eb/ebzip/speedup.c
2016-10-28 20:02:30 -07:00

196 lines
5.3 KiB
C

/* -*- C -*-
* Copyright (c) 2004-2006 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 "ebzip.h"
#define zio_uint1(p) (*(const unsigned char *)(p))
#define zio_uint4(p) ((*(const unsigned char *)(p) << 24) \
+ (*(const unsigned char *)((p) + 1) << 16) \
+ (*(const unsigned char *)((p) + 2) << 8) \
+ (*(const unsigned char *)((p) + 3)))
/*
* Initialize `speeedup'.
*/
void
ebzip_initialize_zip_speedup(Zip_Speedup *speedup)
{
speedup->region_count = 0;
}
/*
* Finalize `speeedup'.
*/
void
ebzip_finalize_zip_speedup(Zip_Speedup *speedup)
{
speedup->region_count = 0;
}
/*
* Read HONMON/START file to set `speedup'.
*/
int
ebzip_set_zip_speedup(Zip_Speedup *speedup, const char *file_name,
Zio_Code zio_code, int index_page)
{
char buffer[EB_SIZE_PAGE];
char *buffer_p;
int start_page;
Zio zio;
int index_count;
int index_code;
int i;
zio_initialize(&zio);
/*
* Open the file and read it's index page.
*/
if (zio_open(&zio, file_name, zio_code) < 0) {
fprintf(stderr, _("%s: failed to open the file: %s\n"),
invoked_name, file_name);
goto failed;
}
if (zio_lseek(&zio, ((off_t) index_page - 1) * EB_SIZE_PAGE, SEEK_SET)
< 0) {
fprintf(stderr, _("%s: failed to read the file: %s\n"),
invoked_name, file_name);
goto failed;
}
if (zio_read(&zio, buffer, EB_SIZE_PAGE) != EB_SIZE_PAGE) {
fprintf(stderr, _("%s: failed to read the file: %s\n"),
invoked_name, file_name);
goto failed;
}
/*
* Read the index page to get `start_page' location.
*/
index_count = zio_uint1(buffer + 1);
buffer_p = buffer + 16;
for (i = 0; i < index_count; i++) {
index_code = zio_uint1(buffer_p);
if (0x90 <= index_code && index_code <= 0x92) {
if (EBZIP_MAX_SPEEDUP_REGION_COUNT <= speedup->region_count)
break;
speedup->regions[speedup->region_count].start_page
= zio_uint4(buffer_p + 2);
speedup->region_count++;
}
buffer_p += 16;
}
/*
* Read `start_page' to get `end_page' location.
*/
for (i = 0; i < speedup->region_count; i++) {
start_page = speedup->regions[i].start_page;
if (zio_lseek(&zio, ((off_t) start_page - 1) * EB_SIZE_PAGE, SEEK_SET)
< 0) {
fprintf(stderr, _("%s: failed to read the file: %s\n"),
invoked_name, file_name);
goto failed;
}
if (zio_read(&zio, buffer, EB_SIZE_PAGE) != EB_SIZE_PAGE) {
fprintf(stderr, _("%s: failed to read the file: %s\n"),
invoked_name, file_name);
goto failed;
}
speedup->regions[i].end_page = start_page + zio_uint1(buffer + 3) - 1;
}
zio_close(&zio);
zio_finalize(&zio);
return 0;
/*
* An error occurs...
*/
failed:
zio_close(&zio);
zio_finalize(&zio);
speedup->region_count = 0;
return -1;
}
/*
* Check if `slice' is lain in/over/across a speedup region.
*/
int
ebzip_is_speedup_slice(Zip_Speedup *speedup, int slice, int ebzip_level)
{
Zip_Speedup_Region *p;
int start_page;
int end_page;
int i;
start_page = slice * (1 << ebzip_level) + 1;
end_page = (slice + 1) * (1 << ebzip_level);
for (i = 0, p = speedup->regions; i < speedup->region_count; i++, p++) {
/*
* speedup region
* +================+
* o------o
* or o-----------------------o
*
*/
if (start_page <= speedup->regions[i].start_page
&& speedup->regions[i].start_page <= end_page)
return 1;
/*
* speedup region
* +================+
* o------o
* or o--------------------o
*/
if (start_page <= speedup->regions[i].end_page
&& speedup->regions[i].end_page <= end_page)
return 1;
/*
* speedup region
* +================+
* o--------o
*/
if (speedup->regions[i].start_page <= start_page
&& end_page <= speedup->regions[i].end_page)
return 1;
}
return 0;
}