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Allow deflatePrime() to insert bits in the middle of a stream.

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This allows the insertion of multiple empty static blocks for the
purpose of efficiently bringing a stream to a byte boundary.
This commit is contained in:
Mark Adler
2012-01-07 09:54:40 -08:00
parent 19761b8506
commit 263b1a05b0
4 changed files with 26 additions and 13 deletions
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22
deflate.c
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@@ -1,5 +1,5 @@
/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2011 Jean-loup Gailly and Mark Adler
* Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
@@ -52,7 +52,7 @@
#include "deflate.h"
const char deflate_copyright[] =
" deflate 1.2.5.3 Copyright 1995-2011 Jean-loup Gailly and Mark Adler ";
" deflate 1.2.5.3 Copyright 1995-2012 Jean-loup Gailly and Mark Adler ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
@@ -464,9 +464,23 @@ int ZEXPORT deflatePrime (strm, bits, value)
int bits;
int value;
{
deflate_state *s;
int put;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
strm->state->bi_valid = bits;
strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
s = strm->state;
if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
return Z_BUF_ERROR;
do {
put = Buf_size - s->bi_valid;
if (put > bits)
put = bits;
s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
s->bi_valid += put;
_tr_flush_bits(s);
value >>= put;
bits -= put;
} while (bits);
return Z_OK;
}