changes to mapfile, read builtins for unbuffered reads

tests/RUN-ONE-TEST

@@ -1,4 +1,4 @@
-BUILD_DIR=/usr/local/build/chet/bash/bash-current
+BUILD_DIR=/usr/local/build/bash/bash-current
 THIS_SH=$BUILD_DIR/bash
 PATH=$PATH:$BUILD_DIR
 

tests/read.right

@@ -30,6 +30,7 @@ argv[1] = <foo>
 argv[1] = <foo>
 argv[1] = < foo>
 a = abcdefg
+xyz
 a = xyz
 a = -xyz 123-
 a = abc
@@ -46,6 +47,7 @@ abcde
 abcde
 ./read3.sub: line 17: read: -1: invalid number
 abc
+defg
 ab
 abc
 #
@@ -76,3 +78,7 @@ unset or null 3
 [?2004h[?2004l
 timeout 3: ok
 unset or null 3
+timeout 4: ok
+abcde
+abcde
+one

tests/read.tests

@@ -112,3 +112,6 @@ ${THIS_SH} ./read6.sub
 
 # test behavior of readline timeouts
 ${THIS_SH} ./read7.sub
+
+# test behavior of read -n and read -d on regular files
+${THIS_SH} ./read8.sub

tests/read1.sub

@@ -15,6 +15,7 @@ a=7
 echo 'abcdefg|xyz' | {
 	read -d '|' a 
 	echo a = "${a-unset}"
+	cat -	# make sure we don't read too much
 }
 
 echo xyz 123 | {

tests/read3.sub

@@ -20,6 +20,7 @@ read -n -1
 echo abcdefg | {
 	read -n 3 xyz
 	echo $xyz
+	cat -	# make sure we don't read too much
 }
 
 # fewer chars than specified

tests/read8.sub

@@ -0,0 +1,15 @@
+tmpf=$TMPDIR/tmp-$$
+printf "%s\n" "one two three four" > $tmpf
+
+# make sure we rewind the input properly when reading a specific number of
+# characters or using a non-standard delimiter from a regular file
+
+exec <$tmpf
+read -n 4 input && echo "$input"
+cat -
+
+exec <$tmpf
+read -d ' ' input && echo "$input"
+cat -
+
+rm -f $tmpf