/*
 * This file Copyright (C) Mnemosyne LLC
 *
 * This file is licensed by the GPL version 2. Works owned by the
 * Transmission project are granted a special exemption to clause 2 (b)
 * so that the bulk of its code can remain under the MIT license.
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 *
 * $Id$
 */

#ifdef HAVE_MEMMEM
 #define _GNU_SOURCE /* glibc's string.h needs this to pick up memmem */
#endif

#if defined (SYS_DARWIN)
 #define HAVE_GETPAGESIZE
 #define HAVE_ICONV_OPEN
 #define HAVE_MKDTEMP
 #define HAVE_VALLOC
#endif

#include <assert.h>
#include <ctype.h> /* isdigit (), isalpha (), tolower () */
#include <errno.h>
#include <float.h> /* DBL_EPSILON */
#include <locale.h> /* localeconv () */
#include <math.h> /* pow (), fabs (), floor () */
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* strerror (), memset (), memmem () */
#include <time.h> /* nanosleep () */

#ifdef HAVE_ICONV_OPEN
 #include <iconv.h>
#endif
#include <libgen.h> /* basename () */
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h> /* stat (), getcwd (), getpagesize (), unlink () */

#include <event2/buffer.h>
#include <event2/event.h>

#ifdef WIN32
 #include <w32api.h>
 #define WINVER WindowsXP /* freeaddrinfo (), getaddrinfo (), getnameinfo () */
 #include <direct.h> /* _getcwd () */
 #include <windows.h> /* Sleep () */
#endif

#include "transmission.h"
#include "fdlimit.h"
#include "ConvertUTF.h"
#include "list.h"
#include "log.h"
#include "utils.h"
#include "platform.h" /* tr_lockLock (), TR_PATH_MAX */
#include "variant.h"
#include "version.h"


time_t __tr_current_time   = 0;

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

struct tm *
tr_localtime_r (const time_t *_clock, struct tm *_result)
{
#ifdef HAVE_LOCALTIME_R
  return localtime_r (_clock, _result);
#else
  struct tm *p = localtime (_clock);
  if (p)
    * (_result) = *p;
  return p;
#endif
}

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

void*
tr_malloc (size_t size)
{
  return size ? malloc (size) : NULL;
}

void*
tr_malloc0 (size_t size)
{
  return size ? calloc (1, size) : NULL;
}

void
tr_free (void * p)
{
  if (p != NULL)
    free (p);
}

void*
tr_memdup (const void * src, size_t byteCount)
{
  return memcpy (tr_malloc (byteCount), src, byteCount);
}

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

const char*
tr_strip_positional_args (const char* str)
{
  char * out;
  static size_t bufsize = 0;
  static char * buf = NULL;
  const char * in = str;
  const size_t  len = str ? strlen (str) : 0;

  if (!buf || (bufsize < len))
    {
      bufsize = len * 2 + 1;
      buf = tr_renew (char, buf, bufsize);
    }

  for (out = buf; str && *str; ++str)
    {
      *out++ = *str;

      if ((*str == '%') && isdigit (str[1]))
        {
          const char * tmp = str + 1;
          while (isdigit (*tmp))
            ++tmp;
          if (*tmp == '$')
            str = tmp[1]=='\'' ? tmp+1 : tmp;
        }

      if ((*str == '%') && (str[1] == '\''))
        str = str + 1;

    }

  *out = '\0';
  return !in || strcmp (buf, in) ? buf : in;
}

/**
***
**/

void
tr_timerAdd (struct event * timer, int seconds, int microseconds)
{
  struct timeval tv;
  tv.tv_sec = seconds;
  tv.tv_usec = microseconds;

  assert (tv.tv_sec >= 0);
  assert (tv.tv_usec >= 0);
  assert (tv.tv_usec < 1000000);

  evtimer_add (timer, &tv);
}

void
tr_timerAddMsec (struct event * timer, int msec)
{
  const int seconds =  msec / 1000;
  const int usec = (msec%1000) * 1000;
  tr_timerAdd (timer, seconds, usec);
}

/**
***
**/

uint8_t *
tr_loadFile (const char * path,
             size_t     * size)
{
  uint8_t * buf;
  struct stat  sb;
  int fd;
  ssize_t n;
  const char * const err_fmt = _("Couldn't read \"%1$s\": %2$s");

  /* try to stat the file */
  errno = 0;
  if (stat (path, &sb))
    {
      const int err = errno;
      tr_logAddDebug (err_fmt, path, tr_strerror (errno));
      errno = err;
      return NULL;
    }

  if ((sb.st_mode & S_IFMT) != S_IFREG)
    {
      tr_logAddError (err_fmt, path, _("Not a regular file"));
      errno = EISDIR;
      return NULL;
    }

  /* Load the torrent file into our buffer */
  fd = tr_open_file_for_scanning (path);
  if (fd < 0)
    {
      const int err = errno;
      tr_logAddError (err_fmt, path, tr_strerror (errno));
      errno = err;
      return NULL;
    }
  buf = tr_malloc (sb.st_size + 1);
  if (!buf)
    {
      const int err = errno;
      tr_logAddError (err_fmt, path, _("Memory allocation failed"));
      tr_close_file (fd);
      errno = err;
      return NULL;
    }
  n = read (fd, buf, (size_t)sb.st_size);
  if (n == -1)
    {
      const int err = errno;
      tr_logAddError (err_fmt, path, tr_strerror (errno));
      tr_close_file (fd);
      free (buf);
      errno = err;
      return NULL;
    }

  tr_close_file (fd);
  buf[ sb.st_size ] = '\0';
  *size = sb.st_size;
  return buf;
}

char*
tr_basename (const char * path)
{
  char * tmp = tr_strdup (path);
  char * ret = tr_strdup (basename (tmp));
  tr_free (tmp);
  return ret;
}

char*
tr_dirname (const char * path)
{
  char * tmp = tr_strdup (path);
  char * ret = tr_strdup (dirname (tmp));
  tr_free (tmp);
  return ret;
}

char*
tr_mkdtemp (char * template)
{
#ifdef HAVE_MKDTEMP
  return mkdtemp (template);
#else
  if (!mktemp (template) || mkdir (template, 0700))
    return NULL;
  return template;
#endif
}

/**
 * @brief Portability wrapper for mkdir ()
 *
 * A portability wrapper around mkdir ().
 * On WIN32, the `permissions' argument is unused.
 *
 * @return zero on success, or -1 if an error occurred
 * (in which case errno is set appropriately).
 */
static int
tr_mkdir (const char * path, int permissions UNUSED)
{
#ifdef WIN32
  if (path && isalpha (path[0]) && path[1] == ':' && !path[2])
    return 0;
  return mkdir (path);
#else
  return mkdir (path, permissions);
#endif
}

int
tr_mkdirp (const char * path_in,
           int          permissions)
{
  char * p;
  char * pp;
  bool done;
  int tmperr;
  int rv;
  struct stat sb;
  char * path = tr_strdup (path_in);

  /* walk past the root */
  p = path;
  while (*p == TR_PATH_DELIMITER)
    ++p;

  pp = p;
  done = false;
  while ((p = strchr (pp, TR_PATH_DELIMITER)) || (p = strchr (pp, '\0')))
    {
      if (!*p)
        done = true;
      else
        *p = '\0';

      tmperr = errno;
      rv = stat (path, &sb);
      errno = tmperr;
      if (rv)
        {
          /* Folder doesn't exist yet */
          if (tr_mkdir (path, permissions))
            {
              tmperr = errno;
              tr_logAddError (_("Couldn't create \"%1$s\": %2$s"), path, tr_strerror (tmperr));
              tr_free (path);
              errno = tmperr;
              return -1;
            }
        }
      else if ((sb.st_mode & S_IFMT) != S_IFDIR)
        {
          /* Node exists but isn't a folder */
          char * buf = tr_strdup_printf (_("File \"%s\" is in the way"), path);
          tr_logAddError (_("Couldn't create \"%1$s\": %2$s"), path_in, buf);
          tr_free (buf);
          tr_free (path);
          errno = ENOTDIR;
          return -1;
        }

      if (done)
        break;

      *p = TR_PATH_DELIMITER;
      p++;
      pp = p;
    }

  tr_free (path);
  return 0;
}

char*
tr_buildPath (const char *first_element, ...)
{
  const char * element;
  char * buf;
  char * pch;
  va_list vl;
  size_t bufLen = 0;

  /* pass 1: allocate enough space for the string */
  va_start (vl, first_element);
  element = first_element;
  while (element)
    {
      bufLen += strlen (element) + 1;
      element = va_arg (vl, const char*);
    }
  pch = buf = tr_new (char, bufLen);
  va_end (vl);

  /* pass 2: build the string piece by piece */
  va_start (vl, first_element);
  element = first_element;
  while (element)
    {
      const size_t elementLen = strlen (element);
      memcpy (pch, element, elementLen);
      pch += elementLen;
      *pch++ = TR_PATH_DELIMITER;
      element = va_arg (vl, const char*);
    }
  va_end (vl);

  /* terminate the string. if nonempty, eat the unwanted trailing slash */
  if (pch != buf)
    --pch;
  *pch++ = '\0';

  /* sanity checks & return */
  assert (pch - buf == (off_t)bufLen);
  return buf;
}

#ifdef SYS_DARWIN
 #define TR_STAT_MTIME(sb)((sb).st_mtimespec.tv_sec)
#else
 #define TR_STAT_MTIME(sb)((sb).st_mtime)
#endif

bool
tr_fileExists (const char * filename, time_t * mtime)
{
  struct stat sb;
  const bool ok = !stat (filename, &sb);

  if (ok && (mtime != NULL))
    *mtime = TR_STAT_MTIME (sb);

  return ok;
}

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

char*
evbuffer_free_to_str (struct evbuffer * buf)
{
  const size_t n = evbuffer_get_length (buf);
  char * ret = tr_new (char, n + 1);
  evbuffer_copyout (buf, ret, n);
  evbuffer_free (buf);
  ret[n] = '\0';
  return ret;
}

char*
tr_strdup (const void * in)
{
  return tr_strndup (in, in ? (int)strlen ((const char *)in) : 0);
}

char*
tr_strndup (const void * in, int len)
{
  char * out = NULL;

  if (len < 0)
    {
      out = tr_strdup (in);
    }
  else if (in)
    {
      out = tr_malloc (len + 1);
      memcpy (out, in, len);
      out[len] = '\0';
    }

  return out;
}

const char*
tr_memmem (const char * haystack, size_t haystacklen,
           const char * needle, size_t needlelen)
{
#ifdef HAVE_MEMMEM
  return memmem (haystack, haystacklen, needle, needlelen);
#else
  size_t i;
  if (!needlelen)
    return haystack;
  if (needlelen > haystacklen || !haystack || !needle)
    return NULL;
  for (i=0; i<=haystacklen-needlelen; ++i)
    if (!memcmp (haystack+i, needle, needlelen))
      return haystack+i;
  return NULL;
#endif
}

char*
tr_strdup_printf (const char * fmt, ...)
{
  va_list ap;
  char * ret;
  size_t len;
  char statbuf[2048];

  va_start (ap, fmt);
  len = evutil_vsnprintf (statbuf, sizeof (statbuf), fmt, ap);
  va_end (ap);

  if (len < sizeof (statbuf))
    {
      ret = tr_strndup (statbuf, len);
    }
  else
    {
      ret = tr_new (char, len + 1);
      va_start (ap, fmt);
      evutil_vsnprintf (ret, len + 1, fmt, ap);
      va_end (ap);
    }

  return ret;
}

const char*
tr_strerror (int i)
{
  const char * ret = strerror (i);

  if (ret == NULL)
    ret = "Unknown Error";

  return ret;
}

int
tr_strcmp0 (const char * str1, const char * str2)
{
  if (str1 && str2) return strcmp (str1, str2);
  if (str1) return 1;
  if (str2) return -1;
  return 0;
}

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

/* https://bugs.launchpad.net/percona-patches/+bug/526863/+attachment/1160199/+files/solaris_10_fix.patch */
char*
tr_strsep (char ** str, const char * delims)
{
#ifdef HAVE_STRSEP
  return strsep (str, delims);
#else
  char *token;

  if (*str == NULL) /* no more tokens */
    return NULL;

  token = *str;
  while (**str != '\0')
    {
      if (strchr (delims, **str) != NULL)
        {
          **str = '\0';
          (*str)++;
            return token;
        }
      (*str)++;
    }

  /* there is not another token */
  *str = NULL;

  return token;
#endif
}

char*
tr_strstrip (char * str)
{
  if (str != NULL)
    {
      size_t pos;
      size_t len = strlen (str);

      while (len && isspace (str[len - 1]))
        --len;

      for (pos = 0; pos < len && isspace (str[pos]);)
        ++pos;

      len -= pos;
      memmove (str, str + pos, len);
      str[len] = '\0';
    }

  return str;
}

bool
tr_str_has_suffix (const char *str, const char *suffix)
{
  size_t str_len;
  size_t suffix_len;

  if (!str)
    return false;
  if (!suffix)
    return true;

  str_len = strlen (str);
  suffix_len = strlen (suffix);
  if (str_len < suffix_len)
    return false;

  return !evutil_ascii_strncasecmp (str + str_len - suffix_len, suffix, suffix_len);
}

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

uint64_t
tr_time_msec (void)
{
  struct timeval tv;

  gettimeofday (&tv, NULL);
  return (uint64_t) tv.tv_sec * 1000 + (tv.tv_usec / 1000);
}

void
tr_wait_msec (long int msec)
{
#ifdef WIN32
  Sleep ((DWORD)msec);
#else
  struct timespec ts;
  ts.tv_sec = msec / 1000;
  ts.tv_nsec = (msec % 1000) * 1000000;
  nanosleep (&ts, NULL);
#endif
}

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

int
tr_snprintf (char * buf, size_t buflen, const char * fmt, ...)
{
  int len;
  va_list args;

  va_start (args, fmt);
  len = evutil_vsnprintf (buf, buflen, fmt, args);
  va_end (args);
  return len;
}

/*
 * Copy src to string dst of size siz. At most siz-1 characters
 * will be copied. Always NUL terminates (unless siz == 0).
 * Returns strlen (src); if retval >= siz, truncation occurred.
 */
size_t
tr_strlcpy (char * dst, const void * src, size_t siz)
{
#ifdef HAVE_STRLCPY
  return strlcpy (dst, src, siz);
#else
  char *      d = dst;
  const char *s = src;
  size_t      n = siz;

  assert (s);
  assert (d);

  /* Copy as many bytes as will fit */
  if (n != 0)
    {
      while (--n != 0)
        {
          if ((*d++ = *s++) == '\0')
            break;
        }
    }

  /* Not enough room in dst, add NUL and traverse rest of src */
  if (n == 0)
    {
      if (siz != 0)
        *d = '\0'; /* NUL-terminate dst */
      while (*s++)
        ;
    }

  return s - (char*)src - 1;  /* count does not include NUL */
#endif
}

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

double
tr_getRatio (uint64_t numerator, uint64_t denominator)
{
  double ratio;

  if (denominator > 0)
    ratio = numerator / (double)denominator;
  else if (numerator > 0)
    ratio = TR_RATIO_INF;
  else
    ratio = TR_RATIO_NA;

  return ratio;
}

void
tr_sha1_to_hex (char * out, const uint8_t * sha1)
{
  int i;
  static const char hex[] = "0123456789abcdef";

  for (i=0; i<20; ++i)
    {
      const unsigned int val = *sha1++;
      *out++ = hex[val >> 4];
      *out++ = hex[val & 0xf];
    }

  *out = '\0';
}

void
tr_hex_to_sha1 (uint8_t * out, const char * in)
{
  int i;
  static const char hex[] = "0123456789abcdef";

  for (i=0; i<20; ++i)
    {
      const int hi = strchr (hex, tolower (*in++)) - hex;
      const int lo = strchr (hex, tolower (*in++)) - hex;
      *out++ = (uint8_t)((hi<<4) | lo);
    }
}

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

static bool
isValidURLChars (const char * url, int url_len)
{
  const char * c;
  const char * end;
  static const char * rfc2396_valid_chars =
    "abcdefghijklmnopqrstuvwxyz" /* lowalpha */
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ" /* upalpha */
    "0123456789"                 /* digit */
    "-_.!~*'()"                  /* mark */
    ";/?:@&=+$,"                 /* reserved */
    "<>#%<\""                    /* delims */
    "{}|\\^[]`";                 /* unwise */

  if (url == NULL)
    return false;

  for (c=url, end=c+url_len; c && *c && c!=end; ++c)
    if (!strchr (rfc2396_valid_chars, *c))
      return false;

  return true;
}

/** @brief return true if the URL is a http or https or UDP one that Transmission understands */
bool
tr_urlIsValidTracker (const char * url)
{
  bool valid;

  if (url == NULL)
    {
      valid = false;
    }
  else
    {
      const int len = strlen (url);

      valid = isValidURLChars (url, len)
           && !tr_urlParse (url, len, NULL, NULL, NULL, NULL)
           && (!memcmp (url,"http://",7) || !memcmp (url,"https://",8) || !memcmp (url,"udp://",6));
    }

  return valid;
}

/** @brief return true if the URL is a http or https or ftp or sftp one that Transmission understands */
bool
tr_urlIsValid (const char * url, int url_len)
{
  bool valid;

  if (url == NULL)
    {
      valid = false;
    }
  else
    {
      if (url_len < 0)
        url_len = strlen (url);

      valid = isValidURLChars (url, url_len)
           && !tr_urlParse (url, url_len, NULL, NULL, NULL, NULL)
           && (!memcmp (url,"http://",7) || !memcmp (url,"https://",8) || !memcmp (url,"ftp://",6) || !memcmp (url,"sftp://",7));
    }

  return valid;
}

bool
tr_addressIsIP (const char * str)
{
  tr_address tmp;
  return tr_address_from_string (&tmp, str);
}

int
tr_urlParse (const char * url_in,
             int          len,
             char **      setme_protocol,
             char **      setme_host,
             int *        setme_port,
             char **      setme_path)
{
  int err;
  int port = 0;
  int n;
  char * tmp;
  char * pch;
  size_t host_len;
  size_t protocol_len;
  const char * host = NULL;
  const char * protocol = NULL;
  const char * path = NULL;

  tmp = tr_strndup (url_in, len);
  if ((pch = strstr (tmp, "://")))
    {
      *pch = '\0';
      protocol = tmp;
      protocol_len = pch - protocol;
      pch += 3;
      if ((n = strcspn (pch, ":/")))
        {
          const int havePort = pch[n] == ':';
          host = pch;
          host_len = n;
          pch += n;
          if (pch && *pch)
            *pch++ = '\0';
          if (havePort)
            {
              char * end;
              port = strtol (pch, &end, 10);
              pch = end;
            }
          path = pch;
        }
    }

  err = !host || !path || !protocol;

  if (!err && !port)
    {
      if (!strcmp (protocol, "udp")) port = 80;
      else if (!strcmp (protocol, "ftp")) port = 21;
      else if (!strcmp (protocol, "sftp")) port = 22;
      else if (!strcmp (protocol, "http")) port = 80;
      else if (!strcmp (protocol, "https")) port = 443;
    }

  if (!err)
    {
      if (setme_protocol) *setme_protocol = tr_strndup (protocol, protocol_len);

      if (setme_host){ ((char*)host)[-3] = ':'; *setme_host =
                        tr_strndup (host, host_len); }

      if (setme_path){ if (!*path) *setme_path = tr_strdup ("/");
                       else if (path[0] == '/') *setme_path = tr_strdup (path);
                       else { ((char*)path)[-1] = '/'; *setme_path = tr_strdup (path - 1); } }

      if (setme_port) *setme_port = port;
    }


  tr_free (tmp);
  return err;
}

#include <string.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>

char *
tr_base64_encode (const void * input, int length, int * setme_len)
{
  int retlen = 0;
  char * ret = NULL;

  if (input != NULL)
    {
      BIO * b64;
      BIO * bmem;
      BUF_MEM * bptr;

      if (length < 1)
        length = (int)strlen (input);

      bmem = BIO_new (BIO_s_mem ());
      b64 = BIO_new (BIO_f_base64 ());
      BIO_set_flags (b64, BIO_FLAGS_BASE64_NO_NL);
      b64 = BIO_push (b64, bmem);
      BIO_write (b64, input, length);
      (void) BIO_flush (b64);
      BIO_get_mem_ptr (b64, &bptr);
      ret = tr_strndup (bptr->data, bptr->length);
      retlen = bptr->length;
      BIO_free_all (b64);
    }

  if (setme_len)
    *setme_len = retlen;

  return ret;
}

char *
tr_base64_decode (const void * input,
                  int          length,
                  int *        setme_len)
{
  char * ret;
  BIO * b64;
  BIO * bmem;
  int retlen;

  if (length < 1)
    length = strlen (input);

  ret = tr_new0 (char, length);
  b64 = BIO_new (BIO_f_base64 ());
  bmem = BIO_new_mem_buf ((unsigned char*)input, length);
  bmem = BIO_push (b64, bmem);
  retlen = BIO_read (bmem, ret, length);
  if (!retlen)
    {
      /* try again, but with the BIO_FLAGS_BASE64_NO_NL flag */
      BIO_free_all (bmem);
      b64 = BIO_new (BIO_f_base64 ());
      BIO_set_flags (b64, BIO_FLAGS_BASE64_NO_NL);
      bmem = BIO_new_mem_buf ((unsigned char*)input, length);
      bmem = BIO_push (b64, bmem);
      retlen = BIO_read (bmem, ret, length);
    }

  if (setme_len)
    *setme_len = retlen;

  BIO_free_all (bmem);
  return ret;
}

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

void
tr_removeElementFromArray (void         * array,
                           unsigned int   index_to_remove,
                           size_t         sizeof_element,
                           size_t         nmemb)
{
  char * a = array;

  memmove (a + sizeof_element * index_to_remove,
           a + sizeof_element * (index_to_remove  + 1),
           sizeof_element * (--nmemb - index_to_remove));
}

int
tr_lowerBound (const void * key,
               const void * base,
               size_t       nmemb,
               size_t       size,
               int     (* compar)(const void* key, const void* arrayMember),
               bool       * exact_match)
{
  size_t first = 0;
  const char * cbase = base;
  bool exact = false;

  while (nmemb != 0)
    {
      const size_t half = nmemb / 2;
      const size_t middle = first + half;
      const int c = compar (key, cbase + size*middle);

      if (c <= 0)
        {
          if (c == 0)
            exact = true;
          nmemb = half;
        }
      else
        {
          first = middle + 1;
          nmemb = nmemb - half - 1;
        }
    }

  *exact_match = exact;
  return first;
}

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

/* Byte-wise swap two items of size SIZE.
   From glibc, written by Douglas C. Schmidt, LGPL 2.1 or higher */
#define SWAP(a, b, size) \
  do { \
    register size_t __size = (size); \
    register char *__a = (a), *__b = (b); \
    if (__a != __b) do { \
      char __tmp = *__a; \
      *__a++ = *__b; \
      *__b++ = __tmp; \
    } while (--__size > 0); \
  } while (0)


static size_t
quickfindPartition (char * base, size_t left, size_t right, size_t size,
                    int (*compar)(const void *, const void *), size_t pivotIndex)
{
  size_t i;
  size_t storeIndex;

  /* move pivot to the end */
  SWAP (base+(size*pivotIndex), base+(size*right), size);

  storeIndex = left;
  for (i=left; i<=right-1; ++i)
    {
      if (compar (base+(size*i), base+(size*right)) <= 0)
        {
          SWAP (base+(size*storeIndex), base+(size*i), size);
          ++storeIndex;
        }
    }

  /* move pivot to its final place */
  SWAP (base+(size*right), base+(size*storeIndex), size);

  /* sanity check the partition */
#ifndef NDEBUG
  assert (storeIndex >= left);
  assert (storeIndex <= right);

  for (i=left; i<storeIndex; ++i)
    assert (compar (base+(size*i), base+(size*storeIndex)) <= 0);
  for (i=storeIndex+1; i<=right; ++i)
    assert (compar (base+(size*i), base+(size*storeIndex)) >= 0);
#endif

  return storeIndex;
}

static void
quickfindFirstK (char * base, size_t left, size_t right, size_t size,
                 int (*compar)(const void *, const void *), size_t k)
{
  if (right > left)
    {
      const size_t pivotIndex = left + (right-left)/2u;

      const size_t pivotNewIndex = quickfindPartition (base, left, right, size, compar, pivotIndex);

      if (pivotNewIndex > left + k) /* new condition */
        quickfindFirstK (base, left, pivotNewIndex-1, size, compar, k);
      else if (pivotNewIndex < left + k)
        quickfindFirstK (base, pivotNewIndex+1, right, size, compar, k+left-pivotNewIndex-1);
    }
}

#ifndef NDEBUG
static void
checkBestScoresComeFirst (char * base, size_t nmemb, size_t size,
                          int (*compar)(const void *, const void *), size_t k)
{
  size_t i;
  size_t worstFirstPos = 0;

  for (i=1; i<k; ++i)
    if (compar (base+(size*worstFirstPos), base+(size*i)) < 0)
      worstFirstPos = i;

  for (i=0; i<k; ++i)
    assert (compar (base+(size*i), base+(size*worstFirstPos)) <= 0);
  for (i=k; i<nmemb; ++i)
    assert (compar (base+(size*i), base+(size*worstFirstPos)) >= 0);
}
#endif

void
tr_quickfindFirstK (void * base, size_t nmemb, size_t size,
                    int (*compar)(const void *, const void *), size_t k)
{
  if (k < nmemb)
    {
      quickfindFirstK (base, 0, nmemb-1, size, compar, k);

#ifndef NDEBUG
      checkBestScoresComeFirst (base, nmemb, size, compar, k);
#endif
    }
}

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

static char*
strip_non_utf8 (const char * in, size_t inlen)
{
  const char * end;
  const char zero = '\0';
  struct evbuffer * buf = evbuffer_new ();

  while (!tr_utf8_validate (in, inlen, &end))
    {
      const int good_len = end - in;

      evbuffer_add (buf, in, good_len);
      inlen -= (good_len + 1);
      in += (good_len + 1);
      evbuffer_add (buf, "?", 1);
    }

  evbuffer_add (buf, in, inlen);
  evbuffer_add (buf, &zero, 1);
  return evbuffer_free_to_str (buf);
}

static char*
to_utf8 (const char * in, size_t inlen)
{
  char * ret = NULL;

#ifdef HAVE_ICONV_OPEN
  int i;
  const char * encodings[] = { "CURRENT", "ISO-8859-15" };
  const int encoding_count = sizeof (encodings) / sizeof (encodings[1]);
  const size_t buflen = inlen*4 + 10;
  char * out = tr_new (char, buflen);

  for (i=0; !ret && i<encoding_count; ++i)
    {
      char * inbuf = (char*) in;
      char * outbuf = out;
      size_t inbytesleft = inlen;
      size_t outbytesleft = buflen;
      const char * test_encoding = encodings[i];

      iconv_t cd = iconv_open ("UTF-8", test_encoding);
      if (cd != (iconv_t)-1)
        {
          if (iconv (cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft) != (size_t)-1)
            ret = tr_strndup (out, buflen-outbytesleft);
          iconv_close (cd);
        }
    }

  tr_free (out);
#endif

  if (ret == NULL)
    ret = strip_non_utf8 (in, inlen);

  return ret;
}

char*
tr_utf8clean (const char * str, int max_len)
{
  char * ret;
  const char * end;

  if (max_len < 0)
    max_len = (int) strlen (str);

  if (tr_utf8_validate (str, max_len, &end))
    ret = tr_strndup (str, max_len);
  else
    ret = to_utf8 (str, max_len);

  assert (tr_utf8_validate (ret, -1, NULL));
  return ret;
}

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

struct number_range
{
  int low;
  int high;
};

/**
 * This should be a single number (ex. "6") or a range (ex. "6-9").
 * Anything else is an error and will return failure.
 */
static bool
parseNumberSection (const char * str, int len, struct number_range * setme)
{
  long a, b;
  bool success;
  char * end;
  const int error = errno;
  char * tmp = tr_strndup (str, len);

  errno = 0;
  a = b = strtol (tmp, &end, 10);
  if (errno || (end == tmp))
    {
      success = false;
    }
  else if (*end != '-')
    {
      success = true;
    }
  else
    {
      const char * pch = end + 1;
      b = strtol (pch, &end, 10);
      if (errno || (pch == end))
        success = false;
      else if (*end) /* trailing data */
        success = false;
      else
        success = true;
    }

  tr_free (tmp);

  setme->low = MIN (a, b);
  setme->high = MAX (a, b);

  errno = error;
  return success;
}

int
compareInt (const void * va, const void * vb)
{
  const int a = * (const int *)va;
  const int b = * (const int *)vb;
  return a - b;
}

/**
 * Given a string like "1-4" or "1-4,6,9,14-51", this allocates and returns an
 * array of setmeCount ints of all the values in the array.
 * For example, "5-8" will return [ 5, 6, 7, 8 ] and setmeCount will be 4.
 * It's the caller's responsibility to call tr_free () on the returned array.
 * If a fragment of the string can't be parsed, NULL is returned.
 */
int*
tr_parseNumberRange (const char * str_in, int len, int * setmeCount)
{
  int n = 0;
  int * uniq = NULL;
  char * str = tr_strndup (str_in, len);
  const char * walk;
  tr_list * ranges = NULL;
  bool success = true;

  walk = str;
  while (walk && *walk && success)
    {
      struct number_range range;
      const char * pch = strchr (walk, ',');
      if (pch)
        {
          success = parseNumberSection (walk, pch-walk, &range);
          walk = pch + 1;
        }
      else
        {
          success = parseNumberSection (walk, strlen (walk), &range);
          walk += strlen (walk);
        }
      if (success)
        tr_list_append (&ranges, tr_memdup (&range, sizeof (struct number_range)));
    }

  if (!success)
    {
      *setmeCount = 0;
      uniq = NULL;
    }
  else
    {
      int i;
      int n2;
      tr_list * l;
      int * sorted = NULL;

      /* build a sorted number array */
      n = n2 = 0;
      for (l=ranges; l!=NULL; l=l->next)
        {
          const struct number_range * r = l->data;
          n += r->high + 1 - r->low;
        }
      sorted = tr_new (int, n);
      for (l=ranges; l!=NULL; l=l->next)
        {
          int i;
          const struct number_range * r = l->data;
          for (i=r->low; i<=r->high; ++i)
            sorted[n2++] = i;
        }
      qsort (sorted, n, sizeof (int), compareInt);
      assert (n == n2);

      /* remove duplicates */
      uniq = tr_new (int, n);
      for (i=n=0; i<n2; ++i)
        if (!n || uniq[n-1] != sorted[i])
          uniq[n++] = sorted[i];

      tr_free (sorted);
    }

  /* cleanup */
  tr_list_free (&ranges, tr_free);
  tr_free (str);

  /* return the result */
  *setmeCount = n;
  return uniq;
}

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

double
tr_truncd (double x, int precision)
{
  char * pt;
  char buf[128];
  const int max_precision = (int) log10 (1.0 / DBL_EPSILON) - 1;
  tr_snprintf (buf, sizeof (buf), "%.*f", max_precision, x);
  if ((pt = strstr (buf, localeconv ()->decimal_point)))
    pt[precision ? precision+1 : 0] = '\0';
  return atof (buf);
}

/* return a truncated double as a string */
static char*
tr_strtruncd (char * buf, double x, int precision, size_t buflen)
{
  tr_snprintf (buf, buflen, "%.*f", precision, tr_truncd (x, precision));
  return buf;
}

char*
tr_strpercent (char * buf, double x, size_t buflen)
{
  if (x < 100.0)
    tr_strtruncd (buf, x, 1, buflen);
  else
    tr_strtruncd (buf, x, 0, buflen);

  return buf;
}

char*
tr_strratio (char * buf, size_t buflen, double ratio, const char * infinity)
{
  if ((int)ratio == TR_RATIO_NA)
    tr_strlcpy (buf, _("None"), buflen);
  else if ((int)ratio == TR_RATIO_INF)
    tr_strlcpy (buf, infinity, buflen);
  else
    tr_strpercent (buf, ratio, buflen);

  return buf;
}

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

int
tr_moveFile (const char * oldpath, const char * newpath, bool * renamed)
{
  int in;
  int out;
  char * buf;
  struct stat st;
  off_t bytesLeft;
  const size_t buflen = 1024 * 128; /* 128 KiB buffer */

  /* make sure the old file exists */
  if (stat (oldpath, &st))
    {
      const int err = errno;
      errno = err;
      return -1;
    }
  if (!S_ISREG (st.st_mode))
    {
      errno = ENOENT;
      return -1;
    }
  bytesLeft = st.st_size;

  /* make sure the target directory exists */
  {
    char * newdir = tr_dirname (newpath);
    int i = tr_mkdirp (newdir, 0777);
    tr_free (newdir);
    if (i)
      return i;
  }

  /* they might be on the same filesystem... */
  {
    const int i = rename (oldpath, newpath);
    if (renamed != NULL)
      *renamed = i == 0;
    if (!i)
      return 0;
  }

  /* copy the file */
  in = tr_open_file_for_scanning (oldpath);
  out = tr_open_file_for_writing (newpath);
  buf = tr_valloc (buflen);
  while (bytesLeft > 0)
    {
      ssize_t bytesWritten;
      const off_t bytesThisPass = MIN (bytesLeft, (off_t)buflen);
      const int numRead = read (in, buf, bytesThisPass);
      if (numRead < 0)
        break;
      bytesWritten = write (out, buf, numRead);
      if (bytesWritten < 0)
        break;
      bytesLeft -= bytesWritten;
    }

  /* cleanup */
  tr_free (buf);
  tr_close_file (out);
  tr_close_file (in);
  if (bytesLeft != 0)
    return -1;

  unlink (oldpath);
  return 0;
}

bool
tr_is_same_file (const char * filename1, const char * filename2)
{
  struct stat sb1, sb2;

  return !stat (filename1, &sb1)
      && !stat (filename2, &sb2)
      && (sb1.st_dev == sb2.st_dev)
      && (sb1.st_ino == sb2.st_ino);
}

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

void*
tr_valloc (size_t bufLen)
{
  size_t allocLen;
  void * buf = NULL;
  static size_t pageSize = 0;

  if (!pageSize)
    {
#ifdef HAVE_GETPAGESIZE
      pageSize = (size_t) getpagesize ();
#else /* guess */
      pageSize = 4096;
#endif
    }

  allocLen = pageSize;
  while (allocLen < bufLen)
    allocLen += pageSize;

#ifdef HAVE_POSIX_MEMALIGN
  if (!buf)
    if (posix_memalign (&buf, pageSize, allocLen))
      buf = NULL; /* just retry with valloc/malloc */
#endif
#ifdef HAVE_VALLOC
  if (!buf)
    buf = valloc (allocLen);
#endif
  if (!buf)
    buf = tr_malloc (allocLen);

  return buf;
}

char *
tr_realpath (const char * path, char * resolved_path)
{
#ifdef WIN32
  /* From a message to the Mingw-msys list, Jun 2, 2005 by Mark Junker. */
  if (GetFullPathNameA (path, TR_PATH_MAX, resolved_path, NULL) == 0)
    return NULL;
  return resolved_path;
#else
  return realpath (path, resolved_path);
#endif
}

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

uint64_t
tr_htonll (uint64_t x)
{
#ifdef HAVE_HTONLL
  return htonll (x);
#else
  /* fallback code by bdonlan at
   * http://stackoverflow.com/questions/809902/64-bit-ntohl-in-c/875505#875505 */
  union { uint32_t lx[2]; uint64_t llx; } u;
  u.lx[0] = htonl (x >> 32);
  u.lx[1] = htonl (x & 0xFFFFFFFFULL);
  return u.llx;
#endif
}

uint64_t
tr_ntohll (uint64_t x)
{
#ifdef HAVE_NTOHLL
  return ntohll (x);
#else
  /* fallback code by bdonlan at
   * http://stackoverflow.com/questions/809902/64-bit-ntohl-in-c/875505#875505 */
  union { uint32_t lx[2]; uint64_t llx; } u;
  u.llx = x;
  return ((uint64_t)ntohl (u.lx[0]) << 32) | (uint64_t)ntohl (u.lx[1]);
#endif
}

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

struct formatter_unit
{
  char * name;
  int64_t value;
};

struct formatter_units
{
  struct formatter_unit units[4];
};

enum { TR_FMT_KB, TR_FMT_MB, TR_FMT_GB, TR_FMT_TB };

static void
formatter_init (struct formatter_units * units,
                unsigned int kilo,
                const char * kb, const char * mb,
                const char * gb, const char * tb)
{
  uint64_t value;

  value = kilo;
  units->units[TR_FMT_KB].name = tr_strdup (kb);
  units->units[TR_FMT_KB].value = value;

  value *= kilo;
  units->units[TR_FMT_MB].name = tr_strdup (mb);
  units->units[TR_FMT_MB].value = value;

  value *= kilo;
  units->units[TR_FMT_GB].name = tr_strdup (gb);
  units->units[TR_FMT_GB].value = value;

  value *= kilo;
  units->units[TR_FMT_TB].name = tr_strdup (tb);
  units->units[TR_FMT_TB].value = value;
}

static char*
formatter_get_size_str (const struct formatter_units * u,
                        char * buf, int64_t bytes, size_t buflen)
{
  int precision;
  double value;
  const char * units;
  const struct formatter_unit * unit;

       if (bytes < u->units[1].value) unit = &u->units[0];
  else if (bytes < u->units[2].value) unit = &u->units[1];
  else if (bytes < u->units[3].value) unit = &u->units[2];
  else                                unit = &u->units[3];

  value = (double)bytes / unit->value;
  units = unit->name;

  if (unit->value == 1)
    precision = 0;
  else if (value < 100)
    precision = 2;
  else
    precision = 1;

  tr_snprintf (buf, buflen, "%.*f %s", precision, value, units);
  return buf;
}

static struct formatter_units size_units;

void
tr_formatter_size_init (unsigned int kilo,
                        const char * kb, const char * mb,
                        const char * gb, const char * tb)
{
  formatter_init (&size_units, kilo, kb, mb, gb, tb);
}

char*
tr_formatter_size_B (char * buf, int64_t bytes, size_t buflen)
{
  return formatter_get_size_str (&size_units, buf, bytes, buflen);
}

static struct formatter_units speed_units;

unsigned int tr_speed_K = 0u;

void
tr_formatter_speed_init (unsigned int kilo,
                         const char * kb, const char * mb,
                         const char * gb, const char * tb)
{
  tr_speed_K = kilo;
  formatter_init (&speed_units, kilo, kb, mb, gb, tb);
}

char*
tr_formatter_speed_KBps (char * buf, double KBps, size_t buflen)
{
  const double K = speed_units.units[TR_FMT_KB].value;
  double speed = KBps;

  if (speed <= 999.95) /* 0.0 KB to 999.9 KB */
    {
      tr_snprintf (buf, buflen, "%d %s", (int)speed, speed_units.units[TR_FMT_KB].name);
    }
  else
    {
      speed /= K;

      if (speed <= 99.995) /* 0.98 MB to 99.99 MB */
        tr_snprintf (buf, buflen, "%.2f %s", speed, speed_units.units[TR_FMT_MB].name);
      else if (speed <= 999.95) /* 100.0 MB to 999.9 MB */
        tr_snprintf (buf, buflen, "%.1f %s", speed, speed_units.units[TR_FMT_MB].name);
      else
        tr_snprintf (buf, buflen, "%.1f %s", speed/K, speed_units.units[TR_FMT_GB].name);
    }

  return buf;
}

static struct formatter_units mem_units;

unsigned int tr_mem_K = 0u;

void
tr_formatter_mem_init (unsigned int kilo,
                       const char * kb, const char * mb,
                       const char * gb, const char * tb)
{
  tr_mem_K = kilo;
  formatter_init (&mem_units, kilo, kb, mb, gb, tb);
}

char*
tr_formatter_mem_B (char * buf, int64_t bytes_per_second, size_t buflen)
{
  return formatter_get_size_str (&mem_units, buf, bytes_per_second, buflen);
}

void
tr_formatter_get_units (void * vdict)
{
  int i;
  tr_variant * l;
  tr_variant * dict = vdict;

  tr_variantDictReserve (dict, 6);

  tr_variantDictAddInt (dict, TR_KEY_memory_bytes, mem_units.units[TR_FMT_KB].value);
  l = tr_variantDictAddList (dict, TR_KEY_memory_units, 4);
  for (i=0; i<4; i++)
    tr_variantListAddStr (l, mem_units.units[i].name);

  tr_variantDictAddInt (dict, TR_KEY_size_bytes,   size_units.units[TR_FMT_KB].value);
  l = tr_variantDictAddList (dict, TR_KEY_size_units, 4);
  for (i=0; i<4; i++)
    tr_variantListAddStr (l, size_units.units[i].name);

  tr_variantDictAddInt (dict, TR_KEY_speed_bytes,  speed_units.units[TR_FMT_KB].value);
  l = tr_variantDictAddList (dict, TR_KEY_speed_units, 4);
  for (i=0; i<4; i++)
    tr_variantListAddStr (l, speed_units.units[i].name);
}