/*

 * Copyright 2018, University Corporation for Atmospheric Research

 * See netcdf/COPYRIGHT file for copying and redistribution conditions.

 */

#include "config.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <assert.h>

#include <errno.h>

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_DIRENT_H

#include <dirent.h>

#endif

#ifdef _WIN32

#include <windows.h>

#include <io.h>

#include <wchar.h>

#include <direct.h>

#endif

#include <locale.h>

#include "netcdf.h"

#include "ncpathmgr.h"

#include "nclog.h"

#include "nclist.h"

#include "ncbytes.h"

#include "ncuri.h"

#include "ncutf8.h"

#undef DEBUGPATH

static int pathdebug = -1;

#undef DEBUG

#ifdef DEBUG

#define REPORT(e,msg) report((e),(msg),__LINE__)

#else

#define REPORT(e,msg)

#endif

#ifdef _WIN32

#define access _access

#define mkdir _mkdir

#define rmdir _rmdir

#define getcwd _getcwd

#if WINVERMAJOR > 10 || (WINVERMAJOR == 10 && WINVERBUILD >= 17134)

/* Should be possible to use UTF8 directly */

#define WINUTF8

#else

#undef WINUTF8

#endif

#endif

#ifndef __OSX__

#if defined(__APPLE__) && defined(__MACH__)

#define __OSX__ 1

#endif

#endif

/*

Code to provide some path conversion code so that

paths in one format can be used on a platform that uses

a different format.

See the documentation in ncpathmgr.h for details.

*/

/* Define legal windows drive letters */

static const char* windrive = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/";

static const char netdrive = '/';

static const size_t cdlen = 10; /* strlen("/cygdrive/") */

static int pathinitialized = 0;

static const char* cygwinspecial[] =

    {"/bin/","/dev/","/etc/","/home/",

     "/lib/","/proc/","/sbin/","/tmp/",

     "/usr/","/var/",NULL};

static const struct Path {

    int kind;

    char drive;

    char* path;

} empty = {NCPD_UNKNOWN,0,NULL};

/* Keep the working directory kind and drive */

static char wdprefix[8192];

/* The current codepage */

#ifdef _WIN32

static int acp = -1;

#endif

/* Keep CYGWIN/MSYS2 mount point */

static struct MountPoint {

    int defined;

    char prefix[8192]; /*minus leading drive */

    char drive;

} mountpoint;

/* Pick the platform kind for testing */

static int platform = 0;

/* Do not treat /d/x as d:/x for msys */

static int env_msys_no_pathconv = 0;

static int parsepath(const char* inpath, struct Path* path);

static int unparsepath(struct Path* p, char** pathp, int platform);

static int getwdpath(void);

static void clearPath(struct Path* path);

static void pathinit(void);

static int iscygwinspecial(const char* path);

static int testurl(const char* path);

#ifdef WINPATH

static int ansi2utf8(const char* local, char** u8p);

static int ansi2wide(const char* local, wchar_t** u16p);

static int utf82wide(const char* utf8, wchar_t** u16p);

static int wide2utf8(const wchar_t* u16, char** u8p);

#endif

/*Forward*/

#ifdef DEBUG

static void report(int stat, const char* msg, int line);

#endif

static char* printPATH(struct Path* p);

EXTERNL

char* /* caller frees */

NCpathcvt(const char* inpath)

{

    int stat = NC_NOERR;

    char* tmp1 = NULL;

    char* result = NULL;

    struct Path inparsed = empty;

    int platform= NCgetlocalpathkind();

    if(inpath == NULL) goto done; /* defensive driving */

    if(!pathinitialized) pathinit();

    if(testurl(inpath)) { /* Pass thru URLs */

  if((result = strdup(inpath))==NULL) stat = NC_ENOMEM;

  goto done;

    }

    if((stat = parsepath(inpath,&inparsed)))

  {REPORT(stat,"NCpathcvt: parsepath"); goto done;}

    if(pathdebug > 0)

        fprintf(stderr,">>> NCpathcvt: inparsed=%s\n",printPATH(&inparsed));

    if((stat = unparsepath(&inparsed,&result,platform)))

        {REPORT(stat,"NCpathcvt: unparsepath"); goto done;}

done:

    if(pathdebug > 0) {

        fprintf(stderr,">>> inpath=|%s| result=|%s|\n",

            inpath?inpath:"NULL",result?result:"NULL");

        fflush(stderr);

    }

    if(stat) {

        nullfree(result); result = NULL;

  nclog(NCLOGERR,"NCpathcvt: stat=%d (%s)",

    stat,nc_strerror(stat));

    }

    nullfree(tmp1);

    clearPath(&inparsed);

    //fprintf(stderr,">>> ncpathcvt: inpath=%s result=%s\n",inpath,result);

    return result;

}

EXTERNL

int

NCpathcanonical(const char* srcpath, char** canonp)

{

    int stat = NC_NOERR;

    char* canon = NULL;

    struct Path path = empty;

    if(srcpath == NULL) goto done;

    if(!pathinitialized) pathinit();

    /* parse the src path */

    if((stat = parsepath(srcpath,&path))) {goto done;}

    /* Convert to cygwin form */

    if((stat = unparsepath(&path,&canon, NCPD_CYGWIN)))

        goto done;

    if(canonp) {*canonp = canon; canon = NULL;}

done:

    nullfree(canon);

    clearPath(&path);

    return stat;

}

EXTERNL

char* /* caller frees */

NCpathabsolute(const char* relpath)

{

    int stat = NC_NOERR;

    struct Path canon = empty;

    char* tmp1 = NULL;

    char* result = NULL;

    size_t len;

    if(relpath == NULL) goto done; /* defensive driving */

    if(!pathinitialized) pathinit();

    /* Decompose path */

    if((stat = parsepath(relpath,&canon)))

  {REPORT(stat,"pathabs: parsepath"); goto done;}

    /* See if relative */

    if(canon.kind == NCPD_REL) {

  /* prepend the wd path to the inpath, including drive letter, if any */

  len = strlen(wdprefix)+strlen(canon.path)+1+1;

  if((tmp1 = (char*)malloc(len))==NULL)

      {stat = NCTHROW(NC_ENOMEM); goto done;}

  tmp1[0] = '\0';

  strlcat(tmp1,wdprefix,len);

  strlcat(tmp1,"/",len);

  strlcat(tmp1,canon.path,len);

        nullfree(canon.path);

        canon.path = NULL;

  /* Reparse */

  result = NCpathabsolute(tmp1);

  goto done;

    }

    /* rebuild */

    if((stat=unparsepath(&canon,&result,NCgetlocalpathkind())))

  {REPORT(stat,"pathabs: unparsepath"); goto done;}

done:

    if(pathdebug > 0) {

        fprintf(stderr,">>> relpath=|%s| result=|%s|\n",

            relpath?relpath:"NULL",result?result:"NULL");

        fflush(stderr);

    }

    if(stat) {

        nullfree(tmp1); tmp1 = NULL;

  nclog(NCLOGERR,"NCpathcvt: stat=%d (%s)",

    stat,nc_strerror(stat));

    }

    clearPath(&canon);

    nullfree(tmp1);

    return result;

}

/* Testing support */

EXTERNL

char* /* caller frees */

NCpathcvt_test(const char* inpath, int ukind, int udrive)

{

    char* result = NULL;

    struct MountPoint old;

    if(!pathinitialized) pathinit();

    old = mountpoint;

    memset(&mountpoint,0,sizeof(mountpoint));

    mountpoint.drive = (char)udrive;

    mountpoint.defined = (mountpoint.drive || nulllen(mountpoint.prefix) > 0);

    platform = ukind;

    result = NCpathcvt(inpath);

    mountpoint = old;

    return result;

}

static void

pathinit(void)

{

    if(pathinitialized) return;

    pathinitialized = 1; /* avoid recursion */

    /* Check for path debug env vars */

    if(pathdebug < 0) {

  const char* s = getenv("NCPATHDEBUG");

        pathdebug = (s == NULL ? 0 : 1);

    }

    (void)getwdpath();

#ifdef _WIN32

    /* Get the current code page */

    acp = GetACP();

#endif

    memset(&mountpoint,0,sizeof(mountpoint));

#ifdef REGEDIT

    { /* See if we can get the MSYS2 prefix from the registry */

  if(getmountpoint(mountpoint.prefix,sizeof(mountpoint.prefix)))

      goto next;

  mountpoint.defined = 1;

if(pathdebug > 0)

  fprintf(stderr,">>>> registry: mountprefix=|%s|\n",mountpoint.prefix);

    }

next:

#endif

    if(!mountpoint.defined) {

  mountpoint.prefix[0] = '\0';

        /* See if MSYS2_PREFIX is defined */

        if(getenv("MSYS2_PREFIX")) {

      const char* m2 = getenv("MSYS2_PREFIX");

      mountpoint.prefix[0] = '\0';

            strlcat(mountpoint.prefix,m2,sizeof(mountpoint.prefix));

  }

        if(pathdebug > 0) {

            fprintf(stderr,">>>> prefix: mountprefix=|%s|\n",mountpoint.prefix);

        }

    }

    if(mountpoint.defined) {

  char* p;

  size_t size = strlen(mountpoint.prefix);

        for(p=mountpoint.prefix;*p;p++) {if(*p == '\\') *p = '/';} /* forward slash*/

  if(mountpoint.prefix[size-1] == '/') {

      size--;

      mountpoint.prefix[size] = '\0'; /* no trailing slash */

  }

  /* Finally extract the drive letter, if any */

  /* assumes mount prefix is in windows form */

  mountpoint.drive = 0;

  if(strchr(windrive,mountpoint.prefix[0]) != NULL

           && mountpoint.prefix[1] == ':') {

      char* q = mountpoint.prefix;

      mountpoint.drive = mountpoint.prefix[0];

      /* Shift prefix left 2 chars */

            for(p=mountpoint.prefix+2;*p;p++) {*q++ = *p;}

      *q = '\0';

  }

    }

    /* Check for the MSYS_NO_PATHCONV env var */

    {

  const char* s = getenv("MSYS_NO_PATHCONV");

  env_msys_no_pathconv = (s == NULL ? 0 : 1);

    }

    pathinitialized = 1;

}

static void

clearPath(struct Path* path)

{

    nullfree(path->path);

    path->path = NULL;

}

/* Unfortunately, not all cygwin paths start with /cygdrive.

   So see if the path starts with one of the special paths.

*/

static int

iscygwinspecial(const char* path)

{

    const char** p;

    if(path == NULL) return 0;

    for(p=cygwinspecial;*p;p++) {

        if(strncmp(*p,path,strlen(*p))==0) return 1;

    }

    return 0;

}

/* return 1 if path looks like a url; 0 otherwise */

static int

testurl(const char* path)

{

    int isurl = 0;

    NCURI* tmpurl = NULL;

    if(path == NULL) return 0;

    /* Ok, try to parse as a url */

    ncuriparse(path,&tmpurl);

    isurl = (tmpurl == NULL?0:1);

    ncurifree(tmpurl);

    return isurl;

}

#ifdef WINPATH

/*

Provide wrappers for Path-related functions

*/

EXTERNL

FILE*

NCfopen(const char* path, const char* flags)

{

    int stat = NC_NOERR;

    FILE* f = NULL;

    char bflags[64];

    char* path8 = NULL; /* ACP -> UTF=8 */

    char* bflags8 = NULL;

    char* cvtpath = NULL;

    wchar_t* wpath = NULL;

    wchar_t* wflags = NULL;

    size_t flaglen = strlen(flags)+1+1;

    bflags[0] = '\0';

    strlcat(bflags, flags, sizeof(bflags));

#ifdef _WIN32

    strlcat(bflags,"b",sizeof(bflags));

#endif

    /* First, convert from current Code Page to utf8 */

    if((stat = ansi2utf8(path,&path8))) goto done;

    if((stat = ansi2utf8(bflags,&bflags8))) goto done;

    /* Localize */

    if((cvtpath = NCpathcvt(path8))==NULL) goto done;

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        /* This should take utf8 directly */ 

        f = fopen(cvtpath,bflags8);

    } else

#endif

    {

        /* Convert from utf8 to wide */

        if((stat = utf82wide(cvtpath,&wpath))) goto done;

        if((stat = utf82wide(bflags8,&wflags))) goto done;

        f = _wfopen(wpath,wflags);

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(bflags8);

    nullfree(wpath);

    nullfree(wflags);

    return f;

}

EXTERNL

int

NCopen3(const char* path, int flags, int mode)

{

    int stat = NC_NOERR;

    int fd = -1;

    char* cvtpath = NULL;

    char* path8 = NULL;

    wchar_t* wpath = NULL;

    /* First, convert from current Code Page to utf8 */

    if((stat = ansi2utf8(path,&path8))) goto done;

    if((cvtpath = NCpathcvt(path8))==NULL) goto done;

#ifdef _WIN32

    flags |= O_BINARY;

#endif

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        /* This should take utf8 directly */ 

        fd = _open(cvtpath,flags,mode);

    } else

#endif

    {

        /* Convert from utf8 to wide */

        if((stat = utf82wide(cvtpath,&wpath))) goto done;

        fd = _wopen(wpath,flags,mode);

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(wpath);

    return fd;

}

EXTERNL

int

NCopen2(const char *path, int flags)

{

    return NCopen3(path,flags,0);

}

#ifdef HAVE_DIRENT_H

EXTERNL

DIR*

NCopendir(const char* path)

{

    DIR* ent = NULL;

    char* cvtname = NCpathcvt(path);

    if(cvtname == NULL) return NULL;

    ent = opendir(cvtname);

    nullfree(cvtname);

    return ent;

}

EXTERNL

int

NCclosedir(DIR* ent)

{

    int stat = NC_NOERR;

    if(closedir(ent) < 0) stat = errno;

    return stat;

}

#endif

/*

Provide wrappers for other file system functions

*/

/* Return access applied to path+mode */

EXTERNL

int

NCaccess(const char* path, int mode)

{

    int stat = 0;

    char* cvtpath = NULL;

    char* path8 = NULL;

    wchar_t* wpath = NULL;

    /* First, convert from current Code Page to utf8 */

    if((stat = ansi2utf8(path,&path8))) goto done;

    if((cvtpath = NCpathcvt(path8)) == NULL) {stat = EINVAL; goto done;}

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        /* This should take utf8 directly */ 

        if(_access(cvtpath,mode) < 0) {stat = errno; goto done;}

    } else

#endif

    {

        /* Convert from utf8 to wide */

        if((stat = utf82wide(cvtpath,&wpath))) goto done;

        if(_waccess(wpath,mode) < 0) {stat = errno; goto done;}

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(wpath);

    errno = stat;

    return (errno?-1:0);

}

EXTERNL

int

NCremove(const char* path)

{

    int status = 0;

    char* path8 = NULL;

    char* cvtpath = NULL;

    wchar_t* wpath = NULL;

    /* First, convert from current Code Page to utf8 */

    if((status = ansi2utf8(path,&path8))) goto done;

    if((cvtpath = NCpathcvt(path8)) == NULL) {status=ENOMEM; goto done;}

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        /* This should take utf8 directly */ 

        if(remove(cvtpath) < 0) {status = errno; goto done;}

    } else

#endif

    {

        if((status = utf82wide(cvtpath,&wpath))) {status = ENOENT; goto done;}

        if(_wremove(wpath) < 0) {status = errno; goto done;}

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(wpath);

    errno = status;

    return (errno?-1:0);

}

EXTERNL

int

NCmkdir(const char* path, int mode)

{

    int status = 0;

    char* cvtpath = NULL;

    char* path8 = NULL;

    wchar_t* wpath = NULL;

    /* First, convert from current Code Page to utf8 */

    if((status = ansi2utf8(path,&path8))) goto done;

    if((cvtpath = NCpathcvt(path8)) == NULL) {status=ENOMEM; goto done;}

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        /* This should take utf8 directly */ 

        if(_mkdir(cvtpath) < 0) {status = errno; goto done;}

    } else

#endif

    {

        if((status = utf82wide(cvtpath,&wpath))) {status = ENOENT; goto done;}

        if(_wmkdir(wpath) < 0) {status = errno; goto done;}

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(wpath);

    errno = status;

    return (errno?-1:0);

}

EXTERNL

int

NCrmdir(const char* path)

{

    int status = 0;

    char* cvtname = NULL;

    char* path8 = NULL;

    /* First, convert from current Code Page to utf8 */

    if((status = ansi2utf8(path,&path8))) goto done;

    cvtname = NCpathcvt(path8);

    if(cvtname == NULL) {errno = ENOENT; status = -1;}

    status = rmdir(cvtname);

done:

    nullfree(cvtname);

    nullfree(path8);

    return status;

}

EXTERNL

char*

NCgetcwd(char* cwdbuf, size_t cwdlen)

{

    int status = NC_NOERR;

    char* path = NULL;

    size_t len;

    struct Path wd;

    errno = 0;

    if(cwdlen == 0) {status = ENAMETOOLONG; goto done;}

    if(!pathinitialized) pathinit();

    if((status = getwdpath())) {status = ENOENT; goto done;}

    if((status = parsepath(wdprefix,&wd))) {status = EINVAL; goto done;}

    if((status = unparsepath(&wd,&path,NCgetlocalpathkind()))) {status = EINVAL; goto done;}

    len = strlen(path);

    if(len >= cwdlen) {status = ENAMETOOLONG; goto done;}

    if(cwdbuf == NULL) {

  if((cwdbuf = malloc(cwdlen))==NULL)

      {status = NCTHROW(ENOMEM); goto done;}

    }

    memcpy(cwdbuf,path,len+1);

done:

    clearPath(&wd);

    nullfree(path);

    errno = status;

    return cwdbuf;

}

EXTERNL

int

NCmkstemp(char* base)

{

    int stat = 0;

    int fd, rno;

    char* tmp = NULL;

    size_t len;

    char* xp = NULL;

    char* cvtpath = NULL;

    int attempts;

    cvtpath = NCpathcvt(base);

    len = strlen(cvtpath);

    xp = cvtpath+(len-6);

    assert(memcmp(xp,"XXXXXX",6)==0);

    for(attempts=10;attempts>0;attempts--) {

        /* The Windows version of mkstemp does not work right;

           it only allows for 26 possible XXXXXX values */

        /* Need to simulate by using some kind of pseudo-random number */

        rno = rand();

        if(rno < 0) rno = -rno;

        snprintf(xp,7,"%06d",rno);

        fd=NCopen3(cvtpath,O_RDWR|O_BINARY|O_CREAT, _S_IREAD|_S_IWRITE);

        if(fd >= 0) break;

    }

    if(fd < 0) {

       nclog(NCLOGERR, "Could not create temp file: %s",tmp);

       stat = EACCES;

       goto done;

    }

done:

    nullfree(cvtpath);

    if(stat && fd >= 0) {close(fd);}

    return (stat?-1:fd);

}

#ifdef HAVE_SYS_STAT_H

EXTERNL

int

NCstat(const char* path, STAT buf)

{

    int status = 0;

    char* cvtpath = NULL;

    char* path8 = NULL;

    wchar_t* wpath = NULL;

    if((status = ansi2utf8(path,&path8))) goto done;

    if((cvtpath = NCpathcvt(path8)) == NULL) {status=ENOMEM; goto done;}

#ifdef WINUTF8

    if(acp == CP_UTF8) {

        if(_stat64(cvtpath,buf) < 0) {status = errno; goto done;}

    } else

#endif

    {

        if((status = utf82wide(cvtpath,&wpath))) {status = ENOENT; goto done;}

        if(_wstat64(wpath,buf) < 0) {status = errno; goto done;}

    }

done:

    nullfree(cvtpath);

    nullfree(path8);

    nullfree(wpath);

    errno = status;

    return (errno?-1:0);

}

#endif /*HAVE_SYS_STAT_H*/

int

NCpath2utf8(const char* s, char** u8p)

{

    return ansi2utf8(s,u8p);

}

int

NCstdbinary(void)

{

    int fd;

    fd = _fileno(stdin);

    if(_setmode(fd,_O_BINARY)<0) return NC_EINVAL;

    fd = _fileno(stdout);

    if(_setmode(fd,_O_BINARY)<0) return NC_EINVAL;

    fd = _fileno(stderr);

    if(_setmode(fd,_O_BINARY)<0) return NC_EINVAL;

    return NC_NOERR;        

}

#else /*!WINPATH*/

int

NCpath2utf8(const char* path, char** u8p)

{

    int stat = NC_NOERR;

    char* u8 = NULL;

    if(path != NULL) {

        u8 = strdup(path);

  if(u8 == NULL) {stat =  NC_ENOMEM; goto done;}

    }

    if(u8p) {*u8p = u8; u8 = NULL;}

done:

    return stat;

}

int

NCstdbinary(void)

{

    return NC_NOERR;

}

#endif /*!WINPATH*/

EXTERNL int

NChasdriveletter(const char* path)

{

    int stat = NC_NOERR;

    int hasdl = 0;

    struct Path canon = empty;

    if(!pathinitialized) pathinit();

    if((stat = parsepath(path,&canon))) goto done;

    hasdl = (canon.drive != 0);

done:

    clearPath(&canon);

    return hasdl;

}

EXTERNL int

NCisnetworkpath(const char* path)

{

    int stat = NC_NOERR;

    int isnp = 0;

    struct Path canon = empty;

    if(!pathinitialized) pathinit();

    if((stat = parsepath(path,&canon))) goto done;

    isnp = (canon.drive == netdrive);

done:

    clearPath(&canon);

    return isnp;

}

/**************************************************/

/* Utilities */

/* Parse a path */

static int

parsepath(const char* inpath, struct Path* path)

{

    int stat = NC_NOERR;

    char* tmp1 = NULL;

    size_t len;

    char* p;

    int platform = NCgetlocalpathkind();

    assert(path);

    memset(path,0,sizeof(struct Path));

    if(inpath == NULL) goto done; /* defensive driving */

    if(!pathinitialized) pathinit();

#if 0

    /* Convert to UTF8 */

    if((stat = NCpath2utf8(inpath,&tmp1))) goto done;

#else

    tmp1 = strdup(inpath);

#endif

    /* Convert to forward slash to simplify later code */

    for(p=tmp1;*p;p++) {if(*p == '\\') *p = '/';}

    /* parse all paths to 2 parts:

  1. drive letter (optional)

  2. path after drive letter

    */

    len = strlen(tmp1);

    /* 1. look for Windows network path //...; drive letter is faked using

          the character '/' */

    if(len >= 2 && (tmp1[0] == '/') && (tmp1[1] == '/')) {

  path->drive = netdrive;

  /* Remainder */

  if(tmp1[2] == '\0')

      path->path = NULL;

  else

      path->path = strdup(tmp1+1); /*keep first '/' */

  if(path == NULL)

      {stat = NC_ENOMEM; goto done;}

  path->kind = NCPD_WIN;

    }

    /* 2. Look for leading /cygdrive/D where D is a single-char drive letter */

    else if(len >= (cdlen+1)

  && memcmp(tmp1,"/cygdrive/",cdlen)==0

  && strchr(windrive,tmp1[cdlen]) != NULL

  && (tmp1[cdlen+1] == '/'

      || tmp1[cdlen+1] == '\0')) {

  /* Assume this is a cygwin path */

  path->drive = tmp1[cdlen];

  /* Remainder */

  if(tmp1[cdlen+1] == '\0')

      path->path = NULL;

  else

      path->path = strdup(tmp1+cdlen+1);

  if(path == NULL)

      {stat = NC_ENOMEM; goto done;}

  path->kind = NCPD_CYGWIN;

    }

    /* 4. Look for windows path:  D:/... where D is a single-char

          drive letter */

    else if(len >= 2

  && strchr(windrive,tmp1[0]) != NULL

  && tmp1[1] == ':'

  && (tmp1[2] == '\0' || tmp1[2] == '/')) {

  /* Assume this is a windows path */

  path->drive = tmp1[0];

  /* Remainder */

  if(tmp1[2] == '\0')

      path->path = NULL;

  else

      path->path = strdup(tmp1+2);

  if(path == NULL)

      {stat = NC_ENOMEM; goto done;}

  path->kind = NCPD_WIN; /* Might be MINGW */

    }

    /* The /D/x/y/z MSYS paths cause much parsing confusion.

       So only use it if the current platform is msys and MSYS_NO_PATHCONV

       is undefined and NCpathsetplatform was called. Otherwise use windows

       paths.

    */

    /* X. look for MSYS path /D/... */

    else if(platform == NCPD_MSYS

  && !env_msys_no_pathconv

        && len >= 2

  && (tmp1[0] == '/')

  && strchr(windrive,tmp1[1]) != NULL

  && (tmp1[2] == '/' || tmp1[2] == '\0')) {

  /* Assume this is that stupid MSYS path format */

  path->drive = tmp1[1];

  /* Remainder */

  if(tmp1[2] == '\0')

      path->path = NULL;

  else

      path->path = strdup(tmp1+2);

  if(path == NULL)

      {stat = NC_ENOMEM; goto done;}

  path->kind = NCPD_MSYS;

    }

    /* 5. look for *nix* path; note this includes MSYS2 paths as well */

    else if(len >= 1 && tmp1[0] == '/') {

  /* Assume this is a *nix path */

  path->drive = 0; /* no drive letter */

  /* Remainder */

  path->path = tmp1; tmp1 = NULL;

  path->kind = NCPD_NIX;

    } else {/* 6. Relative path of unknown type */

  path->kind = NCPD_REL;

  path->path = tmp1; tmp1 = NULL;

    }

done:

    nullfree(tmp1);

    if(stat) {clearPath(path);}

    return stat;

}

static int

unparsepath(struct Path* xp, char** pathp, int platform)

{

    int stat = NC_NOERR;

    size_t len;

    char* path = NULL;

    char sdrive[4] = "\0\0\0\0";

    char* p = NULL;

    int cygspecial = 0;

    char drive = 0;

    /* Short circuit a relative path */

    if(xp->kind == NCPD_REL) {

  /* Pass thru relative paths, but with proper slashes */

  if((path = strdup(xp->path))==NULL) stat = NC_ENOMEM;

  if(platform == NCPD_WIN || platform == NCPD_MSYS) {

      char* p;

            for(p=path;*p;p++) {if(*p == '/') *p = '\\';} /* back slash*/

  }

  goto exit;

    }

    /* We need a two level switch with an arm

       for every pair of (xp->kind,platform)

    */

#define CASE(k,t) case ((k)*10+(t))

    switch (xp->kind*10 + platform) {

    CASE(NCPD_NIX,NCPD_NIX):

  assert(xp->drive == 0);

  len = nulllen(xp->path)+1;

  if((path = (char*)malloc(len))==NULL)

      {stat = NCTHROW(NC_ENOMEM); goto done;}

  path[0] = '\0';

  if(xp->path != NULL)

      strlcat(path,xp->path,len);

  break;

    CASE(NCPD_NIX,NCPD_MSYS):

    CASE(NCPD_NIX,NCPD_WIN):

  assert(xp->drive == 0);

  len = nulllen(xp->path)+1;

  if(!mountpoint.defined)

      {stat = NC_EINVAL; goto done;} /* drive required */

  len += (strlen(mountpoint.prefix) + 2);

  if((path = (char*)malloc(len))==NULL)

      {stat = NCTHROW(NC_ENOMEM); goto done;}

  path[0] = '\0';

  assert(mountpoint.drive != 0);

  sdrive[0] = mountpoint.drive;

  sdrive[1] = ':';

  sdrive[2] = '\0';

  strlcat(path,sdrive,len);

  strlcat(path,mountpoint.prefix,len);

  if(xp->path != NULL) strlcat(path,xp->path,len);

        for(p=path;*p;p++) {if(*p == '/') *p = '\\';} /* restore back slash */

  break;

    CASE(NCPD_NIX,NCPD_CYGWIN):

  assert(xp->drive == 0);

  /* Is this one of the special cygwin paths? */

  cygspecial = iscygwinspecial(xp->path);

  len = 0;

  if(!cygspecial && mountpoint.drive != 0) {

      len = cdlen + 1+1; /* /cygdrive/D */