From cbab7a36cb62b580ec6f0ae3d3808230f3943cf5 Mon Sep 17 00:00:00 2001
From: Thomas Fussell <thomas.fussell@gmail.com>
Date: Tue, 20 Oct 2015 13:53:47 -0400
Subject: [PATCH] clean up styles

---
 include/xlnt/styles/alignment.hpp     |   7 +-
 include/xlnt/styles/borders.hpp       |   5 +-
 include/xlnt/styles/fill.hpp          |   2 +-
 include/xlnt/styles/font.hpp          |  10 +-
 include/xlnt/styles/number_format.hpp |  11 +
 include/xlnt/styles/protection.hpp    |   2 +-
 include/xlnt/styles/style.hpp         |  85 ++++---
 include/xlnt/workbook/workbook.hpp    |   2 +-
 source/cell.cpp                       |  14 +-
 source/detail/cell_impl.cpp           |   3 +-
 source/detail/cell_impl.hpp           |   2 +
 source/detail/workbook_impl.hpp       |  56 ++---
 source/reader.cpp                     |   4 +
 source/style.cpp                      |  41 ++--
 source/style_writer.cpp               |   8 +-
 source/workbook.cpp                   | 339 +++++++-------------------
 source/worksheet_writer.cpp           |  25 +-
 17 files changed, 217 insertions(+), 399 deletions(-)

diff --git a/include/xlnt/styles/alignment.hpp b/include/xlnt/styles/alignment.hpp
index 7dd5e64b..6c051959 100644
--- a/include/xlnt/styles/alignment.hpp
+++ b/include/xlnt/styles/alignment.hpp
@@ -56,12 +56,7 @@ public:
     
     bool operator==(const alignment &other) const
     {
-        return horizontal_ == other.horizontal_
-        && vertical_ == other.vertical_
-        && text_rotation_ == other.text_rotation_
-        && wrap_text_ == other.wrap_text_
-        && shrink_to_fit_ == other.shrink_to_fit_
-        && indent_ == other.indent_;
+        return hash() == other.hash();
     }
     
     std::size_t hash() const { return 0; }
diff --git a/include/xlnt/styles/borders.hpp b/include/xlnt/styles/borders.hpp
index a65f3055..e0acfe4f 100644
--- a/include/xlnt/styles/borders.hpp
+++ b/include/xlnt/styles/borders.hpp
@@ -100,10 +100,7 @@ public:
     
     bool operator==(const border &other) const
     {
-        return start.value == other.start.value
-        && outline == other.outline
-        && diagonal_up == other.diagonal_up
-        && diagonal_down == other.diagonal_down;
+        return hash() == other.hash();
     }
     
     std::size_t hash() const { return 0; }
diff --git a/include/xlnt/styles/fill.hpp b/include/xlnt/styles/fill.hpp
index 12dc4234..e47b1940 100644
--- a/include/xlnt/styles/fill.hpp
+++ b/include/xlnt/styles/fill.hpp
@@ -62,7 +62,7 @@ public:
     
     virtual bool operator==(const fill &other) const
     {
-        return type_ == other.type_;
+        return hash() == other.hash();
     }
     
     virtual std::size_t hash() const { return 0; }
diff --git a/include/xlnt/styles/font.hpp b/include/xlnt/styles/font.hpp
index 613d559e..54246fb6 100644
--- a/include/xlnt/styles/font.hpp
+++ b/include/xlnt/styles/font.hpp
@@ -47,15 +47,7 @@ public:
     
     bool operator==(const font &other) const
     {
-        return name_ == other.name_
-        && size_ == other.size_
-        && bold_ == other.bold_
-        && italic_ == other.italic_
-        && superscript_ == other.superscript_
-        && subscript_ == other.subscript_
-        && underline_ == other.underline_
-        && strikethrough_ == other.strikethrough_
-        && color_ == other.color_;
+        return hash() == other.hash();
     }
     
     int get_size() const { return size_; }
diff --git a/include/xlnt/styles/number_format.hpp b/include/xlnt/styles/number_format.hpp
index 9f8658d0..b551f4d1 100644
--- a/include/xlnt/styles/number_format.hpp
+++ b/include/xlnt/styles/number_format.hpp
@@ -88,6 +88,12 @@ public:
     
     static bool is_builtin(const std::string &format);
     
+    static const number_format &default_number_format()
+    {
+        static number_format default_;
+        return default_;
+    }
+    
     number_format();
     number_format(format code);
     number_format(const std::string &code);
@@ -102,6 +108,11 @@ public:
     int get_format_index() const { return format_index_; }
     
     std::size_t hash() const;
+    
+    bool operator==(const number_format &other) const
+    {
+        return hash() == other.hash();
+    }
 
 private:
     format format_code_;
diff --git a/include/xlnt/styles/protection.hpp b/include/xlnt/styles/protection.hpp
index e8f23bf7..71e8dc42 100644
--- a/include/xlnt/styles/protection.hpp
+++ b/include/xlnt/styles/protection.hpp
@@ -47,7 +47,7 @@ public:
     
     bool operator==(const protection &other) const
     {
-        return locked_ == other.locked_ && hidden_ == other.hidden_;
+        return hash() == other.hash();
     }
     
     std::size_t hash() const { return 0; }
diff --git a/include/xlnt/styles/style.hpp b/include/xlnt/styles/style.hpp
index 1df36535..a218bd55 100644
--- a/include/xlnt/styles/style.hpp
+++ b/include/xlnt/styles/style.hpp
@@ -23,55 +23,68 @@
 // @author: see AUTHORS file
 #pragma once
 
-namespace xlnt {
-namespace detail {
-    
-struct cell_impl;
-    
-} // namespace detail    
+#include "alignment.hpp"
+#include "borders.hpp"
+#include "fill.hpp"
+#include "font.hpp"
+#include "number_format.hpp"
+#include "protection.hpp"
 
-class alignment;
-class border;
-class font;
-class fill;
-class number_format;
-class protection;
-    
-class cell;
+namespace xlnt {
+
+class workbook;
 
 class style
 {
 public:
-    const style default_style();
-    
     style();
-    style(const style &rhs);
-    style &operator=(const style &rhs);
-    
-    style copy() const;
     
     std::size_t hash() const;
     
-    const font &get_font() const;
-    const fill &get_fill() const;
-    const border &get_border() const;
-    const alignment &get_alignment() const;
-    const number_format &get_number_format() const;
-    const protection &get_protection() const;
+    const alignment get_alignment() const;
+    const border get_border() const;
+    const fill get_fill() const;
+    const font get_font() const;
+    const number_format get_number_format() const;
+    const protection get_protection() const;
     bool pivot_button() const;
     bool quote_prefix() const;
     
+    std::size_t get_fill_index() const { return fill_index_; }
+    std::size_t get_font_index() const { return font_index_; }
+    std::size_t get_border_index() const { return border_index_; }
+    std::size_t get_number_format_index() const { return number_format_index_; }
+    
+    bool operator==(const style &other) const
+    {
+        return hash() == other.hash();
+    }
+    
 private:
-    cell get_parent();
-    const cell get_parent() const;
-    detail::cell_impl *parent_;
-    std::size_t font_id_;
-    std::size_t fill_id_;
-    std::size_t border_id_;
-    std::size_t alignment_id_;
-    std::size_t number_format_id_;
-    std::size_t protection_id_;
-    std::size_t style_id_;
+    friend class workbook;
+    
+    std::size_t style_index_;
+    
+    std::size_t alignment_index_;
+    alignment alignment_;
+    
+    std::size_t border_index_;
+    border border_;
+    
+    std::size_t fill_index_;
+    fill fill_;
+    
+    std::size_t font_index_;
+    font font_;
+    
+    std::size_t number_format_index_;
+    number_format number_format_;
+    
+    std::size_t protection_index_;
+    protection protection_;
+    
+    bool pivot_button_;
+    bool quote_prefix_;
 };
 
 } // namespace xlnt
diff --git a/include/xlnt/workbook/workbook.hpp b/include/xlnt/workbook/workbook.hpp
index 0b3fd06c..c27709cd 100644
--- a/include/xlnt/workbook/workbook.hpp
+++ b/include/xlnt/workbook/workbook.hpp
@@ -208,7 +208,7 @@ public:
     void add_color(color c);
     void add_number_format(const std::string &format);
     
-    std::vector<std::array<int, 4>> get_styles() const;
+    std::vector<style> get_styles() const;
     
     std::vector<alignment> get_alignments() const;
     std::vector<border> get_borders() const;
diff --git a/source/cell.cpp b/source/cell.cpp
index b4deced4..7631a3e2 100644
--- a/source/cell.cpp
+++ b/source/cell.cpp
@@ -1035,7 +1035,18 @@ std::size_t cell::get_xf_index() const
 
 const number_format &cell::get_number_format() const
 {
-    return get_parent().get_parent().get_number_format(d_->style_id_);
+    if(d_->has_style_)
+    {
+        return get_parent().get_parent().get_number_format(d_->style_id_);
+    }
+    else if(get_parent().get_parent().get_number_formats().empty())
+    {
+        return number_format::default_number_format();
+    }
+    else
+    {
+        return get_parent().get_parent().get_number_formats().front();
+    }
 }
     
 const font &cell::get_font() const
@@ -1187,6 +1198,7 @@ timedelta cell::get_value() const
 
 void cell::set_number_format(const number_format &number_format_)
 {
+    d_->has_style_ = true;
     d_->style_id_ = get_parent().get_parent().set_number_format(number_format_, d_->style_id_);
 }
 
diff --git a/source/detail/cell_impl.cpp b/source/detail/cell_impl.cpp
index 01ce3a01..3f4c1121 100644
--- a/source/detail/cell_impl.cpp
+++ b/source/detail/cell_impl.cpp
@@ -23,7 +23,8 @@ cell_impl::cell_impl(worksheet_impl *parent, column_t column, row_t row)
       has_hyperlink_(false),
       is_merged_(false),
       xf_index_(0),
-      style_id_(1),
+      has_style_(false),
+      style_id_(0),
       comment_(nullptr)
 {
 }
diff --git a/source/detail/cell_impl.hpp b/source/detail/cell_impl.hpp
index bcf507ab..da61dac1 100644
--- a/source/detail/cell_impl.hpp
+++ b/source/detail/cell_impl.hpp
@@ -196,6 +196,8 @@ struct cell_impl
     bool is_merged_;
     
     std::size_t xf_index_;
+    
+    bool has_style_;
     std::size_t style_id_;
     
     std::unique_ptr<comment_impl> comment_;
diff --git a/source/detail/workbook_impl.hpp b/source/detail/workbook_impl.hpp
index cd956dfa..ce886a07 100644
--- a/source/detail/workbook_impl.hpp
+++ b/source/detail/workbook_impl.hpp
@@ -18,21 +18,13 @@ struct workbook_impl
         properties_(other.properties_), 
         guess_types_(other.guess_types_),
         data_only_(other.data_only_),
-        next_style_id_(other.next_style_id_),
+        styles_(other.styles_),
         alignments_(other.alignments_),
-    borders_(other.borders_),
-    fills_(other.fills_),
-    fonts_(other.fonts_),
-    number_formats_(other.number_formats_),
-    protections_(other.protections_),
-    style_alignment_(other.style_alignment_),
-    style_border_(other.style_border_),
-    style_fill_(other.style_fill_),
-    style_font_(other.style_font_),
-    style_number_format_(other.style_number_format_),
-    style_protection_(other.style_protection_),
-    style_pivot_button_(other.style_pivot_button_),
-    style_quote_prefix_(other.style_quote_prefix_)
+        borders_(other.borders_),
+        fills_(other.fills_),
+        fonts_(other.fonts_),
+        number_formats_(other.number_formats_),
+        protections_(other.protections_)
     {
     }
     
@@ -48,21 +40,13 @@ struct workbook_impl
         properties_ = other.properties_;
         guess_types_ = other.guess_types_;
         data_only_ = other.data_only_;
-        next_style_id_ = other.next_style_id_;
+        styles_ = other.styles_;
         alignments_ = other.alignments_;
         borders_ = other.borders_;
         fills_ = other.fills_;
         fonts_ = other.fonts_;
         number_formats_ = other.number_formats_;
         protections_ = other.protections_;
-        style_alignment_ = other.style_alignment_;
-        style_border_ = other.style_border_;
-        style_fill_ = other.style_fill_;
-        style_font_ = other.style_font_;
-        style_number_format_ = other.style_number_format_;
-        style_protection_ = other.style_protection_;
-        style_pivot_button_ = other.style_pivot_button_;
-        style_quote_prefix_ = other.style_quote_prefix_;
         
         return *this;
     }
@@ -71,25 +55,21 @@ struct workbook_impl
     std::vector<worksheet_impl> worksheets_;
     std::vector<relationship> relationships_;
     std::vector<drawing> drawings_;
+    
     document_properties properties_;
+    
     bool guess_types_;
     bool data_only_;
     
-    std::size_t next_style_id_;
-    std::unordered_map<std::size_t, alignment> alignments_;
-    std::unordered_map<std::size_t, border> borders_;
-    std::unordered_map<std::size_t, fill> fills_;
-    std::unordered_map<std::size_t, font> fonts_;
-    std::unordered_map<std::size_t, number_format> number_formats_;
-    std::unordered_map<std::size_t, protection> protections_;
-    std::unordered_map<std::size_t, std::size_t> style_alignment_;
-    std::unordered_map<std::size_t, std::size_t> style_border_;
-    std::unordered_map<std::size_t, std::size_t> style_fill_;
-    std::unordered_map<std::size_t, std::size_t> style_font_;
-    std::unordered_map<std::size_t, std::size_t> style_number_format_;
-    std::unordered_map<std::size_t, std::size_t> style_protection_;
-    std::unordered_map<std::size_t, bool> style_pivot_button_;
-    std::unordered_map<std::size_t, bool> style_quote_prefix_;
+    std::vector<style> styles_;
+    
+    std::vector<alignment> alignments_;
+    std::vector<border> borders_;
+    std::vector<fill> fills_;
+    std::vector<font> fonts_;
+    std::vector<number_format> number_formats_;
+    std::vector<protection> protections_;
+    
 };
 
 } // namespace detail
diff --git a/source/reader.cpp b/source/reader.cpp
index a619dadd..336e6295 100644
--- a/source/reader.cpp
+++ b/source/reader.cpp
@@ -178,6 +178,10 @@ void read_worksheet_common(xlnt::worksheet ws, const pugi::xml_node &root_node,
                         }
                     }
                 }
+                else
+                {
+                    ws.get_cell(address).set_number_format(xlnt::number_format(xlnt::number_format::format::general));
+                }
             }
         }
     }
diff --git a/source/style.cpp b/source/style.cpp
index 1c1bf7ce..8ebed64a 100644
--- a/source/style.cpp
+++ b/source/style.cpp
@@ -22,17 +22,9 @@ style::style()
 {
 }
 
-style::style(const style &other)
-{
-}
-
-const cell style::get_parent() const
-{
-    return cell(parent_);
-}
-
 std::size_t style::hash() const
 {
+    /*
     std::size_t seed = 100;
     std::hash<std::string> string_hash;
     auto font_ = get_font();
@@ -45,48 +37,51 @@ std::size_t style::hash() const
     bools = bools << 1 & font_.superscript_;
     bools = bools << 1 & font_.subscript_;
     hash_combine(seed, bools);
+     */
+    std::size_t seed = 100;
+    hash_combine(seed, number_format_.hash());
     
     return seed;
 }
 
-const number_format &style::get_number_format() const
+const number_format style::get_number_format() const
 {
-    return get_parent().get_number_format();
+    return number_format_;
 }
 
-const border &style::get_border() const
+const border style::get_border() const
 {
-    return get_parent().get_border();
+    return border_;
 }
 
-const alignment &style::get_alignment() const
+const alignment style::get_alignment() const
 {
-    return get_parent().get_alignment();
+    return alignment_;
 }
     
-const fill &style::get_fill() const
+const fill style::get_fill() const
 {
-    return get_parent().get_fill();
+    return fill_;
 }
 
-const font &style::get_font() const
+const font style::get_font() const
 {
-    return get_parent().get_font();
+    return font_;
 }
 
-const protection &style::get_protection() const
+const protection style::get_protection() const
 {
-    return get_parent().get_protection();
+    return protection_;
 }
 
 bool style::pivot_button() const
 {
-    return get_parent().pivot_button();
+    return pivot_button_;
 }
 
 bool style::quote_prefix() const
 {
-    return get_parent().quote_prefix();
+    return quote_prefix_;
 }
 
 } // namespace xlnt
diff --git a/source/style_writer.cpp b/source/style_writer.cpp
index 596baa93..6efda39c 100644
--- a/source/style_writer.cpp
+++ b/source/style_writer.cpp
@@ -106,11 +106,11 @@ std::string style_writer::write_table() const
     for(auto &style : styles)
     {
         xf_node = cell_xfs_node.append_child("xf");
-        xf_node.append_attribute("numFmtId").set_value(static_cast<int>(style[3]));
+        xf_node.append_attribute("numFmtId").set_value((int)style.get_number_format_index());
         xf_node.append_attribute("applyNumberFormat").set_value(1);
-        xf_node.append_attribute("fontId").set_value(static_cast<int>(style[2]));
-        xf_node.append_attribute("fillId").set_value(static_cast<int>(style[1]));
-        xf_node.append_attribute("borderId").set_value(static_cast<int>(style[0]));
+        xf_node.append_attribute("fontId").set_value((int)style.get_font_index());
+        xf_node.append_attribute("fillId").set_value((int)style.get_fill_index());
+        xf_node.append_attribute("borderId").set_value((int)style.get_border_index());
         
         auto alignment_node = xf_node.append_child("alignment");
         alignment_node.append_attribute("vertical").set_value("top");
diff --git a/source/workbook.cpp b/source/workbook.cpp
index 785885e4..bfed4082 100644
--- a/source/workbook.cpp
+++ b/source/workbook.cpp
@@ -69,7 +69,7 @@ void hash_combine(std::size_t& seed, const T& v)
 namespace xlnt {
 namespace detail {
 
-workbook_impl::workbook_impl() : active_sheet_index_(0), guess_types_(false), data_only_(false), next_style_id_(2)
+workbook_impl::workbook_impl() : active_sheet_index_(0), guess_types_(false), data_only_(false)
 {
 }
 
@@ -81,22 +81,6 @@ workbook::workbook() : d_(new detail::workbook_impl())
     create_relationship("rId2", "sharedStrings.xml", relationship::type::shared_strings);
     create_relationship("rId3", "styles.xml", relationship::type::styles);
     create_relationship("rId4", "theme/theme1.xml", relationship::type::theme);
-
-    d_->alignments_[alignment().hash()] = alignment();
-    d_->borders_[border().hash()] = border();
-    d_->fills_[fill().hash()] = fill();
-    d_->fonts_[font().hash()] = font();
-    d_->number_formats_[number_format().hash()] = number_format();
-    d_->protections_[protection().hash()] = protection();
-    
-    d_->style_alignment_[1] = alignment().hash();
-    d_->style_border_[1] = border().hash();
-    d_->style_font_[1] = font().hash();
-    d_->style_fill_[1] = fill().hash();
-    d_->style_number_format_[1] = number_format().hash();
-    d_->style_protection_[1] = protection().hash();
-    d_->style_pivot_button_[1] = false;
-    d_->style_quote_prefix_[1] = false;
 }
 
 workbook::iterator::iterator(workbook &wb, std::size_t index) : wb_(wb), index_(index)
@@ -753,313 +737,168 @@ std::size_t workbook::add_style(xlnt::style style_)
 
 const number_format &workbook::get_number_format(std::size_t style_id) const
 {
-    return d_->number_formats_[d_->style_number_format_[style_id]];
+    return d_->number_formats_[d_->styles_[style_id].number_format_index_];
 }
 
 const font &workbook::get_font(std::size_t style_id) const
 {
-    return d_->fonts_[d_->style_font_[style_id]];
+    return d_->fonts_[d_->styles_[style_id].font_index_];
 }
 
 std::size_t workbook::set_font(const font &font_, std::size_t style_id)
 {
-    auto hash = font_.hash();
+    auto match = std::find(d_->fonts_.begin(), d_->fonts_.end(), font_);
+    auto font_index = 0;
     
-    if(d_->number_formats_.find(hash) == d_->number_formats_.end())
+    if(match == d_->fonts_.end())
     {
-        d_->fonts_[hash] = font_;
+        d_->fonts_.push_back(font_);
+        font_index = d_->fonts_.size() - 1;
+    }
+    else
+    {
+        font_index = match - d_->fonts_.begin();
     }
     
-    d_->style_font_[d_->next_style_id_] = hash;
+    auto existing_style = d_->styles_[style_id];
     
-    d_->style_alignment_[d_->next_style_id_] = d_->style_alignment_[style_id];
-    d_->style_border_[d_->next_style_id_] = d_->style_border_[style_id];
-    d_->style_fill_[d_->next_style_id_] = d_->style_fill_[style_id];
-    d_->style_number_format_[d_->next_style_id_] = d_->style_number_format_[style_id];
-    d_->style_protection_[d_->next_style_id_] = d_->style_protection_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
+    if(font_index == existing_style.font_index_)
+    {
+        // no change
+        return style_id;
+    }
     
-    return d_->next_style_id_++;
+    auto new_style = existing_style;
+    new_style.font_index_ = font_index;
+    
+    auto style_match = std::find(d_->styles_.begin(), d_->styles_.end(), new_style);
+
+    if(style_match != d_->styles_.end())
+    {
+        return style_match - d_->styles_.begin();
+    }
+    
+    d_->styles_.push_back(new_style);
+    
+    return d_->styles_.size() - 1;
 }
 
 const fill &workbook::get_fill(std::size_t style_id) const
 {
-    return d_->fills_[d_->style_fill_[style_id]];
+    return d_->fills_[d_->styles_[style_id].fill_index_];
 }
 
 std::size_t workbook::set_fill(const fill &fill_, std::size_t style_id)
 {
-    auto hash = fill_.hash();
-    
-    if(d_->fills_.find(hash) == d_->fills_.end())
-    {
-        d_->fills_[hash] = fill_;
-    }
-    
-    d_->style_fill_[d_->next_style_id_] = hash;
-    
-    d_->style_alignment_[d_->next_style_id_] = d_->style_alignment_[style_id];
-    d_->style_border_[d_->next_style_id_] = d_->style_border_[style_id];
-    d_->style_font_[d_->next_style_id_] = d_->style_font_[style_id];
-    d_->style_number_format_[d_->next_style_id_] = d_->style_number_format_[style_id];
-    d_->style_protection_[d_->next_style_id_] = d_->style_protection_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
-    
-    return d_->next_style_id_++;
+    return style_id;
 }
 
 const border &workbook::get_border(std::size_t style_id) const
 {
-    return d_->borders_[d_->style_border_[style_id]];
+    return d_->borders_[d_->styles_[style_id].border_index_];
 }
 
 std::size_t workbook::set_border(const border &border_, std::size_t style_id)
 {
-    auto hash = border_.hash();
-    
-    if(d_->borders_.find(hash) == d_->borders_.end())
-    {
-        d_->borders_[hash] = border_;
-    }
-    
-    d_->style_border_[d_->next_style_id_] = hash;
-    
-    d_->style_alignment_[d_->next_style_id_] = d_->style_alignment_[style_id];
-    d_->style_font_[d_->next_style_id_] = d_->style_font_[style_id];
-    d_->style_fill_[d_->next_style_id_] = d_->style_fill_[style_id];
-    d_->style_number_format_[d_->next_style_id_] = d_->style_number_format_[style_id];
-    d_->style_protection_[d_->next_style_id_] = d_->style_protection_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
-    
-    return d_->next_style_id_++;
+    return style_id;
 }
 
 const alignment &workbook::get_alignment(std::size_t style_id) const
 {
-    return d_->alignments_[d_->style_alignment_[style_id]];
+    return d_->alignments_[d_->styles_[style_id].alignment_index_];
 }
 
 std::size_t workbook::set_alignment(const alignment &alignment_, std::size_t style_id)
 {
-    auto hash = alignment_.hash();
-    
-    if(d_->alignments_.find(hash) == d_->alignments_.end())
-    {
-        d_->alignments_[hash] = alignment_;
-    }
-    
-    d_->style_alignment_[d_->next_style_id_] = hash;
-
-    d_->style_border_[d_->next_style_id_] = d_->style_border_[style_id];
-    d_->style_font_[d_->next_style_id_] = d_->style_font_[style_id];
-    d_->style_fill_[d_->next_style_id_] = d_->style_fill_[style_id];
-    d_->style_number_format_[d_->next_style_id_] = d_->style_number_format_[style_id];
-    d_->style_protection_[d_->next_style_id_] = d_->style_protection_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
-    
-    return d_->next_style_id_++;
+    return style_id;
 }
 
 const protection &workbook::get_protection(std::size_t style_id) const
 {
-    return d_->protections_[d_->style_protection_[style_id]];
+    return d_->protections_[d_->styles_[style_id].number_format_index_];
 }
 
 std::size_t workbook::set_protection(const protection &protection_, std::size_t style_id)
 {
-    auto hash = protection_.hash();
-    
-    if(d_->protections_.find(hash) == d_->protections_.end())
-    {
-        d_->protections_[hash] = protection_;
-    }
-    
-    d_->style_protection_[d_->next_style_id_] = hash;
-    
-    d_->style_alignment_[d_->next_style_id_] = d_->style_alignment_[style_id];
-    d_->style_border_[d_->next_style_id_] = d_->style_border_[style_id];
-    d_->style_font_[d_->next_style_id_] = d_->style_font_[style_id];
-    d_->style_fill_[d_->next_style_id_] = d_->style_fill_[style_id];
-    d_->style_number_format_[d_->next_style_id_] = d_->style_number_format_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
-    
-    return d_->next_style_id_++;
+    return style_id;
 }
 
 bool workbook::get_pivot_button(std::size_t style_id) const
 {
-    return d_->style_pivot_button_[style_id];
+    return d_->styles_[style_id].pivot_button_;
 }
 
 bool workbook::get_quote_prefix(std::size_t style_id) const
 {
-    return d_->style_quote_prefix_[style_id];
+    return d_->styles_[style_id].quote_prefix_;
 }
 
 std::size_t workbook::set_number_format(const xlnt::number_format &format, std::size_t style_id)
 {
-    auto hash = format.hash();
+    auto match = std::find(d_->number_formats_.begin(), d_->number_formats_.end(), format);
+    auto format_index = 0;
     
-    if(d_->number_formats_.find(hash) == d_->number_formats_.end())
+    if(match == d_->number_formats_.end())
     {
-        d_->number_formats_[hash] = format;
+        d_->number_formats_.push_back(format);
+        format_index = d_->number_formats_.size() - 1;
+    }
+    else
+    {
+        format_index = match - d_->number_formats_.begin();
     }
     
-    d_->style_number_format_[d_->next_style_id_] = hash;
+    if(d_->styles_.empty())
+    {
+        style new_style;
+        new_style.style_index_ = 0;
+        new_style.alignment_index_ = 0;
+        new_style.border_index_ = 0;
+        new_style.fill_index_ = 0;
+        new_style.font_index_ = 0;
+        new_style.number_format_index_ = format_index;
+        new_style.protection_index_ = 0;
+        d_->styles_.push_back(new_style);
+        return 0;
+    }
     
-    d_->style_alignment_[d_->next_style_id_] = d_->style_alignment_[style_id];
-    d_->style_border_[d_->next_style_id_] = d_->style_border_[style_id];
-    d_->style_font_[d_->next_style_id_] = d_->style_font_[style_id];
-    d_->style_fill_[d_->next_style_id_] = d_->style_fill_[style_id];
-    d_->style_protection_[d_->next_style_id_] = d_->style_protection_[style_id];
-    d_->style_pivot_button_[d_->next_style_id_] = d_->style_pivot_button_[style_id];
-    d_->style_quote_prefix_[d_->next_style_id_] = d_->style_quote_prefix_[style_id];
+    auto existing_style = d_->styles_[style_id];
     
-    return d_->next_style_id_++;
+    if(format_index == existing_style.number_format_index_)
+    {
+        // no change
+        return style_id;
+    }
+    
+    auto new_style = existing_style;
+    new_style.number_format_index_ = format_index;
+    new_style.number_format_ = format;
+    
+    auto style_match = std::find(d_->styles_.begin(), d_->styles_.end(), new_style);
+    
+    if(style_match != d_->styles_.end())
+    {
+        return style_match - d_->styles_.begin();
+    }
+    
+    d_->styles_.push_back(new_style);
+    
+    return d_->styles_.size() - 1;
 }
     
-std::vector<alignment> workbook::get_alignments() const
+std::vector<style> workbook::get_styles() const
 {
-    std::vector<alignment> alignments;
-    
-    for(auto &pair : d_->alignments_)
-    {
-        alignments.push_back(pair.second);
-    }
-    
-    return alignments;
-}
-
-std::vector<border> workbook::get_borders() const
-{
-    std::vector<border> borders;
-    
-    for(auto &pair : d_->borders_)
-    {
-        borders.push_back(pair.second);
-    }
-    
-    return borders;
-}
-
-std::vector<fill> workbook::get_fills() const
-{
-    std::vector<fill> fills;
-    
-    for(auto &pair : d_->fills_)
-    {
-        fills.push_back(pair.second);
-    }
-    
-    return fills;
-}
-
-std::vector<font> workbook::get_fonts() const
-{
-    std::vector<font> fonts;
-    
-    for(auto &pair : d_->fonts_)
-    {
-        fonts.push_back(pair.second);
-    }
-    
-    return fonts;
+    return d_->styles_;
 }
 
 std::vector<number_format> workbook::get_number_formats() const
 {
-    std::vector<number_format> number_formats;
-    
-    for(auto &pair : d_->number_formats_)
-    {
-        number_formats.push_back(pair.second);
-    }
-    
-    return number_formats;
+    return d_->number_formats_;
 }
 
-std::vector<protection> workbook::get_protections() const
+std::vector<font> workbook::get_fonts() const
 {
-    std::vector<protection> protections;
-    
-    for(auto &pair : d_->protections_)
-    {
-        protections.push_back(pair.second);
-    }
-    
-    return protections;
-}
-    
-std::vector<std::array<int, 4>> workbook::get_styles() const
-{
-    auto borders = get_borders();
-    auto fills = get_fills();
-    auto fonts = get_fonts();
-    auto number_formats = get_number_formats();
-    
-    std::unordered_map<std::size_t, std::array<int, 4>> styles;
-    
-    for(std::size_t i = 1; i < d_->next_style_id_; i++)
-    {
-        std::array<std::size_t, 4> style_hashes = {d_->style_border_[i], d_->style_fill_[i], d_->style_font_[i], d_->style_number_format_[i]};
-        std::array<int, 4> style = {-1, -1, -1, -1};
-        
-        for(std::size_t i = 0; i < borders.size(); i++)
-        {
-            if(borders[i].hash() == style_hashes[0])
-            {
-                style[0] = i;
-                break;
-            }
-        }
-        
-        for(std::size_t i = 0; i < fills.size(); i++)
-        {
-            if(fills[i].hash() == style_hashes[1])
-            {
-                style[1] = i;
-                break;
-            }
-        }
-        
-        for(std::size_t i = 0; i < fonts.size(); i++)
-        {
-            if(fonts[i].hash() == style_hashes[2])
-            {
-                style[2] = i;
-                break;
-            }
-        }
-        
-        for(std::size_t i = 0; i < number_formats.size(); i++)
-        {
-            if(number_formats[i].hash() == style_hashes[3])
-            {
-                style[3] = i;
-                break;
-            }
-        }
-        
-        std::size_t seed = style[0];
-        hash_combine(seed, style[1]);
-        hash_combine(seed, style[2]);
-        hash_combine(seed, style[3]);
-        styles[seed] = style;
-    }
-    
-    std::vector<std::array<int, 4>> styles_vector;
-    
-    for(auto &pair : styles)
-    {
-        styles_vector.push_back(pair.second);
-    }
-    
-    return styles_vector;
+    return d_->fonts_;
 }
     
 } // namespace xlnt
diff --git a/source/worksheet_writer.cpp b/source/worksheet_writer.cpp
index b007ecfc..b35ec942 100644
--- a/source/worksheet_writer.cpp
+++ b/source/worksheet_writer.cpp
@@ -126,11 +126,6 @@ std::string write_worksheet(worksheet ws, const std::vector<std::string> &string
     std::unordered_map<std::string, std::string> hyperlink_references;
     
     auto sheet_data_node = root_node.append_child("sheetData");
-    const auto &styles = ws.get_parent().get_styles();
-    auto borders = ws.get_parent().get_borders();
-    auto fills = ws.get_parent().get_fills();
-    auto fonts = ws.get_parent().get_fonts();
-    auto number_formats = ws.get_parent().get_number_formats();
     
     for(auto row : ws.rows())
     {
@@ -270,25 +265,7 @@ std::string write_worksheet(worksheet ws, const std::vector<std::string> &string
                 }
                 
                 auto style_id = cell.get_style_id();
-                auto border = ws.get_parent().get_border(style_id);
-                auto font = ws.get_parent().get_font(style_id);
-                auto fill = ws.get_parent().get_fill(style_id);
-                auto num_format = ws.get_parent().get_number_format(style_id);
-                int style_index = 0;
-                
-                for(auto &style : styles)
-                {
-                    if(borders[style.at(0)].hash() == border.hash()
-                       && fonts[style.at(1)].hash() == font.hash()
-                       && fills[style.at(2)].hash() == fill.hash()
-                       && number_formats[style.at(3)].hash() == num_format.hash())
-                    {
-                        cell_node.append_attribute("s").set_value(style_index);
-                        break;
-                    }
-                    
-                    style_index++;
-                }
+                cell_node.append_attribute("s").set_value((int)style_id);
             }
         }
     }