New utility class to parse/write CSV files

dic/Makefile.am

@@ -31,6 +31,7 @@ libdic_a_SOURCES = \
 	tile.cpp tile.h \
 	dic.cpp dic.h \
 	dic_search.cpp \
+	csv_helper.cpp csv_helper.h \
 	encoding.cpp encoding.h \
 	stacktrace.cpp stacktrace.h \
 	automaton.cpp automaton.h \

dic/csv_helper.cpp

@@ -0,0 +1,172 @@
+/*****************************************************************************
+ * Eliot
+ * Copyright (C) 2012 Olivier Teulière
+ * Authors: Olivier Teulière <ipkiss @@ gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *****************************************************************************/
+
+#include <boost/foreach.hpp>
+#include <boost/format.hpp>
+
+#include "csv_helper.h"
+
+#include "debug.h"
+
+#if ENABLE_NLS
+#   include <libintl.h>
+#   define _(String) gettext(String)
+#else
+#   define _(String) String
+#endif
+
+using namespace std;
+
+INIT_LOGGER(qt, CsvHelper);
+
+
+vector<CsvHelper::DataRow> CsvHelper::readStream(istream &input)
+{
+    vector<DataRow> data;
+    size_t minLength = (size_t) -1;
+    size_t maxLength = 0;
+    string line;
+    string currField;
+    // XXX: Using getline() prevents from parsing newline chars in fields.
+    // But this limitation is not very big, and it makes the code way simpler.
+    while (getline(input, line))
+    {
+        DataRow row;
+        // Parse the line
+        bool inQuotes = false;
+        size_t pos = 0;
+        while (pos < line.size())
+        {
+            char c = line[pos];
+            if (c == ',' && !inQuotes)
+            {
+                // Field separator
+                row.push_back(currField);
+                currField.clear();
+            }
+            else if (c == '"')
+            {
+                if (inQuotes)
+                {
+                    // Is the next char also a quote?
+                    if (pos + 1 < line.size() && line[pos + 1] == '"')
+                    {
+                        // Escaped quote
+                        currField.push_back(c);
+                        ++pos;
+                    }
+                    else
+                    {
+                        // End of quotation
+                        inQuotes = false;
+                    }
+                }
+                else
+                {
+                    if (currField.empty())
+                    {
+                        // Beginning of quotation
+                        inQuotes = true;
+                    }
+                    else
+                    {
+                        // Normal quote in an unquoted field
+                        currField.push_back(c);
+                    }
+                }
+            }
+            else if (c != '\r' && c != '\n')
+            {
+                // Normal char
+                currField.push_back(c);
+            }
+
+            // Next char
+            ++pos;
+        }
+
+        // Add the last field of the line
+        row.push_back(currField);
+        currField.clear();
+
+        data.push_back(row);
+
+        if (minLength > row.size())
+            minLength = row.size();
+        if (maxLength < row.size())
+            maxLength = row.size();
+    }
+
+    // Normalization (to be tolerant to faulty inputs)
+    if (minLength != maxLength)
+    {
+        boost::format fmt(_("Invalid CSV file (variable number of fields, from %1% to %2%)"));
+        throw CsvException((fmt % minLength % maxLength).str());
+    }
+
+    return data;
+}
+
+
+void CsvHelper::writeStream(ostream &output, const vector<DataRow> &iData)
+{
+    if (iData.empty())
+        return;
+
+    // Make sure the rows have the same number of fields
+    size_t firstLength = iData.front().size();
+    BOOST_FOREACH(const DataRow &row, iData)
+    {
+        if (row.size() != firstLength)
+            throw CsvException(_("Invalid CSV data (variable number of fields)"));
+    }
+
+    BOOST_FOREACH(const DataRow &row, iData)
+    {
+        bool first = true;
+        BOOST_FOREACH(const string &field, row)
+        {
+            // Add the comma
+            if (first)
+                first = false;
+            else
+                output << ',';
+
+            // Needs quoting?
+            if (field.find_first_of(",\"\n") == string::npos)
+                output << field;
+            else
+            {
+                output << '"';
+                BOOST_FOREACH(char c, field)
+                {
+                    output << c;
+                    // Double the quote
+                    if (c == '"')
+                        output << '"';
+                }
+                output << '"';
+            }
+        }
+        // End of the row (CR + LF)
+        output << "\r\n";
+    }
+}
+

dic/csv_helper.h

@@ -0,0 +1,65 @@
+/*****************************************************************************
+ * Eliot
+ * Copyright (C) 2012 Olivier Teulière
+ * Authors: Olivier Teulière <ipkiss @@ gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *****************************************************************************/
+
+#ifndef CSV_HELPER_H_
+#define CSV_HELPER_H_
+
+#include <string>
+#include <vector>
+#include <iosfwd>
+
+#include "logging.h"
+#include "base_exception.h"
+
+using std::string;
+using std::vector;
+using std::istream;
+using std::ostream;
+
+
+/**
+ * Utility class to handle CSV (Comma Separated Value) files.
+ * The CSV format respects the guidelines summary listed here (RFC 4180):
+ * https://en.wikipedia.org/wiki/Comma-separated_values#Toward_standardization
+ * except for the newlines in fields which are not supported when parsing.
+ */
+class CsvHelper
+{
+    DEFINE_LOGGER();
+
+public:
+    typedef vector<string> DataRow;
+
+    static vector<DataRow> readStream(istream &input);
+
+    static void writeStream(ostream &output, const vector<DataRow> &iData);
+
+};
+
+
+class CsvException: public BaseException
+{
+public:
+    CsvException(const std::string &iMessage)
+        : BaseException(iMessage) {}
+};
+
+#endif
+