mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-12-15 04:31:49 +08:00
598 lines
24 KiB
C
598 lines
24 KiB
C
/* enough.c -- determine the maximum size of inflate's Huffman code tables over
|
|
* all possible valid and complete prefix codes, subject to a length limit.
|
|
* Copyright (C) 2007, 2008, 2012, 2018 Mark Adler
|
|
* Version 1.5 5 August 2018 Mark Adler
|
|
*/
|
|
|
|
/* Version history:
|
|
1.0 3 Jan 2007 First version (derived from codecount.c version 1.4)
|
|
1.1 4 Jan 2007 Use faster incremental table usage computation
|
|
Prune examine() search on previously visited states
|
|
1.2 5 Jan 2007 Comments clean up
|
|
As inflate does, decrease root for short codes
|
|
Refuse cases where inflate would increase root
|
|
1.3 17 Feb 2008 Add argument for initial root table size
|
|
Fix bug for initial root table size == max - 1
|
|
Use a macro to compute the history index
|
|
1.4 18 Aug 2012 Avoid shifts more than bits in type (caused endless loop!)
|
|
Clean up comparisons of different types
|
|
Clean up code indentation
|
|
1.5 5 Aug 2018 Clean up code style, formatting, and comments
|
|
Show all the codes for the maximum, and only the maximum
|
|
*/
|
|
|
|
/*
|
|
Examine all possible prefix codes for a given number of symbols and a
|
|
maximum code length in bits to determine the maximum table size for zlib's
|
|
inflate. Only complete prefix codes are counted.
|
|
|
|
Two codes are considered distinct if the vectors of the number of codes per
|
|
length are not identical. So permutations of the symbol assignments result
|
|
in the same code for the counting, as do permutations of the assignments of
|
|
the bit values to the codes (i.e. only canonical codes are counted).
|
|
|
|
We build a code from shorter to longer lengths, determining how many symbols
|
|
are coded at each length. At each step, we have how many symbols remain to
|
|
be coded, what the last code length used was, and how many bit patterns of
|
|
that length remain unused. Then we add one to the code length and double the
|
|
number of unused patterns to graduate to the next code length. We then
|
|
assign all portions of the remaining symbols to that code length that
|
|
preserve the properties of a correct and eventually complete code. Those
|
|
properties are: we cannot use more bit patterns than are available; and when
|
|
all the symbols are used, there are exactly zero possible bit patterns left
|
|
unused.
|
|
|
|
The inflate Huffman decoding algorithm uses two-level lookup tables for
|
|
speed. There is a single first-level table to decode codes up to root bits
|
|
in length (root == 9 for literal/length codes and root == 6 for distance
|
|
codes, in the current inflate implementation). The base table has 1 << root
|
|
entries and is indexed by the next root bits of input. Codes shorter than
|
|
root bits have replicated table entries, so that the correct entry is
|
|
pointed to regardless of the bits that follow the short code. If the code is
|
|
longer than root bits, then the table entry points to a second-level table.
|
|
The size of that table is determined by the longest code with that root-bit
|
|
prefix. If that longest code has length len, then the table has size 1 <<
|
|
(len - root), to index the remaining bits in that set of codes. Each
|
|
subsequent root-bit prefix then has its own sub-table. The total number of
|
|
table entries required by the code is calculated incrementally as the number
|
|
of codes at each bit length is populated. When all of the codes are shorter
|
|
than root bits, then root is reduced to the longest code length, resulting
|
|
in a single, smaller, one-level table.
|
|
|
|
The inflate algorithm also provides for small values of root (relative to
|
|
the log2 of the number of symbols), where the shortest code has more bits
|
|
than root. In that case, root is increased to the length of the shortest
|
|
code. This program, by design, does not handle that case, so it is verified
|
|
that the number of symbols is less than 1 << (root + 1).
|
|
|
|
In order to speed up the examination (by about ten orders of magnitude for
|
|
the default arguments), the intermediate states in the build-up of a code
|
|
are remembered and previously visited branches are pruned. The memory
|
|
required for this will increase rapidly with the total number of symbols and
|
|
the maximum code length in bits. However this is a very small price to pay
|
|
for the vast speedup.
|
|
|
|
First, all of the possible prefix codes are counted, and reachable
|
|
intermediate states are noted by a non-zero count in a saved-results array.
|
|
Second, the intermediate states that lead to (root + 1) bit or longer codes
|
|
are used to look at all sub-codes from those junctures for their inflate
|
|
memory usage. (The amount of memory used is not affected by the number of
|
|
codes of root bits or less in length.) Third, the visited states in the
|
|
construction of those sub-codes and the associated calculation of the table
|
|
size is recalled in order to avoid recalculating from the same juncture.
|
|
Beginning the code examination at (root + 1) bit codes, which is enabled by
|
|
identifying the reachable nodes, accounts for about six of the orders of
|
|
magnitude of improvement for the default arguments. About another four
|
|
orders of magnitude come from not revisiting previous states. Out of
|
|
approximately 2x10^16 possible prefix codes, only about 2x10^6 sub-codes
|
|
need to be examined to cover all of the possible table memory usage cases
|
|
for the default arguments of 286 symbols limited to 15-bit codes.
|
|
|
|
Note that the uintmax_t type is used for counting. It is quite easy to
|
|
exceed the capacity of an eight-byte integer with a large number of symbols
|
|
and a large maximum code length, so multiple-precision arithmetic would need
|
|
to replace the integer arithmetic in that case. This program will abort if
|
|
an overflow occurs. The big_t type identifies where the counting takes
|
|
place.
|
|
|
|
The uintmax_t type is also used for calculating the number of possible codes
|
|
remaining at the maximum length. This limits the maximum code length to the
|
|
number of bits in a long long minus the number of bits needed to represent
|
|
the symbols in a flat code. The code_t type identifies where the bit-pattern
|
|
counting takes place.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <stdarg.h>
|
|
#include <stdint.h>
|
|
#include <assert.h>
|
|
|
|
#define local static
|
|
|
|
// Special data types.
|
|
typedef uintmax_t big_t; // type for code counting
|
|
#define PRIbig "ju" // printf format for big_t
|
|
typedef uintmax_t code_t; // type for bit pattern counting
|
|
struct tab { // type for been-here check
|
|
size_t len; // allocated length of bit vector in octets
|
|
char *vec; // allocated bit vector
|
|
};
|
|
|
|
/* The array for saving results, num[], is indexed with this triplet:
|
|
|
|
syms: number of symbols remaining to code
|
|
left: number of available bit patterns at length len
|
|
len: number of bits in the codes currently being assigned
|
|
|
|
Those indices are constrained thusly when saving results:
|
|
|
|
syms: 3..totsym (totsym == total symbols to code)
|
|
left: 2..syms - 1, but only the evens (so syms == 8 -> 2, 4, 6)
|
|
len: 1..max - 1 (max == maximum code length in bits)
|
|
|
|
syms == 2 is not saved since that immediately leads to a single code. left
|
|
must be even, since it represents the number of available bit patterns at
|
|
the current length, which is double the number at the previous length. left
|
|
ends at syms-1 since left == syms immediately results in a single code.
|
|
(left > sym is not allowed since that would result in an incomplete code.)
|
|
len is less than max, since the code completes immediately when len == max.
|
|
|
|
The offset into the array is calculated for the three indices with the first
|
|
one (syms) being outermost, and the last one (len) being innermost. We build
|
|
the array with length max-1 lists for the len index, with syms-3 of those
|
|
for each symbol. There are totsym-2 of those, with each one varying in
|
|
length as a function of sym. See the calculation of index in map() for the
|
|
index, and the calculation of size in main() for the size of the array.
|
|
|
|
For the deflate example of 286 symbols limited to 15-bit codes, the array
|
|
has 284,284 entries, taking up 2.17 MB for an 8-byte big_t. More than half
|
|
of the space allocated for saved results is actually used -- not all
|
|
possible triplets are reached in the generation of valid prefix codes.
|
|
*/
|
|
|
|
/* The array for tracking visited states, done[], is itself indexed identically
|
|
to the num[] array as described above for the (syms, left, len) triplet.
|
|
Each element in the array is further indexed by the (mem, rem) doublet,
|
|
where mem is the amount of inflate table space used so far, and rem is the
|
|
remaining unused entries in the current inflate sub-table. Each indexed
|
|
element is simply one bit indicating whether the state has been visited or
|
|
not. Since the ranges for mem and rem are not known a priori, each bit
|
|
vector is of a variable size, and grows as needed to accommodate the visited
|
|
states. mem and rem are used to calculate a single index in a triangular
|
|
array. Since the range of mem is expected in the default case to be about
|
|
ten times larger than the range of rem, the array is skewed to reduce the
|
|
memory usage, with eight times the range for mem than for rem. See the
|
|
calculations for offset and bit in been_here() for the details.
|
|
|
|
For the deflate example of 286 symbols limited to 15-bit codes, the bit
|
|
vectors grow to total 5.5 MB, in addition to the 4.3 MB done array itself.
|
|
*/
|
|
|
|
// Type for a variable-length, allocated string.
|
|
typedef struct {
|
|
char *str; // pointer to allocated string
|
|
size_t size; // size of allocation
|
|
size_t len; // length of string, not including terminating zero
|
|
} string_t;
|
|
|
|
// Clear a string_t.
|
|
local void string_clear(string_t *s) {
|
|
s->str[0] = 0;
|
|
s->len = 0;
|
|
}
|
|
|
|
// Initialize a string_t.
|
|
local void string_init(string_t *s) {
|
|
s->size = 16;
|
|
s->str = malloc(s->size);
|
|
assert(s->str != NULL && "out of memory");
|
|
string_clear(s);
|
|
}
|
|
|
|
// Release the allocation of a string_t.
|
|
local void string_free(string_t *s) {
|
|
free(s->str);
|
|
s->str = NULL;
|
|
s->size = 0;
|
|
s->len = 0;
|
|
}
|
|
|
|
// Save the results of printf with fmt and the subsequent argument list to s.
|
|
// Each call appends to s. The allocated space for s is increased as needed.
|
|
local void string_printf(string_t *s, char *fmt, ...) {
|
|
va_list ap;
|
|
va_start(ap, fmt);
|
|
size_t len = s->len;
|
|
int ret = vsnprintf(s->str + len, s->size - len, fmt, ap);
|
|
assert(ret >= 0 && "out of memory");
|
|
s->len += ret;
|
|
if (s->size < s->len + 1) {
|
|
do {
|
|
s->size <<= 1;
|
|
assert(s->size != 0 && "overflow");
|
|
} while (s->size < s->len + 1);
|
|
s->str = realloc(s->str, s->size);
|
|
assert(s->str != NULL && "out of memory");
|
|
vsnprintf(s->str + len, s->size - len, fmt, ap);
|
|
}
|
|
va_end(ap);
|
|
}
|
|
|
|
// Globals to avoid propagating constants or constant pointers recursively.
|
|
struct {
|
|
int max; // maximum allowed bit length for the codes
|
|
int root; // size of base code table in bits
|
|
int large; // largest code table so far
|
|
size_t size; // number of elements in num and done
|
|
big_t tot; // total number of codes with maximum tables size
|
|
string_t out; // display of subcodes for maximum tables size
|
|
int *code; // number of symbols assigned to each bit length
|
|
big_t *num; // saved results array for code counting
|
|
struct tab *done; // states already evaluated array
|
|
} g;
|
|
|
|
// Index function for num[] and done[].
|
|
local inline size_t map(int syms, int left, int len) {
|
|
return ((size_t)((syms - 1) >> 1) * ((syms - 2) >> 1) +
|
|
(left >> 1) - 1) * (g.max - 1) +
|
|
len - 1;
|
|
}
|
|
|
|
// Free allocated space in globals.
|
|
local void cleanup(void) {
|
|
if (g.done != NULL) {
|
|
for (size_t n = 0; n < g.size; n++)
|
|
if (g.done[n].len)
|
|
free(g.done[n].vec);
|
|
g.size = 0;
|
|
free(g.done); g.done = NULL;
|
|
}
|
|
free(g.num); g.num = NULL;
|
|
free(g.code); g.code = NULL;
|
|
string_free(&g.out);
|
|
}
|
|
|
|
// Return the number of possible prefix codes using bit patterns of lengths len
|
|
// through max inclusive, coding syms symbols, with left bit patterns of length
|
|
// len unused -- return -1 if there is an overflow in the counting. Keep a
|
|
// record of previous results in num to prevent repeating the same calculation.
|
|
local big_t count(int syms, int left, int len) {
|
|
// see if only one possible code
|
|
if (syms == left)
|
|
return 1;
|
|
|
|
// note and verify the expected state
|
|
assert(syms > left && left > 0 && len < g.max);
|
|
|
|
// see if we've done this one already
|
|
size_t index = map(syms, left, len);
|
|
big_t got = g.num[index];
|
|
if (got)
|
|
return got; // we have -- return the saved result
|
|
|
|
// we need to use at least this many bit patterns so that the code won't be
|
|
// incomplete at the next length (more bit patterns than symbols)
|
|
int least = (left << 1) - syms;
|
|
if (least < 0)
|
|
least = 0;
|
|
|
|
// we can use at most this many bit patterns, lest there not be enough
|
|
// available for the remaining symbols at the maximum length (if there were
|
|
// no limit to the code length, this would become: most = left - 1)
|
|
int most = (((code_t)left << (g.max - len)) - syms) /
|
|
(((code_t)1 << (g.max - len)) - 1);
|
|
|
|
// count all possible codes from this juncture and add them up
|
|
big_t sum = 0;
|
|
for (int use = least; use <= most; use++) {
|
|
got = count(syms - use, (left - use) << 1, len + 1);
|
|
sum += got;
|
|
if (got == (big_t)-1 || sum < got) // overflow
|
|
return (big_t)-1;
|
|
}
|
|
|
|
// verify that all recursive calls are productive
|
|
assert(sum != 0);
|
|
|
|
// save the result and return it
|
|
g.num[index] = sum;
|
|
return sum;
|
|
}
|
|
|
|
// Return true if we've been here before, set to true if not. Set a bit in a
|
|
// bit vector to indicate visiting this state. Each (syms,len,left) state has a
|
|
// variable size bit vector indexed by (mem,rem). The bit vector is lengthened
|
|
// as needed to allow setting the (mem,rem) bit.
|
|
local int been_here(int syms, int left, int len, int mem, int rem) {
|
|
// point to vector for (syms,left,len), bit in vector for (mem,rem)
|
|
size_t index = map(syms, left, len);
|
|
mem -= 1 << g.root; // mem always includes the root table
|
|
mem >>= 1; // mem and rem are always even
|
|
rem >>= 1;
|
|
size_t offset = (mem >> 3) + rem;
|
|
offset = ((offset * (offset + 1)) >> 1) + rem;
|
|
int bit = 1 << (mem & 7);
|
|
|
|
// see if we've been here
|
|
size_t length = g.done[index].len;
|
|
if (offset < length && (g.done[index].vec[offset] & bit) != 0)
|
|
return 1; // done this!
|
|
|
|
// we haven't been here before -- set the bit to show we have now
|
|
|
|
// see if we need to lengthen the vector in order to set the bit
|
|
if (length <= offset) {
|
|
// if we have one already, enlarge it, zero out the appended space
|
|
char *vector;
|
|
if (length) {
|
|
do {
|
|
length <<= 1;
|
|
} while (length <= offset);
|
|
vector = realloc(g.done[index].vec, length);
|
|
assert(vector != NULL && "out of memory");
|
|
memset(vector + g.done[index].len, 0, length - g.done[index].len);
|
|
}
|
|
|
|
// otherwise we need to make a new vector and zero it out
|
|
else {
|
|
length = 16;
|
|
while (length <= offset)
|
|
length <<= 1;
|
|
vector = calloc(length, 1);
|
|
assert(vector != NULL && "out of memory");
|
|
}
|
|
|
|
// install the new vector
|
|
g.done[index].len = length;
|
|
g.done[index].vec = vector;
|
|
}
|
|
|
|
// set the bit
|
|
g.done[index].vec[offset] |= bit;
|
|
return 0;
|
|
}
|
|
|
|
// Examine all possible codes from the given node (syms, len, left). Compute
|
|
// the amount of memory required to build inflate's decoding tables, where the
|
|
// number of code structures used so far is mem, and the number remaining in
|
|
// the current sub-table is rem.
|
|
local void examine(int syms, int left, int len, int mem, int rem) {
|
|
// see if we have a complete code
|
|
if (syms == left) {
|
|
// set the last code entry
|
|
g.code[len] = left;
|
|
|
|
// complete computation of memory used by this code
|
|
while (rem < left) {
|
|
left -= rem;
|
|
rem = 1 << (len - g.root);
|
|
mem += rem;
|
|
}
|
|
assert(rem == left);
|
|
|
|
// if this is at the maximum, show the sub-code
|
|
if (mem >= g.large) {
|
|
// if this is a new maximum, update the maximum and clear out the
|
|
// printed sub-codes from the previous maximum
|
|
if (mem > g.large) {
|
|
g.large = mem;
|
|
string_clear(&g.out);
|
|
}
|
|
|
|
// compute the starting state for this sub-code
|
|
syms = 0;
|
|
left = 1 << g.max;
|
|
for (int bits = g.max; bits > g.root; bits--) {
|
|
syms += g.code[bits];
|
|
left -= g.code[bits];
|
|
assert((left & 1) == 0);
|
|
left >>= 1;
|
|
}
|
|
|
|
// print the starting state and the resulting sub-code to g.out
|
|
string_printf(&g.out, "<%u, %u, %u>:",
|
|
syms, g.root + 1, ((1 << g.root) - left) << 1);
|
|
for (int bits = g.root + 1; bits <= g.max; bits++)
|
|
if (g.code[bits])
|
|
string_printf(&g.out, " %d[%d]", g.code[bits], bits);
|
|
string_printf(&g.out, "\n");
|
|
}
|
|
|
|
// remove entries as we drop back down in the recursion
|
|
g.code[len] = 0;
|
|
return;
|
|
}
|
|
|
|
// prune the tree if we can
|
|
if (been_here(syms, left, len, mem, rem))
|
|
return;
|
|
|
|
// we need to use at least this many bit patterns so that the code won't be
|
|
// incomplete at the next length (more bit patterns than symbols)
|
|
int least = (left << 1) - syms;
|
|
if (least < 0)
|
|
least = 0;
|
|
|
|
// we can use at most this many bit patterns, lest there not be enough
|
|
// available for the remaining symbols at the maximum length (if there were
|
|
// no limit to the code length, this would become: most = left - 1)
|
|
int most = (((code_t)left << (g.max - len)) - syms) /
|
|
(((code_t)1 << (g.max - len)) - 1);
|
|
|
|
// occupy least table spaces, creating new sub-tables as needed
|
|
int use = least;
|
|
while (rem < use) {
|
|
use -= rem;
|
|
rem = 1 << (len - g.root);
|
|
mem += rem;
|
|
}
|
|
rem -= use;
|
|
|
|
// examine codes from here, updating table space as we go
|
|
for (use = least; use <= most; use++) {
|
|
g.code[len] = use;
|
|
examine(syms - use, (left - use) << 1, len + 1,
|
|
mem + (rem ? 1 << (len - g.root) : 0), rem << 1);
|
|
if (rem == 0) {
|
|
rem = 1 << (len - g.root);
|
|
mem += rem;
|
|
}
|
|
rem--;
|
|
}
|
|
|
|
// remove entries as we drop back down in the recursion
|
|
g.code[len] = 0;
|
|
}
|
|
|
|
// Look at all sub-codes starting with root + 1 bits. Look at only the valid
|
|
// intermediate code states (syms, left, len). For each completed code,
|
|
// calculate the amount of memory required by inflate to build the decoding
|
|
// tables. Find the maximum amount of memory required and show the codes that
|
|
// require that maximum.
|
|
local void enough(int syms) {
|
|
// clear code
|
|
for (int n = 0; n <= g.max; n++)
|
|
g.code[n] = 0;
|
|
|
|
// look at all (root + 1) bit and longer codes
|
|
string_clear(&g.out); // empty saved results
|
|
g.large = 1 << g.root; // base table
|
|
if (g.root < g.max) // otherwise, there's only a base table
|
|
for (int n = 3; n <= syms; n++)
|
|
for (int left = 2; left < n; left += 2) {
|
|
// look at all reachable (root + 1) bit nodes, and the
|
|
// resulting codes (complete at root + 2 or more)
|
|
size_t index = map(n, left, g.root + 1);
|
|
if (g.root + 1 < g.max && g.num[index]) // reachable node
|
|
examine(n, left, g.root + 1, 1 << g.root, 0);
|
|
|
|
// also look at root bit codes with completions at root + 1
|
|
// bits (not saved in num, since complete), just in case
|
|
if (g.num[index - 1] && n <= left << 1)
|
|
examine((n - left) << 1, (n - left) << 1, g.root + 1,
|
|
1 << g.root, 0);
|
|
}
|
|
|
|
// done
|
|
printf("maximum of %d table entries for root = %d\n", g.large, g.root);
|
|
fputs(g.out.str, stdout);
|
|
}
|
|
|
|
// Examine and show the total number of possible prefix codes for a given
|
|
// maximum number of symbols, initial root table size, and maximum code length
|
|
// in bits -- those are the command arguments in that order. The default values
|
|
// are 286, 9, and 15 respectively, for the deflate literal/length code. The
|
|
// possible codes are counted for each number of coded symbols from two to the
|
|
// maximum. The counts for each of those and the total number of codes are
|
|
// shown. The maximum number of inflate table entires is then calculated across
|
|
// all possible codes. Each new maximum number of table entries and the
|
|
// associated sub-code (starting at root + 1 == 10 bits) is shown.
|
|
//
|
|
// To count and examine prefix codes that are not length-limited, provide a
|
|
// maximum length equal to the number of symbols minus one.
|
|
//
|
|
// For the deflate literal/length code, use "enough". For the deflate distance
|
|
// code, use "enough 30 6".
|
|
int main(int argc, char **argv) {
|
|
// set up globals for cleanup()
|
|
g.code = NULL;
|
|
g.num = NULL;
|
|
g.done = NULL;
|
|
string_init(&g.out);
|
|
|
|
// get arguments -- default to the deflate literal/length code
|
|
int syms = 286;
|
|
g.root = 9;
|
|
g.max = 15;
|
|
if (argc > 1) {
|
|
syms = atoi(argv[1]);
|
|
if (argc > 2) {
|
|
g.root = atoi(argv[2]);
|
|
if (argc > 3)
|
|
g.max = atoi(argv[3]);
|
|
}
|
|
}
|
|
if (argc > 4 || syms < 2 || g.root < 1 || g.max < 1) {
|
|
fputs("invalid arguments, need: [sym >= 2 [root >= 1 [max >= 1]]]\n",
|
|
stderr);
|
|
return 1;
|
|
}
|
|
|
|
// if not restricting the code length, the longest is syms - 1
|
|
if (g.max > syms - 1)
|
|
g.max = syms - 1;
|
|
|
|
// determine the number of bits in a code_t
|
|
int bits = 0;
|
|
for (code_t word = 1; word; word <<= 1)
|
|
bits++;
|
|
|
|
// make sure that the calculation of most will not overflow
|
|
if (g.max > bits || (code_t)(syms - 2) >= ((code_t)-1 >> (g.max - 1))) {
|
|
fputs("abort: code length too long for internal types\n", stderr);
|
|
return 1;
|
|
}
|
|
|
|
// reject impossible code requests
|
|
if ((code_t)(syms - 1) > ((code_t)1 << g.max) - 1) {
|
|
fprintf(stderr, "%d symbols cannot be coded in %d bits\n",
|
|
syms, g.max);
|
|
return 1;
|
|
}
|
|
|
|
// allocate code vector
|
|
g.code = calloc(g.max + 1, sizeof(int));
|
|
assert(g.code != NULL && "out of memory");
|
|
|
|
// determine size of saved results array, checking for overflows,
|
|
// allocate and clear the array (set all to zero with calloc())
|
|
if (syms == 2) // iff max == 1
|
|
g.num = NULL; // won't be saving any results
|
|
else {
|
|
g.size = syms >> 1;
|
|
int n = (syms - 1) >> 1;
|
|
assert(g.size <= (size_t)-1 / n && "overflow");
|
|
g.size *= n;
|
|
n = g.max - 1;
|
|
assert(g.size <= (size_t)-1 / n && "overflow");
|
|
g.size *= n;
|
|
g.num = calloc(g.size, sizeof(big_t));
|
|
assert(g.num != NULL && "out of memory");
|
|
}
|
|
|
|
// count possible codes for all numbers of symbols, add up counts
|
|
big_t sum = 0;
|
|
for (int n = 2; n <= syms; n++) {
|
|
big_t got = count(n, 2, 1);
|
|
sum += got;
|
|
assert(got != (big_t)-1 && sum >= got && "overflow");
|
|
}
|
|
printf("%"PRIbig" total codes for 2 to %d symbols", sum, syms);
|
|
if (g.max < syms - 1)
|
|
printf(" (%d-bit length limit)\n", g.max);
|
|
else
|
|
puts(" (no length limit)");
|
|
|
|
// allocate and clear done array for been_here()
|
|
if (syms == 2)
|
|
g.done = NULL;
|
|
else {
|
|
g.done = calloc(g.size, sizeof(struct tab));
|
|
assert(g.done != NULL && "out of memory");
|
|
}
|
|
|
|
// find and show maximum inflate table usage
|
|
if (g.root > g.max) // reduce root to max length
|
|
g.root = g.max;
|
|
if ((code_t)syms < ((code_t)1 << (g.root + 1)))
|
|
enough(syms);
|
|
else
|
|
fputs("cannot handle minimum code lengths > root", stderr);
|
|
|
|
// done
|
|
cleanup();
|
|
return 0;
|
|
}
|