxx_arg_size(T arg)
+{
+ return sizeof(arg + 0);
+}
+
+/* C++ version for storing arguments. */
+static inline void z_cbprintf_cxx_store_arg(uint8_t *dst, float arg)
+{
+ double d = (double)arg;
+
+ z_cbprintf_wcpy((int *)dst, (int *)&d, sizeof(d) / sizeof(int));
+}
+
+template < typename T >
+static inline void z_cbprintf_cxx_store_arg(uint8_t *dst, T arg)
+{
+ size_t wlen = z_cbprintf_cxx_arg_size(arg) / sizeof(int);
+
+ z_cbprintf_wcpy((int *)dst, (int *)&arg, wlen);
+}
+
+/* C++ version for long double detection. */
+static inline int z_cbprintf_cxx_is_longdouble(long double arg)
+{
+ return 1;
+}
+
+template < typename T >
+static inline int z_cbprintf_cxx_is_longdouble(T arg)
+{
+ return 0;
+}
+
+/* C++ version for caluculating argument alignment. */
+static inline size_t z_cbprintf_cxx_alignment(float arg)
+{
+ return VA_STACK_ALIGN(double);
+}
+
+static inline size_t z_cbprintf_cxx_alignment(double arg)
+{
+ return VA_STACK_ALIGN(double);
+}
+
+static inline size_t z_cbprintf_cxx_alignment(long double arg)
+{
+ return VA_STACK_ALIGN(long double);
+}
+
+static inline size_t z_cbprintf_cxx_alignment(long long arg)
+{
+ return VA_STACK_ALIGN(long long);
+}
+
+static inline size_t z_cbprintf_cxx_alignment(unsigned long long arg)
+{
+ return VA_STACK_ALIGN(long long);
+}
+
+template < typename T >
+static inline size_t z_cbprintf_cxx_alignment(T arg)
+{
+ return MAX(__alignof__(arg), VA_STACK_MIN_ALIGN);
+}
+
+#endif /* __cplusplus */
+#endif /* ZEPHYR_INCLUDE_SYS_CBPRINTF_CXX_H_ */

include/sys/cbprintf_internal.h

@@ -15,10 +15,6 @@
 #include <sys/util.h>
 #include <sys/__assert.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /*
  * Special alignment cases
  */
@@ -49,6 +45,20 @@ extern "C" {
 #define VA_STACK_ALIGN(type) MAX(VA_STACK_MIN_ALIGN, __alignof__(type))
 #endif
 
+static inline void z_cbprintf_wcpy(int *dst, int *src, size_t len)
+{
+ for (size_t i = 0; i < len; i++) {
+ dst[i] = src[i];
+ }
+}
+
+#include <sys/cbprintf_cxx.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #if defined(__sparc__)
 /* The SPARC V8 ABI guarantees that the arguments of a variable argument
  * list function are stored on the stack at addresses which are 32-bit
@@ -71,6 +81,9 @@ extern "C" {
  *
  * @return 1 if char * or wchar_t *, 0 otherwise.
  */
+#ifdef __cplusplus
+#define Z_CBPRINTF_IS_PCHAR(x) z_cbprintf_cxx_is_pchar(x)
+#else
 #define Z_CBPRINTF_IS_PCHAR(x) _Generic((x), \
  char * : 1, \
  const char * : 1, \
@@ -82,6 +95,7 @@ extern "C" {
  const volatile wchar_t * : 1, \
  default : \
  0)
+#endif
 
 /** @brief Calculate number of char * or wchar_t * arguments in the arguments.
  *
@@ -123,27 +137,27 @@ extern "C" {
  *
  * @return Number of bytes used for storing the argument.
  */
+#ifdef __cplusplus
+#define Z_CBPRINTF_ARG_SIZE(v) z_cbprintf_cxx_arg_size(v)
+#else
 #define Z_CBPRINTF_ARG_SIZE(v) \
  _Generic((v), \
  float : sizeof(double), \
  default : \
  /* coverity[bad_sizeof] */ \
  sizeof((v) + 0) \
  )
-
-static inline void cbprintf_wcpy(int *dst, int *src, size_t len)
-{
- for (size_t i = 0; i < len; i++) {
- dst[i] = src[i];
- }
-}
+#endif
 
 /** @brief Promote and store argument in the buffer.
  *
  * @param buf Buffer.
  *
  * @param arg Argument.
  */
+#ifdef __cplusplus
+#define Z_CBPRINTF_STORE_ARG(buf, arg) z_cbprintf_cxx_store_arg(buf, arg)
+#else
 #define Z_CBPRINTF_STORE_ARG(buf, arg) do { \
  if (Z_CBPRINTF_VA_STACK_LL_DBL_MEMCPY) { \
  /* If required, copy arguments by word to avoid unaligned access.*/ \
@@ -154,7 +168,7 @@ static inline void cbprintf_wcpy(int *dst, int *src, size_t len)
  0.0); \
  size_t arg_size = Z_CBPRINTF_ARG_SIZE(arg); \
  size_t _wsize = arg_size / sizeof(int); \
- cbprintf_wcpy((int *)buf, \
+ z_cbprintf_wcpy((int *)buf, \
  (int *) _Generic((arg) + 0, float : &_d, default : &_v), \
  _wsize); \
  } else { \
@@ -176,13 +190,17 @@ static inline void cbprintf_wcpy(int *dst, int *src, size_t len)
  (const void **)buf) = arg; \
  } \
 } while (0)
+#endif
 
 /** @brief Return alignment needed for given argument.
  *
  * @param _arg Argument
  *
  * @return Alignment in bytes.
  */
+#ifdef __cplusplus
+#define Z_CBPRINTF_ALIGNMENT(_arg) z_cbprintf_cxx_alignment(_arg)
+#else
 #define Z_CBPRINTF_ALIGNMENT(_arg) \
  MAX(_Generic((_arg) + 0, \
  float : VA_STACK_ALIGN(double), \
@@ -192,15 +210,20 @@ static inline void cbprintf_wcpy(int *dst, int *src, size_t len)
  unsigned long long : VA_STACK_ALIGN(long long), \
  default : \
  __alignof__((_arg) + 0)), VA_STACK_MIN_ALIGN)
+#endif
 
 /** @brief Detect long double variable.
  *
  * @param x Argument.
  *
  * @return 1 if @p x is a long double, 0 otherwise.
  */
+#ifdef __cplusplus
+#define Z_CBPRINTF_IS_LONGDOUBLE(x) z_cbprintf_cxx_is_longdouble(x)
+#else
 #define Z_CBPRINTF_IS_LONGDOUBLE(x) \
  _Generic((x) + 0, long double : 1, default : 0)
+#endif
 
 /** @brief Safely package arguments to a buffer.
  *
@@ -227,7 +250,7 @@ static inline void cbprintf_wcpy(int *dst, int *src, size_t len)
  _align_offset += sizeof(int); \
  } \
  uint32_t _arg_size = Z_CBPRINTF_ARG_SIZE(_arg); \
- if (_buf && _idx < _max) { \
+ if (_buf && _idx < (int)_max) { \
  Z_CBPRINTF_STORE_ARG(&_buf[_idx], _arg); \
  } \
  _idx += _arg_size; \
@@ -302,7 +325,7 @@ do { \
  "Buffer must be aligned."); \
  } \
  uint8_t *_pbuf = buf; \
- size_t _pmax = (buf != NULL) ? _inlen : SIZE_MAX; \
+ size_t _pmax = (buf != NULL) ? _inlen : INT32_MAX; \
  int _pkg_len = 0; \
  int _pkg_offset = _align_offset; \
  union z_cbprintf_hdr *_len_loc; \
@@ -317,11 +340,11 @@ do { \
  /* Pack remaining arguments */\
  FOR_EACH(Z_CBPRINTF_PACK_ARG, (;), __VA_ARGS__);\
  /* Store length */ \
- _outlen = (_pkg_len > _pmax) ? -ENOSPC : _pkg_len; \
+ _outlen = (_pkg_len > (int)_pmax) ? -ENOSPC : _pkg_len; \
  /* Store length in the header, set number of dumped strings to 0 */ \
  if (_pbuf) { \
  union z_cbprintf_hdr hdr = { \
- .desc = {.len = _pkg_len / sizeof(int) } \
+ .desc = {.len = (uint8_t)(_pkg_len / sizeof(int)) } \
  }; \
  *_len_loc = hdr; \
  } \

tests/lib/cbprintf_package/CMakeLists.txt

@@ -4,5 +4,4 @@ cmake_minimum_required(VERSION 3.13.1)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(cbprintf_package)
 
-FILE(GLOB app_sources src/*.c)
-target_sources(app PRIVATE ${app_sources})
+target_sources(app PRIVATE src/main.c src/maincxx.cxx)