fortrangoingonforty/ferp / 3df9d92

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Store patterns with null terminators for exact length tracking

Append null terminators when storing patterns to preserve their exact
length. This enables correct handling of whitespace-only patterns that
would otherwise be space-padded in Fortran's fixed-length strings.
Authored by mfwolffe <wolffemf@dukes.jmu.edu>
SHA
3df9d92b5a436d7f916657b5ee3fe0d4fda7d76b
Parents
b43bcce
Tree
132ef5e

1 changed file

StatusFile+-
M src/ferp_cli.f90 57 9
src/ferp_cli.f90modified
@@ -62,7 +62,8 @@ contains
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       ! After --, everything is a file/pattern argument
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       if (end_of_options) then
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         if (.not. has_explicit_pattern .and. size(patterns) == 0) then
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-          call append_pattern(patterns, trim(arg))
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+          ! Use exact length from get_command_argument to preserve whitespace patterns
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+          call append_pattern(patterns, arg(1:arg_len))
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           has_explicit_pattern = .true.
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         else
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           call append_file(files, trim(arg))
@@ -96,7 +97,8 @@ contains
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       else
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         ! Non-option argument
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         if (.not. has_explicit_pattern .and. size(patterns) == 0) then
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-          call append_pattern(patterns, trim(arg))
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+          ! Use exact length from get_command_argument to preserve whitespace patterns
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+          call append_pattern(patterns, arg(1:arg_len))
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           has_explicit_pattern = .true.
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         else
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           call append_file(files, trim(arg))
@@ -687,41 +689,87 @@ contains
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   end subroutine handle_option_argument
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   subroutine read_patterns_from_file(patterns, filename, ierr)
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+    !> Read patterns from file, preserving exact line lengths (including whitespace-only lines)
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     character(len=max_pattern_len), allocatable, intent(inout) :: patterns(:)
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     character(len=*), intent(in) :: filename
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     integer, intent(out) :: ierr
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-    integer :: unit_num, ios
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+    integer :: unit_num, ios, line_len
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     character(len=max_pattern_len) :: line
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+    character(len=1) :: ch
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     ierr = 0
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-    open(newunit=unit_num, file=filename, status='old', action='read', iostat=ios)
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+    ! Use stream access to read exact line lengths (preserving whitespace patterns)
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+    open(newunit=unit_num, file=filename, status='old', action='read', &
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+         access='stream', form='formatted', iostat=ios)
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     if (ios /= 0) then
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       write(error_unit, '(A)') 'ferp: ' // trim(filename) // ': No such file or directory'
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       ierr = 2
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       return
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     end if
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+    line_len = 0
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+    line = ''
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+
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     do
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-      read(unit_num, '(A)', iostat=ios) line
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-      if (ios /= 0) exit
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-      call append_pattern(patterns, trim(line))
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+      read(unit_num, '(A1)', iostat=ios, advance='no') ch
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+      if (ios /= 0) then
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+        ! EOF or error - save current line if non-empty
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+        if (line_len > 0) then
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+          call append_pattern(patterns, line(1:line_len))
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+        end if
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+        exit
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+      end if
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+
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+      if (ch == char(10)) then
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+        ! Newline - save pattern with exact length (even if zero for empty lines)
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+        if (line_len > 0) then
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+          call append_pattern(patterns, line(1:line_len))
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+        else
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+          ! Empty line - skip (grep ignores empty pattern lines)
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+        end if
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+        line_len = 0
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+        line = ''
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+      else if (ch == char(13)) then
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+        ! Carriage return - ignore (handle Windows line endings)
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+      else
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+        ! Regular character - add to line
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+        if (line_len < max_pattern_len) then
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+          line_len = line_len + 1
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+          line(line_len:line_len) = ch
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+        end if
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+      end if
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     end do
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     close(unit_num)
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   end subroutine read_patterns_from_file
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   subroutine append_pattern(patterns, pattern)
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+    !> Append a pattern to the patterns array, preserving its exact length
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+    !> Uses null terminator to mark the true end of the pattern
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     character(len=max_pattern_len), allocatable, intent(inout) :: patterns(:)
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     character(len=*), intent(in) :: pattern
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     character(len=max_pattern_len), allocatable :: temp(:)
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-    integer :: n
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+    integer :: n, plen
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     n = size(patterns)
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     allocate(temp(n + 1))
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     if (n > 0) temp(1:n) = patterns
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-    temp(n + 1) = pattern
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+
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+    ! Store pattern with null terminator to preserve exact length
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+    plen = len(pattern)
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+    if (plen > 0 .and. plen < max_pattern_len) then
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+      temp(n + 1) = pattern
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+      temp(n + 1)(plen + 1:plen + 1) = char(0)  ! Null terminator
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+    else if (plen == 0) then
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+      ! Empty pattern - store just null terminator
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+      temp(n + 1) = char(0)
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+    else
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+      ! Pattern too long - truncate
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+      temp(n + 1) = pattern(1:max_pattern_len)
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+    end if
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+
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     call move_alloc(temp, patterns)
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   end subroutine append_pattern
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