/****************************************************************************
 *
 * (c) Vladi Belperchinov-Shabanski "Cade" 1996-2015
 * http://cade.datamax.bg/  <cade@biscom.net> <cade@bis.bg> <cade@datamax.bg>
 *
 * SEE `README',`LICENSE' OR `COPYING' FILE FOR LICENSE AND OTHER DETAILS!
 *
 ****************************************************************************/

#include "vsuti.h"
#include "vstring.h"
#include "vstrlib.h"

/*###########################################################################*/

/* adler32.c -- compute the Adler-32 checksum of a data stream
 * Copyright (C) 1995-1996 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#define BASE 65521L /* largest prime smaller than 65536 */
#define NMAX 5552
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */

#define DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
#define DO2(buf,i)  DO1(buf,i); DO1(buf,i+1);
#define DO4(buf,i)  DO2(buf,i); DO2(buf,i+2);
#define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
#define DO16(buf)   DO8(buf,0); DO8(buf,8);

/*---------------------------------------------------------------------------*/

unsigned long adler32(unsigned long adler, const char *buf, unsigned int len)
{
    unsigned long s1 = adler & 0xffff;
    unsigned long s2 = (adler >> 16) & 0xffff;
    int k;

    if (buf == NULL) return 1L;

    while (len > 0) {
        k = len < NMAX ? len : NMAX;
        len -= k;
        while (k >= 16) {
            DO16(buf);
            buf += 16;
            k -= 16;
        }
        if (k != 0) do {
            s1 += *buf++;
            s2 += s1;
        } while (--k);
        s1 %= BASE;
        s2 %= BASE;
    }
    return (s2 << 16) | s1;
}

/*---------------------------------------------------------------------------*/

adler32_t mem_adler32( const void* buff, int size )
{
  return adler32( adler32( 0, NULL, 0 ), (const char *)buff, size );
}

/*---------------------------------------------------------------------------*/

adler32_t str_adler32( const char *s )
{
  return mem_adler32( s, strlen(s) );
}

/*---------------------------------------------------------------------------*/

adler32_t file_adler32( FILE *f, long buffsize  )
{
  ASSERT( f );

  char *buff = (char*)malloc( buffsize );
  if (buff == NULL) return 0;

  adler32_t adler = adler32( 0, NULL, 0 );
  while(42)
    {
    long res = fread( buff, 1, buffsize, f );
    if (res == -1)
      {
      fclose( f );
      return 0;
      }
    adler = adler32( adler, buff, res );
    if ( res != buffsize ) break;
    }
  free( buff );

  return adler;
}

/*---------------------------------------------------------------------------*/

adler32_t file_adler32( const char *fname, long buffsize  )
{
  FILE *f = fopen( fname, "rb" );
  if (!f) return 0;
  adler32_t adler = file_adler32( f, buffsize );
  fclose(f);
  return adler;
}

/*###########################################################################*/
/* FILE functions */

off_t file_size( const char *fname )
{
  struct stat st;
  if (stat( fname, &st )) return -1;
  return st.st_size;
}

/*---------------------------------------------------------------------------*/

off_t file_size( FILE *f )
{
  int res = 0;
  off_t opos = ftello( f );
  if (opos == -1) return -1;
  if (fseeko( f, 0, SEEK_END )) res++;
  off_t size = ftello( f );
  res += (size == -1);
  if (fseeko( f, opos, SEEK_SET )) res++;
  if (res) return -1;
  return size;
}

/*---------------------------------------------------------------------------*/

int file_load( FILE *f, void *buff, int size )
{
  return ( fread( buff, 1, size, f ) != (size_t)size);
}

/*---------------------------------------------------------------------------*/

int file_save( FILE *f, void *buff, int size )
{
  return (fwrite( buff, 1, size, f ) != (size_t)size);
}

/*---------------------------------------------------------------------------*/

int file_load( const char* fname, void *buff, int size )
{
  FILE *f = fopen( fname, "rb" );
  if (!f) return 1;
  int res = file_load( f, buff, size );
  fclose( f );
  return res;
}

/*---------------------------------------------------------------------------*/

int file_save( const char* fname, void *buff, int size )
{
  FILE *f = fopen( fname, "wb" );
  if (!f) return 1;
  int res = file_save( f, buff, size );
  fclose( f );
  return res;
}

/*---------------------------------------------------------------------------*/

int file_load_crc32( const char* fname, void *buff, int size )
{
  crc32_t crc;
  FILE *f = fopen( fname, "rb" );
  if (!f) return 1;
  int res = 0;
  res += ( fread( buff, 1, size, f ) != (size_t)size );
  res += ( fread( &crc, 1, sizeof(crc), f ) != sizeof(crc) );
  fclose(f);
  res += ( crc != mem_crc32( buff, size ) );
  return res;
}

/*---------------------------------------------------------------------------*/

int file_save_crc32( const char* fname, void *buff, int size )
{
  crc32_t crc = mem_crc32( buff, size );
  FILE *f = fopen( fname, "wb" );
  if (!f) return 1;
  int res = 0;
  res += ( fwrite( buff, 1, size, f ) != (size_t)size );
  res += ( fwrite( &crc, 1, sizeof(crc), f ) != sizeof(crc) );
  fclose(f);
  return res;
}


int file_is_link( const char* fname )
{
  #ifdef _TARGET_GO32_
  return 0;
  #else
  struct stat st;
  if (lstat( fname, &st )) return 0; /* consider it not link */
  return !!( S_ISLNK(st.st_mode) );
  #endif
}

/*---------------------------------------------------------------------------*/

int file_is_dir( const char* fname )
{
  struct stat st;
  if (stat( fname, &st )) return 0; /* consider it not link */
  return !!( S_ISDIR(st.st_mode) );
}

/*---------------------------------------------------------------------------*/

int file_is_dir( struct stat st )
{
  return !!( S_ISDIR(st.st_mode) );
}

int file_exists( const char* fname )
{
  return access( fname, F_OK ) == 0;
}

/*****************************************************************************
**
** tilde_expand() expands ~/path and ~name/path to real pathname.
** it uses $HOME environment variable for ~ substitution.
**
*****************************************************************************/

VString tilde_expand( const char* a_path )
{
#ifdef _TARGET_UNIX_
  VString path;
  struct passwd* pwd;
  if ( !a_path || !a_path[0] || a_path[0] != '~' )
    return VString( a_path );

  int z = 1; // first after ~
  while( a_path[z] != '/' && a_path[z] != 0 )
    str_add_ch( path, a_path[z++] );

  if ( path == "" )
    path = getenv( "USER" );
  if ( path != "" )
    {
    pwd = getpwnam( path );
    if (!pwd) return VString( a_path );
    path = pwd->pw_dir;
    }
  else
    {
    char* pw_dir = getenv("HOME");
    if (!pw_dir) return VString( a_path );
    path = pw_dir;
    }
  // get rid of trailing `/' if exists
  str_fix_path( path );
  str_chop( path );
  path += a_path + z;
  return path;
#else //_TARGET_UNIX_
  VString path = a_path;
  return path;
#endif //_TARGET_UNIX_
}

/*****************************************************************************
**
** make_path() create new directory including non-existing path entries.
** It can create /a/b/c/d/e/ without existing of `/a/' for example.
** return 0 for success
**
*****************************************************************************/

int make_path( const char *s, long mode )
{
  char str[MAX_PATH];
  char tmp[MAX_PATH];
  strcpy( tmp, s );
  str_fix_path( tmp );
  int l = strlen( tmp );
  strcpy( str, tmp ); // to hold original expanded path
  while(1)
    {
    while ( l >= 0 && tmp[l] != '/' ) l--;
    ASSERT( l < 0 || tmp[l] == '/' );
    if ( l < 0 )
      break;
    else
      tmp[l+1] = 0;
    if ( access( tmp, F_OK ) == 0 ) break;
    l--;
    }
  while(1)
    {
      l++;
      while ( str[l] != 0 && str[l] != '/' ) l++;
      if ( str[l] == 0 ) break;
      strncpy( tmp, str, l );
      tmp[l] = 0;
      int res = mkdir( tmp, mode );
      if (res) return res;
    }
  return 0;
}

/*****************************************************************************
**
** expand_path() resolves symlinks etc.
**
*****************************************************************************/

char* expand_path( const char *src, char *dest )
{
  #ifdef _TARGET_UNIX_
  if (!realpath( src, dest))
    strcpy( dest, src );
  #endif

  #ifdef _TARGET_GO32_
  _fixpath( src, dest );
  #endif

  return dest;
}

VString expand_path( const char* src )
{
  char temp[MAX_PATH];
  VString dest = expand_path( src, temp );
  return dest;
}

/*****************************************************************************
**
** dosstat() is fast stat() designed for DOS FAT filesystems under DJGPP.
**
*****************************************************************************/

#ifdef _TARGET_GO32_

/*
  This is specific to djgpp/libc 2.01 -- if it changes later this
  must be changed too...
*/

struct ___DIR {
  int num_read;
  char *name;
  int flags;
  struct ffblk ff;
  struct dirent de;
  int need_fake_dot_dotdot; /* 0=no, 1=.., 2=. */
}

/* Convert file date and time to time_t value suitable for
   struct stat fields.  */
time_t _file_time_stamp(unsigned int dos_ftime)
{
  struct tm file_tm;
  memset(&file_tm, 0, sizeof(struct tm));
  file_tm.tm_isdst = -1;    /* let mktime() determine if DST is in effect */
  file_tm.tm_sec  = (dos_ftime & 0x1f) * 2;
  file_tm.tm_min  = (dos_ftime >>  5) & 0x3f;
  file_tm.tm_hour = (dos_ftime >> 11) & 0x1f;
  file_tm.tm_mday = (dos_ftime >> 16) & 0x1f;
  file_tm.tm_mon  = ((dos_ftime >> 21) & 0x0f) - 1; /* 0 = January */
  file_tm.tm_year = (dos_ftime >> 25) + 80;
  return mktime(&file_tm);
}

int dosstat( DIR *dir, struct stat *statbuf )
{
  #define ff_blk (((___DIR*)(dir))->ff)

  #define READ_ACCESS     (S_IRUSR | S_IRGRP | S_IROTH)
  #define WRITE_ACCESS    S_IWUSR
  #define EXEC_ACCESS     (S_IXUSR | S_IXGRP | S_IXOTH)

  memset(statbuf, 0, sizeof(struct stat));

  unsigned dos_ftime = 0;
  dos_ftime = ( (unsigned short)ff_blk.ff_fdate << 16 ) +
                (unsigned short)ff_blk.ff_ftime;

  statbuf->st_uid     = getuid();
  statbuf->st_gid     = getgid();
  statbuf->st_nlink   = 1;
  statbuf->st_size    = ff_blk.ff_fsize;
  statbuf->st_mode   |= READ_ACCESS;
  if ( !(ff_blk.ff_attrib & 0x07) )  /* no R, H or S bits set */
     statbuf->st_mode |= WRITE_ACCESS;
  if (ff_blk.ff_attrib & 0x10)
     statbuf->st_mode |= (S_IFDIR | EXEC_ACCESS);
  /* Set regular file bit.  */
  statbuf->st_mode |= S_IFREG;

  /* Time fields. */
  statbuf->st_atime = statbuf->st_mtime = statbuf->st_ctime =
    _file_time_stamp(dos_ftime);

  if ( ! strcmp(ff_blk.lfn_magic,"LFN32") )
    {
      unsigned xtime;
      xtime = *(unsigned *)&ff_blk.lfn_ctime;
      if(xtime)                 /* May be zero if file written w/o lfn active */
        statbuf->st_ctime = _file_time_stamp(xtime);
      xtime = *(unsigned *)&ff_blk.lfn_atime;
      if(xtime > dos_ftime)     /* Accessed time is date only, no time */
        statbuf->st_atime = _file_time_stamp(xtime);
    }

  return 0;
  #undef ff_blk
}

#endif /* _TARGET_GO32_ */

/*****************************************************************************
**
** ftwalk() traverses directory tree and calls func() for every entri it
** encounters. It supports DOS FAT filesystems under DJGPP.
**
*****************************************************************************/

int __ftwalk_process( const char *origin,
                      const char *path,
                      int (*func)( const char* origin,    /* origin path */
                                   const char* fname,     /* full file name */
                                   const struct stat* st, /* stat or NULL */
                                   int is_link,           /* 1 if link */
                                   int flag ),
                      int level = -1 )
{
  DIR           *dir;
  struct dirent *de;
  struct stat   st;
  int           flag;

  if ( level != -1 && level == 0) return 0; /* required level reqched */

  VString this_path = path;
  int this_path_len = str_len( this_path );

  dir = opendir( this_path );
  if (!dir) return 0; /* consider it ok */

  while( (de = readdir(dir)) )
    {
    if ( strcmp( de->d_name, "." ) == 0 || strcmp(de->d_name, "..") == 0 ) continue;

    this_path += de->d_name;
    int is_link = file_is_link( this_path );
    #ifdef _TARGET_GO32_
    if (dosstat(dir, &st)) /* dosstat() will never return != 0 */
    #else
    if (stat(this_path, &st))
    #endif
      flag = FTWALK_NS;
    else if (S_ISDIR(st.st_mode))
      flag = FTWALK_D;
    else
      flag = FTWALK_F;

    int r = func( origin, this_path, &st, is_link, flag );
    if ( r )
      {
        closedir(dir);
        return r;
      }

    if ( flag == FTWALK_D && !is_link )
      {
      this_path += "/";
      r = __ftwalk_process( origin, this_path, func, level - 1 );
      if ( r )
        {
        closedir(dir);
        return r;
        }
      str_trim_right( this_path, 1 ); /* remove trailing `/' */
      int r = func( origin, this_path, &st, is_link, FTWALK_DX );
      if ( r )
        {
          closedir(dir);
          return r;
        }
      }
    str_sleft( this_path, this_path_len );
    } /* while readdir(dir) */

  closedir(dir);
  return 0;
}

int ftwalk( const char *origin,
            int (*func)( const char* origin,    /* origin path */
                         const char* fname,     /* full file name */
                         const struct stat* st, /* stat struture or NULL */
                         int is_link,           /* 1 if link */
                         int flag ),
            int level )
{
  int r;

  if ( !origin || !func || !origin[0] ) return 255;

  VString o = origin;
  str_fix_path( o );

  if ( !file_is_dir( o ) ) return 255;
  r = __ftwalk_process( o, o, func, level );
  return r;
}

/*****************************************************************************
**
** get_rc_directory() return application rc directory (and possibly create it)
** returned dir is $HOME/.dir_prefix or $HOME/$RC_PREFIX/dir_prefix depending
** on $RC_PREFIX existence.
**
*****************************************************************************/


VString get_rc_directory( const char* dir_prefix )
{
  VString rc_dir;

  rc_dir = getenv("HOME");
  if ( rc_dir == "" ) rc_dir = "/tmp/";
  #ifdef _TARGET_GO32_
  str_tr( rc_dir, "\\", "/" );
  #endif
  str_fix_path( rc_dir );

  int rcprefix = 1;
  if (getenv("RC_PREFIX"))
    rc_dir += getenv("RC_PREFIX");
  else
    rcprefix = 0;
  str_fix_path( rc_dir );
  if ( dir_prefix && dir_prefix[0] )
    {
    if ( rcprefix )
      rc_dir += dir_prefix;
    else
      {
      #ifdef _TARGET_GO32_
      rc_dir += "_";
      #else
      rc_dir += ".";
      #endif
      rc_dir += dir_prefix;
      }
    str_fix_path( rc_dir );
    }
  make_path( rc_dir );
  return rc_dir;
}

/*****************************************************************************
**
** EOF
**
*****************************************************************************/


