ceph/src/common/TextTable.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2012 Inktank Storage, Inc.
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15 #ifndef TEXT_TABLE_H_
  16 #define TEXT_TABLE_H_
  17
  18 #include <vector>
  19 #include <sstream>
  20 #include <iomanip>
  21 #include <string>
  22 #include "include/assert.h"
  23
  24 /**
  25  * TextTable:
  26  * Manage tabular output of data.  Caller defines heading of each column
  27  * and alignment of heading and column data,
  28  * then inserts rows of data including tuples of
  29  * length (ncolumns) terminated by TextTable::endrow.  When all rows
  30  * are inserted, caller asks for output with ostream <<
  31  * which sizes/pads/dumps the table to ostream.
  32  *
  33  * Columns autosize to largest heading or datum.  One space is printed
  34  * between columns.
  35  */
  36
  37 class TextTable {
  38
  39 public:
  40   enum Align {LEFT = 1, CENTER, RIGHT};
  41
  42 private:
  43   struct TextTableColumn {
  44     std::string heading;
  45     int width;
  46     Align hd_align;
  47     Align col_align;
  48
  49     TextTableColumn() {}
  50     TextTableColumn(std::string h, int w, Align ha, Align ca) :
  51                     heading(h), width(w), hd_align(ha), col_align(ca) { }
  52     ~TextTableColumn() {}
  53   };
  54
  55   std::vector<TextTableColumn> col;     // column definitions
  56   unsigned int curcol, currow;          // col, row being inserted into
  57   unsigned int indent;                  // indent width when rendering
  58
  59 protected:
  60   std::vector<std::vector<std::string> > row;   // row data array
  61
  62 public:
  63   TextTable(): curcol(0), currow(0), indent(0) {}
  64   ~TextTable() {}
  65
  66   /**
  67    * Define a column in the table.
  68    *
  69    * @param heading Column heading string (or "")
  70    * @param hd_align Alignment for heading in column
  71    * @param col_align Data alignment
  72    *
  73    * @note alignment is of type TextTable::Align; values are
  74    * TextTable::LEFT, TextTable::CENTER, or TextTable::RIGHT
  75    *
  76    */
  77   void define_column(const std::string& heading, Align hd_align,
  78                      Align col_align);
  79
  80   /**
  81    * Set indent for table.  Only affects table output.
  82    *
  83    * @param i Number of spaces to indent
  84    */
  85   void set_indent(int i) { indent = i; }
  86
  87   /**
  88    * Add item to table, perhaps on new row.
  89    * table << val1 << val2 << TextTable::endrow;
  90    *
  91    * @param: value to output.
  92    *
  93    * @note: Numerics are output in decimal; strings are not truncated.
  94    * Output formatting choice is limited to alignment in define_column().
  95    *
  96    * @return TextTable& for chaining.
  97    */
  98
  99   template<typename T> TextTable& operator<<(const T& item)
 100   {
 101     if (row.size() < currow + 1)
 102       row.resize(currow + 1);
 103
 104     /**
 105      * col.size() is a good guess for how big row[currow] needs to be,
 106      * so just expand it out now
 107      */
 108     if (row[currow].size() < col.size()) {
 109       row[currow].resize(col.size());
 110     }
 111
 112     // inserting more items than defined columns is a coding error
 113     assert(curcol + 1 <= col.size());
 114
 115     // get rendered width of item alone
 116     std::ostringstream oss;
 117     oss << item;
 118     int width = oss.str().length();
 119     oss.seekp(0);
 120
 121     // expand column width if necessary
 122     if (width > col[curcol].width) {
 123       col[curcol].width = width;
 124     }
 125
 126     // now store the rendered item with its proper width
 127     row[currow][curcol] = oss.str();
 128
 129     curcol++;
 130     return *this;
 131   }
 132
 133   /**
 134    * Degenerate type/variable here is just to allow selection of the
 135    * following operator<< for "<< TextTable::endrow"
 136    */
 137
 138   struct endrow_t {};
 139   static endrow_t endrow;
 140
 141   /**
 142    * Implements TextTable::endrow
 143    */
 144
 145   TextTable &operator<<(endrow_t)
 146   {
 147     curcol = 0;
 148     currow++;
 149     return *this;
 150   }
 151
 152   /**
 153    * Render table to ostream (i.e. cout << table)
 154    */
 155
 156   friend std::ostream &operator<<(std::ostream &out, const TextTable &t);
 157
 158   /**
 159    * clear: Reset everything in a TextTable except column defs
 160    * resize cols to heading widths, clear indent
 161    */
 162
 163   void clear();
 164 };
 165
 166 #endif
 167