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In several converters, a __GCONV_ILLEGAL_INPUT result gets overwritten with __GCONV_FULL_OUTPUT. As a result, iconv (the function) returns E2BIG instead of EILSEQ. The iconv program does not see the original EILSEQ failure, does not recognize the invalid input, and may incorrectly exit successfully. To address this, a new __flags bit is used to indicate a sticky input error state. All __GCONV_ILLEGAL_INPUT results are replaced with a function call that sets this new __GCONV_ENCOUNTERED_ILLEGAL_INPUT and returns __GCONV_ILLEGAL_INPUT. The iconv program checks for __GCONV_ENCOUNTERED_ILLEGAL_INPUT and overrides the exit status. The converter changes introducing __gconv_mark_illegal_input are mostly mechanical, except for the res variable initialization in iconvdata/iso-2022-jp.c: this error gets overwritten with __GCONV_OK and other results in the following code. If res == __GCONV_ILLEGAL_INPUT afterwards, STANDARD_TO_LOOP_ERR_HANDLER below will handle it. The __gconv_mark_illegal_input changes do not alter the errno value set by the iconv function. This is simpler to implement than reviewing each __GCONV_FULL_OUTPUT result and adjust it not to override a previous __GCONV_ILLEGAL_INPUT result. Doing it that way would also change some E2BIG errors in to EILSEQ errors, so it had to be done conditionally (under a flag set by the iconv program only), to avoid confusing buffer management in other applications. Reviewed-by: DJ Delorie <dj@redhat.com>
218 lines
6.2 KiB
C
218 lines
6.2 KiB
C
/* Conversion module for Unicode
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Copyright (C) 1999-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <byteswap.h>
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#include <dlfcn.h>
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#include <gconv.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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/* This is the Byte Order Mark character (BOM). */
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#define BOM 0xfeff
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/* And in the other endian format. */
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#define BOM_OE 0xfffe
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/* Definitions used in the body of the `gconv' function. */
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#define FROM_LOOP from_unicode_loop
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#define TO_LOOP to_unicode_loop
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#define DEFINE_INIT 0
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#define DEFINE_FINI 0
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#define MIN_NEEDED_FROM 2
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#define MIN_NEEDED_TO 4
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#define ONE_DIRECTION 0
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#define FROM_DIRECTION (dir == from_unicode)
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#define PREPARE_LOOP \
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enum direction dir = ((struct unicode_data *) step->__data)->dir; \
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int swap; \
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if (FROM_DIRECTION) \
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{ \
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if (data->__invocation_counter == 0) \
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{ \
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/* We have to find out which byte order the file is encoded in. */ \
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if (inptr + 2 > inend) \
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return (inptr == inend \
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? __GCONV_EMPTY_INPUT : __GCONV_INCOMPLETE_INPUT); \
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\
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if (get16 (inptr) == BOM) \
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/* Simply ignore the BOM character. */ \
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*inptrp = inptr += 2; \
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else if (get16 (inptr) == BOM_OE) \
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{ \
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data->__flags |= __GCONV_SWAP; \
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*inptrp = inptr += 2; \
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} \
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} \
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} \
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else if (!data->__internal_use && data->__invocation_counter == 0) \
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{ \
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/* Emit the Byte Order Mark. */ \
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if (__glibc_unlikely (outbuf + 2 > outend)) \
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return __GCONV_FULL_OUTPUT; \
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\
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put16 (outbuf, BOM); \
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outbuf += 2; \
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} \
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swap = data->__flags & __GCONV_SWAP;
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#define EXTRA_LOOP_ARGS , swap
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/* Direction of the transformation. */
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enum direction
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{
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illegal_dir,
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to_unicode,
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from_unicode
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};
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struct unicode_data
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{
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enum direction dir;
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};
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extern int gconv_init (struct __gconv_step *step);
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int
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gconv_init (struct __gconv_step *step)
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{
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/* Determine which direction. */
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struct unicode_data *new_data;
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enum direction dir = illegal_dir;
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int result;
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if (strcmp (step->__from_name, "UNICODE//") == 0)
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dir = from_unicode;
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else
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dir = to_unicode;
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new_data = (struct unicode_data *) malloc (sizeof (struct unicode_data));
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result = __GCONV_NOMEM;
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if (new_data != NULL)
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{
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new_data->dir = dir;
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step->__data = new_data;
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if (dir == from_unicode)
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{
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step->__min_needed_from = MIN_NEEDED_FROM;
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step->__max_needed_from = MIN_NEEDED_FROM;
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step->__min_needed_to = MIN_NEEDED_TO;
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step->__max_needed_to = MIN_NEEDED_TO;
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}
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else
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{
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step->__min_needed_from = MIN_NEEDED_TO;
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step->__max_needed_from = MIN_NEEDED_TO;
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step->__min_needed_to = MIN_NEEDED_FROM;
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step->__max_needed_to = MIN_NEEDED_FROM;
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}
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step->__stateful = 0;
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result = __GCONV_OK;
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}
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return result;
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}
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extern void gconv_end (struct __gconv_step *data);
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void
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gconv_end (struct __gconv_step *data)
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{
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free (data->__data);
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}
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/* Convert from the internal (UCS4-like) format to UCS2. */
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#define MIN_NEEDED_INPUT MIN_NEEDED_TO
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#define MIN_NEEDED_OUTPUT MIN_NEEDED_FROM
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#define LOOPFCT TO_LOOP
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#define BODY \
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{ \
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uint32_t c = get32 (inptr); \
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\
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if (__glibc_unlikely (c >= 0x10000)) \
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{ \
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UNICODE_TAG_HANDLER (c, 4); \
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STANDARD_TO_LOOP_ERR_HANDLER (4); \
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} \
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else if (__glibc_unlikely (c >= 0xd800 && c < 0xe000)) \
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{ \
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/* Surrogate characters in UCS-4 input are not valid. \
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We must catch this, because the UCS-2 output might be \
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interpreted as UTF-16 by other programs. If we let \
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surrogates pass through, attackers could make a security \
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hole exploit by synthesizing any desired plane 1-16 \
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character. */ \
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result = __gconv_mark_illegal_input (step_data); \
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if (! ignore_errors_p ()) \
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break; \
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inptr += 4; \
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++*irreversible; \
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continue; \
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} \
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else \
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{ \
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put16 (outptr, c); \
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outptr += 2; \
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} \
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\
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inptr += 4; \
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}
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#define LOOP_NEED_FLAGS
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#define EXTRA_LOOP_DECLS \
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, int swap
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#include <iconv/loop.c>
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/* Convert from UCS2 to the internal (UCS4-like) format. */
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#define MIN_NEEDED_INPUT MIN_NEEDED_FROM
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#define MIN_NEEDED_OUTPUT MIN_NEEDED_TO
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#define LOOPFCT FROM_LOOP
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#define BODY \
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{ \
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uint16_t u1 = get16 (inptr); \
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\
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if (swap) \
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u1 = bswap_16 (u1); \
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\
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if (__glibc_unlikely (u1 >= 0xd800 && u1 < 0xe000)) \
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{ \
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/* Surrogate characters in UCS-2 input are not valid. Reject \
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them. (Catching this here is not security relevant.) */ \
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STANDARD_FROM_LOOP_ERR_HANDLER (2); \
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} \
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\
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put32 (outptr, u1); \
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\
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inptr += 2; \
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outptr += 4; \
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}
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#define LOOP_NEED_FLAGS
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#define EXTRA_LOOP_DECLS \
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, int swap
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#include <iconv/loop.c>
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/* Now define the toplevel functions. */
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#include <iconv/skeleton.c>
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