Handle disconnected units and pad='no'

Author: awvwgk

doc/specs/stdlib_io.md

@@ -236,12 +236,14 @@ Read a whole line from a formatted unit into a string variable
 
 ### Syntax
 
-`call [[stdlib_io(module):getline(interface)]](unit, line[, iostat][, iomsg])`
+`call [[stdlib_io(module):getline(interface)]] (unit, line[, iostat][, iomsg])`
+`call [[stdlib_io(module):getline(interface)]] (line[, iostat][, iomsg])`
 
 ### Arguments
 
 `unit`: Formatted input unit.
         This argument is `intent(in)`.
+        If `unit` is not specified standard input is used.
 
 `line`: Deferred length character or `string_type` variable.
         This argument is `intent(out)`.

src/stdlib_io.fypp

@@ -6,6 +6,7 @@ module stdlib_io
   !! Provides a support for file handling
   !! ([Specification](../page/specs/stdlib_io.html))
 
+  use, intrinsic :: iso_fortran_env, only : input_unit
   use stdlib_kinds, only: sp, dp, xdp, qp, &
       int8, int16, int32, int64
   use stdlib_error, only: error_stop
@@ -38,6 +39,8 @@ module stdlib_io
   interface getline
     module procedure :: getline_char
     module procedure :: getline_string
+    module procedure :: getline_input_char
+    module procedure :: getline_input_string
   end interface getline
 
   interface loadtxt
@@ -356,17 +359,28 @@ contains
     integer, parameter :: bufsize = 512
     character(len=bufsize) :: buffer, msg
     integer :: chunk, stat
+    logical :: opened
+
+    if (unit /= -1) then
+      inquire(unit=unit, opened=opened)
+    else
+      opened = .false.
+    end if
+
+    if (opened) then
+      open(unit=unit, pad="yes", iostat=stat, iomsg=msg)
+    else
+      stat = 1
+      msg = "Unit is not connected"
+    end if
 
     line = ""
-    do
+    do while (stat == 0)
       read(unit, '(a)', advance='no', iostat=stat, iomsg=msg, size=chunk) buffer
       if (stat > 0) exit
       line = line // buffer(:chunk)
-      if (stat < 0) then
-        if (is_iostat_eor(stat)) stat = 0
-        exit
-      end if
     end do
+    if (is_iostat_eor(stat)) stat = 0
 
     if (stat /= 0 .and. present(iomsg)) iomsg = trim(msg)
     if (present(iostat)) then
@@ -395,4 +409,32 @@ contains
     line = string_type(buffer)
   end subroutine getline_string
 
+  !> Version: experimental
+  !>
+  !> Read a whole line from the standard input into a deferred length character variable
+  subroutine getline_input_char(line, iostat, iomsg)
+    !> Line to read
+    character(len=:), allocatable, intent(out) :: line
+    !> Status of operation
+    integer, intent(out), optional :: iostat
+    !> Error message
+    character(len=:), allocatable, optional :: iomsg
+
+    call getline(input_unit, line, iostat, iomsg)
+  end subroutine getline_input_char
+
+  !> Version: experimental
+  !>
+  !> Read a whole line from the standard input into a string variable
+  subroutine getline_input_string(line, iostat, iomsg)
+    !> Line to read
+    type(string_type), intent(out) :: line
+    !> Status of operation
+    integer, intent(out), optional :: iostat
+    !> Error message
+    character(len=:), allocatable, optional :: iomsg
+
+    call getline(input_unit, line, iostat, iomsg)
+  end subroutine getline_input_string
+
 end module stdlib_io

src/tests/io/test_getline.f90

@@ -16,7 +16,11 @@ subroutine collect_getline(testsuite)
 
         testsuite = [ &
             new_unittest("read-char", test_read_char), &
-            new_unittest("read-string", test_read_string) &
+            new_unittest("read-string", test_read_string), &
+            new_unittest("pad-no", test_pad_no), &
+            new_unittest("iostat-end", test_iostat_end), &
+            new_unittest("closed-unit", test_closed_unit, should_fail=.true.), &
+            new_unittest("no-unit", test_no_unit, should_fail=.true.) &
             ]
     end subroutine collect_getline
 
@@ -34,7 +38,9 @@ subroutine test_read_char(error)
         do i = 1, 3
           call getline(io, line, stat)
           call check(error, stat)
+          if (allocated(error)) exit
           call check(error, len(line), 3*10**i)
+          if (allocated(error)) exit
         end do
         close(io)
     end subroutine test_read_char
@@ -53,11 +59,86 @@ subroutine test_read_string(error)
         do i = 1, 3
           call getline(io, line, stat)
           call check(error, stat)
+          if (allocated(error)) exit
           call check(error, len(line), 3*10**i)
+          if (allocated(error)) exit
         end do
         close(io)
     end subroutine test_read_string
 
+    subroutine test_pad_no(error)
+        !> Error handling
+        type(error_type), allocatable, intent(out) :: error
+
+        integer :: io, i, stat
+        character(len=:), allocatable :: line
+
+        open(newunit=io, status="scratch", pad="no")
+        write(io, "(a)") repeat("abc", 10), repeat("def", 100), repeat("ghi", 1000)
+        rewind(io)
+
+        do i = 1, 3
+          call getline(io, line, stat)
+          call check(error, stat)
+          if (allocated(error)) exit
+          call check(error, len(line), 3*10**i)
+          if (allocated(error)) exit
+        end do
+        close(io)
+    end subroutine test_pad_no
+
+    subroutine test_iostat_end(error)
+        use, intrinsic :: iso_fortran_env, only : iostat_end
+        !> Error handling
+        type(error_type), allocatable, intent(out) :: error
+
+        integer :: io, i, stat
+        character(len=:), allocatable :: line
+
+        open(newunit=io, status="scratch")
+        write(io, "(a)") repeat("abc", 10), repeat("def", 100), repeat("ghi", 1000)
+        rewind(io)
+
+        do i = 1, 3
+          call getline(io, line, stat)
+          call check(error, stat)
+          if (allocated(error)) exit
+          call check(error, len(line), 3*10**i)
+          if (allocated(error)) exit
+        end do
+        if (.not.allocated(error)) then
+          call getline(io, line, stat)
+          call check(error, stat, iostat_end)
+        end if
+        close(io)
+    end subroutine test_iostat_end
+
+    subroutine test_closed_unit(error)
+        !> Error handling
+        type(error_type), allocatable, intent(out) :: error
+
+        integer :: io, stat
+        character(len=:), allocatable :: line, msg
+
+        open(newunit=io, status="scratch")
+        close(io)
+
+        call getline(io, line, stat, msg)
+        call check(error, stat, msg)
+    end subroutine test_closed_unit
+
+    subroutine test_no_unit(error)
+        !> Error handling
+        type(error_type), allocatable, intent(out) :: error
+
+        integer :: io, stat
+        character(len=:), allocatable :: line, msg
+
+        io = -1
+        call getline(io, line, stat, msg)
+        call check(error, stat, msg)
+    end subroutine test_no_unit
+
 end module test_getline