lightningsunbird
0.9+nobinonly

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Defines  
#define  MAXBITS 15 
Functions  
int  inflate_table (codetype type, unsigned short FAR *lens, unsigned codes, code FAR *FAR *table, unsigned FAR *bits, unsigned short FAR *work) 
Variables  
const char  inflate_copyright [] = " inflate 1.2.3 Copyright 19952005 Mark Adler " 
Definition at line 9 of file inftrees.c.
int inflate_table  (  codetype  type, 
unsigned short FAR *  lens,  
unsigned  codes,  
code FAR * FAR *  table,  
unsigned FAR *  bits,  
unsigned short FAR *  work  
) 
Definition at line 32 of file inftrees.c.
{ unsigned len; /* a code's length in bits */ unsigned sym; /* index of code symbols */ unsigned min, max; /* minimum and maximum code lengths */ unsigned root; /* number of index bits for root table */ unsigned curr; /* number of index bits for current table */ unsigned drop; /* code bits to drop for subtable */ int left; /* number of prefix codes available */ unsigned used; /* code entries in table used */ unsigned huff; /* Huffman code */ unsigned incr; /* for incrementing code, index */ unsigned fill; /* index for replicating entries */ unsigned low; /* low bits for current root entry */ unsigned mask; /* mask for low root bits */ code this; /* table entry for duplication */ code FAR *next; /* next available space in table */ const unsigned short FAR *base; /* base value table to use */ const unsigned short FAR *extra; /* extra bits table to use */ int end; /* use base and extra for symbol > end */ unsigned short count[MAXBITS+1]; /* number of codes of each length */ unsigned short offs[MAXBITS+1]; /* offsets in table for each length */ static const unsigned short lbase[31] = { /* Length codes 257..285 base */ 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; static const unsigned short lext[31] = { /* Length codes 257..285 extra */ 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 201, 196}; static const unsigned short dbase[32] = { /* Distance codes 0..29 base */ 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0}; static const unsigned short dext[32] = { /* Distance codes 0..29 extra */ 16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 64, 64}; /* Process a set of code lengths to create a canonical Huffman code. The code lengths are lens[0..codes1]. Each length corresponds to the symbols 0..codes1. 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 subtable sizes when building the decoding tables. */ /* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */ for (len = 0; len <= MAXBITS; len++) count[len] = 0; for (sym = 0; sym < codes; sym++) count[lens[sym]]++; /* bound code lengths, force root to be within code lengths */ root = *bits; for (max = MAXBITS; max >= 1; max) if (count[max] != 0) break; if (root > max) root = max; if (max == 0) { /* no symbols to code at all */ this.op = (unsigned char)64; /* invalid code marker */ this.bits = (unsigned char)1; this.val = (unsigned short)0; *(*table)++ = this; /* make a table to force an error */ *(*table)++ = this; *bits = 1; return 0; /* no symbols, but wait for decoding to report error */ } for (min = 1; min <= MAXBITS; min++) if (count[min] != 0) break; if (root < min) root = min; /* check for an oversubscribed or incomplete set of lengths */ left = 1; for (len = 1; len <= MAXBITS; len++) { left <<= 1; left = count[len]; if (left < 0) return 1; /* oversubscribed */ } if (left > 0 && (type == CODES  max != 1)) return 1; /* incomplete set */ /* generate offsets into symbol table for each length for sorting */ offs[1] = 0; for (len = 1; len < MAXBITS; len++) offs[len + 1] = offs[len] + count[len]; /* sort symbols by length, by symbol order within each length */ for (sym = 0; sym < codes; sym++) if (lens[sym] != 0) work[offs[lens[sym]]++] = (unsigned short)sym; /* 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, subtables 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 subtable should be started. drop is zero when the root table is being filled, and drop is root when subtables are being filled. When a new subtable is needed, it is necessary to look ahead in the code lengths to determine what size subtable 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 when a LENS table is being made against the space in *table, ENOUGH, minus the maximum space needed by the worst case distance code, MAXD. This should never happen, but the sufficiency of ENOUGH has not been proven exhaustively, hence the check. This assumes that when type == LENS, bits == 9. 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. */ /* set up for code type */ switch (type) { case CODES: base = extra = work; /* dummy valuenot used */ end = 19; break; case LENS: base = lbase; base = 257; extra = lext; extra = 257; end = 256; break; default: /* DISTS */ base = dbase; extra = dext; end = 1; } /* initialize state for loop */ huff = 0; /* starting code */ sym = 0; /* starting code symbol */ len = min; /* starting code length */ next = *table; /* current table to fill in */ curr = root; /* current table index bits */ drop = 0; /* current bits to drop from code for index */ low = (unsigned)(1); /* trigger new subtable when len > root */ used = 1U << root; /* use root table entries */ mask = used  1; /* mask for comparing low */ /* check available table space */ if (type == LENS && used >= ENOUGH  MAXD) return 1; /* process all codes and make table entries */ for (;;) { /* create table entry */ this.bits = (unsigned char)(len  drop); if ((int)(work[sym]) < end) { this.op = (unsigned char)0; this.val = work[sym]; } else if ((int)(work[sym]) > end) { this.op = (unsigned char)(extra[work[sym]]); this.val = base[work[sym]]; } else { this.op = (unsigned char)(32 + 64); /* end of block */ this.val = 0; } /* replicate for those indices with low len bits equal to huff */ incr = 1U << (len  drop); fill = 1U << curr; min = fill; /* save offset to next table */ do { fill = incr; next[(huff >> drop) + fill] = this; } while (fill != 0); /* backwards increment the lenbit code huff */ incr = 1U << (len  1); while (huff & incr) incr >>= 1; if (incr != 0) { huff &= incr  1; huff += incr; } else huff = 0; /* go to next symbol, update count, len */ sym++; if ((count[len]) == 0) { if (len == max) break; len = lens[work[sym]]; } /* create new subtable if needed */ if (len > root && (huff & mask) != low) { /* if first time, transition to subtables */ if (drop == 0) drop = root; /* increment past last table */ next += min; /* here min is 1 << curr */ /* determine length of next table */ curr = len  drop; left = (int)(1 << curr); while (curr + drop < max) { left = count[curr + drop]; if (left <= 0) break; curr++; left <<= 1; } /* check for enough space */ used += 1U << curr; if (type == LENS && used >= ENOUGH  MAXD) return 1; /* point entry in root table to subtable */ low = huff & mask; (*table)[low].op = (unsigned char)curr; (*table)[low].bits = (unsigned char)root; (*table)[low].val = (unsigned short)(next  *table); } } /* Fill in rest of table for incomplete codes. This loop is similar to the loop above in incrementing huff for table indices. It is assumed that len is equal to curr + drop, so there is no loop needed to increment through high index bits. When the current subtable is filled, the loop drops back to the root table to fill in any remaining entries there. */ this.op = (unsigned char)64; /* invalid code marker */ this.bits = (unsigned char)(len  drop); this.val = (unsigned short)0; while (huff != 0) { /* when done with subtable, drop back to root table */ if (drop != 0 && (huff & mask) != low) { drop = 0; len = root; next = *table; this.bits = (unsigned char)len; } /* put invalid code marker in table */ next[huff >> drop] = this; /* backwards increment the lenbit code huff */ incr = 1U << (len  1); while (huff & incr) incr >>= 1; if (incr != 0) { huff &= incr  1; huff += incr; } else huff = 0; } /* set return parameters */ *table += used; *bits = root; return 0; }
const char inflate_copyright[] = " inflate 1.2.3 Copyright 19952005 Mark Adler " 
Definition at line 11 of file inftrees.c.