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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [machine/] [spu/] [strcpy.h] - Blame information for rev 207

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1 207 jeremybenn
/*
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  (C) Copyright 2008
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  International Business Machines Corporation,
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  All rights reserved.
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  Redistribution and use in source and binary forms, with or without
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  modification, are permitted provided that the following conditions are met:
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    * Redistributions of source code must retain the above copyright notice,
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  this list of conditions and the following disclaimer.
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    * Redistributions in binary form must reproduce the above copyright
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  notice, this list of conditions and the following disclaimer in the
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  documentation and/or other materials provided with the distribution.
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    * Neither the names of the copyright holders nor the names of their
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  contributors may be used to endorse or promote products derived from
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  this software without specific prior written permission.
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  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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  OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <spu_intrinsics.h>
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#include "vec_literal.h"
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#include <string.h>
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/*
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 * Supply an inline _strncpy for strcpy/cat and strncpy/cat. Relies on
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 * checklen and lastzero code being optimized out when they are constant
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 * zero values.
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 */
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static inline void * _strncpy(char * __restrict__ dest, const char *
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                              __restrict__ src, size_t maxlen, int
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                              checklen, int lastzero)
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{
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  int adjust, offset, soffset, doffset, shift;
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  vec_uchar16 *vsrc, *vdest;
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  vec_uchar16 sdata1, sdata2, sdata, shuffle;
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  vec_uchar16 mask1, maskzero, cmp0;
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  vec_uint4 nonzeroes, gathered_cmp, vtmp, vtmp2;
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  vec_uint4 curlen; /* assumes size_t is 4 bytes */
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  const vec_uint4 val31 = { 31, 31, 31, 31 };
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  const vec_uint4 val_0123 = { 0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F };
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  const vec_uchar16 all_ones = { 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff,
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                                 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff };
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  vsrc = (vec_uchar16 *) src;
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  vdest = (vec_uchar16 *) dest;
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  soffset = (int) src & 15;
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  doffset = (int) dest & 15;
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  if (checklen) {
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    /*
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     * Set curlen so it is the number of bytes we would copy if starting
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     * from vdest & ~0xf.
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     *
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     * curlen could probably be replaced by comparing vdest plus some
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     * offset to dest + maxlen, that would help mainly in the while loop
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     * but would lose only one instruction (the curlen -= 16).
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     */
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    curlen = spu_splats((unsigned int) (maxlen + doffset));
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  }
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  /*
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   * Setup a shuffle pattern to align the source string with the
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   * alignment of the destination string.
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   */
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  vtmp = spu_cmpgt(spu_promote(doffset, 0), spu_promote(soffset, 0));
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  adjust = spu_extract(vtmp, 0);
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  offset  = soffset - doffset;
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  offset += adjust & 16;
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  shuffle = spu_splats((unsigned char) offset);
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  shuffle = (vec_uchar16) spu_add((vec_uint4) shuffle, val_0123);
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  vsrc += adjust;
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  sdata1 = *vsrc++;
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  sdata2 = *vsrc++;
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  sdata = spu_shuffle(sdata1, sdata2, shuffle);
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  /*
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   * mask out leading bytes
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   */
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  mask1 = spu_rlmaskqwbyte(all_ones, -doffset);
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  cmp0 = spu_and(mask1, spu_cmpeq(sdata, 0));
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  nonzeroes = spu_cntlz(spu_gather(cmp0));
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  /*
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   * First element of nonzeroes - 15 is the number of leading non-zero
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   * bytes plus 1 for the zero byte.
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   */
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  if (checklen) {
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    vtmp = spu_add(curlen, 15);
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    vtmp2 = spu_cmpgt(nonzeroes, vtmp);
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    nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2);
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  }
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  vtmp = spu_cmpgt(nonzeroes, val31);
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  /*
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   * Note: using immediate (constant 31) vs a vector value (val31) does
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   * not give different results, and we have to have a vector val31 for
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   * the spu_sel below, so use val31 everywhere.
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   */
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  vtmp = spu_sel(nonzeroes, val31, vtmp);
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  /*
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   * So vtmp is now min(nonzeroes, 31), the number of bytes + 16 that we
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   * want to copy from the first 16 bytes of the source.
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   */
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  if (checklen) {
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    curlen = spu_sub(vtmp, curlen);
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    curlen = spu_sub(15, curlen);
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  }
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  /*
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   * We want a right shift 0xff with fill by ones of (vtmp - 15) bytes, but
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   * that doesn't exist so use spu_slqwbyte and vtmp all ones left by
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   * (31 - vtmp). Note: this can also use spu_rlqwbytebc with spu_rlqw.
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   */
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  shift = spu_extract(spu_sub(val31, vtmp), 0);
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  maskzero = spu_slqwbyte(all_ones, shift);
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  maskzero = spu_and(mask1, maskzero);
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  *vdest = spu_sel(*vdest, sdata, maskzero);
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  vtmp = spu_cmpgt(nonzeroes, val31);
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  if (checklen) {
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    vtmp2 = spu_cmpgt(curlen, 0);
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    vtmp = spu_and(vtmp, vtmp2);
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  }
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  if (spu_extract(vtmp, 0)) {
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    sdata1 = sdata2;
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    sdata2 = *vsrc++;
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    sdata = spu_shuffle(sdata1, sdata2, shuffle);
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    cmp0 = spu_cmpeq(sdata, 0);
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    gathered_cmp = spu_gather(cmp0);
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    /*
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     * Copy 16 bytes at a time.
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     */
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    while ((spu_extract(gathered_cmp, 0) == 0) &&
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           (!checklen || (spu_extract(curlen, 0) > 15))) {
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      if (checklen)
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        curlen = spu_add(curlen, -16);
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      *++vdest = sdata;
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      sdata1 = sdata2;
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      sdata2 = *vsrc++;
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      sdata = spu_shuffle(sdata1, sdata2, shuffle);
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      cmp0 = spu_cmpeq(sdata, 0);
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      gathered_cmp = spu_gather(cmp0);
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    }
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    /*
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     * Copy 0 to 15 trailing bytes, either up to the smaller of curlen or
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     * the number of non-zero bytes.
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     */
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    nonzeroes = spu_cntlz(gathered_cmp);
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    if (checklen) {
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      vtmp = spu_add(curlen, 15);
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      vtmp2 = spu_cmpgt(nonzeroes, vtmp);
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      nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2);
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      curlen = spu_sub(nonzeroes, curlen);
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      curlen = spu_sub(15, curlen);
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    }
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    shift = spu_extract(spu_sub(val31, nonzeroes), 0);
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    maskzero = spu_slqwbyte(all_ones, shift);
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    ++vdest;
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    *vdest = spu_sel(*vdest, sdata, maskzero);
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  }
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  if (checklen && lastzero) {
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    /*
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     * For strncat.
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     */
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    dest[maxlen - spu_extract(curlen, 0)] = '\0';
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  }
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  /* Pad null bytes if the length of the "src" is less than "n" (strncpy).  */
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  if (checklen && !lastzero && spu_extract(curlen, 0))
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    memset(dest + maxlen - spu_extract(curlen, 0), 0, spu_extract(curlen, 0));
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  return (dest);
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}

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