Re: [Quickfix-developers] Field name to number conversion

[Mike G. <mg...@co...>]

George,

If I understand correctly, you need a lookup of field name (as string) 
-> field number (as int)?

What about leveraging the code generator? I.e. create a stylesheet in 
the spec/ dir:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
version="1.0">
  <xsl:output method="text" encoding="UTF-8"/>

  <xsl:template match="text()"/>

  <xsl:template match="/">/* -*- C++ -*- */
  <xsl:copy-of select="document('COPYRIGHT.xml')"/>
#ifndef FIX_FIELDNAMESTONUMBERS_H
#define FIX_FIELDNAMESTONUMBERS_H

#include &lt;map&gt;
#include &lt;string&gt;

class FieldNamesToNumbers
{
private:
	std::map&lt;std::string,int&gt; fieldNamesToNumbers_;

public:

	int get(const std::string &amp; fieldName)
	{
		return fieldNamesToNumbers_[fieldName];
	}

	FieldNamesToNumbers()
	{
		<xsl:apply-templates/>
	}
};

#endif
</xsl:template>
<xsl:template match="fields/field">
		fieldNamesToNumbers_["<xsl:value-of select="@name"/>"] = <xsl:value-of 
select="@number"/>;
</xsl:template>
</xsl:stylesheet>

Run this command (or better yet, add it to spec/generate_c++.sh):
xsltproc -o ../src/C++/FieldNamesToNumbers.h FieldNamesToNumbers.xsl 
FIX44.xml

And in your code:

#include <quickfix/FieldNamesToNumbers.h>
FieldNamesToNumbers conv;
/* ... */
message.getField(conv.get(field_name_1_from_config_file));
message.getField(conv.get(field_name_2_from_config_file));

Now you'll always be up-to-date with the lastest data dictionary. 
Simply re-run the generator if it changes.

-- 
Mike Gatny
Connamara Systems, LLC
http://www.connamara.com/