[lmi-commits] [lmi] master a873fa4 4/6: Introduce additional paginator data members

[Greg Chicares]

branch: master
commit a873fa4900e439818694ef99619a39a9b05e4e40
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Introduce additional paginator data members
    
    The exact number of lines on the last page is not yet calculated.
---
 report_table.cpp |  5 ++++-
 report_table.hpp | 21 ++++++++++++++++++---
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/report_table.cpp b/report_table.cpp
index 807c9e5..9ef9522 100644
--- a/report_table.cpp
+++ b/report_table.cpp
@@ -193,6 +193,9 @@ paginator::paginator(int total_rows, int rows_per_group, 
int max_lines_per_page)
     // "+ 1": no blank-line separator after the last group.
     ,groups_per_page_    {(max_lines_per_page_ + 1) / lines_per_group_}
     ,rows_per_page_      {rows_per_group_ * groups_per_page_}
+    // "-1 +": no blank-line separator after the last group.
+    ,lines_on_full_page_ {-1 + lines_per_group_ * groups_per_page_}
+    ,lines_on_last_page_ {lines_on_full_page_}
     ,page_count_         {1}
 {
     LMI_ASSERT(0 <= total_rows);
@@ -211,7 +214,7 @@ paginator::paginator(int total_rows, int rows_per_group, 
int max_lines_per_page)
     int const rows_on_last_page = total_rows_ - (page_count_ - 1) * 
rows_per_page_;
 
     // Avoid widowing a partial group on the last page, by moving it
-    // to the preceding page if there's room.
+    // to the preceding page (which becomes the last) if there's room.
     if(1 < page_count_)
         {
         int const free_lines = max_lines_per_page_ - lines_per_group_ * 
groups_per_page_;
diff --git a/report_table.hpp b/report_table.hpp
index b548cf2..cf768d5 100644
--- a/report_table.hpp
+++ b/report_table.hpp
@@ -106,8 +106,19 @@ std::vector<int> LMI_SO set_column_widths
 /// Display table rows in groups separated by blank lines.
 ///
 /// Nomenclature:
-///  - a 'line' is a printable zone of unit height;
-///  - a 'row' is a series of data to be shown side by side.
+///  - A 'line' is a printable zone of unit height.
+///  - A 'row' is a series of data to be shown side by side.
+///  - A 'full' page has as many complete groups of rows as can fit,
+///    and nothing more. All pages except the last are always full;
+///    the last may also happen to be full.
+///  - The 'last' page is the one with the highest page number. It may
+///    have exactly as many rows as any 'full' page (if the cardinality
+///    of the data is congruent to zero (mod rows_per_group)); or
+///    fewer, as is naturally most common; or more, if a final partial
+///    group is displayed on the last page to avoid widowing.
+/// If a table prints on a single page, then the first is a 'last'
+/// page; it may or may not be full.
+///
 /// With quinquennial spacing, the Morse alphabet is printed thus:
 ///
 ///   A   .-     line  0   row  0
@@ -139,7 +150,9 @@ class LMI_SO paginator
   public:
     paginator(int total_rows, int rows_per_group, int max_lines_per_page);
 
-    int page_count() const {return page_count_;}
+    int lines_on_full_page() const {return lines_on_full_page_;}
+    int lines_on_last_page() const {return lines_on_last_page_;}
+    int page_count        () const {return page_count_        ;}
 
   private:
     // Ctor arguments.
@@ -151,6 +164,8 @@ class LMI_SO paginator
     int const lines_per_group_;
     int const groups_per_page_;
     int const rows_per_page_;
+    int const lines_on_full_page_;
+    int       lines_on_last_page_;
     int       page_count_;
 };