* compress_common.c
*
* Code for compression shared among multiple compression formats.
- */
-
-/*
- * Copyright (C) 2012, 2013, 2014 Eric Biggers
- *
- * This file is part of wimlib, a library for working with WIM files.
- *
- * wimlib is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3 of the License, or (at your option)
- * any later version.
*
- * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE. See the GNU General Public License for more
- * details.
+ * Author: Eric Biggers
+ * Year: 2012 - 2014
*
- * You should have received a copy of the GNU General Public License
- * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ * The author dedicates this file to the public domain.
+ * You can do whatever you want with this file.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
-#include "wimlib/assert.h"
-#include "wimlib/endianness.h"
-#include "wimlib/compiler.h"
-#include "wimlib/compress_common.h"
-#include "wimlib/util.h"
-
#include <string.h>
-/* Writes @num_bits bits, given by the @num_bits least significant bits of
- * @bits, to the output @ostream. */
-void
-bitstream_put_bits(struct output_bitstream *ostream, u32 bits,
- unsigned num_bits)
-{
- bits &= (1U << num_bits) - 1;
- while (num_bits > ostream->free_bits) {
- /* Buffer variable does not have space for the new bits. It
- * needs to be flushed as a 16-bit integer. Bits in the second
- * byte logically precede those in the first byte
- * (little-endian), but within each byte the bits are ordered
- * from high to low. This is true for both XPRESS and LZX
- * compression. */
-
- /* There must be at least 2 bytes of space remaining. */
- if (unlikely(ostream->bytes_remaining < 2)) {
- ostream->overrun = true;
- return;
- }
-
- /* Fill the buffer with as many bits that fit. */
- unsigned fill_bits = ostream->free_bits;
-
- ostream->bitbuf <<= fill_bits;
- ostream->bitbuf |= bits >> (num_bits - fill_bits);
-
- *(le16*)ostream->bit_output = cpu_to_le16(ostream->bitbuf);
- ostream->bit_output = ostream->next_bit_output;
- ostream->next_bit_output = ostream->output;
- ostream->output += 2;
- ostream->bytes_remaining -= 2;
-
- ostream->free_bits = 16;
- num_bits -= fill_bits;
- bits &= (1U << num_bits) - 1;
- }
-
- /* Buffer variable has space for the new bits. */
- ostream->bitbuf = (ostream->bitbuf << num_bits) | bits;
- ostream->free_bits -= num_bits;
-}
-
-void
-bitstream_put_byte(struct output_bitstream *ostream, u8 n)
-{
- if (unlikely(ostream->bytes_remaining < 1)) {
- ostream->overrun = true;
- return;
- }
- *ostream->output++ = n;
- ostream->bytes_remaining--;
-}
-
-/* Flushes any remaining bits to the output bitstream.
- *
- * Returns -1 if the stream has overrun; otherwise returns the total number of
- * bytes in the output. */
-input_idx_t
-flush_output_bitstream(struct output_bitstream *ostream)
-{
- if (unlikely(ostream->overrun))
- return ~(input_idx_t)0;
-
- *(le16*)ostream->bit_output =
- cpu_to_le16((u16)((u32)ostream->bitbuf << ostream->free_bits));
- *(le16*)ostream->next_bit_output =
- cpu_to_le16(0);
-
- return ostream->output - ostream->output_start;
-}
-
-/* Initializes an output bit buffer to write its output to the memory location
- * pointer to by @data. */
-void
-init_output_bitstream(struct output_bitstream *ostream,
- void *data, unsigned num_bytes)
-{
- wimlib_assert(num_bytes >= 4);
-
- ostream->bitbuf = 0;
- ostream->free_bits = 16;
- ostream->output_start = data;
- ostream->bit_output = data;
- ostream->next_bit_output = data + 2;
- ostream->output = data + 4;
- ostream->bytes_remaining = num_bytes - 4;
- ostream->overrun = false;
-}
+#include "wimlib/compress_common.h"
+#include "wimlib/util.h"
/* Given the binary tree node A[subtree_idx] whose children already
* satisfy the maxheap property, swap the node with its greater child
* Tests were done with building the codes for LZX. Results may
* vary for different compression algorithms...! */
- num_counters = (DIV_ROUND_UP(num_syms, 4) + 3) & ~3;
+ num_counters = ALIGN(DIV_ROUND_UP(num_syms, 4), 4);
unsigned counters[num_counters];
u32 *A = codewords;
unsigned num_used_syms;
- /* Assumptions */
- wimlib_assert2(num_syms >= 2);
- wimlib_assert2(num_syms <= (1 << NUM_SYMBOL_BITS));
- wimlib_assert2(max_codeword_len > 0);
- wimlib_assert2(max_codeword_len <= 32);
-
/* We begin by sorting the symbols primarily by frequency and
* secondarily by symbol value. As an optimization, the array
* used for this purpose ('A') shares storage with the space in
git://wimlib.net / wimlib / blobdiff