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src/java.base/share/native/libzip/zlib/inftrees.c

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  6  * published by the Free Software Foundation.  Oracle designates this
  7  * particular file as subject to the "Classpath" exception as provided
  8  * by Oracle in the LICENSE file that accompanied this code.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  */
 24 
 25 /* inftrees.c -- generate Huffman trees for efficient decoding
 26  * Copyright (C) 1995-2022 Mark Adler
 27  * For conditions of distribution and use, see copyright notice in zlib.h
 28  */
 29 
 30 #include "zutil.h"
 31 #include "inftrees.h"
 32 
 33 #define MAXBITS 15
 34 
 35 const char inflate_copyright[] =
 36    " inflate 1.2.13 Copyright 1995-2022 Mark Adler ";
 37 /*
 38   If you use the zlib library in a product, an acknowledgment is welcome
 39   in the documentation of your product. If for some reason you cannot
 40   include such an acknowledgment, I would appreciate that you keep this
 41   copyright string in the executable of your product.
 42  */
 43 
 44 /*
 45    Build a set of tables to decode the provided canonical Huffman code.
 46    The code lengths are lens[0..codes-1].  The result starts at *table,
 47    whose indices are 0..2^bits-1.  work is a writable array of at least
 48    lens shorts, which is used as a work area.  type is the type of code
 49    to be generated, CODES, LENS, or DISTS.  On return, zero is success,
 50    -1 is an invalid code, and +1 means that ENOUGH isn't enough.  table
 51    on return points to the next available entry's address.  bits is the
 52    requested root table index bits, and on return it is the actual root
 53    table index bits.  It will differ if the request is greater than the
 54    longest code or if it is less than the shortest code.
 55  */
 56 int ZLIB_INTERNAL inflate_table(type, lens, codes, table, bits, work)
 57 codetype type;
 58 unsigned short FAR *lens;
 59 unsigned codes;
 60 code FAR * FAR *table;
 61 unsigned FAR *bits;
 62 unsigned short FAR *work;
 63 {
 64     unsigned len;               /* a code's length in bits */
 65     unsigned sym;               /* index of code symbols */
 66     unsigned min, max;          /* minimum and maximum code lengths */
 67     unsigned root;              /* number of index bits for root table */
 68     unsigned curr;              /* number of index bits for current table */
 69     unsigned drop;              /* code bits to drop for sub-table */
 70     int left;                   /* number of prefix codes available */
 71     unsigned used;              /* code entries in table used */
 72     unsigned huff;              /* Huffman code */
 73     unsigned incr;              /* for incrementing code, index */
 74     unsigned fill;              /* index for replicating entries */
 75     unsigned low;               /* low bits for current root entry */
 76     unsigned mask;              /* mask for low root bits */
 77     code here;                  /* table entry for duplication */
 78     code FAR *next;             /* next available space in table */
 79     const unsigned short FAR *base;     /* base value table to use */
 80     const unsigned short FAR *extra;    /* extra bits table to use */
 81     unsigned match;             /* use base and extra for symbol >= match */
 82     unsigned short count[MAXBITS+1];    /* number of codes of each length */
 83     unsigned short offs[MAXBITS+1];     /* offsets in table for each length */
 84     static const unsigned short lbase[31] = { /* Length codes 257..285 base */
 85         3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
 86         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
 87     static const unsigned short lext[31] = { /* Length codes 257..285 extra */
 88         16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
 89         19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 194, 65};
 90     static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
 91         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
 92         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
 93         8193, 12289, 16385, 24577, 0, 0};
 94     static const unsigned short dext[32] = { /* Distance codes 0..29 extra */
 95         16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22,
 96         23, 23, 24, 24, 25, 25, 26, 26, 27, 27,
 97         28, 28, 29, 29, 64, 64};
 98 
 99     /*
100        Process a set of code lengths to create a canonical Huffman code.  The
101        code lengths are lens[0..codes-1].  Each length corresponds to the
102        symbols 0..codes-1.  The Huffman code is generated by first sorting the
103        symbols by length from short to long, and retaining the symbol order
104        for codes with equal lengths.  Then the code starts with all zero bits
105        for the first code of the shortest length, and the codes are integer
106        increments for the same length, and zeros are appended as the length
107        increases.  For the deflate format, these bits are stored backwards
108        from their more natural integer increment ordering, and so when the
109        decoding tables are built in the large loop below, the integer codes

  6  * published by the Free Software Foundation.  Oracle designates this
  7  * particular file as subject to the "Classpath" exception as provided
  8  * by Oracle in the LICENSE file that accompanied this code.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  */
 24 
 25 /* inftrees.c -- generate Huffman trees for efficient decoding
 26  * Copyright (C) 1995-2024 Mark Adler
 27  * For conditions of distribution and use, see copyright notice in zlib.h
 28  */
 29 
 30 #include "zutil.h"
 31 #include "inftrees.h"
 32 
 33 #define MAXBITS 15
 34 
 35 const char inflate_copyright[] =
 36    " inflate 1.3.1 Copyright 1995-2024 Mark Adler ";
 37 /*
 38   If you use the zlib library in a product, an acknowledgment is welcome
 39   in the documentation of your product. If for some reason you cannot
 40   include such an acknowledgment, I would appreciate that you keep this
 41   copyright string in the executable of your product.
 42  */
 43 
 44 /*
 45    Build a set of tables to decode the provided canonical Huffman code.
 46    The code lengths are lens[0..codes-1].  The result starts at *table,
 47    whose indices are 0..2^bits-1.  work is a writable array of at least
 48    lens shorts, which is used as a work area.  type is the type of code
 49    to be generated, CODES, LENS, or DISTS.  On return, zero is success,
 50    -1 is an invalid code, and +1 means that ENOUGH isn't enough.  table
 51    on return points to the next available entry's address.  bits is the
 52    requested root table index bits, and on return it is the actual root
 53    table index bits.  It will differ if the request is greater than the
 54    longest code or if it is less than the shortest code.
 55  */
 56 int ZLIB_INTERNAL inflate_table(codetype type, unsigned short FAR *lens,
 57                                 unsigned codes, code FAR * FAR *table,
 58                                 unsigned FAR *bits, unsigned short FAR *work) {





 59     unsigned len;               /* a code's length in bits */
 60     unsigned sym;               /* index of code symbols */
 61     unsigned min, max;          /* minimum and maximum code lengths */
 62     unsigned root;              /* number of index bits for root table */
 63     unsigned curr;              /* number of index bits for current table */
 64     unsigned drop;              /* code bits to drop for sub-table */
 65     int left;                   /* number of prefix codes available */
 66     unsigned used;              /* code entries in table used */
 67     unsigned huff;              /* Huffman code */
 68     unsigned incr;              /* for incrementing code, index */
 69     unsigned fill;              /* index for replicating entries */
 70     unsigned low;               /* low bits for current root entry */
 71     unsigned mask;              /* mask for low root bits */
 72     code here;                  /* table entry for duplication */
 73     code FAR *next;             /* next available space in table */
 74     const unsigned short FAR *base;     /* base value table to use */
 75     const unsigned short FAR *extra;    /* extra bits table to use */
 76     unsigned match;             /* use base and extra for symbol >= match */
 77     unsigned short count[MAXBITS+1];    /* number of codes of each length */
 78     unsigned short offs[MAXBITS+1];     /* offsets in table for each length */
 79     static const unsigned short lbase[31] = { /* Length codes 257..285 base */
 80         3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
 81         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
 82     static const unsigned short lext[31] = { /* Length codes 257..285 extra */
 83         16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
 84         19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 203, 77};
 85     static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
 86         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
 87         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
 88         8193, 12289, 16385, 24577, 0, 0};
 89     static const unsigned short dext[32] = { /* Distance codes 0..29 extra */
 90         16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22,
 91         23, 23, 24, 24, 25, 25, 26, 26, 27, 27,
 92         28, 28, 29, 29, 64, 64};
 93 
 94     /*
 95        Process a set of code lengths to create a canonical Huffman code.  The
 96        code lengths are lens[0..codes-1].  Each length corresponds to the
 97        symbols 0..codes-1.  The Huffman code is generated by first sorting the
 98        symbols by length from short to long, and retaining the symbol order
 99        for codes with equal lengths.  Then the code starts with all zero bits
100        for the first code of the shortest length, and the codes are integer
101        increments for the same length, and zeros are appended as the length
102        increases.  For the deflate format, these bits are stored backwards
103        from their more natural integer increment ordering, and so when the
104        decoding tables are built in the large loop below, the integer codes
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