iconv/loop.c

   1 /* Conversion loop frame work.
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 /* This file provides a frame for the reader loop in all conversion modules.
  22    The actual code must (of course) be provided in the actual module source
  23    code but certain actions can be written down generically, with some
  24    customization options which are these:
  25
  26      MIN_NEEDED_INPUT   minimal number of input bytes needed for the next
  27                         conversion.
  28      MIN_NEEDED_OUTPUT  minimal number of bytes produced by the next round
  29                         of conversion.
  30
  31      MAX_NEEDED_INPUT   you guess it, this is the maximal number of input
  32                         bytes needed.  It defaults to MIN_NEEDED_INPUT
  33      MAX_NEEDED_OUTPUT  likewise for output bytes.
  34
  35      LOOPFCT            name of the function created.  If not specified
  36                         the name is `loop' but this prevents the use
  37                         of multiple functions in the same file.
  38
  39      COUNT_CONVERTED    optional macro which is used to count the actual
  40                         number of characters converted.  For some conversion
  41                         it is easy to compute the value afterwards, but for
  42                         others explicit counting is cheaper.
  43
  44      BODY               this is supposed to expand to the body of the loop.
  45                         The user must provide this.
  46
  47      EXTRA_LOOP_DECLS   extra arguments passed from converion loop call.
  48
  49      INIT_PARAMS        code to define and initialize variables from params.
  50      UPDATE_PARAMS      code to store result in params.
  51 */
  52
  53 #include <gconv.h>
  54 #include <sys/param.h>          /* For MIN.  */
  55 #define __need_size_t
  56 #include <stddef.h>
  57
  58
  59 /* We need at least one byte for the next round.  */
  60 #ifndef MIN_NEEDED_INPUT
  61 # error "MIN_NEEDED_INPUT definition missing"
  62 #endif
  63
  64 /* Let's see how many bytes we produce.  */
  65 #ifndef MAX_NEEDED_INPUT
  66 # define MAX_NEEDED_INPUT       MIN_NEEDED_INPUT
  67 #endif
  68
  69 /* We produce at least one byte in the next round.  */
  70 #ifndef MIN_NEEDED_OUTPUT
  71 # error "MIN_NEEDED_OUTPUT definition missing"
  72 #endif
  73
  74 /* Let's see how many bytes we produce.  */
  75 #ifndef MAX_NEEDED_OUTPUT
  76 # define MAX_NEEDED_OUTPUT      MIN_NEEDED_OUTPUT
  77 #endif
  78
  79 /* Default name for the function.  */
  80 #ifndef LOOPFCT
  81 # define LOOPFCT                loop
  82 #endif
  83
  84 /* Make sure we have a loop body.  */
  85 #ifndef BODY
  86 # error "Definition of BODY missing for function" LOOPFCT
  87 #endif
  88
  89 /* We can calculate the number of converted characters easily if one
  90    of the character sets has a fixed width.  */
  91 #ifndef COUNT_CONVERTED
  92 # if MIN_NEEDED_INPUT == MAX_NEEDED_INPUT
  93 #  if MIN_NEEDED_OUTPUT == MAX_NEEDED_OUTPUT
  94 /* Decide whether one of the charsets has size 1.  */
  95 #   if MIN_NEEDED_INPUT == 1
  96 #    define COUNT_CONVERTED     (inptr - *inptrp)
  97 #   elif MIN_NEEDED_OUTPUT == 1
  98 #    define COUNT_CONVERTED     (outptr - *outptrp)
  99 #   else
 100 /* Else we should see whether one of the two numbers is a power of 2.  */
 101 #    define COUNT_CONVERTED \
 102   ((MIN_NEEDED_INPUT & (-MIN_NEEDED_INPUT)) == MIN_NEEDED_INPUT               \
 103    ? (inptr - *inptrp) : (outptr - *outptrp))
 104 #   endif
 105 #  else
 106 #   define COUNT_CONVERTED      ((inptr - *inptrp) / MIN_NEEDED_INPUT)
 107 #  endif
 108 # elif MIN_NEEDED_OUTPUT == MAX_NEEDED_OUTPUT
 109 #  define COUNT_CONVERTED       ((outptr - *outptrp) / MIN_NEEDED_OUTPUT)
 110 # endif
 111 #endif
 112
 113
 114 /* If no arguments have to passed to the loop function define the macro
 115    as empty.  */
 116 #ifndef EXTRA_LOOP_DECLS
 117 # define EXTRA_LOOP_DECLS
 118 #endif
 119
 120
 121 /* The function returns the status, as defined in gconv.h.  */
 122 static inline int
 123 LOOPFCT (const unsigned char **inptrp, const unsigned char *inend,
 124          unsigned char **outptrp, unsigned char *outend, mbstate_t *state,
 125          void *data, size_t *converted EXTRA_LOOP_DECLS)
 126 {
 127   int result = GCONV_OK;
 128   const unsigned char *inptr = *inptrp;
 129   unsigned char *outptr = *outptrp;
 130 #ifndef COUNT_CONVERTED
 131   size_t done = 0;
 132 #endif
 133
 134   /* We run one loop where we avoid checks for underflow/overflow of the
 135      buffers to speed up the conversion a bit.  */
 136   size_t min_in_rounds = (inend - inptr) / MAX_NEEDED_INPUT;
 137   size_t min_out_rounds = (outend - outptr) / MAX_NEEDED_OUTPUT;
 138   size_t min_rounds = MIN (min_in_rounds, min_out_rounds);
 139
 140 #ifdef INIT_PARAMS
 141   INIT_PARAMS;
 142 #endif
 143
 144 #undef NEED_LENGTH_TEST
 145 #define NEED_LENGTH_TEST        0
 146   while (min_rounds-- > 0)
 147     {
 148       /* Here comes the body the user provides.  It can stop with RESULT
 149          set to GCONV_INCOMPLETE_INPUT (if the size of the input characters
 150          vary in size), GCONV_ILLEGAL_INPUT, or GCONV_FULL_OUTPUT (if the
 151          output characters vary in size.  */
 152       BODY
 153
 154       /* If necessary count the successful conversion.  */
 155 #ifndef COUNT_CONVERTED
 156       ++done;
 157 #endif
 158     }
 159
 160   if (result == GCONV_OK)
 161     {
 162 #if MIN_NEEDED_INPUT == MAX_NEEDED_INPUT \
 163     && MIN_NEEDED_OUTPUT == MAX_NEEDED_OUTPUT
 164       /* We don't need to start another loop since we were able to determine
 165          the maximal number of characters to copy in advance.  What remains
 166          to be determined is the status.  */
 167       if (inptr == inend)
 168         /* No more input.  */
 169         result = GCONV_EMPTY_INPUT;
 170       else if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
 171                || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
 172         /* Overflow in the output buffer.  */
 173         result = GCONV_FULL_OUTPUT;
 174       else
 175         /* We have something left in the input buffer.  */
 176         result = GCONV_INCOMPLETE_INPUT;
 177 #else
 178       result = GCONV_EMPTY_INPUT;
 179
 180 # undef NEED_LENGTH_TEST
 181 # define NEED_LENGTH_TEST       1
 182       while (inptr != inend)
 183         {
 184           /* `if' cases for MIN_NEEDED_OUTPUT ==/!= 1 is made to help the
 185              compiler generating better code.  It will optimized away
 186              since MIN_NEEDED_OUTPUT is always a constant.  */
 187           if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
 188               || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
 189             {
 190               /* Overflow in the output buffer.  */
 191               result = GCONV_FULL_OUTPUT;
 192               break;
 193             }
 194           if (MIN_NEEDED_INPUT > 1 && inptr + MIN_NEEDED_INPUT > inend)
 195             {
 196               /* We don't have enough input for another complete input
 197                  character.  */
 198               result = GCONV_INCOMPLETE_INPUT;
 199               break;
 200             }
 201
 202           /* Here comes the body the user provides.  It can stop with
 203              RESULT set to GCONV_INCOMPLETE_INPUT (if the size of the
 204              input characters vary in size), GCONV_ILLEGAL_INPUT, or
 205              GCONV_FULL_OUTPUT (if the output characters vary in size).  */
 206           BODY
 207
 208           /* If necessary count the successful conversion.  */
 209 # ifndef COUNT_CONVERTED
 210           ++done;
 211 # endif
 212         }
 213 #endif  /* Input and output charset are not both fixed width.  */
 214     }
 215
 216   /* Add the number of characters we actually converted.  */
 217 #ifdef COUNT_CONVERTED
 218   *converted += COUNT_CONVERTED;
 219 #else
 220   *converted += done;
 221 #endif
 222
 223   /* Update the pointers pointed to by the parameters.  */
 224   *inptrp = inptr;
 225   *outptrp = outptr;
 226 #ifdef UPDATE_PARAMS
 227   UPDATE_PARAMS;
 228 #endif
 229
 230   return result;
 231 }
 232
 233
 234 /* We remove the macro definitions so that we can include this file again
 235    for the definition of another function.  */
 236 #undef MIN_NEEDED_INPUT
 237 #undef MAX_NEEDED_INPUT
 238 #undef MIN_NEEDED_OUTPUT
 239 #undef MAX_NEEDED_OUTPUT
 240 #undef LOOPFCT
 241 #undef COUNT_CONVERTED
 242 #undef BODY
 243 #undef LOOPFCT
 244 #undef EXTRA_LOOP_DECLS
 245 #undef INIT_PARAMS
 246 #undef UPDATE_PARAMS