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glibc/iconv/skeleton.c

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/* Skeleton for a conversion module.
Copyright (C) 1998-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* 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.
FROM_LOOP_MIN_NEEDED_FROM
FROM_LOOP_MAX_NEEDED_FROM
minimal/maximal number of bytes needed on input
of one round through the FROM_LOOP. Defaults
to MIN_NEEDED_FROM and MAX_NEEDED_FROM, respectively.
FROM_LOOP_MIN_NEEDED_TO
FROM_LOOP_MAX_NEEDED_TO
minimal/maximal number of bytes needed on output
of one round through the FROM_LOOP. Defaults
to MIN_NEEDED_TO and MAX_NEEDED_TO, respectively.
TO_LOOP_MIN_NEEDED_FROM
TO_LOOP_MAX_NEEDED_FROM
minimal/maximal number of bytes needed on input
of one round through the TO_LOOP. Defaults
to MIN_NEEDED_TO and MAX_NEEDED_TO, respectively.
TO_LOOP_MIN_NEEDED_TO
TO_LOOP_MAX_NEEDED_TO
minimal/maximal number of bytes needed on output
of one round through the TO_LOOP. Defaults
to MIN_NEEDED_FROM and MAX_NEEDED_FROM, respectively.
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 bytes which bring the current state into
the initial state.
FROM_LOOP name of the function implementing the conversion
from the current character set.
TO_LOOP likewise for the other direction
ONE_DIRECTION optional. If defined to 1, only one conversion
direction is defined instead of two. In this
case, FROM_DIRECTION should be defined to 1, and
FROM_LOOP and TO_LOOP should have the same value.
SAVE_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.
Note that if the conversion has skipped over
irreversible characters (due to
__GCONV_IGNORE_ERRORS) there is no longer a direct
correspondence between input and output pointers,
and this macro is not called.
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.
STORE_REST optional, needed only when MAX_NEEDED_FROM > 4.
This macro stores the seen but unconverted input bytes
in the state.
FROM_ONEBYTE optional. If defined, should be the name of a
specialized conversion function for a single byte
from the current character set to INTERNAL. This
function has prototype
wint_t
FROM_ONEBYTE (struct __gconv_step *, unsigned char);
and does a special conversion:
- The input is a single byte.
- The output is a single uint32_t.
- The state before the conversion is the initial state;
the state after the conversion is irrelevant.
- No transliteration.
- __invocation_counter = 0.
- __internal_use = 1.
- do_flush = 0.
Modules can use mbstate_t to store conversion state as follows:
* Bits 2..0 of '__count' contain the number of lookahead input bytes
stored in __value.__wchb. Always zero if the converter never
returns __GCONV_INCOMPLETE_INPUT.
* Bits 31..3 of '__count' are module dependent shift state.
* __value: When STORE_REST/UNPACK_BYTES aren't defined and when the
converter has returned __GCONV_INCOMPLETE_INPUT, this contains
at most 4 lookahead bytes. Converters with an mb_cur_max > 4
(currently only UTF-8) must find a way to store their state
in __value.__wch and define STORE_REST/UNPACK_BYTES appropriately.
When __value contains lookahead, __count must not be zero, because
the converter is not in the initial state then, and mbsinit() --
defined as a (__count == 0) test -- must reflect this.
*/
#include <assert.h>
#include <iconv/gconv_int.h>
#include <string.h>
#define __need_size_t
#define __need_NULL
#include <stddef.h>
#ifndef STATIC_GCONV
# include <dlfcn.h>
#endif
#include <pointer_guard.h>
#include <stdint.h>
#ifndef DL_CALL_FCT
# define DL_CALL_FCT(fct, args) fct args
#endif
/* The direction objects. */
#if DEFINE_INIT
# ifndef FROM_DIRECTION
# define FROM_DIRECTION_VAL NULL
# define TO_DIRECTION_VAL ((void *) ~((uintptr_t) 0))
# define FROM_DIRECTION (step->__data == FROM_DIRECTION_VAL)
# endif
#else
# ifndef FROM_DIRECTION
# error "FROM_DIRECTION must be provided if non-default init is 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
/* Defaults for the per-direction min/max constants. */
#ifndef FROM_LOOP_MIN_NEEDED_FROM
# define FROM_LOOP_MIN_NEEDED_FROM MIN_NEEDED_FROM
#endif
#ifndef FROM_LOOP_MAX_NEEDED_FROM
# define FROM_LOOP_MAX_NEEDED_FROM MAX_NEEDED_FROM
#endif
#ifndef FROM_LOOP_MIN_NEEDED_TO
# define FROM_LOOP_MIN_NEEDED_TO MIN_NEEDED_TO
#endif
#ifndef FROM_LOOP_MAX_NEEDED_TO
# define FROM_LOOP_MAX_NEEDED_TO MAX_NEEDED_TO
#endif
#ifndef TO_LOOP_MIN_NEEDED_FROM
# define TO_LOOP_MIN_NEEDED_FROM MIN_NEEDED_TO
#endif
#ifndef TO_LOOP_MAX_NEEDED_FROM
# define TO_LOOP_MAX_NEEDED_FROM MAX_NEEDED_TO
#endif
#ifndef TO_LOOP_MIN_NEEDED_TO
# define TO_LOOP_MIN_NEEDED_TO MIN_NEEDED_FROM
#endif
#ifndef TO_LOOP_MAX_NEEDED_TO
# define TO_LOOP_MAX_NEEDED_TO MAX_NEEDED_FROM
#endif
/* For conversions from a fixed width character set to another fixed width
character set we can define RESET_INPUT_BUFFER in a very fast way. */
#if !defined RESET_INPUT_BUFFER && !defined SAVE_RESET_STATE
# if FROM_LOOP_MIN_NEEDED_FROM == FROM_LOOP_MAX_NEEDED_FROM \
&& FROM_LOOP_MIN_NEEDED_TO == FROM_LOOP_MAX_NEEDED_TO \
&& TO_LOOP_MIN_NEEDED_FROM == TO_LOOP_MAX_NEEDED_FROM \
&& TO_LOOP_MIN_NEEDED_TO == TO_LOOP_MAX_NEEDED_TO
/* We have to use these `if's here since the compiler cannot know that
(outbuf - outerr) is always divisible by FROM/TO_LOOP_MIN_NEEDED_TO.
The ?:1 avoids division by zero warnings that gcc 3.2 emits even for
obviously unreachable code. */
# define RESET_INPUT_BUFFER \
if (FROM_DIRECTION) \
{ \
if (FROM_LOOP_MIN_NEEDED_FROM % FROM_LOOP_MIN_NEEDED_TO == 0) \
*inptrp -= (outbuf - outerr) \
* (FROM_LOOP_MIN_NEEDED_FROM / FROM_LOOP_MIN_NEEDED_TO); \
else if (FROM_LOOP_MIN_NEEDED_TO % FROM_LOOP_MIN_NEEDED_FROM == 0) \
*inptrp -= (outbuf - outerr) \
/ (FROM_LOOP_MIN_NEEDED_TO / FROM_LOOP_MIN_NEEDED_FROM \
? : 1); \
else \
*inptrp -= ((outbuf - outerr) / FROM_LOOP_MIN_NEEDED_TO) \
* FROM_LOOP_MIN_NEEDED_FROM; \
} \
else \
{ \
if (TO_LOOP_MIN_NEEDED_FROM % TO_LOOP_MIN_NEEDED_TO == 0) \
*inptrp -= (outbuf - outerr) \
* (TO_LOOP_MIN_NEEDED_FROM / TO_LOOP_MIN_NEEDED_TO); \
else if (TO_LOOP_MIN_NEEDED_TO % TO_LOOP_MIN_NEEDED_FROM == 0) \
*inptrp -= (outbuf - outerr) \
/ (TO_LOOP_MIN_NEEDED_TO / TO_LOOP_MIN_NEEDED_FROM ? : 1); \
else \
*inptrp -= ((outbuf - outerr) / TO_LOOP_MIN_NEEDED_TO) \
* TO_LOOP_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
extern int gconv_init (struct __gconv_step *step);
int
gconv_init (struct __gconv_step *step)
{
/* Determine which direction. */
if (strcmp (step->__from_name, CHARSET_NAME) == 0)
{
step->__data = FROM_DIRECTION_VAL;
step->__min_needed_from = FROM_LOOP_MIN_NEEDED_FROM;
step->__max_needed_from = FROM_LOOP_MAX_NEEDED_FROM;
step->__min_needed_to = FROM_LOOP_MIN_NEEDED_TO;
step->__max_needed_to = FROM_LOOP_MAX_NEEDED_TO;
#ifdef FROM_ONEBYTE
step->__btowc_fct = FROM_ONEBYTE;
#endif
}
else if (__builtin_expect (strcmp (step->__to_name, CHARSET_NAME), 0) == 0)
{
step->__data = TO_DIRECTION_VAL;
step->__min_needed_from = TO_LOOP_MIN_NEEDED_FROM;
step->__max_needed_from = TO_LOOP_MAX_NEEDED_FROM;
step->__min_needed_to = TO_LOOP_MIN_NEEDED_TO;
step->__max_needed_to = TO_LOOP_MAX_NEEDED_TO;
}
else
return __GCONV_NOCONV;
#ifdef SAVE_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
we don't 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
/* The macros are used to access the function to convert single characters. */
#define SINGLE(fct) SINGLE2 (fct)
#define SINGLE2(fct) fct##_single
extern int FUNCTION_NAME (struct __gconv_step *step,
struct __gconv_step_data *data,
const unsigned char **inptrp,
const unsigned char *inend,
unsigned char **outbufstart, size_t *irreversible,
int do_flush, int consume_incomplete);
int
FUNCTION_NAME (struct __gconv_step *step, struct __gconv_step_data *data,
const unsigned char **inptrp, const unsigned char *inend,
unsigned char **outbufstart, size_t *irreversible, int do_flush,
int consume_incomplete)
{
struct __gconv_step *next_step = step + 1;
struct __gconv_step_data *next_data = data + 1;
__gconv_fct fct = NULL;
int status;
if ((data->__flags & __GCONV_IS_LAST) == 0)
{
fct = next_step->__fct;
if (next_step->__shlib_handle != NULL)
PTR_DEMANGLE (fct);
}
/* 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 (__glibc_unlikely (do_flush))
{
/* This should never happen during error handling. */
assert (outbufstart == NULL);
status = __GCONV_OK;
#ifdef EMIT_SHIFT_TO_INIT
if (do_flush == 1)
{
/* We preserve the initial values of the pointer variables. */
unsigned char *outbuf = data->__outbuf;
unsigned char *outstart = outbuf;
unsigned char *outend = data->__outbufend;
# ifdef PREPARE_LOOP
PREPARE_LOOP
# endif
# ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (1);
# endif
/* Emit the escape sequence to reset the state. */
EMIT_SHIFT_TO_INIT;
/* Call the steps down the chain if there are any but only if we
successfully emitted the escape sequence. This should only
fail if the output buffer is full. If the input is invalid
it should be discarded since the user wants to start from a
clean state. */
if (status == __GCONV_OK)
{
if (data->__flags & __GCONV_IS_LAST)
/* Store information about how many bytes are available. */
data->__outbuf = outbuf;
else
{
/* Write out all output which was produced. */
if (outbuf > outstart)
{
const unsigned char *outerr = outstart;
int result;
result = DL_CALL_FCT (fct, (next_step, next_data,
&outerr, outbuf, NULL,
irreversible, 0,
consume_incomplete));
if (result != __GCONV_EMPTY_INPUT)
{
if (__glibc_unlikely (outerr != outbuf))
{
/* We have a problem. Undo the conversion. */
outbuf = outstart;
/* Restore the state. */
# ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (0);
# endif
}
/* Change the status. */
status = result;
}
}
if (status == __GCONV_OK)
/* Now flush the remaining steps. */
status = DL_CALL_FCT (fct, (next_step, next_data, NULL,
NULL, NULL, irreversible, 1,
consume_incomplete));
}
}
}
else
#endif
{
/* Clear the state object. There might be bytes in there from
previous calls with CONSUME_INCOMPLETE == 1. But don't emit
escape sequences. */
memset (data->__statep, '\0', sizeof (*data->__statep));
if (! (data->__flags & __GCONV_IS_LAST))
/* Now flush the remaining steps. */
status = DL_CALL_FCT (fct, (next_step, next_data, NULL, NULL,
NULL, irreversible, do_flush,
consume_incomplete));
}
}
else
{
/* We preserve the initial values of the pointer variables,
but only some conversion modules need it. */
const unsigned char *inptr __attribute__ ((__unused__)) = *inptrp;
unsigned char *outbuf = (__builtin_expect (outbufstart == NULL, 1)
? data->__outbuf : *outbufstart);
unsigned char *outend = data->__outbufend;
unsigned char *outstart;
/* This variable is used to count the number of characters we
actually converted. */
size_t lirreversible = 0;
size_t *lirreversiblep = irreversible ? &lirreversible : NULL;
#ifdef PREPARE_LOOP
PREPARE_LOOP
#endif
#if FROM_LOOP_MAX_NEEDED_FROM > 1 || TO_LOOP_MAX_NEEDED_FROM > 1
/* If the function is used to implement the mb*towc*() or wc*tomb*()
functions we must test whether any bytes from the last call are
stored in the `state' object. */
if (((FROM_LOOP_MAX_NEEDED_FROM > 1 && TO_LOOP_MAX_NEEDED_FROM > 1)
|| (FROM_LOOP_MAX_NEEDED_FROM > 1 && FROM_DIRECTION)
|| (TO_LOOP_MAX_NEEDED_FROM > 1 && !FROM_DIRECTION))
&& consume_incomplete && (data->__statep->__count & 7) != 0)
{
/* Yep, we have some bytes left over. Process them now.
But this must not happen while we are called from an
error handler. */
assert (outbufstart == NULL);
# if FROM_LOOP_MAX_NEEDED_FROM > 1
if (TO_LOOP_MAX_NEEDED_FROM == 1 || FROM_DIRECTION)
status = SINGLE(FROM_LOOP) (step, data, inptrp, inend, &outbuf,
outend, lirreversiblep
EXTRA_LOOP_ARGS);
# endif
# if !ONE_DIRECTION
# if FROM_LOOP_MAX_NEEDED_FROM > 1 && TO_LOOP_MAX_NEEDED_FROM > 1
else
# endif
# if TO_LOOP_MAX_NEEDED_FROM > 1
status = SINGLE(TO_LOOP) (step, data, inptrp, inend, &outbuf,
outend, lirreversiblep EXTRA_LOOP_ARGS);
# endif
# endif
if (__builtin_expect (status, __GCONV_OK) != __GCONV_OK)
return status;
}
#endif
while (1)
{
/* Remember the start value for this round. */
inptr = *inptrp;
/* The outbuf buffer is empty. */
outstart = outbuf;
#ifdef RESET_INPUT_BUFFER
/* Remember how many irreversible characters were skipped before
this round. */
size_t loop_irreversible
= lirreversible + (irreversible ? *irreversible : 0);
#endif
#ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (1);
#endif
if (FROM_DIRECTION)
/* Run the conversion loop. */
status = FROM_LOOP (step, data, inptrp, inend, &outbuf, outend,
lirreversiblep EXTRA_LOOP_ARGS);
else
/* Run the conversion loop. */
status = TO_LOOP (step, data, inptrp, inend, &outbuf, outend,
lirreversiblep EXTRA_LOOP_ARGS);
/* If we were called as part of an error handling module we
don't do anything else here. */
if (__glibc_unlikely (outbufstart != NULL))
{
*outbufstart = outbuf;
return status;
}
/* We finished one use of the loops. */
++data->__invocation_counter;
/* If this is the last step leave the loop, there is nothing
we can do. */
if (__glibc_unlikely (data->__flags & __GCONV_IS_LAST))
{
/* Store information about how many bytes are available. */
data->__outbuf = outbuf;
/* Remember how many non-identical characters we
converted in an irreversible way. */
*irreversible += lirreversible;
break;
}
/* Write out all output which was produced. */
if (__glibc_likely (outbuf > outstart))
{
const unsigned char *outerr = data->__outbuf;
int result;
result = DL_CALL_FCT (fct, (next_step, next_data, &outerr,
outbuf, NULL, irreversible, 0,
consume_incomplete));
if (result != __GCONV_EMPTY_INPUT)
{
if (__glibc_unlikely (outerr != outbuf))
{
#ifdef RESET_INPUT_BUFFER
/* RESET_INPUT_BUFFER can only work when there were
no new irreversible characters skipped during
this round. */
if (loop_irreversible
== lirreversible + (irreversible ? *irreversible : 0))
{
RESET_INPUT_BUFFER;
goto done_reset;
}
#endif
/* We have a problem in one of the functions below.
Undo the conversion upto the error point. */
size_t nstatus __attribute__ ((unused));
/* Reload the pointers. */
*inptrp = inptr;
outbuf = outstart;
/* Restore the state. */
#ifdef SAVE_RESET_STATE
SAVE_RESET_STATE (0);
#endif
if (FROM_DIRECTION)
/* Run the conversion loop. */
nstatus = FROM_LOOP (step, data, inptrp, inend,
&outbuf, outerr,
lirreversiblep
EXTRA_LOOP_ARGS);
else
/* Run the conversion loop. */
nstatus = TO_LOOP (step, data, inptrp, inend,
&outbuf, outerr,
lirreversiblep
EXTRA_LOOP_ARGS);
/* We must run out of output buffer space in this
rerun. */
assert (outbuf == outerr);
assert (nstatus == __GCONV_FULL_OUTPUT);
/* If we haven't consumed a single byte decrement
the invocation counter. */
if (__glibc_unlikely (outbuf == outstart))
--data->__invocation_counter;
}
#ifdef RESET_INPUT_BUFFER
done_reset:
#endif
/* 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;
outbuf = data->__outbuf;
}
}
if (status != __GCONV_OK)
break;
/* Reset the output buffer pointer for the next round. */
outbuf = data->__outbuf;
}
#ifdef END_LOOP
END_LOOP
#endif
/* If we are supposed to consume all character store now all of the
remaining characters in the `state' object. */
#if FROM_LOOP_MAX_NEEDED_FROM > 1 || TO_LOOP_MAX_NEEDED_FROM > 1
if (((FROM_LOOP_MAX_NEEDED_FROM > 1 && TO_LOOP_MAX_NEEDED_FROM > 1)
|| (FROM_LOOP_MAX_NEEDED_FROM > 1 && FROM_DIRECTION)
|| (TO_LOOP_MAX_NEEDED_FROM > 1 && !FROM_DIRECTION))
&& __builtin_expect (consume_incomplete, 0)
&& status == __GCONV_INCOMPLETE_INPUT)
{
# ifdef STORE_REST
mbstate_t *state = data->__statep;
STORE_REST
# else
/* Make sure the remaining bytes fit into the state objects
buffer. */
size_t cnt_after = inend - *inptrp;
assert (cnt_after <= sizeof (data->__statep->__value.__wchb));
size_t cnt;
for (cnt = 0; cnt < cnt_after; ++cnt)
data->__statep->__value.__wchb[cnt] = (*inptrp)[cnt];
*inptrp = inend;
data->__statep->__count &= ~7;
data->__statep->__count |= cnt;
# endif
}
#endif
#undef unaligned
#undef POSSIBLY_UNALIGNED
}
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 FROM_LOOP_MIN_NEEDED_FROM
#undef FROM_LOOP_MAX_NEEDED_FROM
#undef FROM_LOOP_MIN_NEEDED_TO
#undef FROM_LOOP_MAX_NEEDED_TO
#undef TO_LOOP_MIN_NEEDED_FROM
#undef TO_LOOP_MAX_NEEDED_FROM
#undef TO_LOOP_MIN_NEEDED_TO
#undef TO_LOOP_MAX_NEEDED_TO
#undef FROM_DIRECTION
#undef EMIT_SHIFT_TO_INIT
#undef FROM_LOOP
#undef TO_LOOP
#undef ONE_DIRECTION
#undef SAVE_RESET_STATE
#undef RESET_INPUT_BUFFER
#undef FUNCTION_NAME
#undef PREPARE_LOOP
#undef END_LOOP
#undef EXTRA_LOOP_ARGS
#undef STORE_REST
#undef FROM_ONEBYTE
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