gpujpeg_image_save_to_file: (const char *) fname

gpujpeg_image_save_to_file() - take (const char *) for filename instead
of (char *).

This reverts back the change in the function prototype by the commit
de0f3a8 (2025-02-28). The (const char *) still can be modified as per
the change but it is rather a special case that is docuemented in doxy.

refer to GH-98

Author: MartinPulec

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.10.0 FATAL_ERROR)
 # change version also in configure.ac
-project(gpujpeg VERSION 0.27.0 LANGUAGES C CUDA)
+project(gpujpeg VERSION 0.27.1 LANGUAGES C CUDA)
 
 # options
 set(BUILD_OPENGL OFF CACHE STRING "Build with OpenGL support, options are: AUTO ON OFF")

NEWS.md

@@ -1,3 +1,9 @@
+2025-05-14 - 0.27.1
+----------
+
+- gpujpeg_image_save_to_file() - take (const char *) for filename instead
+of (char *)
+
 2025-05-12 - 0.27.0
 ----------
 

configure.ac

@@ -1,6 +1,6 @@
 AC_PREREQ([2.65])
 # change version also in CMakeLists.txt
-AC_INIT([libgpujpeg],[0.27.0],[https://github.com/CESNET/GPUJPEG/issues],[libgpujpeg],[https://github.com/CESNET/GPUJPEG])
+AC_INIT([libgpujpeg],[0.27.1],[https://github.com/CESNET/GPUJPEG/issues],[libgpujpeg],[https://github.com/CESNET/GPUJPEG])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/main.c])
 AC_CONFIG_AUX_DIR([.])

libgpujpeg/gpujpeg_common.h

@@ -414,7 +414,8 @@ gpujpeg_image_load_from_file(const char* filename, uint8_t** image, size_t* imag
  * Use the extension "XXX" (eg. "image.XXX") to automatically select the
  * extension according to param_image. PNM is used for grayscale or RGB, PAM for
  * RGBA, Y4M ottherwise. "XXX" placeholder in filename is replaced with used
- * extension.
+ * extension. It is user responsibility to ensure that @ref filename is writable
+ * in this case.
  *
  * @param filaname  Image filename
  * @param image  Image data buffer
@@ -423,7 +424,7 @@ gpujpeg_image_load_from_file(const char* filename, uint8_t** image, size_t* imag
  * @return 0 if succeeds, otherwise nonzero
  */
 GPUJPEG_API int
-gpujpeg_image_save_to_file(char* filename, const uint8_t* image, size_t image_size,
+gpujpeg_image_save_to_file(const char* filename, const uint8_t* image, size_t image_size,
                            const struct gpujpeg_image_parameters* param_image);
 
 /**

src/gpujpeg_common.c

@@ -1246,12 +1246,13 @@ set_file_extension(char *filename,
 
 /* Documented at declaration */
 int
-gpujpeg_image_save_to_file(char* filename, const uint8_t* image, size_t image_size,
+gpujpeg_image_save_to_file(const char* filename, const uint8_t* image, size_t image_size,
                            const struct gpujpeg_image_parameters* param_image)
 {
     if (strrchr(filename, '.') != NULL &&
         strcmp(strrchr(filename, '.'), ".XXX") == 0) {
-        set_file_extension(filename, param_image);
+        // caller must ensure the filename to be mutable if ext is .XXX
+        set_file_extension((char *) filename, param_image);
     }
 
     enum gpujpeg_image_file_format format = gpujpeg_image_get_file_format(filename);