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zio.c
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zio.c
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/* -*- C -*-
* Copyright (c) 1998-2006 Motoyuki Kasahara
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio.h>
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <fcntl.h>
#include <zlib.h>
#include "zio.h"
/*
* Flags for open().
*/
#ifndef O_BINARY
#define O_BINARY 0
#endif
/*
* Debug message handler.
*/
extern int eb_log_flag;
extern void eb_log(const char *, ...);
#define LOG(x) do {if (eb_log_flag) eb_log x;} while (0)
/*
* Get an unsigned value from an octet stream buffer.
*/
#define zio_uint1(p) (*(const unsigned char *)(p))
#define zio_uint2(p) ((*(const unsigned char *)(p) << 8) \
+ (*(const unsigned char *)((p) + 1)))
#define zio_uint3(p) ((*(const unsigned char *)(p) << 16) \
+ (*(const unsigned char *)((p) + 1) << 8) \
+ (*(const unsigned char *)((p) + 2)))
#define zio_uint4(p) (((off_t) *(const unsigned char *)(p) << 24) \
+ (*(const unsigned char *)((p) + 1) << 16) \
+ (*(const unsigned char *)((p) + 2) << 8) \
+ (*(const unsigned char *)((p) + 3)))
#define zio_uint5(p) (((off_t) (*(const unsigned char *)(p)) << 32) \
+ ((off_t) (*(const unsigned char *)((p) + 1)) << 24) \
+ (*(const unsigned char *)((p) + 2) << 16) \
+ (*(const unsigned char *)((p) + 3) << 8) \
+ (*(const unsigned char *)((p) + 4)))
/*
* Size of a page (The term `page' means `block' in JIS X 4081).
*/
#define ZIO_SIZE_PAGE 2048
/*
* Size of a cache buffer.
* It must be large enough to memory an uncompressed slice.
*
* (In EBZIP and EPWING compressions, the size of uncompressed slice
* is 2048. In S-EBXA compression, the size is 4096.)
*/
#define ZIO_CACHE_BUFFER_SIZE (ZIO_SIZE_PAGE << ZIO_MAX_EBZIP_LEVEL)
/*
* NULL Zio ID.
*/
#define ZIO_ID_NONE -1
/*
* Buffer for caching uncompressed data.
*/
static char *cache_buffer = NULL;
/*
* Zio ID which caches data in `cache_buffer'.
*/
static int cache_zio_id = ZIO_ID_NONE;
/*
* Offset of the beginning of the cached data `cache_buffer'.
*/
static off_t cache_location;
/*
* Zio object counter.
*/
static int zio_counter = 0;
/*
* Test whether `off_t' represents a large integer.
*/
#define off_t_is_large \
((((off_t) 1 << 41) + ((off_t) 1 << 40) + 1) % 9999991 == 7852006)
/*
* Unexported function.
*/
static int zio_reopen(Zio *zio, const char *file_name);
static int zio_open_plain(Zio *zio, const char *file_name);
static int zio_open_ebzip(Zio *zio, const char *file_name);
static int zio_open_epwing(Zio *zio, const char *file_name);
static int zio_open_epwing6(Zio *zio, const char *file_name);
static int zio_make_epwing_huffman_tree(Zio *zio, int leaf_count);
static ssize_t zio_read_ebzip(Zio *zio, char *buffer, size_t length);
static ssize_t zio_read_epwing(Zio *zio, char *buffer, size_t length);
static ssize_t zio_read_sebxa(Zio *zio, char *buffer, size_t length);
static int zio_unzip_slice_ebzip1(Zio *zio, char *out_buffer,
size_t zipped_slice_size);
static int zio_unzip_slice_epwing(Zio *zio, char *out_buffer);
static int zio_unzip_slice_epwing6(Zio *zio, char *out_buffer);
static int zio_unzip_slice_sebxa(Zio *zio, char *out_buffer);
static int zio_open_raw(Zio *zio, const char *file_name);
static void zio_close_raw(Zio *zio);
static off_t zio_lseek_raw(Zio *zio, off_t offset, int whence);
static ssize_t zio_read_raw(Zio *zio, void *buffer, size_t length);
/*
* Initialize cache buffer.
*/
int
zio_initialize_library(void)
{
LOG(("in: zio_initialize_library()"));
/*
* Allocate memory for cache buffer.
*/
if (cache_buffer == NULL) {
cache_buffer = (char *) malloc(ZIO_CACHE_BUFFER_SIZE);
if (cache_buffer == NULL)
goto failed;
}
LOG(("out: zio_initialize_library() = %d", 0));
return 0;
/*
* An error occurs...
*/
failed:
LOG(("out: zio_initialize_library() = %d", -1));
return -1;
}
/*
* Clear cache buffer.
*/
void
zio_finalize_library(void)
{
LOG(("in: zio_finalize_library()"));
if (cache_buffer != NULL)
free(cache_buffer);
cache_buffer = NULL;
cache_zio_id = ZIO_ID_NONE;
LOG(("out: zio_finalize_library()"));
}
/*
* Initialize `zio'.
*/
void
zio_initialize(Zio *zio)
{
LOG(("in: zio_initialize()"));
zio->id = -1;
zio->file = -1;
zio->huffman_nodes = NULL;
zio->huffman_root = NULL;
zio->code = ZIO_INVALID;
zio->file_size = 0;
LOG(("out: zio_initialize()"));
}
/*
* Finalize `zio'.
*/
void
zio_finalize(Zio *zio)
{
LOG(("in: zio_finalize(zio=%d)", (int)zio->id));
zio_close(zio);
if (zio->huffman_nodes != NULL)
free(zio->huffman_nodes);
zio->id = -1;
zio->huffman_nodes = NULL;
zio->huffman_root = NULL;
zio->code = ZIO_INVALID;
LOG(("out: zio_finalize()"));
}
/*
* Set S-EBXA compression mode.
*/
int
zio_set_sebxa_mode(Zio *zio, off_t index_location, off_t index_base,
off_t zio_start_location, off_t zio_end_location)
{
LOG(("in: zio_set_sebxa_mode(zio=%d, index_location=%ld, index_base=%ld, \
zio_start_location=%ld, zio_end_location=%ld)",
(int)zio->id, (long)index_location, (long)index_base,
(long)zio_start_location, (long)zio_end_location));
if (zio->code != ZIO_PLAIN)
goto failed;
zio->code = ZIO_SEBXA;
zio->index_location = index_location;
zio->index_base = index_base;
zio->zio_start_location = zio_start_location;
zio->zio_end_location = zio_end_location;
zio->file_size = zio_end_location;
LOG(("out: zio_set_sebxa_mode() = %d", 0));
return 0;
/*
* An error occurs...
*/
failed:
LOG(("out: zio_set_sebxa_mode() = %d", -1));
return -1;
}
/*
* Open `file'.
*/
int
zio_open(Zio *zio, const char *file_name, Zio_Code zio_code)
{
int result;
LOG(("in: zio_open(zio=%d, file_name=%s, zio_code=%d)",
(int)zio->id, file_name, zio_code));
if (0 <= zio->file) {
if (zio_code == ZIO_REOPEN) {
result = 0;
goto succeeded;
}
zio_finalize(zio);
zio_initialize(zio);
}
switch (zio_code) {
case ZIO_REOPEN:
result = zio_reopen(zio, file_name);
break;
case ZIO_PLAIN:
result = zio_open_plain(zio, file_name);
break;
case ZIO_EBZIP1:
result = zio_open_ebzip(zio, file_name);
break;
case ZIO_EPWING:
result = zio_open_epwing(zio, file_name);
break;
case ZIO_EPWING6:
result = zio_open_epwing6(zio, file_name);
break;
case ZIO_SEBXA:
result = zio_open_plain(zio, file_name);
break;
default:
result = -1;
}
succeeded:
LOG(("out: zio_open() = %d", result));
return result;
}
/*
* Reopen a file.
*/
static int
zio_reopen(Zio *zio, const char *file_name)
{
LOG(("in: zio_reopen(zio=%d, file_name=%s)", (int)zio->id, file_name));
if (zio->code == ZIO_INVALID)
goto failed;
if (zio_open_raw(zio, file_name) < 0) {
zio->code = ZIO_INVALID;
goto failed;
}
zio->location = 0;
LOG(("out: zio_reopen() = %d", zio->file));
return zio->file;
/*
* An error occurs...
*/
failed:
LOG(("out: zio_reopen() = %d", -1));
return -1;
}
/*
* Open an non-compressed file.
*/
static int
zio_open_plain(Zio *zio, const char *file_name)
{
LOG(("in: zio_open_plain(zio=%d, file_name=%s)", (int)zio->id, file_name));
if (zio_open_raw(zio, file_name) < 0)
goto failed;
zio->code = ZIO_PLAIN;
zio->slice_size = ZIO_SIZE_PAGE;
zio->file_size = zio_lseek_raw(zio, 0, SEEK_END);
if (zio->file_size < 0 || zio_lseek_raw(zio, 0, SEEK_SET) < 0)
goto failed;
/*
* Assign ID.
*/
zio->id = zio_counter++;
LOG(("out: zio_open_plain(zio=%d) = %d", (int)zio->id, zio->file));
return zio->file;
/*
* An error occurs...
*/
failed:
if (0 <= zio->file)
zio_close_raw(zio);
zio->file = -1;
zio->code = ZIO_INVALID;
LOG(("out: zio_open_plain() = %d", -1));
return -1;
}
/*
* Open an EBZIP compression file.
*/
static int
zio_open_ebzip(Zio *zio, const char *file_name)
{
char header[ZIO_SIZE_EBZIP_HEADER];
int ebzip_mode;
LOG(("in: zio_open_ebzip(zio=%d, file_name=%s)", (int)zio->id, file_name));
/*
* Try to open a `*.ebz' file.
*/
if (zio_open_raw(zio, file_name) < 0)
goto failed;
/*
* Read header part of the ebzip'ped file.
*/
if (zio_read_raw(zio, header, ZIO_SIZE_EBZIP_HEADER)
!= ZIO_SIZE_EBZIP_HEADER)
goto failed;
ebzip_mode = zio_uint1(header + 5) >> 4;
zio->code = ZIO_EBZIP1;
zio->zip_level = zio_uint1(header + 5) & 0x0f;
zio->slice_size = ZIO_SIZE_PAGE << zio->zip_level;
zio->file_size = zio_uint5(header + 9);
zio->crc = zio_uint4(header + 14);
zio->mtime = zio_uint4(header + 18);
zio->location = 0;
if (zio->file_size < (off_t) 1 << 16)
zio->index_width = 2;
else if (zio->file_size < (off_t) 1 << 24)
zio->index_width = 3;
else if (zio->file_size < (off_t) 1 << 32 || !off_t_is_large)
zio->index_width = 4;
else
zio->index_width = 5;
/*
* Check zio header information.
*/
if (memcmp(header, "EBZip", 5) != 0
|| ZIO_SIZE_PAGE << ZIO_MAX_EBZIP_LEVEL < zio->slice_size)
goto failed;
if (off_t_is_large) {
if (ebzip_mode != 1 && ebzip_mode != 2)
goto failed;
} else {
if (ebzip_mode != 1)
goto failed;
}
/*
* Assign ID.
*/
zio->id = zio_counter++;
LOG(("out: zio_open_ebzip(zio=%d) = %d", (int)zio->id, zio->file));
return zio->file;
/*
* An error occurs...
*/
failed:
if (0 <= zio->file)
zio_close_raw(zio);
zio->file = -1;
zio->code = ZIO_INVALID;
LOG(("out: zio_open_ebzip() = %d", -1));
return -1;
}
/*
* The buffer size must be 512 bytes, the number of 8 bit nodes.
*/
#define ZIO_EPWING_BUFFER_SIZE 512
/*
* Open an EPWING compression file.
*/
static int
zio_open_epwing(Zio *zio, const char *file_name)
{
int leaf16_count;
int leaf_count;
char buffer[ZIO_EPWING_BUFFER_SIZE];
char *buffer_p;
ssize_t read_length;
Zio_Huffman_Node *tail_node_p;
int i;
LOG(("in: zio_open_epwing(zio=%d, file_name=%s)", (int)zio->id,
file_name));
zio->code = ZIO_EPWING;
zio->huffman_nodes = NULL;
/*
* Open `HONMON2'.
*/
if (zio_open_raw(zio, file_name) < 0)
goto failed;
/*
* Read a header of `HONMON2' (32 bytes).
* When `frequencies_length' is shorter than 512, we assumes the
* file is broken.
*/
if (zio_read_raw(zio, buffer, 32) != 32)
goto failed;
zio->location = 0;
zio->slice_size = ZIO_SIZE_PAGE;
zio->index_location = zio_uint4(buffer);
zio->index_length = zio_uint4(buffer + 4);
zio->frequencies_location = zio_uint4(buffer + 8);
zio->frequencies_length = zio_uint4(buffer + 12);
leaf16_count = (zio->frequencies_length - (256 * 2)) / 4;
leaf_count = leaf16_count + 256 + 1;
if (zio->index_length < 36 || zio->frequencies_length < 512)
goto failed;
/*
* Check for the length of an uncompressed file.
*
* If the index of the non-first page in the last index group
* is 0x0000, we assumes the data corresponding with the index
* doesn't exist.
*/
if (zio_lseek_raw(zio, zio->index_location
+ ((off_t) zio->index_length - 36) / 36 * 36, SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, 36) != 36)
goto failed;
zio->file_size = ((off_t) zio->index_length / 36) * (ZIO_SIZE_PAGE * 16);
for (i = 1, buffer_p = buffer + 4 + 2; i < 16; i++, buffer_p += 2) {
if (zio_uint2(buffer_p) == 0)
break;
}
zio->file_size -= ZIO_SIZE_PAGE * (16 - i);
/*
* Allocate memory for huffman nodes.
*/
zio->huffman_nodes = (Zio_Huffman_Node *) malloc(sizeof(Zio_Huffman_Node)
* leaf_count * 2);
if (zio->huffman_nodes == NULL)
goto failed;
tail_node_p = zio->huffman_nodes;
/*
* Make leafs for 16bit character.
*/
read_length = ZIO_EPWING_BUFFER_SIZE - (ZIO_EPWING_BUFFER_SIZE % 4);
if (zio_lseek_raw(zio, zio->frequencies_location, SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
for (i = 0; i < leaf16_count; i++) {
if (buffer + read_length <= buffer_p) {
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
}
tail_node_p->type = ZIO_HUFFMAN_NODE_LEAF16;
tail_node_p->value = zio_uint2(buffer_p);
tail_node_p->frequency = zio_uint2(buffer_p + 2);
tail_node_p->left = NULL;
tail_node_p->right = NULL;
buffer_p += 4;
tail_node_p++;
}
/*
* Make leafs for 8bit character.
*/
if (zio_lseek_raw(zio, zio->frequencies_location + leaf16_count * 4,
SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, 512) != 512)
goto failed;
buffer_p = buffer;
for (i = 0; i < 256; i++) {
tail_node_p->type = ZIO_HUFFMAN_NODE_LEAF8;
tail_node_p->value = i;
tail_node_p->frequency = zio_uint2(buffer_p);
tail_node_p->left = NULL;
tail_node_p->right = NULL;
buffer_p += 2;
tail_node_p++;
}
/*
* Make a leaf for the end-of-page character.
*/
tail_node_p->type = ZIO_HUFFMAN_NODE_EOF;
tail_node_p->value = 256;
tail_node_p->frequency = 1;
tail_node_p++;
/*
* Make a huffman tree.
*/
if (zio_make_epwing_huffman_tree(zio, leaf_count) < 0)
goto failed;
/*
* Assign ID.
*/
zio->id = zio_counter++;
LOG(("out: zio_open_epwing(zio=%d) = %d", (int)zio->id, zio->file));
return zio->file;
/*
* An error occurs...
*/
failed:
if (0 <= zio->file)
zio_close_raw(zio);
if (zio->huffman_nodes != NULL)
free(zio->huffman_nodes);
zio->file = -1;
zio->huffman_nodes = NULL;
zio->huffman_root = NULL;
zio->code = ZIO_INVALID;
LOG(("out: zio_open_epwing() = %d", -1));
return -1;
}
/*
* Open an EPWING compression file.
*/
static int
zio_open_epwing6(Zio *zio, const char *file_name)
{
int leaf32_count;
int leaf16_count;
int leaf_count;
char buffer[ZIO_EPWING_BUFFER_SIZE];
char *buffer_p;
ssize_t read_length;
Zio_Huffman_Node *tail_node_p;
int i;
LOG(("in: zio_open_epwing6(zio=%d, file_name=%s)", (int)zio->id,
file_name));
zio->code = ZIO_EPWING6;
zio->huffman_nodes = NULL;
/*
* Open `HONMON2'.
*/
if (zio_open_raw(zio, file_name) < 0)
goto failed;
/*
* Read a header of `HONMON2' (48 bytes).
* When `frequencies_length' is shorter than 512, we assumes the
* file is broken.
*/
if (zio_read_raw(zio, buffer, 48) != 48)
goto failed;
zio->location = 0;
zio->slice_size = ZIO_SIZE_PAGE;
zio->index_location = zio_uint4(buffer);
zio->index_length = zio_uint4(buffer + 4);
zio->frequencies_location = zio_uint4(buffer + 8);
zio->frequencies_length = zio_uint4(buffer + 12);
leaf16_count = 0x400;
leaf32_count = (zio->frequencies_length - (leaf16_count * 4) - (256 * 2))
/ 6;
leaf_count = leaf32_count + leaf16_count + 256 + 1;
if (zio->index_length < 36 || zio->frequencies_length < 512)
goto failed;
/*
* Check for the length of an uncompressed file.
*
* If the index of the non-first page in the last index group
* is 0x0000, we assumes the data corresponding with the index
* doesn't exist.
*/
if (zio_lseek_raw(zio, zio->index_location
+ ((off_t) zio->index_length - 36) / 36 * 36, SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, 36) != 36)
goto failed;
zio->file_size = ((off_t) zio->index_length / 36) * (ZIO_SIZE_PAGE * 16);
for (i = 1, buffer_p = buffer + 4 + 2; i < 16; i++, buffer_p += 2) {
if (zio_uint2(buffer_p) == 0)
break;
}
zio->file_size -= ZIO_SIZE_PAGE * (16 - i);
/*
* Allocate memory for huffman nodes.
*/
zio->huffman_nodes = (Zio_Huffman_Node *) malloc(sizeof(Zio_Huffman_Node)
* leaf_count * 2);
if (zio->huffman_nodes == NULL)
goto failed;
tail_node_p = zio->huffman_nodes;
/*
* Make leafs for 32bit character.
*/
read_length = ZIO_EPWING_BUFFER_SIZE - (ZIO_EPWING_BUFFER_SIZE % 6);
if (zio_lseek_raw(zio, zio->frequencies_location, SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
for (i = 0; i < leaf32_count; i++) {
if (buffer + read_length <= buffer_p) {
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
}
tail_node_p->type = ZIO_HUFFMAN_NODE_LEAF32;
tail_node_p->value = zio_uint4(buffer_p);
tail_node_p->frequency = zio_uint2(buffer_p + 4);
tail_node_p->left = NULL;
tail_node_p->right = NULL;
buffer_p += 6;
tail_node_p++;
}
/*
* Make leafs for 16bit character.
*/
read_length = ZIO_EPWING_BUFFER_SIZE - (ZIO_EPWING_BUFFER_SIZE % 4);
if (zio_lseek_raw(zio, zio->frequencies_location + leaf32_count * 6,
SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
for (i = 0; i < leaf16_count; i++) {
if (buffer + read_length <= buffer_p) {
if (zio_read_raw(zio, buffer, read_length) != read_length)
goto failed;
buffer_p = buffer;
}
tail_node_p->type = ZIO_HUFFMAN_NODE_LEAF16;
tail_node_p->value = zio_uint2(buffer_p);
tail_node_p->frequency = zio_uint2(buffer_p + 2);
tail_node_p->left = NULL;
tail_node_p->right = NULL;
buffer_p += 4;
tail_node_p++;
}
/*
* Make leafs for 8bit character.
*/
if (zio_lseek_raw(zio, zio->frequencies_location + leaf32_count * 6
+ leaf16_count * 4, SEEK_SET) < 0)
goto failed;
if (zio_read_raw(zio, buffer, 512) != 512)
goto failed;
buffer_p = buffer;
for (i = 0; i < 256; i++) {
tail_node_p->type = ZIO_HUFFMAN_NODE_LEAF8;
tail_node_p->value = i;
tail_node_p->frequency = zio_uint2(buffer_p);
tail_node_p->left = NULL;
tail_node_p->right = NULL;
buffer_p += 2;
tail_node_p++;
}
/*
* Make a leaf for the end-of-page character.
*/
tail_node_p->type = ZIO_HUFFMAN_NODE_EOF;
tail_node_p->value = 256;
tail_node_p->frequency = 1;
tail_node_p++;
/*
* Make a huffman tree.
*/
if (zio_make_epwing_huffman_tree(zio, leaf_count) < 0)
goto failed;
/*
* Assign ID.
*/
zio->id = zio_counter++;
LOG(("out: zio_open_epwing6(zio=%d) = %d", (int)zio->id, zio->file));
return zio->file;
/*
* An error occurs...
*/
failed:
if (0 <= zio->file)
zio_close_raw(zio);
if (zio->huffman_nodes != NULL)
free(zio->huffman_nodes);
zio->file = -1;
zio->huffman_nodes = NULL;
zio->huffman_root = NULL;
zio->code = ZIO_INVALID;
LOG(("out: zio_open_epwing6() = %d", -1));
return -1;
}
/*
* Make a huffman tree for decompressing EPWING compression data.
*/
static int
zio_make_epwing_huffman_tree(Zio *zio, int leaf_count)
{
Zio_Huffman_Node *target_node;
Zio_Huffman_Node *most_node;
Zio_Huffman_Node *node_p;
Zio_Huffman_Node temporary_node;
Zio_Huffman_Node *least_node_p;
Zio_Huffman_Node *tail_node_p;
int i;
int j;
LOG(("in: zio_make_epwing_huffman_tree(zio=%d, leaf_count=%d)",
(int)zio->id, leaf_count));
tail_node_p = zio->huffman_nodes + leaf_count;
/*
* Sort the leaf nodes in frequency order.
*/
for (i = 0; i < leaf_count - 1; i++) {
target_node = zio->huffman_nodes + i;
most_node = target_node;
node_p = zio->huffman_nodes + i + 1;
for (j = i + 1; j < leaf_count; j++) {
if (most_node->frequency < node_p->frequency)
most_node = node_p;
node_p++;
}
temporary_node.type = most_node->type;
temporary_node.value = most_node->value;
temporary_node.frequency = most_node->frequency;
most_node->type = target_node->type;
most_node->value = target_node->value;
most_node->frequency = target_node->frequency;
target_node->type = temporary_node.type;
target_node->value = temporary_node.value;
target_node->frequency = temporary_node.frequency;
}
/*
* Make intermediate nodes of the huffman tree.
* The number of intermediate nodes of the tree is <the number of
* leaf nodes> - 1.
*/
for (i = 1; i < leaf_count; i++) {
/*
* Initialize a new intermediate node.
*/
tail_node_p->type = ZIO_HUFFMAN_NODE_INTERMEDIATE;
tail_node_p->left = NULL;
tail_node_p->right = NULL;
/*
* Find for a least frequent node.
* That node becomes a left child of the new intermediate node.
*/
least_node_p = NULL;
for (node_p = zio->huffman_nodes; node_p < tail_node_p; node_p++) {
if (node_p->frequency == 0)
continue;
if (least_node_p == NULL
|| node_p->frequency <= least_node_p->frequency)
least_node_p = node_p;
}
if (least_node_p == NULL)
goto failed;
tail_node_p->left = least_node_p;
tail_node_p->frequency = least_node_p->frequency;
least_node_p->frequency = 0;
/*
* Find for a next least frequent node.
* That node becomes a right child of the new intermediate node.
*/
least_node_p = NULL;
for (node_p = zio->huffman_nodes; node_p < tail_node_p; node_p++) {
if (node_p->frequency == 0)
continue;
if (least_node_p == NULL
|| node_p->frequency <= least_node_p->frequency)
least_node_p = node_p;
}
if (least_node_p == NULL)
goto failed;
tail_node_p->right = least_node_p;
tail_node_p->frequency += least_node_p->frequency;
least_node_p->frequency = 0;
tail_node_p++;
}
/*
* Set a root node of the huffman tree.
*/
zio->huffman_root = tail_node_p - 1;
LOG(("out: zio_make_epwing_huffman_tree() = %d", 0));
return 0;
/*
* An error occurs...
*/
failed:
LOG(("out: zio_make_epwing_huffman_tree() = %d", -1));
return -1;
}
/*
* Close `zio'.
*/
void
zio_close(Zio *zio)
{
LOG(("in: zio_close(zio=%d)", (int)zio->id));
/*
* If contents of the file is cached, clear the cache.
*/
if (0 <= zio->file)
zio_close_raw(zio);
zio->file = -1;
LOG(("out: zio_close()"));
}
/*
* Return file descriptor of `zio'.
*/
int
zio_file(Zio *zio)
{
LOG(("in+out: zio_file(zio=%d) = %d", (int)zio->id, zio->file));
return zio->file;
}
/*
* Return compression mode of `zio'.
*/
Zio_Code
zio_mode(Zio *zio)
{
LOG(("in+out: zio_mode(zio=%d) = %d", (int)zio->id, zio->code));
return zio->code;
}
/*
* Seek `zio'.
*/
off_t
zio_lseek(Zio *zio, off_t location, int whence)
{
off_t result;
LOG(("in: zio_lseek(zio=%d, location=%ld, whence=%d)",
(int)zio->id, (long)location, whence));
if (zio->file < 0)
goto failed;
if (zio->code == ZIO_PLAIN) {
/*
* If `zio' is not compressed, simply call lseek().
*/
result = zio_lseek_raw(zio, location, whence);
} else {
/*
* Calculate new location according with `whence'.
*/
switch (whence) {
case SEEK_SET:
zio->location = location;
break;
case SEEK_CUR:
zio->location = zio->location + location;
break;
case SEEK_END:
zio->location = zio->file_size - location;
break;
default:
#ifdef EINVAL