Avoid using non-portable debian.h
[yaz-moved-to-github.git] / src / siconv.c
index 3b5928d..42220e2 100644 (file)
-/*
- * Copyright (C) 1995-2005, Index Data ApS
+/* This file is part of the YAZ toolkit.
+ * Copyright (C) Index Data
  * See the file LICENSE for details.
- *
- * $Id: siconv.c,v 1.8 2005-01-15 19:47:14 adam Exp $
  */
 /**
- * \file siconv.c
+ * \file
  * \brief Implements simple ICONV
  *
  * This implements an interface similar to that of iconv and
  * is used by YAZ to interface with iconv (if present).
  * For systems where iconv is not present, this layer
- * provides a few important conversion: UTF-8, MARC-8, Latin-1.
+ * provides a few important conversions: UTF-8, MARC-8, Latin-1.
+ *
  */
 
 #if HAVE_CONFIG_H
 #include <config.h>
 #endif
 
+#include <assert.h>
 #include <errno.h>
 #include <string.h>
-#include <ctype.h>
-#if HAVE_WCHAR_H
-#include <wchar.h>
-#endif
 
 #if HAVE_ICONV_H
 #include <iconv.h>
 #endif
 
-#include <yaz/yaz-util.h>
+#include <yaz/xmalloc.h>
+#include <yaz/errno.h>
+#include "iconv-p.h"
 
-unsigned long yaz_marc8_1_conv (unsigned char *inp, size_t inbytesleft,
-                             size_t *no_read, int *combining);
-unsigned long yaz_marc8_2_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_3_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_4_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_5_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_6_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_7_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_8_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-unsigned long yaz_marc8_9_conv (unsigned char *inp, size_t inbytesleft,
-                               size_t *no_read, int *combining);
-    
 struct yaz_iconv_struct {
     int my_errno;
     int init_flag;
-    size_t (*init_handle)(yaz_iconv_t cd, unsigned char *inbuf,
-                          size_t inbytesleft, size_t *no_read);
-    unsigned long (*read_handle)(yaz_iconv_t cd, unsigned char *inbuf,
-                                 size_t inbytesleft, size_t *no_read);
-    size_t (*write_handle)(yaz_iconv_t cd, unsigned long x,
-                           char **outbuf, size_t *outbytesleft);
-    int marc8_esc_mode;
-    int marc8_comb_x;
-    int marc8_comb_no_read;
+    size_t no_read_x;
+    unsigned long unget_x;
 #if HAVE_ICONV_H
     iconv_t iconv_cd;
 #endif
+    struct yaz_iconv_encoder_s encoder;
+    struct yaz_iconv_decoder_s decoder;
 };
 
-static unsigned long yaz_read_ISO8859_1 (yaz_iconv_t cd, unsigned char *inp,
-                                         size_t inbytesleft, size_t *no_read)
-{
-    unsigned long x = inp[0];
-    *no_read = 1;
-    return x;
-}
-
-static size_t yaz_init_UTF8 (yaz_iconv_t cd, unsigned char *inp,
-                             size_t inbytesleft, size_t *no_read)
-{
-    if (inp[0] != 0xef)
-    {
-        *no_read = 0;
-        return 0;
-    }
-    if (inbytesleft < 3)
-    {
-        cd->my_errno = YAZ_ICONV_EINVAL;
-        return (size_t) -1;
-    }
-    if (inp[1] != 0xbb || inp[2] != 0xbf)
-    {
-        cd->my_errno = YAZ_ICONV_EILSEQ;
-        return (size_t) -1;
-    }
-    *no_read = 3;
-    return 0;
-}
-
-static unsigned long yaz_read_UTF8 (yaz_iconv_t cd, unsigned char *inp,
-                                    size_t inbytesleft, size_t *no_read)
-{
-    unsigned long x = 0;
-
-    if (inp[0] <= 0x7f)
-    {
-        x = inp[0];
-        *no_read = 1;
-    }
-    else if (inp[0] <= 0xbf || inp[0] >= 0xfe)
-    {
-        *no_read = 0;
-        cd->my_errno = YAZ_ICONV_EILSEQ;
-    }
-    else if (inp[0] <= 0xdf && inbytesleft >= 2)
-    {
-        x = ((inp[0] & 0x1f) << 6) | (inp[1] & 0x3f);
-        if (x >= 0x80)
-            *no_read = 2;
-        else
-        {
-            *no_read = 0;
-            cd->my_errno = YAZ_ICONV_EILSEQ;
-        }
-    }
-    else if (inp[0] <= 0xef && inbytesleft >= 3)
-    {
-        x = ((inp[0] & 0x0f) << 12) | ((inp[1] & 0x3f) << 6) |
-            (inp[1] & 0x3f);
-        if (x >= 0x800)
-            *no_read = 3;
-        else
-        {
-            *no_read = 0;
-            cd->my_errno = YAZ_ICONV_EILSEQ;
-        }
-    }
-    else if (inp[0] <= 0xf7 && inbytesleft >= 4)
-    {
-        x =  ((inp[0] & 0x07) << 18) | ((inp[1] & 0x3f) << 12) |
-            ((inp[2] & 0x3f) << 6) | (inp[3] & 0x3f);
-        if (x >= 0x10000)
-            *no_read = 4;
-        else
-        {
-            *no_read = 0;
-            cd->my_errno = YAZ_ICONV_EILSEQ;
-        }
-    }
-    else if (inp[0] <= 0xfb && inbytesleft >= 5)
-    {
-        x =  ((inp[0] & 0x03) << 24) | ((inp[1] & 0x3f) << 18) |
-            ((inp[2] & 0x3f) << 12) | ((inp[3] & 0x3f) << 6) |
-            (inp[4] & 0x3f);
-        if (x >= 0x200000)
-            *no_read = 5;
-        else
-        {
-            *no_read = 0;
-            cd->my_errno = YAZ_ICONV_EILSEQ;
-        }
-    }
-    else if (inp[0] <= 0xfd && inbytesleft >= 6)
-    {
-        x =  ((inp[0] & 0x01) << 30) | ((inp[1] & 0x3f) << 24) |
-            ((inp[2] & 0x3f) << 18) | ((inp[3] & 0x3f) << 12) |
-            ((inp[4] & 0x3f) << 6) | (inp[5] & 0x3f);
-        if (x >= 0x4000000)
-            *no_read = 6;
-        else
-        {
-            *no_read = 0;
-            cd->my_errno = YAZ_ICONV_EILSEQ;
-        }
-    }
-    else
-    {
-        *no_read = 0;
-        cd->my_errno = YAZ_ICONV_EINVAL;
-    }
-    return x;
-}
-
-static unsigned long yaz_read_UCS4 (yaz_iconv_t cd, unsigned char *inp,
-                                    size_t inbytesleft, size_t *no_read)
-{
-    unsigned long x = 0;
-    
-    if (inbytesleft < 4)
-    {
-        cd->my_errno = YAZ_ICONV_EINVAL; /* incomplete input */
-        *no_read = 0;
-    }
-    else
-    {
-        x = (inp[0]<<24) | (inp[1]<<16) | (inp[2]<<8) | inp[3];
-        *no_read = 4;
-    }
-    return x;
-}
-
-static unsigned long yaz_read_UCS4LE (yaz_iconv_t cd, unsigned char *inp,
-                                      size_t inbytesleft, size_t *no_read)
-{
-    unsigned long x = 0;
-    
-    if (inbytesleft < 4)
-    {
-        cd->my_errno = YAZ_ICONV_EINVAL; /* incomplete input */
-        *no_read = 0;
-    }
-    else
-    {
-        x = (inp[3]<<24) | (inp[2]<<16) | (inp[1]<<8) | inp[0];
-        *no_read = 4;
-    }
-    return x;
-}
 
-#if HAVE_WCHAR_H
-static unsigned long yaz_read_wchar_t (yaz_iconv_t cd, unsigned char *inp,
-                                       size_t inbytesleft, size_t *no_read)
-{
-    unsigned long x = 0;
-    
-    if (inbytesleft < sizeof(wchar_t))
-    {
-        cd->my_errno = YAZ_ICONV_EINVAL; /* incomplete input */
-        *no_read = 0;
-    }
-    else
-    {
-        wchar_t wch;
-        memcpy (&wch, inp, sizeof(wch));
-        x = wch;
-        *no_read = sizeof(wch);
-    }
-    return x;
-}
-#endif
-
-static unsigned long yaz_read_marc8 (yaz_iconv_t cd, unsigned char *inp,
-                                     size_t inbytesleft, size_t *no_read)
-{
-    if (cd->marc8_comb_x)
-    {
-       unsigned long x = cd->marc8_comb_x;
-       *no_read = cd->marc8_comb_no_read;
-       cd->marc8_comb_x = 0;
-       return x;
-    }
-    *no_read = 0;
-    while(inbytesleft >= 1 && inp[0] == 27)
-    {
-       size_t inbytesleft0 = inbytesleft;
-       inp++;
-       inbytesleft--;
-       while(inbytesleft > 0 && strchr("(,$!", *inp))
-       {
-           inbytesleft--;
-           inp++;
-       }
-       if (inbytesleft <= 0)
-       {
-           *no_read = 0;
-           cd->my_errno = YAZ_ICONV_EINVAL;
-           return 0;
-       }
-       cd->marc8_esc_mode = *inp++;
-       inbytesleft--;
-       (*no_read) += inbytesleft0 - inbytesleft;
-    }
-    if (inbytesleft <= 0)
-       return 0;
-    else
-    {
-       unsigned long x;
-       int comb = 0;
-       size_t no_read_sub = 0;
-
-       switch(cd->marc8_esc_mode)
-       {
-       case 'B':  /* Basic ASCII */
-       case 'E':  /* ANSEL */
-       case 's':  /* ASCII */
-           x = yaz_marc8_1_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case 'g':  /* Greek */
-           x = yaz_marc8_2_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case 'b':  /* Subscripts */
-           x = yaz_marc8_3_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case 'p':  /* Superscripts */
-           x = yaz_marc8_4_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case '2':  /* Basic Hebrew */
-           x = yaz_marc8_5_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case 'N':  /* Basic Cyrillic */
-       case 'Q':  /* Extended Cyrillic */
-           x = yaz_marc8_6_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case '3':  /* Basic Arabic */
-       case '4':  /* Extended Arabic */
-           x = yaz_marc8_7_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case 'S':  /* Greek */
-           x = yaz_marc8_8_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       case '1':  /* Chinese, Japanese, Korean (EACC) */
-           x = yaz_marc8_9_conv(inp, inbytesleft, &no_read_sub, &comb);
-           break;
-       default:
-           *no_read = 0;
-           cd->my_errno = YAZ_ICONV_EILSEQ;
-           return 0;
-       }
-#if 0
-       printf ("esc mode=%c x=%04lX comb=%d\n", cd->marc8_esc_mode, x, comb);
-#endif
-       *no_read += no_read_sub;
-
-       if (comb && cd->marc8_comb_x == 0)
-       {
-           size_t tmp_read = 0;
-           unsigned long next_x;
-
-           /* read next char .. */
-           next_x = yaz_read_marc8(cd, inp + *no_read,
-                                   inbytesleft - *no_read, &tmp_read);
-           /* save this x for later .. */
-           cd->marc8_comb_x = x;
-           /* save next read for later .. */
-           cd->marc8_comb_no_read = tmp_read;
-           /* return next x - thereby swap */
-           x = next_x;
-       }
-       return x;
-    }
-}
-
-static size_t yaz_write_UTF8 (yaz_iconv_t cd, unsigned long x,
-                              char **outbuf, size_t *outbytesleft)
-{
-    unsigned char *outp = (unsigned char *) *outbuf;
-    if (x <= 0x7f && *outbytesleft >= 1)
-    {
-        *outp++ = (unsigned char) x;
-        (*outbytesleft)--;
-    } 
-    else if (x <= 0x7ff && *outbytesleft >= 2)
-    {
-        *outp++ = (unsigned char) ((x >> 6) | 0xc0);
-        *outp++ = (unsigned char) ((x & 0x3f) | 0x80);
-        (*outbytesleft) -= 2;
-    }
-    else if (x <= 0xffff && *outbytesleft >= 3)
-    {
-        *outp++ = (unsigned char) ((x >> 12) | 0xe0);
-        *outp++ = (unsigned char) (((x >> 6) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) ((x & 0x3f) | 0x80);
-        (*outbytesleft) -= 3;
-    }
-    else if (x <= 0x1fffff && *outbytesleft >= 4)
-    {
-        *outp++ = (unsigned char) ((x >> 18) | 0xf0);
-        *outp++ = (unsigned char) (((x >> 12) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 6)  & 0x3f) | 0x80);
-        *outp++ = (unsigned char) ((x & 0x3f) | 0x80);
-        (*outbytesleft) -= 4;
-    }
-    else if (x <= 0x3ffffff && *outbytesleft >= 5)
-    {
-        *outp++ = (unsigned char) ((x >> 24) | 0xf8);
-        *outp++ = (unsigned char) (((x >> 18) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 12) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 6)  & 0x3f) | 0x80);
-        *outp++ = (unsigned char) ((x & 0x3f) | 0x80);
-        (*outbytesleft) -= 5;
-    }
-    else if (*outbytesleft >= 6)
-    {
-        *outp++ = (unsigned char) ((x >> 30) | 0xfc);
-        *outp++ = (unsigned char) (((x >> 24) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 18) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 12) & 0x3f) | 0x80);
-        *outp++ = (unsigned char) (((x >> 6)  & 0x3f) | 0x80);
-        *outp++ = (unsigned char) ((x & 0x3f) | 0x80);
-        (*outbytesleft) -= 6;
-    }
-    else 
-    {
-        cd->my_errno = YAZ_ICONV_E2BIG;  /* not room for output */
-        return (size_t)(-1);
-    }
-    *outbuf = (char *) outp;
-    return 0;
-}
-
-static size_t yaz_write_ISO8859_1 (yaz_iconv_t cd, unsigned long x,
-                                   char **outbuf, size_t *outbytesleft)
+int yaz_iconv_isbuiltin(yaz_iconv_t cd)
 {
-    unsigned char *outp = (unsigned char *) *outbuf;
-    if (x > 255 || x < 1)
-    {
-        cd->my_errno = YAZ_ICONV_EILSEQ;
-        return (size_t) -1;
-    }
-    else if (*outbytesleft >= 1)
-    {
-        *outp++ = (unsigned char) x;
-        (*outbytesleft)--;
-    }
-    else 
-    {
-        cd->my_errno = YAZ_ICONV_E2BIG;
-        return (size_t)(-1);
-    }
-    *outbuf = (char *) outp;
-    return 0;
+    return cd->decoder.read_handle && cd->encoder.write_handle;
 }
 
 
-static size_t yaz_write_UCS4 (yaz_iconv_t cd, unsigned long x,
-                              char **outbuf, size_t *outbytesleft)
+static int prepare_encoders(yaz_iconv_t cd, const char *tocode)
 {
-    unsigned char *outp = (unsigned char *) *outbuf;
-    if (*outbytesleft >= 4)
-    {
-        *outp++ = (unsigned char) (x>>24);
-        *outp++ = (unsigned char) (x>>16);
-        *outp++ = (unsigned char) (x>>8);
-        *outp++ = (unsigned char) x;
-        (*outbytesleft) -= 4;
-    }
-    else
-    {
-        cd->my_errno = YAZ_ICONV_E2BIG;
-        return (size_t)(-1);
-    }
-    *outbuf = (char *) outp;
+    if (yaz_marc8_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_utf8_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_ucs4_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_iso_8859_1_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_iso_5428_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_advancegreek_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_wchar_encoder(tocode, &cd->encoder))
+        return 1;
+    if (yaz_danmarc_encoder(tocode, &cd->encoder))
+        return 1;
     return 0;
 }
 
-static size_t yaz_write_UCS4LE (yaz_iconv_t cd, unsigned long x,
-                                char **outbuf, size_t *outbytesleft)
+static int prepare_decoders(yaz_iconv_t cd, const char *tocode)
 {
-    unsigned char *outp = (unsigned char *) *outbuf;
-    if (*outbytesleft >= 4)
-    {
-        *outp++ = (unsigned char) x;
-        *outp++ = (unsigned char) (x>>8);
-        *outp++ = (unsigned char) (x>>16);
-        *outp++ = (unsigned char) (x>>24);
-        (*outbytesleft) -= 4;
-    }
-    else
-    {
-        cd->my_errno = YAZ_ICONV_E2BIG;
-        return (size_t)(-1);
-    }
-    *outbuf = (char *) outp;
+    if (yaz_marc8_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_iso5426_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_utf8_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_ucs4_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_iso_8859_1_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_iso_5428_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_advancegreek_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_wchar_decoder(tocode, &cd->decoder))
+        return 1;
+    if (yaz_danmarc_decoder(tocode, &cd->decoder))
+        return 1;
     return 0;
 }
 
-#if HAVE_WCHAR_H
-static size_t yaz_write_wchar_t (yaz_iconv_t cd, unsigned long x,
-                                 char **outbuf, size_t *outbytesleft)
+yaz_iconv_t yaz_iconv_open(const char *tocode, const char *fromcode)
 {
-    unsigned char *outp = (unsigned char *) *outbuf;
+    yaz_iconv_t cd = (yaz_iconv_t) xmalloc(sizeof(*cd));
 
-    if (*outbytesleft >= sizeof(wchar_t))
-    {
-        wchar_t wch = x;
-        memcpy(outp, &wch, sizeof(wch));
-        outp += sizeof(wch);
-        (*outbytesleft) -= sizeof(wch);
-    }
-    else
-    {
-        cd->my_errno = YAZ_ICONV_E2BIG;
-        return (size_t)(-1);
-    }
-    *outbuf = (char *) outp;
-    return 0;
-}
-#endif
+    cd->encoder.data = 0;
+    cd->encoder.write_handle = 0;
+    cd->encoder.flush_handle = 0;
+    cd->encoder.init_handle = 0;
+    cd->encoder.destroy_handle = 0;
 
-int yaz_iconv_isbuiltin(yaz_iconv_t cd)
-{
-    return cd->read_handle && cd->write_handle;
-}
+    cd->decoder.data = 0;
+    cd->decoder.read_handle = 0;
+    cd->decoder.init_handle = 0;
+    cd->decoder.destroy_handle = 0;
 
-yaz_iconv_t yaz_iconv_open (const char *tocode, const char *fromcode)
-{
-    yaz_iconv_t cd = (yaz_iconv_t) xmalloc (sizeof(*cd));
-
-    cd->write_handle = 0;
-    cd->read_handle = 0;
-    cd->init_handle = 0;
     cd->my_errno = YAZ_ICONV_UNKNOWN;
-    cd->marc8_esc_mode = 'B';
-    cd->marc8_comb_x = 0;
 
     /* a useful hack: if fromcode has leading @,
        the library not use YAZ's own conversions .. */
@@ -509,66 +115,42 @@ yaz_iconv_t yaz_iconv_open (const char *tocode, const char *fromcode)
         fromcode++;
     else
     {
-        if (!yaz_matchstr(fromcode, "UTF8"))
-        {
-            cd->read_handle = yaz_read_UTF8;
-            cd->init_handle = yaz_init_UTF8;
-        }
-        else if (!yaz_matchstr(fromcode, "ISO88591"))
-            cd->read_handle = yaz_read_ISO8859_1;
-        else if (!yaz_matchstr(fromcode, "UCS4"))
-            cd->read_handle = yaz_read_UCS4;
-        else if (!yaz_matchstr(fromcode, "UCS4LE"))
-            cd->read_handle = yaz_read_UCS4LE;
-        else if (!yaz_matchstr(fromcode, "MARC8"))
-            cd->read_handle = yaz_read_marc8;
-#if HAVE_WCHAR_H
-        else if (!yaz_matchstr(fromcode, "WCHAR_T"))
-            cd->read_handle = yaz_read_wchar_t;
-#endif
-        
-        if (!yaz_matchstr(tocode, "UTF8"))
-            cd->write_handle = yaz_write_UTF8;
-        else if (!yaz_matchstr(tocode, "ISO88591"))
-            cd->write_handle = yaz_write_ISO8859_1;
-        else if (!yaz_matchstr (tocode, "UCS4"))
-            cd->write_handle = yaz_write_UCS4;
-        else if (!yaz_matchstr(tocode, "UCS4LE"))
-            cd->write_handle = yaz_write_UCS4LE;
-#if HAVE_WCHAR_H
-        else if (!yaz_matchstr(tocode, "WCHAR_T"))
-            cd->write_handle = yaz_write_wchar_t;
-#endif
+        prepare_encoders(cd, tocode);
+        prepare_decoders(cd, fromcode);
     }
+    if (cd->decoder.read_handle && cd->encoder.write_handle)
+    {
 #if HAVE_ICONV_H
-    cd->iconv_cd = 0;
-    if (!cd->read_handle || !cd->write_handle)
+        cd->iconv_cd = (iconv_t) (-1);
+#endif
+        ;
+    }
+    else
     {
-        cd->iconv_cd = iconv_open (tocode, fromcode);
+#if HAVE_ICONV_H
+        cd->iconv_cd = iconv_open(tocode, fromcode);
         if (cd->iconv_cd == (iconv_t) (-1))
         {
-            xfree (cd);
+            yaz_iconv_close(cd);
             return 0;
         }
-    }
 #else
-    if (!cd->read_handle || !cd->write_handle)
-    {
-        xfree (cd);
+        yaz_iconv_close(cd);
         return 0;
-    }
 #endif
+    }
     cd->init_flag = 1;
     return cd;
 }
 
-size_t yaz_iconv (yaz_iconv_t cd, char **inbuf, size_t *inbytesleft,
-                  char **outbuf, size_t *outbytesleft)
+size_t yaz_iconv(yaz_iconv_t cd, char **inbuf, size_t *inbytesleft,
+                 char **outbuf, size_t *outbytesleft)
 {
-    char *inbuf0;
+    char *inbuf0 = 0;
     size_t r = 0;
+
 #if HAVE_ICONV_H
-    if (cd->iconv_cd)
+    if (cd->iconv_cd != (iconv_t) (-1))
     {
         size_t r =
             iconv(cd->iconv_cd, inbuf, inbytesleft, outbuf, outbytesleft);
@@ -592,21 +174,28 @@ size_t yaz_iconv (yaz_iconv_t cd, char **inbuf, size_t *inbytesleft,
         return r;
     }
 #endif
-    if (inbuf == 0 || *inbuf == 0)
-    {
-        cd->init_flag = 1;
-        cd->my_errno = YAZ_ICONV_UNKNOWN;
-        return 0;
-    }
-    inbuf0 = *inbuf;
+
+    if (inbuf)
+        inbuf0 = *inbuf;
 
     if (cd->init_flag)
     {
-        if (cd->init_handle)
+        cd->my_errno = YAZ_ICONV_UNKNOWN;
+
+        if (cd->encoder.init_handle)
+            (*cd->encoder.init_handle)(&cd->encoder);
+
+        cd->unget_x = 0;
+        cd->no_read_x = 0;
+
+        if (cd->decoder.init_handle)
         {
-            size_t no_read;
-            size_t r = (cd->init_handle)(cd, (unsigned char *) *inbuf,
-                                         *inbytesleft, &no_read);
+            size_t no_read = 0;
+            size_t r = (cd->decoder.init_handle)(
+                cd, &cd->decoder,
+                inbuf ? (unsigned char *) *inbuf : 0,
+                inbytesleft ? *inbytesleft : 0,
+                &no_read);
             if (r)
             {
                 if (cd->my_errno == YAZ_ICONV_EINVAL)
@@ -614,54 +203,109 @@ size_t yaz_iconv (yaz_iconv_t cd, char **inbuf, size_t *inbytesleft,
                 cd->init_flag = 0;
                 return r;
             }
-            *inbytesleft -= no_read;
-            *inbuf += no_read;
+            if (inbytesleft)
+                *inbytesleft -= no_read;
+            if (inbuf)
+                *inbuf += no_read;
+        }
+    }
+    cd->init_flag = 0;
+
+    if (!inbuf || !*inbuf)
+    {
+        if (outbuf && *outbuf)
+        {
+            if (cd->unget_x)
+                r = (*cd->encoder.write_handle)(cd, &cd->encoder,
+                                                cd->unget_x, outbuf, outbytesleft);
+            if (cd->encoder.flush_handle)
+                r = (*cd->encoder.flush_handle)(cd, &cd->encoder,
+                                                outbuf, outbytesleft);
         }
-        cd->init_flag = 0;
+        if (r == 0)
+            cd->init_flag = 1;
+        cd->unget_x = 0;
+        return r;
     }
     while (1)
     {
         unsigned long x;
         size_t no_read;
 
-        if (*inbytesleft == 0)
+        if (cd->unget_x)
         {
-            r = *inbuf - inbuf0;
-            break;
+            x = cd->unget_x;
+            no_read = cd->no_read_x;
         }
-        
-        x = (cd->read_handle)(cd, (unsigned char *) *inbuf, *inbytesleft,
-                              &no_read);
-        if (no_read == 0)
+        else
         {
-            r = (size_t)(-1);
-            break;
+            if (*inbytesleft == 0)
+            {
+                r = *inbuf - inbuf0;
+                break;
+            }
+            x = (*cd->decoder.read_handle)(
+                cd, &cd->decoder,
+                (unsigned char *) *inbuf, *inbytesleft, &no_read);
+            if (no_read == 0)
+            {
+                r = (size_t)(-1);
+                break;
+            }
+        }
+        if (x)
+        {
+            r = (*cd->encoder.write_handle)(cd, &cd->encoder,
+                                            x, outbuf, outbytesleft);
+            if (r)
+            {
+                /* unable to write it. save it because read_handle cannot
+                   rewind .. */
+                if (cd->my_errno == YAZ_ICONV_E2BIG)
+                {
+                    cd->unget_x = x;
+                    cd->no_read_x = no_read;
+                    break;
+                }
+            }
+            cd->unget_x = 0;
         }
-       if (x)
-       {
-           r = (cd->write_handle)(cd, x, outbuf, outbytesleft);
-           if (r)
-               break;
-       }
         *inbytesleft -= no_read;
         (*inbuf) += no_read;
     }
     return r;
 }
 
-int yaz_iconv_error (yaz_iconv_t cd)
+int yaz_iconv_error(yaz_iconv_t cd)
 {
     return cd->my_errno;
 }
 
-int yaz_iconv_close (yaz_iconv_t cd)
+int yaz_iconv_close(yaz_iconv_t cd)
 {
 #if HAVE_ICONV_H
-    if (cd->iconv_cd)
-        iconv_close (cd->iconv_cd);
+    if (cd->iconv_cd != (iconv_t) (-1))
+        iconv_close(cd->iconv_cd);
 #endif
-    xfree (cd);
+    if (cd->encoder.destroy_handle)
+        (*cd->encoder.destroy_handle)(&cd->encoder);
+    if (cd->decoder.destroy_handle)
+        (*cd->decoder.destroy_handle)(&cd->decoder);
+    xfree(cd);
     return 0;
 }
 
-    
+void yaz_iconv_set_errno(yaz_iconv_t cd, int no)
+{
+    cd->my_errno = no;
+}
+
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * c-file-style: "Stroustrup"
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
+