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glibc/iconv/skeleton.c
Ulrich Drepper 513552fa5a Update comment for *written modification.
2000-01-19 03:19:51 +00:00

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/* Skeleton for a conversion module.
Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* This file can be included to provide definitions of several things
many modules have in common. It can be customized using the following
macros:
DEFINE_INIT define the default initializer. This requires the
following symbol to be defined.
CHARSET_NAME string with official name of the coded character
set (in all-caps)
DEFINE_FINI define the default destructor function.
MIN_NEEDED_FROM minimal number of bytes needed for the from-charset.
MIN_NEEDED_TO likewise for the to-charset.
MAX_NEEDED_FROM maximal number of bytes needed for the from-charset.
This macro is optional, it defaults to MIN_NEEDED_FROM.
MAX_NEEDED_TO likewise for the to-charset.
DEFINE_DIRECTION_OBJECTS
two objects will be defined to be used when the
`gconv' function must only distinguish two
directions. This is implied by DEFINE_INIT.
If this macro is not defined the following
macro must be available.
FROM_DIRECTION this macro is supposed to return a value != 0
if we convert from the current character set,
otherwise it return 0.
EMIT_SHIFT_TO_INIT this symbol is optional. If it is defined it
defines some code which writes out a sequence
of characters which bring the current state into
the initial state.
FROM_LOOP name of the function implementing the conversion
from the current characters.
TO_LOOP likewise for the other direction
RESET_STATE in case of an error we must reset the state for
the rerun so this macro must be defined for
stateful encodings. It takes an argument which
is nonzero when saving.
RESET_INPUT_BUFFER If the input character sets allow this the macro
can be defined to reset the input buffer pointers
to cover only those characters up to the error.
FUNCTION_NAME if not set the conversion function is named `gconv'.
PREPARE_LOOP optional code preparing the conversion loop. Can
contain variable definitions.
END_LOOP also optional, may be used to store information
EXTRA_LOOP_ARGS optional macro specifying extra arguments passed
to loop function.
*/
#include <assert.h>
#include <gconv.h>
#include <string.h>
#define __need_size_t
#define __need_NULL
#include <stddef.h>
#ifndef STATIC_GCONV
# include <dlfcn.h>
#endif
#include <ldsodefs.h>
/* The direction objects. */
#if DEFINE_DIRECTION_OBJECTS || DEFINE_INIT
static int from_object;
static int to_object;
# ifndef FROM_DIRECTION
# define FROM_DIRECTION (step->data == &from_object)
# endif
#else
# ifndef FROM_DIRECTION
# error "FROM_DIRECTION must be provided if direction objects are not used"
# endif
#endif
/* How many bytes are needed at most for the from-charset. */
#ifndef MAX_NEEDED_FROM
# define MAX_NEEDED_FROM MIN_NEEDED_FROM
#endif
/* Same for the to-charset. */
#ifndef MAX_NEEDED_TO
# define MAX_NEEDED_TO MIN_NEEDED_TO
#endif
/* For conversions from a fixed width character sets to another fixed width
character set we we can define RESET_INPUT_BUFFER is necessary. */
#if !defined RESET_INPUT_BUFFER && !defined SAVE_RESET_STATE
# if MIN_NEEDED_FROM == MAX_NEEDED_FROM && MIN_NEEDED_TO == MAX_NEEDED_TO
/* We have to use these `if's here since the compiler cannot know that
(outbuf - outerr) is always divisible by MIN_NEEDED_TO. */
# define RESET_INPUT_BUFFER \
if (MIN_NEEDED_FROM % MIN_NEEDED_TO == 0) \
*inbuf -= (outbuf - outerr) * (MIN_NEEDED_FROM / MIN_NEEDED_TO); \
else if (MIN_NEEDED_TO % MIN_NEEDED_FROM == 0) \
*inbuf -= (outbuf - outerr) / (MIN_NEEDED_TO / MIN_NEEDED_FROM); \
else \
*inbuf -= ((outbuf - outerr) / MIN_NEEDED_TO) * MIN_NEEDED_FROM
# endif
#endif
/* The default init function. It simply matches the name and initializes
the step data to point to one of the objects above. */
#if DEFINE_INIT
# ifndef CHARSET_NAME
# error "CHARSET_NAME not defined"
# endif
int
gconv_init (struct gconv_step *step)
{
/* Determine which direction. */
if (strcmp (step->from_name, CHARSET_NAME) == 0)
{
step->data = &from_object;
step->min_needed_from = MIN_NEEDED_FROM;
step->max_needed_from = MAX_NEEDED_FROM;
step->min_needed_to = MIN_NEEDED_TO;
step->max_needed_to = MAX_NEEDED_TO;
}
else if (strcmp (step->to_name, CHARSET_NAME) == 0)
{
step->data = &to_object;
step->min_needed_from = MIN_NEEDED_TO;
step->max_needed_from = MAX_NEEDED_TO;
step->min_needed_to = MIN_NEEDED_FROM;
step->max_needed_to = MAX_NEEDED_FROM;
}
else
return GCONV_NOCONV;
#ifdef RESET_STATE
step->stateful = 1;
#else
step->stateful = 0;
#endif
return GCONV_OK;
}
#endif
/* The default destructor function does nothing in the moment and so
be define it at all. But we still provide the macro just in case
we need it some day. */
#if DEFINE_FINI
#endif
/* If no arguments have to passed to the loop function define the macro
as empty. */
#ifndef EXTRA_LOOP_ARGS
# define EXTRA_LOOP_ARGS
#endif
/* This is the actual conversion function. */
#ifndef FUNCTION_NAME
# define FUNCTION_NAME gconv
#endif
int
FUNCTION_NAME (struct gconv_step *step, struct gconv_step_data *data,
const unsigned char **inbuf, const unsigned char *inbufend,
size_t *written, int do_flush)
{
struct gconv_step *next_step = step + 1;
struct gconv_step_data *next_data = data + 1;
gconv_fct fct = data->is_last ? NULL : next_step->fct;
int status;
/* If the function is called with no input this means we have to reset
to the initial state. The possibly partly converted input is
dropped. */
if (do_flush)
{
status = GCONV_OK;
#ifdef EMIT_SHIFT_TO_INIT
/* Emit the escape sequence to reset the state. */
EMIT_SHIFT_TO_INIT;
#endif
/* Call the steps down the chain if there are any but only if we
successfully emitted the escape sequence. */
if (status == GCONV_OK && ! data->is_last)
status = DL_CALL_FCT (fct, (next_step, next_data, NULL, NULL,
written, 1));
}
else
{
/* We preserve the initial values of the pointer variables. */
const unsigned char *inptr = *inbuf;
unsigned char *outbuf = data->outbuf;
unsigned char *outend = data->outbufend;
unsigned char *outstart;
/* This variable is used to count the number of characters we
actually converted. */
size_t converted = 0;
#ifdef PREPARE_LOOP
PREPARE_LOOP
#endif
do
{
/* Remember the start value for this round. */
inptr = *inbuf;
/* The outbuf buffer is empty. */
outstart = outbuf;
#ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (1);
#endif
if (FROM_DIRECTION)
/* Run the conversion loop. */
status = FROM_LOOP (inbuf, inbufend, &outbuf, outend,
data->statep, step->data, &converted
EXTRA_LOOP_ARGS);
else
/* Run the conversion loop. */
status = TO_LOOP (inbuf, inbufend, &outbuf, outend,
data->statep, step->data, &converted
EXTRA_LOOP_ARGS);
/* If this is the last step leave the loop, there is nothing
we can do. */
if (data->is_last)
{
/* Store information about how many bytes are available. */
data->outbuf = outbuf;
/* Remember how many non-identical characters we converted. */
*written += converted;
break;
}
/* Write out all output which was produced. */
if (outbuf > outstart)
{
const unsigned char *outerr = data->outbuf;
int result;
result = DL_CALL_FCT (fct, (next_step, next_data, &outerr,
outbuf, written, 0));
if (result != GCONV_EMPTY_INPUT)
{
if (outerr != outbuf)
{
#ifdef RESET_INPUT_BUFFER
RESET_INPUT_BUFFER;
#else
/* We have a problem with the in on of the functions
below. Undo the conversion upto the error point. */
size_t nstatus;
/* Reload the pointers. */
*inbuf = inptr;
outbuf = outstart;
/* Reset the state. */
# ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (0);
# endif
if (FROM_DIRECTION)
/* Run the conversion loop. */
nstatus = FROM_LOOP ((const unsigned char **) inbuf,
(const unsigned char *) inbufend,
(unsigned char **) &outbuf,
(unsigned char *) outerr,
data->statep, step->data,
&converted EXTRA_LOOP_ARGS);
else
/* Run the conversion loop. */
nstatus = TO_LOOP ((const unsigned char **) inbuf,
(const unsigned char *) inbufend,
(unsigned char **) &outbuf,
(unsigned char *) outerr,
data->statep, step->data,
&converted EXTRA_LOOP_ARGS);
/* We must run out of output buffer space in this
rerun. */
assert (outbuf == outerr);
assert (nstatus == GCONV_FULL_OUTPUT);
#endif /* reset input buffer */
}
/* Change the status. */
status = result;
}
else
/* All the output is consumed, we can make another run
if everything was ok. */
if (status == GCONV_FULL_OUTPUT)
status = GCONV_OK;
}
}
while (status == GCONV_OK);
#ifdef END_LOOP
END_LOOP
#endif
/* We finished one use of this step. */
++data->invocation_counter;
}
return status;
}
#undef DEFINE_INIT
#undef CHARSET_NAME
#undef DEFINE_FINI
#undef MIN_NEEDED_FROM
#undef MIN_NEEDED_TO
#undef MAX_NEEDED_FROM
#undef MAX_NEEDED_TO
#undef DEFINE_DIRECTION_OBJECTS
#undef FROM_DIRECTION
#undef EMIT_SHIFT_TO_INIT
#undef FROM_LOOP
#undef TO_LOOP
#undef RESET_STATE
#undef RESET_INPUT_BUFFER
#undef FUNCTION_NAME
#undef PREPARE_LOOP
#undef END_LOOP
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