From 97b8db334a63e89a0571b625595024872e40307c Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Tue, 1 Dec 2015 13:34:19 +0100
Subject: [PATCH] avutil/rational: Test av_rescale_rnd() with combinations of
 "special" values

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavutil/Makefile   |  1 +
 libavutil/rational.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/libavutil/Makefile b/libavutil/Makefile
index 1bac2b978e..b43cede0c2 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -106,6 +106,7 @@ OBJS = adler32.o                                                        \
        hash.o                                                           \
        hmac.o                                                           \
        imgutils.o                                                       \
+       integer.o                                                        \
        intmath.o                                                        \
        lfg.o                                                            \
        lls.o                                                            \
diff --git a/libavutil/rational.c b/libavutil/rational.c
index 81a940210c..6b3f50a02a 100644
--- a/libavutil/rational.c
+++ b/libavutil/rational.c
@@ -183,9 +183,18 @@ uint32_t av_q2intfloat(AVRational q) {
 }
 
 #ifdef TEST
+
+#include "integer.h"
+
 int main(void)
 {
     AVRational a,b,r;
+    int i,j,k;
+    static const int64_t numlist[] = {
+        INT64_MIN, INT64_MIN+1, INT64_MAX, INT32_MIN, INT32_MAX, 1,0,-1,
+        123456789, INT32_MAX-1, INT32_MAX+1LL, UINT32_MAX-1, UINT32_MAX, UINT32_MAX+1LL
+    };
+
     for (a.num = -2; a.num <= 2; a.num++) {
         for (a.den = -2; a.den <= 2; a.den++) {
             for (b.num = -2; b.num <= 2; b.num++) {
@@ -207,6 +216,41 @@ int main(void)
         }
     }
 
+    for (i = 0; i < FF_ARRAY_ELEMS(numlist); i++) {
+        int64_t a = numlist[i];
+
+        for (j = 0; j < FF_ARRAY_ELEMS(numlist); j++) {
+            int64_t b = numlist[j];
+            if (b<=0)
+                continue;
+            for (k = 0; k < FF_ARRAY_ELEMS(numlist); k++) {
+                int64_t c = numlist[k];
+                int64_t res;
+                AVInteger ai;
+
+                if (c<=0)
+                    continue;
+                res = av_rescale_rnd(a,b,c, AV_ROUND_ZERO);
+
+                ai = av_mul_i(av_int2i(a), av_int2i(b));
+                ai = av_div_i(ai, av_int2i(c));
+
+                if (av_cmp_i(ai, av_int2i(INT64_MAX)) > 0 && res == INT64_MIN)
+                    continue;
+                if (av_cmp_i(ai, av_int2i(INT64_MIN)) < 0 && res == INT64_MIN)
+                    continue;
+                if (av_cmp_i(ai, av_int2i(res)) == 0)
+                    continue;
+
+                // Special exception for INT64_MIN, remove this in case INT64_MIN is handled without off by 1 error
+                if (av_cmp_i(ai, av_int2i(res-1)) == 0 && a == INT64_MIN)
+                    continue;
+
+                av_log(NULL, AV_LOG_ERROR, "%"PRId64" * %"PRId64" / %"PRId64" = %"PRId64" or %"PRId64"\n", a,b,c, res, av_i2int(ai));
+            }
+        }
+    }
+
     for (a.num = 1; a.num <= 10; a.num++) {
         for (a.den = 1; a.den <= 10; a.den++) {
             if (av_gcd(a.num, a.den) > 1)