From b29b8512813ef2242562f46c08195f14e02f2fd9 Mon Sep 17 00:00:00 2001
From: Ole Tange <ole@tange.dk>
Date: Sun, 16 Aug 2020 22:18:09 +0200
Subject: [PATCH] binsearch: Supports -q and -2.

---
 binsearch/binsearch   | 98 ++++++++++++++++++++++++++++++++++---------
 splitvideo/splitvideo |  2 +-
 2 files changed, 79 insertions(+), 21 deletions(-)

diff --git a/binsearch/binsearch b/binsearch/binsearch
index a0d7017..31dbf6b 100755
--- a/binsearch/binsearch
+++ b/binsearch/binsearch
@@ -19,16 +19,57 @@ B<binsearch> runs I<command> with a single number. It returns highest
 value that I<command> succeeds for.
 
 
+=head1 OPTIONS
+
+=over 4
+
+=item B<-2>
+
+Instead of the command a single argument, give the command 2 argument:
+I<from> I<to>.
+
+=item B<-q>
+
+Quiet. Ignore output from B<command>.
+
+
+=back
+
+
 =head1 EXAMPLES
 
+=head2 Find the last file
+
+This is a silly way to find the last non-existing file (namely 244):
+
+  touch {245..800}
+  binsearch ls
+
+This is a silly way to find the last file (namely 800):
+
+  touch {1..800}
+  binsearch ls
+
 =head2 Test a bash function
 
+Test how long an argument /bin/echo can take
+
   . $(which binsearch)
   singleecho() {
     /bin/echo $(perl -e 'print "x"x'$1) >/dev/null
   }
   binsearch singleecho
 
+=head2 Test a bash function that takes from and to as arguments
+
+Use a function that takes two arguments
+
+  . $(which binsearch)
+  greplines() {
+      env | perl -ne "$1..$2 and print" | grep HOME=
+  }
+  binsearch -2 -q greplines
+
 
 =head1 AUTHOR
 
@@ -60,19 +101,6 @@ B<eval>(1)
 
 =cut
 
-
-# Example: find the max line length
-#
-# singleecho() {
-#     /bin/echo $(perl -e 'print "x"x'$1) >/dev/null
-# }
-# 
-# multiecho() {
-#     /bin/echo $(perl -e 'print "x "x'$(($1/2)) ) >/dev/null
-# }
-#
-# binsearch singleecho
-
 binsearch() {
     _binsearch() {
 	low=$1
@@ -84,7 +112,7 @@ binsearch() {
 	shift
 	shift
 	middle=$(( ( $low + $high ) / 2 ))
-	if eval "$@ $middle" ; then
+	if _run $low $middle "$@" ; then
 	    low=$middle
 	else
 	    high=$middle
@@ -92,9 +120,35 @@ binsearch() {
 	_binsearch $low $high "$@"
     }
     
-    low=1
+    _run() {
+	local a="$1"
+	local b="$2"
+	shift
+	shift
+	# echo "a=$a b=$b $@"
+	if $opt2 ; then
+	    eval "$not" "$@ $a $b" "$quiet"
+	else
+	    eval "$not" "$@ $b" "$quiet"
+	fi
+    }
+
+    quiet=""
+    opt2=false
+    args=$(getopt 'q2' $*) || exit
+    # now we have the sanitized args... replace the original with it
+    set -- $args
+
+    while true; do
+	case $1 in
+	    (-2)   opt2=true;  shift;;
+	    (-q)   quiet=">/dev/null 2>/dev/null"; shift;;
+	    (--)   shift; break;;
+	esac
+    done
+
     # If function(1) = false: run 'not function()' instead
-    if eval "$@ $low" ; then
+    if _run 1 1 "$@" ; then
 	not=''
     else
 	not='!'
@@ -102,17 +156,21 @@ binsearch() {
     # exponential search for the first value that is false
     # low = previous value (function($low) == true)
     # high = low * 2 (function($high) == false)
-    high=$low
-    while eval "$not" "$@ $high" 2>/dev/null ; do
+    high=1
+    while _run 1 $high "$@" ; do
 	low=$high
 	high=$(( $high*2 ))
+	if [ $high -gt 4611686018427387900 ] ; then
+	    echo "$0: Error: exit value does not change of '$@'" >&2
+	    return
+	fi
     done
     # echo "low: $low high: $high not: $not"
-    _binsearch $low $high "$not $@" 2>/dev/null
+    _binsearch $low $high "$@" 2>/dev/null
     echo $low
 }
 
-if [ -z "$@" ] ; then
+if [ -z "$*" ] ; then
     # source the bash function
     # . $(which binsearch)
     true
diff --git a/splitvideo/splitvideo b/splitvideo/splitvideo
index d9d5233..9ddda49 100755
--- a/splitvideo/splitvideo
+++ b/splitvideo/splitvideo
@@ -9,7 +9,7 @@ splitvideo - Split video at time stamp
 
 =head1 SYNOPSIS
 
-B<splitvideo> time videofile
+B<splitvideo> I<time> I<videofile>
 
 
 =head1 DESCRIPTION