[lmi-commits] [lmi] master 938a89f 2/3: Simplify arithmetic; improve documentation

[Greg Chicares]

branch: master
commit 938a89f3f92e5c8936230d430d0ebb4c163e84e9
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Simplify arithmetic; improve documentation
---
 report_table.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/report_table.cpp b/report_table.cpp
index 618c7ec..215136a 100644
--- a/report_table.cpp
+++ b/report_table.cpp
@@ -182,6 +182,12 @@ namespace
 std::logic_error yikes("Rows per group must be positive.");
 } // Unnamed namespace.
 
+/// Calculate pagination parameters.
+///
+/// Either of the final if-statements may be skipped. The first may be
+/// skipped if widow control is not wanted. The second may be skipped
+/// if zero rows of input should produce zero pages of output.
+///
 /// Asserted preconditions:
 ///   0 <= number_of_rows
 ///   0 < rows_per_group <= max_lines_per_page
@@ -226,7 +232,8 @@ prepaginator::prepaginator
     // to the preceding page (which becomes the last) if there's room.
     if(1 < number_of_pages_)
         {
-        int const free_lines = max_lines_per_page_ - lines_per_group_ * 
groups_per_page_;
+        // "+ 1": need separator before antiwidowed partial group.
+        int const free_lines = max_lines_per_page_ - (lines_on_full_page_ + 1);
         LMI_ASSERT(free_lines < rows_per_group_);
         if(rows_on_last_page <= free_lines)
             {