Algorithm 版 (精华区)
发信人: lofe ()感激生活(), 信区: Algorithm
标 题: ar002--ar.c
发信站: 哈工大紫丁香 (Sun Sep 3 08:26:55 2000), 转信
/***********************************************************
ar.c -- main file
***********************************************************/
static char *usage =
"ar -- compression archiver -- written by Haruhiko Okumura\n"
" PC-VAN:SCIENCE CompuServe:74050,1022\n"
" NIFTY-Serve:PAF01022 INTERNET:74050.1022@compuserve.com\n"
"Usage: ar command archive [file ...]\n"
"Commands:\n"
" a: Add files to archive (replace if present)\n"
" x: Extract files from archive\n"
" r: Replace files in archive\n"
" d: Delete files from archive\n"
" p: Print files on standard output\n"
" l: List contents of archive\n"
"If no files are named, all files in archive are processed,\n"
" except for commands 'a' and 'd'.\n"
"You may copy, distribute, and rewrite this program freely.\n";
/***********************************************************
Structure of archive block (low order byte first):
-----preheader
1 basic header size
= 25 + strlen(filename) (= 0 if end of archive)
1 basic header algebraic sum (mod 256)
-----basic header
5 method ("-lh0-" = stored, "-lh5-" = compressed)
4 compressed size (including extended headers)
4 original size
4 not used
1 0x20
1 0x01
1 filename length (x)
x filename
2 original file's CRC
1 0x20
2 first extended header size (0 if none)
-----first extended header, etc.
-----compressed file
***********************************************************/
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "ar.h"
#define FNAME_MAX (255 - 25) /* max strlen(filename) */
#define namelen header[19]
#define filename ((char *)&header[20])
int unpackable; /* global, set in io.c */
ulong compsize, origsize; /* global */
static uchar buffer[DICSIZ];
static uchar header[255];
static uchar headersize, headersum;
static uint file_crc;
static char *temp_name;
static uint ratio(ulong a, ulong b) /* [(1000a + [b/2]) / b] */
{
int i;
for (i = 0; i < 3; i++)
if (a <= ULONG_MAX / 10) a *= 10; else b /= 10;
if ((ulong)(a + (b >> 1)) < a) { a >>= 1; b >>= 1; }
if (b == 0) return 0;
return (uint)((a + (b >> 1)) / b);
}
static void put_to_header(int i, int n, ulong x)
{
while (--n >= 0) {
header[i++] = (uchar)((uint)x & 0xFF); x >>= 8;
}
}
static ulong get_from_header(int i, int n)
{
ulong s;
s = 0;
while (--n >= 0) s = (s << 8) + header[i + n]; /* little endian */
return s;
}
static uint calc_headersum(void)
{
int i;
uint s;
s = 0;
for (i = 0; i < headersize; i++) s += header[i];
return s & 0xFF;
}
static int read_header(void)
{
headersize = (uchar) fgetc(arcfile);
if (headersize == 0) return 0; /* end of archive */
headersum = (uchar) fgetc(arcfile);
fread_crc(header, headersize, arcfile); /* CRC not used */
if (calc_headersum() != headersum) error("Header sum error");
compsize = get_from_header(5, 4);
origsize = get_from_header(9, 4);
file_crc = (uint)get_from_header(headersize - 5, 2);
filename[namelen] = '\0';
return 1; /* success */
}
static void write_header(void)
{
fputc(headersize, outfile);
/* We've destroyed file_crc by null-terminating filename. */
put_to_header(headersize - 5, 2, (ulong)file_crc);
fputc(calc_headersum(), outfile);
fwrite_crc(header, headersize, outfile); /* CRC not used */
}
static void skip(void)
{
fseek(arcfile, compsize, SEEK_CUR);
}
static void copy(void)
{
uint n;
write_header();
while (compsize != 0) {
n = (uint)((compsize > DICSIZ) ? DICSIZ : compsize);
if (fread ((char *)buffer, 1, n, arcfile) != n)
error("Can't read");
if (fwrite((char *)buffer, 1, n, outfile) != n)
error("Can't write");
compsize -= n;
}
}
static void store(void)
{
uint n;
origsize = 0;
crc = INIT_CRC;
while ((n = fread((char *)buffer, 1, DICSIZ, infile)) != 0) {
fwrite_crc(buffer, n, outfile); origsize += n;
}
compsize = origsize;
}
static int add(int replace_flag)
{
long headerpos, arcpos;
uint r;
if ((infile = fopen(filename, "rb")) == NULL) {
fprintf(stderr, "Can't open %s\n", filename);
return 0; /* failure */
}
if (replace_flag) {
printf("Replacing %s ", filename); skip();
} else
printf("Adding %s ", filename);
headerpos = ftell(outfile);
namelen = strlen(filename);
headersize = 25 + namelen;
memcpy(header, "-lh5-", 5); /* compress */
write_header(); /* temporarily */
arcpos = ftell(outfile);
origsize = compsize = 0; unpackable = 0;
crc = INIT_CRC; encode();
if (unpackable) {
header[3] = '0'; /* store */
rewind(infile);
fseek(outfile, arcpos, SEEK_SET);
store();
}
file_crc = crc ^ INIT_CRC;
fclose(infile);
put_to_header(5, 4, compsize);
put_to_header(9, 4, origsize);
memcpy(header + 13, "\0\0\0\0\x20\x01", 6);
memcpy(header + headersize - 3, "\x20\0\0", 3);
fseek(outfile, headerpos, SEEK_SET);
write_header(); /* true header */
fseek(outfile, 0L, SEEK_END);
r = ratio(compsize, origsize);
printf(" %d.%d%%\n", r / 10, r % 10);
return 1; /* success */
}
int get_line(char *s, int n)
{
int i, c;
i = 0;
while ((c = getchar()) != EOF && c != '\n')
if (i < n) s[i++] = (char)c;
s[i] = '\0';
return i;
}
static void extract(int to_file)
{
int n, method;
uint ext_headersize;
if (to_file) {
while ((outfile = fopen(filename, "wb")) == NULL) {
fprintf(stderr, "Can't open %s\nNew filename: ", filename);
if (get_line(filename, FNAME_MAX) == 0) {
fprintf(stderr, "Not extracted\n");
skip(); return;
}
namelen = strlen(filename);
}
printf("Extracting %s ", filename);
} else {
outfile = stdout;
printf("===== %s =====\n", filename);
}
crc = INIT_CRC;
method = header[3]; header[3] = ' ';
if (! strchr("045", method) || memcmp("-lh -", header, 5)) {
fprintf(stderr, "Unknown method: %u\n", method);
skip();
} else {
ext_headersize = (uint)get_from_header(headersize - 2, 2);
while (ext_headersize != 0) {
fprintf(stderr, "There's an extended header of size %u.\n",
ext_headersize);
compsize -= ext_headersize;
if (fseek(arcfile, ext_headersize - 2, SEEK_CUR))
error("Can't read");
ext_headersize = fgetc(arcfile);
ext_headersize += (uint)fgetc(arcfile) << 8;
}
crc = INIT_CRC;
if (method != '0') decode_start();
while (origsize != 0) {
n = (uint)((origsize > DICSIZ) ? DICSIZ : origsize);
if (method != '0') decode(n, buffer);
else if (fread((char *)buffer, 1, n, arcfile) != n)
error("Can't read");
fwrite_crc(buffer, n, outfile);
if (outfile != stdout) putc('.', stderr);
origsize -= n;
}
}
if (to_file) fclose(outfile); else outfile = NULL;
printf("\n");
if ((crc ^ INIT_CRC) != file_crc)
fprintf(stderr, "CRC error\n");
}
static void list_start(void)
{
printf("Filename Original Compressed Ratio CRC Method\n");
}
static void list(void)
{
uint r;
printf("%-14s", filename);
if (namelen > 14) printf("\n ");
r = ratio(compsize, origsize);
printf(" %10lu %10lu %u.%03u %04X %5.5s\n",
origsize, compsize, r / 1000, r % 1000, file_crc, header);
}
static int match(char *s1, char *s2)
{
for ( ; ; ) {
while (*s2 == '*' || *s2 == '?') {
if (*s2++ == '*')
while (*s1 && *s1 != *s2) s1++;
else if (*s1 == 0)
return 0;
else s1++;
}
if (*s1 != *s2) return 0;
if (*s1 == 0 ) return 1;
s1++; s2++;
}
}
static int search(int argc, char *argv[])
{
int i;
if (argc == 3) return 1;
for (i = 3; i < argc; i++)
if (match(filename, argv[i])) return 1;
return 0;
}
static void exitfunc(void)
{
fclose(outfile); remove(temp_name);
}
int main(int argc, char *argv[])
{
int i, j, cmd, count, nfiles, found, done;
/* Check command line arguments. */
if (argc < 3
|| argv[1][1] != '\0'
|| ! strchr("AXRDPL", cmd = toupper(argv[1][0]))
|| (argc == 3 && strchr("AD", cmd)))
error(usage);
/* Wildcards used? */
for (i = 3; i < argc; i++)
if (strpbrk(argv[i], "*?")) break;
if (cmd == 'A' && i < argc)
error("Filenames may not contain '*' and '?'");
if (i < argc) nfiles = -1; /* contains wildcards */
else nfiles = argc - 3; /* number of files to process */
/* Open archive. */
arcfile = fopen(argv[2], "rb");
if (arcfile == NULL && cmd != 'A')
error("Can't open archive '%s'", argv[2]);
/* Open temporary file. */
if (strchr("ARD", cmd)) {
temp_name = tmpnam(NULL);
outfile = fopen(temp_name, "wb");
if (outfile == NULL)
error("Can't open temporary file");
atexit(exitfunc);
} else temp_name = NULL;
make_crctable(); count = done = 0;
if (cmd == 'A') {
for (i = 3; i < argc; i++) {
for (j = 3; j < i; j++)
if (strcmp(argv[j], argv[i]) == 0) break;
if (j == i) {
strcpy(filename, argv[i]);
if (add(0)) count++; else argv[i][0] = 0;
} else nfiles--;
}
if (count == 0 || arcfile == NULL) done = 1;
}
while (! done && read_header()) {
found = search(argc, argv);
switch (cmd) {
case 'R':
if (found) {
if (add(1)) count++; else copy();
} else copy();
break;
case 'A': case 'D':
if (found) {
count += (cmd == 'D'); skip();
} else copy();
break;
case 'X': case 'P':
if (found) {
extract(cmd == 'X');
if (++count == nfiles) done = 1;
} else skip();
break;
case 'L':
if (found) {
if (count == 0) list_start();
list();
if (++count == nfiles) done = 1;
}
skip(); break;
}
}
if (temp_name != NULL && count != 0) {
fputc(0, outfile); /* end of archive */
if (ferror(outfile) || fclose(outfile) == EOF)
error("Can't write");
remove(argv[2]); rename(temp_name, argv[2]);
}
printf(" %d files\n", count);
return EXIT_SUCCESS;
}
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※ 修改:．haojs 于 Sep 3 08:24:27 修改本文．[FROM: bbs.hit.edu.cn]
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