FreeTDS Development Group

["James K. Lowden" <jklowden AT schemamania.org>]

Now that we're going to use iconv for more than ascii-ucs2 conversion, we
need better names and more flexible functions.  tdsiconvinfo can be
simplified as follows:

typedef struct tdsiconvinfo
{
        int use_iconv;
#if HAVE_ICONV
        int bytes_per_char;
        char client_charset[64];
        iconv_t cdto_ucs2;   /* conversion from client charset to UCS2LE
MSSQLServer */
        iconv_t cdfrom_ucs2; /* conversion from UCS2LE MSSQLServer to client
charset */
        iconv_t cdto_srv;    /* conversion from client charset to SQL Server
ASCII charset */
        iconv_t cdfrom_srv;  /* conversion from SQL Server ASCII charset  to
client charset */
#endif
} TDSICONVINFO;

becomes:

typedef struct tdsiconvinfo
{
        char client_charset[64];
        char server_charset[64];
        iconv_t to_wire;   /* conversion from client charset to server's 
format
*/
        iconv_t from_wire; /* conversion from server's format to client 
charset
*/
} TDSICONVINFO;

If either iconv_t is NULL, that's the equivalent of use_iconv == 0.  

Then, instead of 

char* tds7_ascii2unicode(TDSSOCKET * tds, const char *in_string, 
                         char *out_string, int maxlen);

and its complement, I propose:

size_t tds_iconv (iconv_t cd, const char *input, size_t * input_size,
                         char *out_string, size_t maxlen);

[I don't understand why iconv uses char* instead of unsigned char*.]

If "cd" is NULL, fallback to #if !HAVE_ICONV behavior.  Whether you're
converting from or to wire format is controlled by passing the to_wire or
from_wire descriptor.  

I've eliminated bytes_per_char, too, since utf-8 has no fixed value for
it.  If we need to estimate how big a buffer to use in conversion, 4
bytes/char is always safe for the foreseeable future.  

These changes will remove assumptions about the server's format and TDS
version (allowing migration to UTF-8 as a Sybase server character set). 
Please tell me if I've overlooked something, or if you have a better idea,
or if you think I've lost my mind.  

Regards, 

--jkl