Add new plist_mem_free() function

Thanks to @azerg for bringing this to my attention.

Instead of having multiple (internally identical) plist_*_free() functions,
this commit introduces a single plist_mem_free() that can be used to free
the memory allocated by plist_to_xml(), plist_to_bin(), plist_get_key_val(),
plist_get_string_val(), and plist_get_data_val().
Note: This commit REMOVES plist_to_bin_free() and plist_to_xml_free().

include/plist/plist.h

@@ -449,6 +449,7 @@ extern "C"
      * @param node the node
      * @param val a pointer to a C-string. This function allocates the memory,
      *            caller is responsible for freeing it.
+     * @note Use plist_mem_free() to free the allocated memory.
      */
     void plist_get_key_val(plist_t node, char **val);
 
@@ -459,6 +460,7 @@ extern "C"
      * @param node the node
      * @param val a pointer to a C-string. This function allocates the memory,
      *            caller is responsible for freeing it. Data is UTF-8 encoded.
+     * @note Use plist_mem_free() to free the allocated memory.
      */
     void plist_get_string_val(plist_t node, char **val);
 
@@ -510,6 +512,7 @@ extern "C"
      * @param val a pointer to an unallocated char buffer. This function allocates the memory,
      *            caller is responsible for freeing it.
      * @param length the length of the buffer
+     * @note Use plist_mem_free() to free the allocated memory.
      */
     void plist_get_data_val(plist_t node, char **val, uint64_t * length);
 
@@ -642,33 +645,21 @@ extern "C"
      * @param plist_xml a pointer to a C-string. This function allocates the memory,
      *            caller is responsible for freeing it. Data is UTF-8 encoded.
      * @param length a pointer to an uint32_t variable. Represents the length of the allocated buffer.
+     * @note Use plist_mem_free() to free the allocated memory.
      */
     void plist_to_xml(plist_t plist, char **plist_xml, uint32_t * length);
 
-    /**
-     * Frees the memory allocated by plist_to_xml().
-     *
-     * @param plist_xml The buffer allocated by plist_to_xml().
-     */
-    void plist_to_xml_free(char *plist_xml);
-
     /**
      * Export the #plist_t structure to binary format.
      *
      * @param plist the root node to export
      * @param plist_bin a pointer to a char* buffer. This function allocates the memory,
      *            caller is responsible for freeing it.
      * @param length a pointer to an uint32_t variable. Represents the length of the allocated buffer.
+     * @note Use plist_mem_free() to free the allocated memory.
      */
     void plist_to_bin(plist_t plist, char **plist_bin, uint32_t * length);
 
-    /**
-     * Frees the memory allocated by plist_to_bin().
-     *
-     * @param plist_bin The buffer allocated by plist_to_bin().
-     */
-    void plist_to_bin_free(char *plist_bin);
-
     /**
      * Import the #plist_t structure from XML format.
      *
@@ -945,6 +936,21 @@ extern "C"
      */
     int plist_data_val_contains(plist_t datanode, const uint8_t* cmpval, size_t n);
 
+    /**
+     * Free memory allocated by relevant libplist API calls:
+     * - plist_to_xml()
+     * - plist_to_bin()
+     * - plist_get_key_val()
+     * - plist_get_string_val()
+     * - plist_get_data_val()
+     *
+     * @param ptr pointer to the memory to free
+     *
+     * @note Do not use this function to free plist_t nodes, use plist_free()
+     *     instead.
+     */
+    void plist_mem_free(void* ptr);
+
     /*@}*/
 
 #ifdef __cplusplus

src/bplist.c

@@ -1374,8 +1374,3 @@ PLIST_API void plist_to_bin(plist_t plist, char **plist_bin, uint32_t * length)
     bplist_buff->data = NULL; // make sure we don't free the output buffer
     byte_array_free(bplist_buff);
 }
-
-PLIST_API void plist_to_bin_free(char *plist_bin)
-{
-    free(plist_bin);
-}

src/plist.c

@@ -382,6 +382,14 @@ PLIST_API void plist_free(plist_t plist)
     }
 }
 
+PLIST_API void plist_mem_free(void* ptr)
+{
+    if (ptr)
+    {
+        free(ptr);
+    }
+}
+
 static plist_t plist_copy_node(node_t *node)
 {
     plist_type node_type = PLIST_NONE;

src/xplist.c

@@ -530,11 +530,6 @@ PLIST_API void plist_to_xml(plist_t plist, char **plist_xml, uint32_t * length)
     str_buf_free(outbuf);
 }
 
-PLIST_API void plist_to_xml_free(char *plist_xml)
-{
-    free(plist_xml);
-}
-
 struct _parse_ctx {
     const char *pos;
     const char *end;