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<html><!-- Created using the cpp_pretty_printer from the dlib C++ library. See http://dlib.net for updates. --><head><title>dlib C++ Library - inftrees.c</title></head><body bgcolor='white'><pre>
<font color='#009900'>/* inftrees.c -- generate Huffman trees for efficient decoding
* Copyright (C) 1995-2013 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/</font>
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='zutil.h.html'>zutil.h</a>"
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='inftrees.h.html'>inftrees.h</a>"
<font color='#0000FF'>#define</font> MAXBITS <font color='#979000'>15</font>
<font color='#0000FF'>const</font> <font color='#0000FF'><u>char</u></font> inflate_copyright[] <font color='#5555FF'>=</font>
"<font color='#CC0000'> inflate 1.2.8 Copyright 1995-2013 Mark Adler </font>";
<font color='#009900'>/*
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
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/</font>
<font color='#009900'>/*
Build a set of tables to decode the provided canonical Huffman code.
The code lengths are lens[0..codes-1]. The result starts at *table,
whose indices are 0..2^bits-1. work is a writable array of at least
lens shorts, which is used as a work area. type is the type of code
to be generated, CODES, LENS, or DISTS. On return, zero is success,
-1 is an invalid code, and +1 means that ENOUGH isn't enough. table
on return points to the next available entry's address. bits is the
requested root table index bits, and on return it is the actual root
table index bits. It will differ if the request is greater than the
longest code or if it is less than the shortest code.
*/</font>
<font color='#0000FF'><u>int</u></font> ZLIB_INTERNAL <b><a name='inflate_table'></a>inflate_table</b><font face='Lucida Console'>(</font>type, lens, codes, table, bits, work<font face='Lucida Console'>)</font>
codetype type;
<font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> FAR <font color='#5555FF'>*</font>lens;
<font color='#0000FF'><u>unsigned</u></font> codes;
code FAR <font color='#5555FF'>*</font> FAR <font color='#5555FF'>*</font>table;
<font color='#0000FF'><u>unsigned</u></font> FAR <font color='#5555FF'>*</font>bits;
<font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> FAR <font color='#5555FF'>*</font>work;
<b>{</b>
<font color='#0000FF'><u>unsigned</u></font> len; <font color='#009900'>/* a code's length in bits */</font>
<font color='#0000FF'><u>unsigned</u></font> sym; <font color='#009900'>/* index of code symbols */</font>
<font color='#0000FF'><u>unsigned</u></font> min, max; <font color='#009900'>/* minimum and maximum code lengths */</font>
<font color='#0000FF'><u>unsigned</u></font> root; <font color='#009900'>/* number of index bits for root table */</font>
<font color='#0000FF'><u>unsigned</u></font> curr; <font color='#009900'>/* number of index bits for current table */</font>
<font color='#0000FF'><u>unsigned</u></font> drop; <font color='#009900'>/* code bits to drop for sub-table */</font>
<font color='#0000FF'><u>int</u></font> left; <font color='#009900'>/* number of prefix codes available */</font>
<font color='#0000FF'><u>unsigned</u></font> used; <font color='#009900'>/* code entries in table used */</font>
<font color='#0000FF'><u>unsigned</u></font> huff; <font color='#009900'>/* Huffman code */</font>
<font color='#0000FF'><u>unsigned</u></font> incr; <font color='#009900'>/* for incrementing code, index */</font>
<font color='#0000FF'><u>unsigned</u></font> fill; <font color='#009900'>/* index for replicating entries */</font>
<font color='#0000FF'><u>unsigned</u></font> low; <font color='#009900'>/* low bits for current root entry */</font>
<font color='#0000FF'><u>unsigned</u></font> mask; <font color='#009900'>/* mask for low root bits */</font>
code here; <font color='#009900'>/* table entry for duplication */</font>
code FAR <font color='#5555FF'>*</font>next; <font color='#009900'>/* next available space in table */</font>
<font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> FAR <font color='#5555FF'>*</font>base; <font color='#009900'>/* base value table to use */</font>
<font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> FAR <font color='#5555FF'>*</font>extra; <font color='#009900'>/* extra bits table to use */</font>
<font color='#0000FF'><u>int</u></font> end; <font color='#009900'>/* use base and extra for symbol &gt; end */</font>
<font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> count[MAXBITS<font color='#5555FF'>+</font><font color='#979000'>1</font>]; <font color='#009900'>/* number of codes of each length */</font>
<font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> offs[MAXBITS<font color='#5555FF'>+</font><font color='#979000'>1</font>]; <font color='#009900'>/* offsets in table for each length */</font>
<font color='#0000FF'>static</font> <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> lbase[<font color='#979000'>31</font>] <font color='#5555FF'>=</font> <b>{</b> <font color='#009900'>/* Length codes 257..285 base */</font>
<font color='#979000'>3</font>, <font color='#979000'>4</font>, <font color='#979000'>5</font>, <font color='#979000'>6</font>, <font color='#979000'>7</font>, <font color='#979000'>8</font>, <font color='#979000'>9</font>, <font color='#979000'>10</font>, <font color='#979000'>11</font>, <font color='#979000'>13</font>, <font color='#979000'>15</font>, <font color='#979000'>17</font>, <font color='#979000'>19</font>, <font color='#979000'>23</font>, <font color='#979000'>27</font>, <font color='#979000'>31</font>,
<font color='#979000'>35</font>, <font color='#979000'>43</font>, <font color='#979000'>51</font>, <font color='#979000'>59</font>, <font color='#979000'>67</font>, <font color='#979000'>83</font>, <font color='#979000'>99</font>, <font color='#979000'>115</font>, <font color='#979000'>131</font>, <font color='#979000'>163</font>, <font color='#979000'>195</font>, <font color='#979000'>227</font>, <font color='#979000'>258</font>, <font color='#979000'>0</font>, <font color='#979000'>0</font><b>}</b>;
<font color='#0000FF'>static</font> <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> lext[<font color='#979000'>31</font>] <font color='#5555FF'>=</font> <b>{</b> <font color='#009900'>/* Length codes 257..285 extra */</font>
<font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>17</font>, <font color='#979000'>17</font>, <font color='#979000'>17</font>, <font color='#979000'>17</font>, <font color='#979000'>18</font>, <font color='#979000'>18</font>, <font color='#979000'>18</font>, <font color='#979000'>18</font>,
<font color='#979000'>19</font>, <font color='#979000'>19</font>, <font color='#979000'>19</font>, <font color='#979000'>19</font>, <font color='#979000'>20</font>, <font color='#979000'>20</font>, <font color='#979000'>20</font>, <font color='#979000'>20</font>, <font color='#979000'>21</font>, <font color='#979000'>21</font>, <font color='#979000'>21</font>, <font color='#979000'>21</font>, <font color='#979000'>16</font>, <font color='#979000'>72</font>, <font color='#979000'>78</font><b>}</b>;
<font color='#0000FF'>static</font> <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> dbase[<font color='#979000'>32</font>] <font color='#5555FF'>=</font> <b>{</b> <font color='#009900'>/* Distance codes 0..29 base */</font>
<font color='#979000'>1</font>, <font color='#979000'>2</font>, <font color='#979000'>3</font>, <font color='#979000'>4</font>, <font color='#979000'>5</font>, <font color='#979000'>7</font>, <font color='#979000'>9</font>, <font color='#979000'>13</font>, <font color='#979000'>17</font>, <font color='#979000'>25</font>, <font color='#979000'>33</font>, <font color='#979000'>49</font>, <font color='#979000'>65</font>, <font color='#979000'>97</font>, <font color='#979000'>129</font>, <font color='#979000'>193</font>,
<font color='#979000'>257</font>, <font color='#979000'>385</font>, <font color='#979000'>513</font>, <font color='#979000'>769</font>, <font color='#979000'>1025</font>, <font color='#979000'>1537</font>, <font color='#979000'>2049</font>, <font color='#979000'>3073</font>, <font color='#979000'>4097</font>, <font color='#979000'>6145</font>,
<font color='#979000'>8193</font>, <font color='#979000'>12289</font>, <font color='#979000'>16385</font>, <font color='#979000'>24577</font>, <font color='#979000'>0</font>, <font color='#979000'>0</font><b>}</b>;
<font color='#0000FF'>static</font> <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font> dext[<font color='#979000'>32</font>] <font color='#5555FF'>=</font> <b>{</b> <font color='#009900'>/* Distance codes 0..29 extra */</font>
<font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>16</font>, <font color='#979000'>17</font>, <font color='#979000'>17</font>, <font color='#979000'>18</font>, <font color='#979000'>18</font>, <font color='#979000'>19</font>, <font color='#979000'>19</font>, <font color='#979000'>20</font>, <font color='#979000'>20</font>, <font color='#979000'>21</font>, <font color='#979000'>21</font>, <font color='#979000'>22</font>, <font color='#979000'>22</font>,
<font color='#979000'>23</font>, <font color='#979000'>23</font>, <font color='#979000'>24</font>, <font color='#979000'>24</font>, <font color='#979000'>25</font>, <font color='#979000'>25</font>, <font color='#979000'>26</font>, <font color='#979000'>26</font>, <font color='#979000'>27</font>, <font color='#979000'>27</font>,
<font color='#979000'>28</font>, <font color='#979000'>28</font>, <font color='#979000'>29</font>, <font color='#979000'>29</font>, <font color='#979000'>64</font>, <font color='#979000'>64</font><b>}</b>;
<font color='#009900'>/*
Process a set of code lengths to create a canonical Huffman code. The
code lengths are lens[0..codes-1]. Each length corresponds to the
symbols 0..codes-1. The Huffman code is generated by first sorting the
symbols by length from short to long, and retaining the symbol order
for codes with equal lengths. Then the code starts with all zero bits
for the first code of the shortest length, and the codes are integer
increments for the same length, and zeros are appended as the length
increases. For the deflate format, these bits are stored backwards
from their more natural integer increment ordering, and so when the
decoding tables are built in the large loop below, the integer codes
are incremented backwards.
This routine assumes, but does not check, that all of the entries in
lens[] are in the range 0..MAXBITS. The caller must assure this.
1..MAXBITS is interpreted as that code length. zero means that that
symbol does not occur in this code.
The codes are sorted by computing a count of codes for each length,
creating from that a table of starting indices for each length in the
sorted table, and then entering the symbols in order in the sorted
table. The sorted table is work[], with that space being provided by
the caller.
The length counts are used for other purposes as well, i.e. finding
the minimum and maximum length codes, determining if there are any
codes at all, checking for a valid set of lengths, and looking ahead
at length counts to determine sub-table sizes when building the
decoding tables.
*/</font>
<font color='#009900'>/* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>=</font> <font color='#979000'>0</font>; len <font color='#5555FF'>&lt;</font><font color='#5555FF'>=</font> MAXBITS; len<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font>
count[len] <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>sym <font color='#5555FF'>=</font> <font color='#979000'>0</font>; sym <font color='#5555FF'>&lt;</font> codes; sym<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font>
count[lens[sym]]<font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
<font color='#009900'>/* bound code lengths, force root to be within code lengths */</font>
root <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>bits;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>max <font color='#5555FF'>=</font> MAXBITS; max <font color='#5555FF'>&gt;</font><font color='#5555FF'>=</font> <font color='#979000'>1</font>; max<font color='#5555FF'>-</font><font color='#5555FF'>-</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>count[max] <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <font color='#0000FF'>break</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>root <font color='#5555FF'>&gt;</font> max<font face='Lucida Console'>)</font> root <font color='#5555FF'>=</font> max;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>max <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <b>{</b> <font color='#009900'>/* no symbols to code at all */</font>
here.op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font color='#979000'>64</font>; <font color='#009900'>/* invalid code marker */</font>
here.bits <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font color='#979000'>1</font>;
here.val <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font><font face='Lucida Console'>)</font><font color='#979000'>0</font>;
<font color='#5555FF'>*</font><font face='Lucida Console'>(</font><font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font><font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> here; <font color='#009900'>/* make a table to force an error */</font>
<font color='#5555FF'>*</font><font face='Lucida Console'>(</font><font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font><font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> here;
<font color='#5555FF'>*</font>bits <font color='#5555FF'>=</font> <font color='#979000'>1</font>;
<font color='#0000FF'>return</font> <font color='#979000'>0</font>; <font color='#009900'>/* no symbols, but wait for decoding to report error */</font>
<b>}</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>min <font color='#5555FF'>=</font> <font color='#979000'>1</font>; min <font color='#5555FF'>&lt;</font> max; min<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>count[min] <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <font color='#0000FF'>break</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>root <font color='#5555FF'>&lt;</font> min<font face='Lucida Console'>)</font> root <font color='#5555FF'>=</font> min;
<font color='#009900'>/* check for an over-subscribed or incomplete set of lengths */</font>
left <font color='#5555FF'>=</font> <font color='#979000'>1</font>;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>=</font> <font color='#979000'>1</font>; len <font color='#5555FF'>&lt;</font><font color='#5555FF'>=</font> MAXBITS; len<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
left <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font><font color='#5555FF'>=</font> <font color='#979000'>1</font>;
left <font color='#5555FF'>-</font><font color='#5555FF'>=</font> count[len];
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>left <font color='#5555FF'>&lt;</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <font color='#0000FF'>return</font> <font color='#5555FF'>-</font><font color='#979000'>1</font>; <font color='#009900'>/* over-subscribed */</font>
<b>}</b>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>left <font color='#5555FF'>&gt;</font> <font color='#979000'>0</font> <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> <font face='Lucida Console'>(</font>type <font color='#5555FF'>=</font><font color='#5555FF'>=</font> CODES <font color='#5555FF'>|</font><font color='#5555FF'>|</font> max <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>1</font><font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>return</font> <font color='#5555FF'>-</font><font color='#979000'>1</font>; <font color='#009900'>/* incomplete set */</font>
<font color='#009900'>/* generate offsets into symbol table for each length for sorting */</font>
offs[<font color='#979000'>1</font>] <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>=</font> <font color='#979000'>1</font>; len <font color='#5555FF'>&lt;</font> MAXBITS; len<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font>
offs[len <font color='#5555FF'>+</font> <font color='#979000'>1</font>] <font color='#5555FF'>=</font> offs[len] <font color='#5555FF'>+</font> count[len];
<font color='#009900'>/* sort symbols by length, by symbol order within each length */</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>sym <font color='#5555FF'>=</font> <font color='#979000'>0</font>; sym <font color='#5555FF'>&lt;</font> codes; sym<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>lens[sym] <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> work[offs[lens[sym]]<font color='#5555FF'>+</font><font color='#5555FF'>+</font>] <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font><font face='Lucida Console'>)</font>sym;
<font color='#009900'>/*
Create and fill in decoding tables. In this loop, the table being
filled is at next and has curr index bits. The code being used is huff
with length len. That code is converted to an index by dropping drop
bits off of the bottom. For codes where len is less than drop + curr,
those top drop + curr - len bits are incremented through all values to
fill the table with replicated entries.
root is the number of index bits for the root table. When len exceeds
root, sub-tables are created pointed to by the root entry with an index
of the low root bits of huff. This is saved in low to check for when a
new sub-table should be started. drop is zero when the root table is
being filled, and drop is root when sub-tables are being filled.
When a new sub-table is needed, it is necessary to look ahead in the
code lengths to determine what size sub-table is needed. The length
counts are used for this, and so count[] is decremented as codes are
entered in the tables.
used keeps track of how many table entries have been allocated from the
provided *table space. It is checked for LENS and DIST tables against
the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in
the initial root table size constants. See the comments in inftrees.h
for more information.
sym increments through all symbols, and the loop terminates when
all codes of length max, i.e. all codes, have been processed. This
routine permits incomplete codes, so another loop after this one fills
in the rest of the decoding tables with invalid code markers.
*/</font>
<font color='#009900'>/* set up for code type */</font>
<font color='#0000FF'>switch</font> <font face='Lucida Console'>(</font>type<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>case</font> CODES:
base <font color='#5555FF'>=</font> extra <font color='#5555FF'>=</font> work; <font color='#009900'>/* dummy value--not used */</font>
end <font color='#5555FF'>=</font> <font color='#979000'>19</font>;
<font color='#0000FF'>break</font>;
<font color='#0000FF'>case</font> LENS:
base <font color='#5555FF'>=</font> lbase;
base <font color='#5555FF'>-</font><font color='#5555FF'>=</font> <font color='#979000'>257</font>;
extra <font color='#5555FF'>=</font> lext;
extra <font color='#5555FF'>-</font><font color='#5555FF'>=</font> <font color='#979000'>257</font>;
end <font color='#5555FF'>=</font> <font color='#979000'>256</font>;
<font color='#0000FF'>break</font>;
<font color='#0000FF'>default</font>: <font color='#009900'>/* DISTS */</font>
base <font color='#5555FF'>=</font> dbase;
extra <font color='#5555FF'>=</font> dext;
end <font color='#5555FF'>=</font> <font color='#5555FF'>-</font><font color='#979000'>1</font>;
<b>}</b>
<font color='#009900'>/* initialize state for loop */</font>
huff <font color='#5555FF'>=</font> <font color='#979000'>0</font>; <font color='#009900'>/* starting code */</font>
sym <font color='#5555FF'>=</font> <font color='#979000'>0</font>; <font color='#009900'>/* starting code symbol */</font>
len <font color='#5555FF'>=</font> min; <font color='#009900'>/* starting code length */</font>
next <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>table; <font color='#009900'>/* current table to fill in */</font>
curr <font color='#5555FF'>=</font> root; <font color='#009900'>/* current table index bits */</font>
drop <font color='#5555FF'>=</font> <font color='#979000'>0</font>; <font color='#009900'>/* current bits to drop from code for index */</font>
low <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font><font color='#5555FF'>-</font><font color='#979000'>1</font><font face='Lucida Console'>)</font>; <font color='#009900'>/* trigger new sub-table when len &gt; root */</font>
used <font color='#5555FF'>=</font> <font color='#979000'>1</font>U <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> root; <font color='#009900'>/* use root table entries */</font>
mask <font color='#5555FF'>=</font> used <font color='#5555FF'>-</font> <font color='#979000'>1</font>; <font color='#009900'>/* mask for comparing low */</font>
<font color='#009900'>/* check available table space */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>type <font color='#5555FF'>=</font><font color='#5555FF'>=</font> LENS <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> used <font color='#5555FF'>&gt;</font> ENOUGH_LENS<font face='Lucida Console'>)</font> <font color='#5555FF'>|</font><font color='#5555FF'>|</font>
<font face='Lucida Console'>(</font>type <font color='#5555FF'>=</font><font color='#5555FF'>=</font> DISTS <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> used <font color='#5555FF'>&gt;</font> ENOUGH_DISTS<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>return</font> <font color='#979000'>1</font>;
<font color='#009900'>/* process all codes and make table entries */</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>;;<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* create table entry */</font>
here.bits <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>len <font color='#5555FF'>-</font> drop<font face='Lucida Console'>)</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>work[sym]<font face='Lucida Console'>)</font> <font color='#5555FF'>&lt;</font> end<font face='Lucida Console'>)</font> <b>{</b>
here.op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font color='#979000'>0</font>;
here.val <font color='#5555FF'>=</font> work[sym];
<b>}</b>
<font color='#0000FF'>else</font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>work[sym]<font face='Lucida Console'>)</font> <font color='#5555FF'>&gt;</font> end<font face='Lucida Console'>)</font> <b>{</b>
here.op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>extra[work[sym]]<font face='Lucida Console'>)</font>;
here.val <font color='#5555FF'>=</font> base[work[sym]];
<b>}</b>
<font color='#0000FF'>else</font> <b>{</b>
here.op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font><font color='#979000'>32</font> <font color='#5555FF'>+</font> <font color='#979000'>64</font><font face='Lucida Console'>)</font>; <font color='#009900'>/* end of block */</font>
here.val <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<b>}</b>
<font color='#009900'>/* replicate for those indices with low len bits equal to huff */</font>
incr <font color='#5555FF'>=</font> <font color='#979000'>1</font>U <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>-</font> drop<font face='Lucida Console'>)</font>;
fill <font color='#5555FF'>=</font> <font color='#979000'>1</font>U <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> curr;
min <font color='#5555FF'>=</font> fill; <font color='#009900'>/* save offset to next table */</font>
<font color='#0000FF'>do</font> <b>{</b>
fill <font color='#5555FF'>-</font><font color='#5555FF'>=</font> incr;
next[<font face='Lucida Console'>(</font>huff <font color='#5555FF'>&gt;</font><font color='#5555FF'>&gt;</font> drop<font face='Lucida Console'>)</font> <font color='#5555FF'>+</font> fill] <font color='#5555FF'>=</font> here;
<b>}</b> <font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>fill <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font>;
<font color='#009900'>/* backwards increment the len-bit code huff */</font>
incr <font color='#5555FF'>=</font> <font color='#979000'>1</font>U <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>-</font> <font color='#979000'>1</font><font face='Lucida Console'>)</font>;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>huff <font color='#5555FF'>&amp;</font> incr<font face='Lucida Console'>)</font>
incr <font color='#5555FF'>&gt;</font><font color='#5555FF'>&gt;</font><font color='#5555FF'>=</font> <font color='#979000'>1</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>incr <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <b>{</b>
huff <font color='#5555FF'>&amp;</font><font color='#5555FF'>=</font> incr <font color='#5555FF'>-</font> <font color='#979000'>1</font>;
huff <font color='#5555FF'>+</font><font color='#5555FF'>=</font> incr;
<b>}</b>
<font color='#0000FF'>else</font>
huff <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#009900'>/* go to next symbol, update count, len */</font>
sym<font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font color='#5555FF'>-</font><font color='#5555FF'>-</font><font face='Lucida Console'>(</font>count[len]<font face='Lucida Console'>)</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>=</font><font color='#5555FF'>=</font> max<font face='Lucida Console'>)</font> <font color='#0000FF'>break</font>;
len <font color='#5555FF'>=</font> lens[work[sym]];
<b>}</b>
<font color='#009900'>/* create new sub-table if needed */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>len <font color='#5555FF'>&gt;</font> root <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> <font face='Lucida Console'>(</font>huff <font color='#5555FF'>&amp;</font> mask<font face='Lucida Console'>)</font> <font color='#5555FF'>!</font><font color='#5555FF'>=</font> low<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* if first time, transition to sub-tables */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>drop <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font>
drop <font color='#5555FF'>=</font> root;
<font color='#009900'>/* increment past last table */</font>
next <font color='#5555FF'>+</font><font color='#5555FF'>=</font> min; <font color='#009900'>/* here min is 1 &lt;&lt; curr */</font>
<font color='#009900'>/* determine length of next table */</font>
curr <font color='#5555FF'>=</font> len <font color='#5555FF'>-</font> drop;
left <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font><font color='#979000'>1</font> <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> curr<font face='Lucida Console'>)</font>;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>curr <font color='#5555FF'>+</font> drop <font color='#5555FF'>&lt;</font> max<font face='Lucida Console'>)</font> <b>{</b>
left <font color='#5555FF'>-</font><font color='#5555FF'>=</font> count[curr <font color='#5555FF'>+</font> drop];
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>left <font color='#5555FF'>&lt;</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <font color='#0000FF'>break</font>;
curr<font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
left <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font><font color='#5555FF'>=</font> <font color='#979000'>1</font>;
<b>}</b>
<font color='#009900'>/* check for enough space */</font>
used <font color='#5555FF'>+</font><font color='#5555FF'>=</font> <font color='#979000'>1</font>U <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> curr;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>type <font color='#5555FF'>=</font><font color='#5555FF'>=</font> LENS <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> used <font color='#5555FF'>&gt;</font> ENOUGH_LENS<font face='Lucida Console'>)</font> <font color='#5555FF'>|</font><font color='#5555FF'>|</font>
<font face='Lucida Console'>(</font>type <font color='#5555FF'>=</font><font color='#5555FF'>=</font> DISTS <font color='#5555FF'>&amp;</font><font color='#5555FF'>&amp;</font> used <font color='#5555FF'>&gt;</font> ENOUGH_DISTS<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>return</font> <font color='#979000'>1</font>;
<font color='#009900'>/* point entry in root table to sub-table */</font>
low <font color='#5555FF'>=</font> huff <font color='#5555FF'>&amp;</font> mask;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font>[low].op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font>curr;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font>[low].bits <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font>root;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font>[low].val <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>next <font color='#5555FF'>-</font> <font color='#5555FF'>*</font>table<font face='Lucida Console'>)</font>;
<b>}</b>
<b>}</b>
<font color='#009900'>/* fill in remaining table entry if code is incomplete (guaranteed to have
at most one remaining entry, since if the code is incomplete, the
maximum code length that was allowed to get this far is one bit) */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>huff <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <b>{</b>
here.op <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font color='#979000'>64</font>; <font color='#009900'>/* invalid code marker */</font>
here.bits <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>len <font color='#5555FF'>-</font> drop<font face='Lucida Console'>)</font>;
here.val <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>short</u></font><font face='Lucida Console'>)</font><font color='#979000'>0</font>;
next[huff] <font color='#5555FF'>=</font> here;
<b>}</b>
<font color='#009900'>/* set return parameters */</font>
<font color='#5555FF'>*</font>table <font color='#5555FF'>+</font><font color='#5555FF'>=</font> used;
<font color='#5555FF'>*</font>bits <font color='#5555FF'>=</font> root;
<font color='#0000FF'>return</font> <font color='#979000'>0</font>;
<b>}</b>
</pre></body></html>