Work around broken floating point limits on some systems.

The values of {FLT,DBL}_{MAX,MIN} macros on some systems (older musl
libc, some BSD flavours) are not exactly representable, i.e.
(double)DBL_MAX == DBL_MAX is false
This violates (at least some interpretations of) the C99 standard and
breaks code (e.g. in vf_fps) like
double f = DBL_MAX;
[...]
if (f == DBL_MAX) { // f has not been changed yet
    [....]
}

2 files changed, 57 insertions, 0 deletions

diff --git a/compat/float/float.h b/compat/float/float.h
new file mode 100644
index 0000000000..c69f728e32
--- /dev/null
+++ b/compat/float/float.h
@@ -0,0 +1,35 @@
+/*
+ * Work around broken floating point limits on some systems.
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include_next <float.h>
+
+#ifdef FLT_MAX
+#undef  FLT_MAX
+#define FLT_MAX 3.40282346638528859812e+38F
+
+#undef  FLT_MIN
+#define FLT_MIN 1.17549435082228750797e-38F
+
+#undef  DBL_MAX
+#define DBL_MAX ((double)1.79769313486231570815e+308L)
+
+#undef  DBL_MIN
+#define DBL_MIN ((double)2.22507385850720138309e-308L)
+#endif
diff --git a/compat/float/limits.h b/compat/float/limits.h
new file mode 100644
index 0000000000..9150bc8134
--- /dev/null
+++ b/compat/float/limits.h
@@ -0,0 +1,22 @@
+/*
+ * Work around broken floating point limits on some systems.
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include_next <limits.h>
+#include <float.h>