lavu/avstring: deprecate av_d2str().

It is no longer used in our code base and does not seem
to be used much in other projects.

doc/APIchanges

@@ -15,6 +15,10 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+=======
+2020-08-21 - xxxxxxxxxx - lavu 56.58.100 - avstring.h
+  Deprecate av_d2str(). Use av_asprintf() instead.
+
 2020-08-04 - xxxxxxxxxx - lavu 56.58.100 - channel_layout.h
   Add AV_CH_LAYOUT_22POINT2 together with its newly required pieces:
   AV_CH_TOP_SIDE_LEFT, AV_CH_TOP_SIDE_RIGHT, AV_CH_BOTTOM_FRONT_CENTER,

libavutil/avstring.c

@@ -136,6 +136,7 @@ end:
     return p;
 }
 
+#if FF_API_D2STR
 char *av_d2str(double d)
 {
     char *str = av_malloc(16);
@@ -143,6 +144,7 @@ char *av_d2str(double d)
         snprintf(str, 16, "%f", d);
     return str;
 }
+#endif
 
 #define WHITESPACES " \n\t\r"
 

libavutil/avstring.h

@@ -24,6 +24,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include "attributes.h"
+#include "version.h"
 
 /**
  * @addtogroup lavu_string
@@ -155,10 +156,14 @@ static inline size_t av_strnlen(const char *s, size_t len)
  */
 char *av_asprintf(const char *fmt, ...) av_printf_format(1, 2);
 
+#if FF_API_D2STR
 /**
  * Convert a number to an av_malloced string.
+ * @deprecated  use av_asprintf() with "%f" or a more specific format
  */
+attribute_deprecated
 char *av_d2str(double d);
+#endif
 
 /**
  * Unescape the given string until a non escaped terminating char,

libavutil/tests/avstring.c

@@ -109,6 +109,8 @@ int main(void)
     TEST_STRIREPLACE(haystack, needle [2], "Education consists mainly in what we have instead.");
     TEST_STRIREPLACE(haystack, needle [1], "Education consists mainly in what we have instead");
 
+#if FF_API_D2STR
+FF_DISABLE_DEPRECATION_WARNINGS
     /*Testing av_d2str()*/
     #define TEST_D2STR(value, expected) \
         if((ptr = av_d2str(value)) == NULL){ \
@@ -121,5 +123,7 @@ int main(void)
     TEST_D2STR(0         ,  "0.000000");
     TEST_D2STR(-1.2333234, "-1.233323");
     TEST_D2STR(-1.2333237, "-1.233324");
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
     return 0;
 }

libavutil/version.h

@@ -132,6 +132,9 @@
 #ifndef FF_API_CHILD_CLASS_NEXT
 #define FF_API_CHILD_CLASS_NEXT         (LIBAVUTIL_VERSION_MAJOR < 57)
 #endif
+#ifndef FF_API_D2STR
+#define FF_API_D2STR                    (LIBAVUTIL_VERSION_MAJOR < 58)
+#endif
 
 /**
  * @}