156 lines
3.0 KiB
C
156 lines
3.0 KiB
C
/*
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(c) Copyright 1992 Eric Backus
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This software may be used freely so long as this copyright notice is
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left intact. There is no warrantee on this software.
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*/
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#include "dos.h" /* For intdos() */
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#include <errno.h> /* For errno */
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#include <string.h> /* For strlen() */
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int
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_get_default_drive(void)
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{
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union REGS regs;
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regs.h.ah = 0x19; /* DOS Get Default Drive call */
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regs.h.al = 0;
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(void) intdos(®s, ®s);
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return regs.h.al;
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}
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static char *
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get_current_directory(char *out, int drive_number)
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{
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union REGS regs;
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regs.h.ah = 0x47;
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regs.h.dl = drive_number + 1;
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regs.x.si = (unsigned long) (out + 1);
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(void) intdos(®s, ®s);
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if (regs.x.cflag != 0)
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{
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errno = regs.x.ax;
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return out;
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}
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else
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{
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/* Root path, don't insert "/", it'll be added later */
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if (*(out + 1) != '\0')
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*out = '/';
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else
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*out = '\0';
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return out + strlen(out);
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}
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}
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static int
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is_slash(int c)
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{
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return c == '/' || c == '\\';
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}
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static int
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is_term(int c)
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{
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return c == '/' || c == '\\' || c == '\0';
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}
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/* Takes as input an arbitrary path. Fixes up the path by:
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1. Removing consecutive slashes
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2. Removing trailing slashes
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3. Making the path absolute if it wasn't already
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4. Removing "." in the path
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5. Removing ".." entries in the path (and the directory above them)
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6. Adding a drive specification if one wasn't there
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7. Converting all slashes to '/'
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*/
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void
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_fixpath(const char *in, char *out)
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{
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int drive_number;
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const char *ip = in;
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char *op = out;
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/* Add drive specification to output string */
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if (*(ip + 1) == ':' && ((*ip >= 'a' && *ip <= 'z') ||
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(*ip >= 'A' && *ip <= 'Z')))
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{
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if (*ip >= 'a' && *ip <= 'z')
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drive_number = *ip - 'a';
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else
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drive_number = *ip - 'A';
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*op++ = *ip++;
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*op++ = *ip++;
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}
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else
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{
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drive_number = _get_default_drive();
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*op++ = drive_number + 'a';
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*op++ = ':';
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}
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/* Convert relative path to absolute */
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if (!is_slash(*ip))
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op = get_current_directory(op, drive_number);
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/* Step through the input path */
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while (*ip)
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{
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/* Skip input slashes */
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if (is_slash(*ip))
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{
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ip++;
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continue;
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}
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/* Skip "." and output nothing */
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if (*ip == '.' && is_term(*(ip + 1)))
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{
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ip++;
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continue;
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}
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/* Skip ".." and remove previous output directory */
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if (*ip == '.' && *(ip + 1) == '.' && is_term(*(ip + 2)))
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{
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ip += 2;
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/* Don't back up over drive spec */
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if (op > out + 2)
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/* This requires "/" to follow drive spec */
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while (!is_slash(*--op));
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continue;
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}
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/* Copy path component from in to out */
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*op++ = '/';
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while (!is_term(*ip)) *op++ = *ip++;
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}
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/* If root directory, insert trailing slash */
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if (op == out + 2) *op++ = '/';
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/* Null terminate the output */
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*op = '\0';
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}
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#ifdef TEST
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#include <stdio.h>
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int
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main(int argc, char **argv)
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{
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char path[90];
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int i;
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for (i = 1; i < argc; i++)
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{
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_fixpath(argv[i], path);
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(void) printf("'%s' -> '%s'\n", argv[i], path);
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}
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return 0;
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}
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#endif
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