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