forked from luck/tmp_suning_uos_patched
3c5f616254
Change the error message in gunzip_exactly to be more verbose. Besides the identifier being unrelated to the current function name, the user had no indication if the corruption was near the beginning or the end. Signed-off-by: Milton Miller <miltonm@bga.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
207 lines
6.6 KiB
C
207 lines
6.6 KiB
C
/*
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* Copyright 2007 David Gibson, IBM Corporation.
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* Based on earlier work, Copyright (C) Paul Mackerras 1997.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <stddef.h>
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#include "string.h"
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#include "stdio.h"
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#include "ops.h"
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#include "gunzip_util.h"
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#define HEAD_CRC 2
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#define EXTRA_FIELD 4
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#define ORIG_NAME 8
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#define COMMENT 0x10
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#define RESERVED 0xe0
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/**
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* gunzip_start - prepare to decompress gzip data
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* @state: decompressor state structure to be initialized
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* @src: buffer containing gzip compressed or uncompressed data
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* @srclen: size in bytes of the buffer at src
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*
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* If the buffer at @src contains a gzip header, this function
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* initializes zlib to decompress the data, storing the decompression
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* state in @state. The other functions in this file can then be used
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* to decompress data from the gzipped stream.
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*
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* If the buffer at @src does not contain a gzip header, it is assumed
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* to contain uncompressed data. The buffer information is recorded
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* in @state and the other functions in this file will simply copy
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* data from the uncompressed data stream at @src.
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*
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* Any errors, such as bad compressed data, cause an error to be
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* printed an the platform's exit() function to be called.
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*/
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void gunzip_start(struct gunzip_state *state, void *src, int srclen)
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{
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char *hdr = src;
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int hdrlen = 0;
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memset(state, 0, sizeof(*state));
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/* Check for gzip magic number */
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if ((hdr[0] == 0x1f) && (hdr[1] == 0x8b)) {
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/* gzip data, initialize zlib parameters */
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int r, flags;
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state->s.workspace = state->scratch;
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if (zlib_inflate_workspacesize() > sizeof(state->scratch))
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fatal("insufficient scratch space for gunzip\n\r");
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/* skip header */
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hdrlen = 10;
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flags = hdr[3];
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if (hdr[2] != Z_DEFLATED || (flags & RESERVED) != 0)
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fatal("bad gzipped data\n\r");
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if ((flags & EXTRA_FIELD) != 0)
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hdrlen = 12 + hdr[10] + (hdr[11] << 8);
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if ((flags & ORIG_NAME) != 0)
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while (hdr[hdrlen++] != 0)
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;
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if ((flags & COMMENT) != 0)
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while (hdr[hdrlen++] != 0)
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;
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if ((flags & HEAD_CRC) != 0)
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hdrlen += 2;
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if (hdrlen >= srclen)
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fatal("gunzip_start: ran out of data in header\n\r");
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r = zlib_inflateInit2(&state->s, -MAX_WBITS);
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if (r != Z_OK)
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fatal("inflateInit2 returned %d\n\r", r);
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}
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state->s.next_in = src + hdrlen;
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state->s.avail_in = srclen - hdrlen;
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}
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/**
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* gunzip_partial - extract bytes from a gzip data stream
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* @state: gzip state structure previously initialized by gunzip_start()
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* @dst: buffer to store extracted data
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* @dstlen: maximum number of bytes to extract
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*
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* This function extracts at most @dstlen bytes from the data stream
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* previously associated with @state by gunzip_start(), decompressing
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* if necessary. Exactly @dstlen bytes are extracted unless the data
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* stream doesn't contain enough bytes, in which case the entire
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* remainder of the stream is decompressed.
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*
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* Returns the actual number of bytes extracted. If any errors occur,
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* such as a corrupted compressed stream, an error is printed an the
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* platform's exit() function is called.
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*/
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int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen)
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{
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int len;
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if (state->s.workspace) {
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/* gunzipping */
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int r;
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state->s.next_out = dst;
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state->s.avail_out = dstlen;
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r = zlib_inflate(&state->s, Z_FULL_FLUSH);
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if (r != Z_OK && r != Z_STREAM_END)
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fatal("inflate returned %d msg: %s\n\r", r, state->s.msg);
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len = state->s.next_out - (unsigned char *)dst;
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} else {
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/* uncompressed image */
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len = min(state->s.avail_in, (unsigned)dstlen);
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memcpy(dst, state->s.next_in, len);
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state->s.next_in += len;
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state->s.avail_in -= len;
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}
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return len;
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}
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/**
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* gunzip_exactly - extract a fixed number of bytes from a gzip data stream
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* @state: gzip state structure previously initialized by gunzip_start()
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* @dst: buffer to store extracted data
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* @dstlen: number of bytes to extract
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*
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* This function extracts exactly @dstlen bytes from the data stream
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* previously associated with @state by gunzip_start(), decompressing
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* if necessary.
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*
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* If there are less @dstlen bytes available in the data stream, or if
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* any other errors occur, such as a corrupted compressed stream, an
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* error is printed an the platform's exit() function is called.
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*/
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void gunzip_exactly(struct gunzip_state *state, void *dst, int dstlen)
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{
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int len;
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len = gunzip_partial(state, dst, dstlen);
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if (len < dstlen)
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fatal("\n\rgunzip_exactly: ran out of data!"
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" Wanted %d, got %d.\n\r", dstlen, len);
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}
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/**
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* gunzip_discard - discard bytes from a gzip data stream
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* @state: gzip state structure previously initialized by gunzip_start()
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* @len: number of bytes to discard
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*
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* This function extracts, then discards exactly @len bytes from the
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* data stream previously associated with @state by gunzip_start().
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* Subsequent gunzip_partial(), gunzip_exactly() or gunzip_finish()
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* calls will extract the data following the discarded bytes in the
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* data stream.
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*
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* If there are less @len bytes available in the data stream, or if
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* any other errors occur, such as a corrupted compressed stream, an
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* error is printed an the platform's exit() function is called.
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*/
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void gunzip_discard(struct gunzip_state *state, int len)
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{
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static char discard_buf[128];
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while (len > sizeof(discard_buf)) {
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gunzip_exactly(state, discard_buf, sizeof(discard_buf));
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len -= sizeof(discard_buf);
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}
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if (len > 0)
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gunzip_exactly(state, discard_buf, len);
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}
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/**
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* gunzip_finish - extract all remaining bytes from a gzip data stream
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* @state: gzip state structure previously initialized by gunzip_start()
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* @dst: buffer to store extracted data
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* @dstlen: maximum number of bytes to extract
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*
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* This function extracts all remaining data, or at most @dstlen
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* bytes, from the stream previously associated with @state by
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* gunzip_start(). zlib is then shut down, so it is an error to use
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* any of the functions in this file on @state until it is
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* re-initialized with another call to gunzip_start().
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*
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* If any errors occur, such as a corrupted compressed stream, an
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* error is printed an the platform's exit() function is called.
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*/
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int gunzip_finish(struct gunzip_state *state, void *dst, int dstlen)
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{
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int len;
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if (state->s.workspace) {
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len = gunzip_partial(state, dst, dstlen);
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zlib_inflateEnd(&state->s);
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} else {
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/* uncompressed image */
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len = min(state->s.avail_in, (unsigned)dstlen);
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memcpy(dst, state->s.next_in, len);
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}
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return len;
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}
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