--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/urlapi.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,1449 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#include "urldata.h"
+#include "urlapi-int.h"
+#include "strcase.h"
+#include "dotdot.h"
+#include "url.h"
+#include "escape.h"
+#include "curl_ctype.h"
+#include "inet_pton.h"
+
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+  /* MSDOS/Windows style drive prefix, eg c: in c:foo */
+#define STARTS_WITH_DRIVE_PREFIX(str) \
+  ((('a' <= str[0] && str[0] <= 'z') || \
+    ('A' <= str[0] && str[0] <= 'Z')) && \
+   (str[1] == ':'))
+
+  /* MSDOS/Windows style drive prefix, optionally with
+   * a '|' instead of ':', followed by a slash or NUL */
+#define STARTS_WITH_URL_DRIVE_PREFIX(str) \
+  ((('a' <= (str)[0] && (str)[0] <= 'z') || \
+    ('A' <= (str)[0] && (str)[0] <= 'Z')) && \
+   ((str)[1] == ':' || (str)[1] == '|') && \
+   ((str)[2] == '/' || (str)[2] == '\\' || (str)[2] == 0))
+
+/* Internal representation of CURLU. Point to URL-encoded strings. */
+struct Curl_URL {
+  char *scheme;
+  char *user;
+  char *password;
+  char *options; /* IMAP only? */
+  char *host;
+  char *zoneid; /* for numerical IPv6 addresses */
+  char *port;
+  char *path;
+  char *query;
+  char *fragment;
+
+  char *scratch; /* temporary scratch area */
+  long portnum; /* the numerical version */
+};
+
+#define DEFAULT_SCHEME "https"
+
+static void free_urlhandle(struct Curl_URL *u)
+{
+  free(u->scheme);
+  free(u->user);
+  free(u->password);
+  free(u->options);
+  free(u->host);
+  free(u->zoneid);
+  free(u->port);
+  free(u->path);
+  free(u->query);
+  free(u->fragment);
+  free(u->scratch);
+}
+
+/* move the full contents of one handle onto another and
+   free the original */
+static void mv_urlhandle(struct Curl_URL *from,
+                         struct Curl_URL *to)
+{
+  free_urlhandle(to);
+  *to = *from;
+  free(from);
+}
+
+/*
+ * Find the separator at the end of the host name, or the '?' in cases like
+ * http://www.url.com?id=2380
+ */
+static const char *find_host_sep(const char *url)
+{
+  const char *sep;
+  const char *query;
+
+  /* Find the start of the hostname */
+  sep = strstr(url, "//");
+  if(!sep)
+    sep = url;
+  else
+    sep += 2;
+
+  query = strchr(sep, '?');
+  sep = strchr(sep, '/');
+
+  if(!sep)
+    sep = url + strlen(url);
+
+  if(!query)
+    query = url + strlen(url);
+
+  return sep < query ? sep : query;
+}
+
+/*
+ * Decide in an encoding-independent manner whether a character in an
+ * URL must be escaped. The same criterion must be used in strlen_url()
+ * and strcpy_url().
+ */
+static bool urlchar_needs_escaping(int c)
+{
+    return !(ISCNTRL(c) || ISSPACE(c) || ISGRAPH(c));
+}
+
+/*
+ * strlen_url() returns the length of the given URL if the spaces within the
+ * URL were properly URL encoded.
+ * URL encoding should be skipped for host names, otherwise IDN resolution
+ * will fail.
+ */
+static size_t strlen_url(const char *url, bool relative)
+{
+  const unsigned char *ptr;
+  size_t newlen = 0;
+  bool left = TRUE; /* left side of the ? */
+  const unsigned char *host_sep = (const unsigned char *) url;
+
+  if(!relative)
+    host_sep = (const unsigned char *) find_host_sep(url);
+
+  for(ptr = (unsigned char *)url; *ptr; ptr++) {
+
+    if(ptr < host_sep) {
+      ++newlen;
+      continue;
+    }
+
+    switch(*ptr) {
+    case '?':
+      left = FALSE;
+      /* FALLTHROUGH */
+    default:
+      if(urlchar_needs_escaping(*ptr))
+        newlen += 2;
+      newlen++;
+      break;
+    case ' ':
+      if(left)
+        newlen += 3;
+      else
+        newlen++;
+      break;
+    }
+  }
+  return newlen;
+}
+
+/* strcpy_url() copies a url to a output buffer and URL-encodes the spaces in
+ * the source URL accordingly.
+ * URL encoding should be skipped for host names, otherwise IDN resolution
+ * will fail.
+ */
+static void strcpy_url(char *output, const char *url, bool relative)
+{
+  /* we must add this with whitespace-replacing */
+  bool left = TRUE;
+  const unsigned char *iptr;
+  char *optr = output;
+  const unsigned char *host_sep = (const unsigned char *) url;
+
+  if(!relative)
+    host_sep = (const unsigned char *) find_host_sep(url);
+
+  for(iptr = (unsigned char *)url;    /* read from here */
+      *iptr;         /* until zero byte */
+      iptr++) {
+
+    if(iptr < host_sep) {
+      *optr++ = *iptr;
+      continue;
+    }
+
+    switch(*iptr) {
+    case '?':
+      left = FALSE;
+      /* FALLTHROUGH */
+    default:
+      if(urlchar_needs_escaping(*iptr)) {
+        msnprintf(optr, 4, "%%%02x", *iptr);
+        optr += 3;
+      }
+      else
+        *optr++=*iptr;
+      break;
+    case ' ':
+      if(left) {
+        *optr++='%'; /* add a '%' */
+        *optr++='2'; /* add a '2' */
+        *optr++='0'; /* add a '0' */
+      }
+      else
+        *optr++='+'; /* add a '+' here */
+      break;
+    }
+  }
+  *optr = 0; /* zero terminate output buffer */
+
+}
+
+/*
+ * Returns true if the given URL is absolute (as opposed to relative) within
+ * the buffer size. Returns the scheme in the buffer if TRUE and 'buf' is
+ * non-NULL.
+ */
+bool Curl_is_absolute_url(const char *url, char *buf, size_t buflen)
+{
+  size_t i;
+#ifdef WIN32
+  if(STARTS_WITH_DRIVE_PREFIX(url))
+    return FALSE;
+#endif
+  for(i = 0; i < buflen && url[i]; ++i) {
+    char s = url[i];
+    if((s == ':') && (url[i + 1] == '/')) {
+      if(buf)
+        buf[i] = 0;
+      return TRUE;
+    }
+    /* RFC 3986 3.1 explains:
+      scheme      = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
+    */
+    else if(ISALNUM(s) || (s == '+') || (s == '-') || (s == '.') ) {
+      if(buf)
+        buf[i] = (char)TOLOWER(s);
+    }
+    else
+      break;
+  }
+  return FALSE;
+}
+
+/*
+ * Concatenate a relative URL to a base URL making it absolute.
+ * URL-encodes any spaces.
+ * The returned pointer must be freed by the caller unless NULL
+ * (returns NULL on out of memory).
+ */
+static char *concat_url(const char *base, const char *relurl)
+{
+  /***
+   TRY to append this new path to the old URL
+   to the right of the host part. Oh crap, this is doomed to cause
+   problems in the future...
+  */
+  char *newest;
+  char *protsep;
+  char *pathsep;
+  size_t newlen;
+  bool host_changed = FALSE;
+
+  const char *useurl = relurl;
+  size_t urllen;
+
+  /* we must make our own copy of the URL to play with, as it may
+     point to read-only data */
+  char *url_clone = strdup(base);
+
+  if(!url_clone)
+    return NULL; /* skip out of this NOW */
+
+  /* protsep points to the start of the host name */
+  protsep = strstr(url_clone, "//");
+  if(!protsep)
+    protsep = url_clone;
+  else
+    protsep += 2; /* pass the slashes */
+
+  if('/' != relurl[0]) {
+    int level = 0;
+
+    /* First we need to find out if there's a ?-letter in the URL,
+       and cut it and the right-side of that off */
+    pathsep = strchr(protsep, '?');
+    if(pathsep)
+      *pathsep = 0;
+
+    /* we have a relative path to append to the last slash if there's one
+       available, or if the new URL is just a query string (starts with a
+       '?')  we append the new one at the end of the entire currently worked
+       out URL */
+    if(useurl[0] != '?') {
+      pathsep = strrchr(protsep, '/');
+      if(pathsep)
+        *pathsep = 0;
+    }
+
+    /* Check if there's any slash after the host name, and if so, remember
+       that position instead */
+    pathsep = strchr(protsep, '/');
+    if(pathsep)
+      protsep = pathsep + 1;
+    else
+      protsep = NULL;
+
+    /* now deal with one "./" or any amount of "../" in the newurl
+       and act accordingly */
+
+    if((useurl[0] == '.') && (useurl[1] == '/'))
+      useurl += 2; /* just skip the "./" */
+
+    while((useurl[0] == '.') &&
+          (useurl[1] == '.') &&
+          (useurl[2] == '/')) {
+      level++;
+      useurl += 3; /* pass the "../" */
+    }
+
+    if(protsep) {
+      while(level--) {
+        /* cut off one more level from the right of the original URL */
+        pathsep = strrchr(protsep, '/');
+        if(pathsep)
+          *pathsep = 0;
+        else {
+          *protsep = 0;
+          break;
+        }
+      }
+    }
+  }
+  else {
+    /* We got a new absolute path for this server */
+
+    if((relurl[0] == '/') && (relurl[1] == '/')) {
+      /* the new URL starts with //, just keep the protocol part from the
+         original one */
+      *protsep = 0;
+      useurl = &relurl[2]; /* we keep the slashes from the original, so we
+                              skip the new ones */
+      host_changed = TRUE;
+    }
+    else {
+      /* cut off the original URL from the first slash, or deal with URLs
+         without slash */
+      pathsep = strchr(protsep, '/');
+      if(pathsep) {
+        /* When people use badly formatted URLs, such as
+           "http://www.url.com?dir=/home/daniel" we must not use the first
+           slash, if there's a ?-letter before it! */
+        char *sep = strchr(protsep, '?');
+        if(sep && (sep < pathsep))
+          pathsep = sep;
+        *pathsep = 0;
+      }
+      else {
+        /* There was no slash. Now, since we might be operating on a badly
+           formatted URL, such as "http://www.url.com?id=2380" which doesn't
+           use a slash separator as it is supposed to, we need to check for a
+           ?-letter as well! */
+        pathsep = strchr(protsep, '?');
+        if(pathsep)
+          *pathsep = 0;
+      }
+    }
+  }
+
+  /* If the new part contains a space, this is a mighty stupid redirect
+     but we still make an effort to do "right". To the left of a '?'
+     letter we replace each space with %20 while it is replaced with '+'
+     on the right side of the '?' letter.
+  */
+  newlen = strlen_url(useurl, !host_changed);
+
+  urllen = strlen(url_clone);
+
+  newest = malloc(urllen + 1 + /* possible slash */
+                  newlen + 1 /* zero byte */);
+
+  if(!newest) {
+    free(url_clone); /* don't leak this */
+    return NULL;
+  }
+
+  /* copy over the root url part */
+  memcpy(newest, url_clone, urllen);
+
+  /* check if we need to append a slash */
+  if(('/' == useurl[0]) || (protsep && !*protsep) || ('?' == useurl[0]))
+    ;
+  else
+    newest[urllen++]='/';
+
+  /* then append the new piece on the right side */
+  strcpy_url(&newest[urllen], useurl, !host_changed);
+
+  free(url_clone);
+
+  return newest;
+}
+
+/*
+ * parse_hostname_login()
+ *
+ * Parse the login details (user name, password and options) from the URL and
+ * strip them out of the host name
+ *
+ */
+static CURLUcode parse_hostname_login(struct Curl_URL *u,
+                                      const struct Curl_handler *h,
+                                      char **hostname,
+                                      unsigned int flags)
+{
+  CURLUcode result = CURLUE_OK;
+  CURLcode ccode;
+  char *userp = NULL;
+  char *passwdp = NULL;
+  char *optionsp = NULL;
+
+  /* At this point, we're hoping all the other special cases have
+   * been taken care of, so conn->host.name is at most
+   *    [user[:password][;options]]@]hostname
+   *
+   * We need somewhere to put the embedded details, so do that first.
+   */
+
+  char *ptr = strchr(*hostname, '@');
+  char *login = *hostname;
+
+  if(!ptr)
+    goto out;
+
+  /* We will now try to extract the
+   * possible login information in a string like:
+   * ftp://user:password@ftp.my.site:8021/README */
+  *hostname = ++ptr;
+
+  /* We could use the login information in the URL so extract it. Only parse
+     options if the handler says we should. Note that 'h' might be NULL! */
+  ccode = Curl_parse_login_details(login, ptr - login - 1,
+                                   &userp, &passwdp,
+                                   (h && (h->flags & PROTOPT_URLOPTIONS)) ?
+                                   &optionsp:NULL);
+  if(ccode) {
+    result = CURLUE_MALFORMED_INPUT;
+    goto out;
+  }
+
+  if(userp) {
+    if(flags & CURLU_DISALLOW_USER) {
+      /* Option DISALLOW_USER is set and url contains username. */
+      result = CURLUE_USER_NOT_ALLOWED;
+      goto out;
+    }
+
+    u->user = userp;
+  }
+
+  if(passwdp)
+    u->password = passwdp;
+
+  if(optionsp)
+    u->options = optionsp;
+
+  return CURLUE_OK;
+  out:
+
+  free(userp);
+  free(passwdp);
+  free(optionsp);
+
+  return result;
+}
+
+UNITTEST CURLUcode Curl_parse_port(struct Curl_URL *u, char *hostname)
+{
+  char *portptr = NULL;
+  char endbracket;
+  int len;
+
+  /*
+   * Find the end of an IPv6 address, either on the ']' ending bracket or
+   * a percent-encoded zone index.
+   */
+  if(1 == sscanf(hostname, "[%*45[0123456789abcdefABCDEF:.]%c%n",
+                 &endbracket, &len)) {
+    if(']' == endbracket)
+      portptr = &hostname[len];
+    else if('%' == endbracket) {
+      int zonelen = len;
+      if(1 == sscanf(hostname + zonelen, "%*[^]]%c%n", &endbracket, &len)) {
+        if(']' != endbracket)
+          return CURLUE_MALFORMED_INPUT;
+        portptr = &hostname[--zonelen + len + 1];
+      }
+      else
+        return CURLUE_MALFORMED_INPUT;
+    }
+    else
+      return CURLUE_MALFORMED_INPUT;
+
+    /* this is a RFC2732-style specified IP-address */
+    if(portptr && *portptr) {
+      if(*portptr != ':')
+        return CURLUE_MALFORMED_INPUT;
+    }
+    else
+      portptr = NULL;
+  }
+  else
+    portptr = strchr(hostname, ':');
+
+  if(portptr) {
+    char *rest;
+    long port;
+    char portbuf[7];
+
+    /* Browser behavior adaptation. If there's a colon with no digits after,
+       just cut off the name there which makes us ignore the colon and just
+       use the default port. Firefox, Chrome and Safari all do that. */
+    if(!portptr[1]) {
+      *portptr = '\0';
+      return CURLUE_OK;
+    }
+
+    if(!ISDIGIT(portptr[1]))
+      return CURLUE_BAD_PORT_NUMBER;
+
+    port = strtol(portptr + 1, &rest, 10);  /* Port number must be decimal */
+
+    if((port <= 0) || (port > 0xffff))
+      /* Single unix standard says port numbers are 16 bits long, but we don't
+         treat port zero as OK. */
+      return CURLUE_BAD_PORT_NUMBER;
+
+    if(rest[0])
+      return CURLUE_BAD_PORT_NUMBER;
+
+    *portptr++ = '\0'; /* cut off the name there */
+    *rest = 0;
+    /* generate a new port number string to get rid of leading zeroes etc */
+    msnprintf(portbuf, sizeof(portbuf), "%ld", port);
+    u->portnum = port;
+    u->port = strdup(portbuf);
+    if(!u->port)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  return CURLUE_OK;
+}
+
+/* scan for byte values < 31 or 127 */
+static CURLUcode junkscan(char *part)
+{
+  if(part) {
+    static const char badbytes[]={
+      /* */ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+      0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+      0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+      0x7f,
+      0x00 /* zero terminate */
+    };
+    size_t n = strlen(part);
+    size_t nfine = strcspn(part, badbytes);
+    if(nfine != n)
+      /* since we don't know which part is scanned, return a generic error
+         code */
+      return CURLUE_MALFORMED_INPUT;
+  }
+  return CURLUE_OK;
+}
+
+static CURLUcode hostname_check(struct Curl_URL *u, char *hostname)
+{
+  size_t len;
+  size_t hlen = strlen(hostname);
+
+  if(hostname[0] == '[') {
+    char dest[16]; /* fits a binary IPv6 address */
+    const char *l = "0123456789abcdefABCDEF:.";
+    hostname++;
+    hlen -= 2;
+
+    if(hostname[hlen] != ']')
+      return CURLUE_MALFORMED_INPUT;
+
+    /* only valid letters are ok */
+    len = strspn(hostname, l);
+    if(hlen != len) {
+      hlen = len;
+      if(hostname[len] == '%') {
+        /* this could now be '%[zone id]' */
+        char zoneid[16];
+        int i = 0;
+        char *h = &hostname[len + 1];
+        /* pass '25' if present and is a url encoded percent sign */
+        if(!strncmp(h, "25", 2) && h[2] && (h[2] != ']'))
+          h += 2;
+        while(*h && (*h != ']') && (i < 15))
+          zoneid[i++] = *h++;
+        if(!i || (']' != *h))
+          return CURLUE_MALFORMED_INPUT;
+        zoneid[i] = 0;
+        u->zoneid = strdup(zoneid);
+        if(!u->zoneid)
+          return CURLUE_OUT_OF_MEMORY;
+        hostname[len] = ']'; /* insert end bracket */
+        hostname[len + 1] = 0; /* terminate the hostname */
+      }
+      else
+        return CURLUE_MALFORMED_INPUT;
+      /* hostname is fine */
+    }
+#ifdef ENABLE_IPV6
+    hostname[hlen] = 0; /* end the address there */
+    if(1 != Curl_inet_pton(AF_INET6, hostname, dest))
+      return CURLUE_MALFORMED_INPUT;
+    hostname[hlen] = ']'; /* restore ending bracket */
+#endif
+  }
+  else {
+    /* letters from the second string is not ok */
+    len = strcspn(hostname, " ");
+    if(hlen != len)
+      /* hostname with bad content */
+      return CURLUE_MALFORMED_INPUT;
+  }
+  if(!hostname[0])
+    return CURLUE_NO_HOST;
+  return CURLUE_OK;
+}
+
+#define HOSTNAME_END(x) (((x) == '/') || ((x) == '?') || ((x) == '#'))
+
+static CURLUcode seturl(const char *url, CURLU *u, unsigned int flags)
+{
+  char *path;
+  bool path_alloced = FALSE;
+  char *hostname;
+  char *query = NULL;
+  char *fragment = NULL;
+  CURLUcode result;
+  bool url_has_scheme = FALSE;
+  char schemebuf[MAX_SCHEME_LEN + 1];
+  char *schemep = NULL;
+  size_t schemelen = 0;
+  size_t urllen;
+  const struct Curl_handler *h = NULL;
+
+  if(!url)
+    return CURLUE_MALFORMED_INPUT;
+
+  /*************************************************************
+   * Parse the URL.
+   ************************************************************/
+  /* allocate scratch area */
+  urllen = strlen(url);
+  if(urllen > CURL_MAX_INPUT_LENGTH)
+    /* excessive input length */
+    return CURLUE_MALFORMED_INPUT;
+
+  path = u->scratch = malloc(urllen * 2 + 2);
+  if(!path)
+    return CURLUE_OUT_OF_MEMORY;
+
+  hostname = &path[urllen + 1];
+  hostname[0] = 0;
+
+  if(Curl_is_absolute_url(url, schemebuf, sizeof(schemebuf))) {
+    url_has_scheme = TRUE;
+    schemelen = strlen(schemebuf);
+  }
+
+  /* handle the file: scheme */
+  if(url_has_scheme && strcasecompare(schemebuf, "file")) {
+    /* path has been allocated large enough to hold this */
+    strcpy(path, &url[5]);
+
+    hostname = NULL; /* no host for file: URLs */
+    u->scheme = strdup("file");
+    if(!u->scheme)
+      return CURLUE_OUT_OF_MEMORY;
+
+    /* Extra handling URLs with an authority component (i.e. that start with
+     * "file://")
+     *
+     * We allow omitted hostname (e.g. file:/<path>) -- valid according to
+     * RFC 8089, but not the (current) WHAT-WG URL spec.
+     */
+    if(path[0] == '/' && path[1] == '/') {
+      /* swallow the two slashes */
+      char *ptr = &path[2];
+
+      /*
+       * According to RFC 8089, a file: URL can be reliably dereferenced if:
+       *
+       *  o it has no/blank hostname, or
+       *
+       *  o the hostname matches "localhost" (case-insensitively), or
+       *
+       *  o the hostname is a FQDN that resolves to this machine.
+       *
+       * For brevity, we only consider URLs with empty, "localhost", or
+       * "127.0.0.1" hostnames as local.
+       *
+       * Additionally, there is an exception for URLs with a Windows drive
+       * letter in the authority (which was accidentally omitted from RFC 8089
+       * Appendix E, but believe me, it was meant to be there. --MK)
+       */
+      if(ptr[0] != '/' && !STARTS_WITH_URL_DRIVE_PREFIX(ptr)) {
+        /* the URL includes a host name, it must match "localhost" or
+           "127.0.0.1" to be valid */
+        if(!checkprefix("localhost/", ptr) &&
+           !checkprefix("127.0.0.1/", ptr)) {
+          /* Invalid file://hostname/, expected localhost or 127.0.0.1 or
+             none */
+          return CURLUE_MALFORMED_INPUT;
+        }
+        ptr += 9; /* now points to the slash after the host */
+      }
+
+      path = ptr;
+    }
+
+#if !defined(MSDOS) && !defined(WIN32) && !defined(__CYGWIN__)
+    /* Don't allow Windows drive letters when not in Windows.
+     * This catches both "file:/c:" and "file:c:" */
+    if(('/' == path[0] && STARTS_WITH_URL_DRIVE_PREFIX(&path[1])) ||
+       STARTS_WITH_URL_DRIVE_PREFIX(path)) {
+      /* File drive letters are only accepted in MSDOS/Windows */
+      return CURLUE_MALFORMED_INPUT;
+    }
+#else
+    /* If the path starts with a slash and a drive letter, ditch the slash */
+    if('/' == path[0] && STARTS_WITH_URL_DRIVE_PREFIX(&path[1])) {
+      /* This cannot be done with strcpy, as the memory chunks overlap! */
+      memmove(path, &path[1], strlen(&path[1]) + 1);
+    }
+#endif
+
+  }
+  else {
+    /* clear path */
+    const char *p;
+    const char *hostp;
+    size_t len;
+    path[0] = 0;
+
+    if(url_has_scheme) {
+      int i = 0;
+      p = &url[schemelen + 1];
+      while(p && (*p == '/') && (i < 4)) {
+        p++;
+        i++;
+      }
+      if((i < 1) || (i>3))
+        /* less than one or more than three slashes */
+        return CURLUE_MALFORMED_INPUT;
+
+      schemep = schemebuf;
+      if(!Curl_builtin_scheme(schemep) &&
+         !(flags & CURLU_NON_SUPPORT_SCHEME))
+        return CURLUE_UNSUPPORTED_SCHEME;
+
+      if(junkscan(schemep))
+        return CURLUE_MALFORMED_INPUT;
+    }
+    else {
+      /* no scheme! */
+
+      if(!(flags & (CURLU_DEFAULT_SCHEME|CURLU_GUESS_SCHEME)))
+        return CURLUE_MALFORMED_INPUT;
+      if(flags & CURLU_DEFAULT_SCHEME)
+        schemep = (char *) DEFAULT_SCHEME;
+
+      /*
+       * The URL was badly formatted, let's try without scheme specified.
+       */
+      p = url;
+    }
+    hostp = p; /* host name starts here */
+
+    while(*p && !HOSTNAME_END(*p)) /* find end of host name */
+      p++;
+
+    len = p - hostp;
+    if(!len)
+      return CURLUE_MALFORMED_INPUT;
+
+    memcpy(hostname, hostp, len);
+    hostname[len] = 0;
+
+    if((flags & CURLU_GUESS_SCHEME) && !schemep) {
+      /* legacy curl-style guess based on host name */
+      if(checkprefix("ftp.", hostname))
+        schemep = (char *)"ftp";
+      else if(checkprefix("dict.", hostname))
+        schemep = (char *)"dict";
+      else if(checkprefix("ldap.", hostname))
+        schemep = (char *)"ldap";
+      else if(checkprefix("imap.", hostname))
+        schemep = (char *)"imap";
+      else if(checkprefix("smtp.", hostname))
+        schemep = (char *)"smtp";
+      else if(checkprefix("pop3.", hostname))
+        schemep = (char *)"pop3";
+      else
+        schemep = (char *)"http";
+    }
+
+    len = strlen(p);
+    memcpy(path, p, len);
+    path[len] = 0;
+
+    u->scheme = strdup(schemep);
+    if(!u->scheme)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  /* if this is a known scheme, get some details */
+  h = Curl_builtin_scheme(u->scheme);
+
+  if(junkscan(path))
+    return CURLUE_MALFORMED_INPUT;
+
+  query = strchr(path, '?');
+  if(query)
+    *query++ = 0;
+
+  fragment = strchr(query?query:path, '#');
+  if(fragment)
+    *fragment++ = 0;
+
+  if(!path[0])
+    /* if there's no path set, unset */
+    path = NULL;
+  else if(!(flags & CURLU_PATH_AS_IS)) {
+    /* sanitise paths and remove ../ and ./ sequences according to RFC3986 */
+    char *newp = Curl_dedotdotify(path);
+    if(!newp)
+      return CURLUE_OUT_OF_MEMORY;
+
+    if(strcmp(newp, path)) {
+      /* if we got a new version */
+      path = newp;
+      path_alloced = TRUE;
+    }
+    else
+      free(newp);
+  }
+  if(path) {
+    u->path = path_alloced?path:strdup(path);
+    if(!u->path)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  if(hostname) {
+    /*
+     * Parse the login details and strip them out of the host name.
+     */
+    if(junkscan(hostname))
+      return CURLUE_MALFORMED_INPUT;
+
+    result = parse_hostname_login(u, h, &hostname, flags);
+    if(result)
+      return result;
+
+    result = Curl_parse_port(u, hostname);
+    if(result)
+      return result;
+
+    result = hostname_check(u, hostname);
+    if(result)
+      return result;
+
+    u->host = strdup(hostname);
+    if(!u->host)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  if(query) {
+    u->query = strdup(query);
+    if(!u->query)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+  if(fragment && fragment[0]) {
+    u->fragment = strdup(fragment);
+    if(!u->fragment)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  free(u->scratch);
+  u->scratch = NULL;
+
+  return CURLUE_OK;
+}
+
+/*
+ * Parse the URL and set the relevant members of the Curl_URL struct.
+ */
+static CURLUcode parseurl(const char *url, CURLU *u, unsigned int flags)
+{
+  CURLUcode result = seturl(url, u, flags);
+  if(result) {
+    free_urlhandle(u);
+    memset(u, 0, sizeof(struct Curl_URL));
+  }
+  return result;
+}
+
+/*
+ */
+CURLU *curl_url(void)
+{
+  return calloc(sizeof(struct Curl_URL), 1);
+}
+
+void curl_url_cleanup(CURLU *u)
+{
+  if(u) {
+    free_urlhandle(u);
+    free(u);
+  }
+}
+
+#define DUP(dest, src, name)         \
+  if(src->name) {                    \
+    dest->name = strdup(src->name);  \
+    if(!dest->name)                  \
+      goto fail;                     \
+  }
+
+CURLU *curl_url_dup(CURLU *in)
+{
+  struct Curl_URL *u = calloc(sizeof(struct Curl_URL), 1);
+  if(u) {
+    DUP(u, in, scheme);
+    DUP(u, in, user);
+    DUP(u, in, password);
+    DUP(u, in, options);
+    DUP(u, in, host);
+    DUP(u, in, port);
+    DUP(u, in, path);
+    DUP(u, in, query);
+    DUP(u, in, fragment);
+    u->portnum = in->portnum;
+  }
+  return u;
+  fail:
+  curl_url_cleanup(u);
+  return NULL;
+}
+
+CURLUcode curl_url_get(CURLU *u, CURLUPart what,
+                       char **part, unsigned int flags)
+{
+  char *ptr;
+  CURLUcode ifmissing = CURLUE_UNKNOWN_PART;
+  char portbuf[7];
+  bool urldecode = (flags & CURLU_URLDECODE)?1:0;
+  bool plusdecode = FALSE;
+  (void)flags;
+  if(!u)
+    return CURLUE_BAD_HANDLE;
+  if(!part)
+    return CURLUE_BAD_PARTPOINTER;
+  *part = NULL;
+
+  switch(what) {
+  case CURLUPART_SCHEME:
+    ptr = u->scheme;
+    ifmissing = CURLUE_NO_SCHEME;
+    urldecode = FALSE; /* never for schemes */
+    break;
+  case CURLUPART_USER:
+    ptr = u->user;
+    ifmissing = CURLUE_NO_USER;
+    break;
+  case CURLUPART_PASSWORD:
+    ptr = u->password;
+    ifmissing = CURLUE_NO_PASSWORD;
+    break;
+  case CURLUPART_OPTIONS:
+    ptr = u->options;
+    ifmissing = CURLUE_NO_OPTIONS;
+    break;
+  case CURLUPART_HOST:
+    ptr = u->host;
+    ifmissing = CURLUE_NO_HOST;
+    break;
+  case CURLUPART_ZONEID:
+    ptr = u->zoneid;
+    break;
+  case CURLUPART_PORT:
+    ptr = u->port;
+    ifmissing = CURLUE_NO_PORT;
+    urldecode = FALSE; /* never for port */
+    if(!ptr && (flags & CURLU_DEFAULT_PORT) && u->scheme) {
+      /* there's no stored port number, but asked to deliver
+         a default one for the scheme */
+      const struct Curl_handler *h =
+        Curl_builtin_scheme(u->scheme);
+      if(h) {
+        msnprintf(portbuf, sizeof(portbuf), "%ld", h->defport);
+        ptr = portbuf;
+      }
+    }
+    else if(ptr && u->scheme) {
+      /* there is a stored port number, but ask to inhibit if
+         it matches the default one for the scheme */
+      const struct Curl_handler *h =
+        Curl_builtin_scheme(u->scheme);
+      if(h && (h->defport == u->portnum) &&
+         (flags & CURLU_NO_DEFAULT_PORT))
+        ptr = NULL;
+    }
+    break;
+  case CURLUPART_PATH:
+    ptr = u->path;
+    if(!ptr) {
+      ptr = u->path = strdup("/");
+      if(!u->path)
+        return CURLUE_OUT_OF_MEMORY;
+    }
+    break;
+  case CURLUPART_QUERY:
+    ptr = u->query;
+    ifmissing = CURLUE_NO_QUERY;
+    plusdecode = urldecode;
+    break;
+  case CURLUPART_FRAGMENT:
+    ptr = u->fragment;
+    ifmissing = CURLUE_NO_FRAGMENT;
+    break;
+  case CURLUPART_URL: {
+    char *url;
+    char *scheme;
+    char *options = u->options;
+    char *port = u->port;
+    char *allochost = NULL;
+    if(u->scheme && strcasecompare("file", u->scheme)) {
+      url = aprintf("file://%s%s%s",
+                    u->path,
+                    u->fragment? "#": "",
+                    u->fragment? u->fragment : "");
+    }
+    else if(!u->host)
+      return CURLUE_NO_HOST;
+    else {
+      const struct Curl_handler *h = NULL;
+      if(u->scheme)
+        scheme = u->scheme;
+      else if(flags & CURLU_DEFAULT_SCHEME)
+        scheme = (char *) DEFAULT_SCHEME;
+      else
+        return CURLUE_NO_SCHEME;
+
+      if(scheme) {
+        h = Curl_builtin_scheme(scheme);
+        if(!port && (flags & CURLU_DEFAULT_PORT)) {
+          /* there's no stored port number, but asked to deliver
+             a default one for the scheme */
+          if(h) {
+            msnprintf(portbuf, sizeof(portbuf), "%ld", h->defport);
+            port = portbuf;
+          }
+        }
+        else if(port) {
+          /* there is a stored port number, but asked to inhibit if it matches
+             the default one for the scheme */
+          if(h && (h->defport == u->portnum) &&
+             (flags & CURLU_NO_DEFAULT_PORT))
+            port = NULL;
+        }
+      }
+      if(h && !(h->flags & PROTOPT_URLOPTIONS))
+        options = NULL;
+
+      if((u->host[0] == '[') && u->zoneid) {
+        /* make it '[ host %25 zoneid ]' */
+        size_t hostlen = strlen(u->host);
+        size_t alen = hostlen + 3 + strlen(u->zoneid) + 1;
+        allochost = malloc(alen);
+        if(!allochost)
+          return CURLUE_OUT_OF_MEMORY;
+        memcpy(allochost, u->host, hostlen - 1);
+        msnprintf(&allochost[hostlen - 1], alen - hostlen + 1,
+                  "%%25%s]", u->zoneid);
+      }
+
+      url = aprintf("%s://%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
+                    scheme,
+                    u->user ? u->user : "",
+                    u->password ? ":": "",
+                    u->password ? u->password : "",
+                    options ? ";" : "",
+                    options ? options : "",
+                    (u->user || u->password || options) ? "@": "",
+                    allochost ? allochost : u->host,
+                    port ? ":": "",
+                    port ? port : "",
+                    (u->path && (u->path[0] != '/')) ? "/": "",
+                    u->path ? u->path : "/",
+                    (u->query && u->query[0]) ? "?": "",
+                    (u->query && u->query[0]) ? u->query : "",
+                    u->fragment? "#": "",
+                    u->fragment? u->fragment : "");
+      free(allochost);
+    }
+    if(!url)
+      return CURLUE_OUT_OF_MEMORY;
+    *part = url;
+    return CURLUE_OK;
+  }
+  default:
+    ptr = NULL;
+    break;
+  }
+  if(ptr) {
+    *part = strdup(ptr);
+    if(!*part)
+      return CURLUE_OUT_OF_MEMORY;
+    if(plusdecode) {
+      /* convert + to space */
+      char *plus;
+      for(plus = *part; *plus; ++plus) {
+        if(*plus == '+')
+          *plus = ' ';
+      }
+    }
+    if(urldecode) {
+      char *decoded;
+      size_t dlen;
+      CURLcode res = Curl_urldecode(NULL, *part, 0, &decoded, &dlen, TRUE);
+      free(*part);
+      if(res) {
+        *part = NULL;
+        return CURLUE_URLDECODE;
+      }
+      *part = decoded;
+    }
+    return CURLUE_OK;
+  }
+  else
+    return ifmissing;
+}
+
+CURLUcode curl_url_set(CURLU *u, CURLUPart what,
+                       const char *part, unsigned int flags)
+{
+  char **storep = NULL;
+  long port = 0;
+  bool urlencode = (flags & CURLU_URLENCODE)? 1 : 0;
+  bool plusencode = FALSE;
+  bool urlskipslash = FALSE;
+  bool appendquery = FALSE;
+  bool equalsencode = FALSE;
+
+  if(!u)
+    return CURLUE_BAD_HANDLE;
+  if(!part) {
+    /* setting a part to NULL clears it */
+    switch(what) {
+    case CURLUPART_URL:
+      break;
+    case CURLUPART_SCHEME:
+      storep = &u->scheme;
+      break;
+    case CURLUPART_USER:
+      storep = &u->user;
+      break;
+    case CURLUPART_PASSWORD:
+      storep = &u->password;
+      break;
+    case CURLUPART_OPTIONS:
+      storep = &u->options;
+      break;
+    case CURLUPART_HOST:
+      storep = &u->host;
+      break;
+    case CURLUPART_ZONEID:
+      storep = &u->zoneid;
+      break;
+    case CURLUPART_PORT:
+      u->portnum = 0;
+      storep = &u->port;
+      break;
+    case CURLUPART_PATH:
+      storep = &u->path;
+      break;
+    case CURLUPART_QUERY:
+      storep = &u->query;
+      break;
+    case CURLUPART_FRAGMENT:
+      storep = &u->fragment;
+      break;
+    default:
+      return CURLUE_UNKNOWN_PART;
+    }
+    if(storep && *storep) {
+      free(*storep);
+      *storep = NULL;
+    }
+    return CURLUE_OK;
+  }
+
+  switch(what) {
+  case CURLUPART_SCHEME:
+    if(strlen(part) > MAX_SCHEME_LEN)
+      /* too long */
+      return CURLUE_MALFORMED_INPUT;
+    if(!(flags & CURLU_NON_SUPPORT_SCHEME) &&
+       /* verify that it is a fine scheme */
+       !Curl_builtin_scheme(part))
+      return CURLUE_UNSUPPORTED_SCHEME;
+    storep = &u->scheme;
+    urlencode = FALSE; /* never */
+    break;
+  case CURLUPART_USER:
+    storep = &u->user;
+    break;
+  case CURLUPART_PASSWORD:
+    storep = &u->password;
+    break;
+  case CURLUPART_OPTIONS:
+    storep = &u->options;
+    break;
+  case CURLUPART_HOST:
+    storep = &u->host;
+    free(u->zoneid);
+    u->zoneid = NULL;
+    break;
+  case CURLUPART_ZONEID:
+    storep = &u->zoneid;
+    break;
+  case CURLUPART_PORT:
+  {
+    char *endp;
+    urlencode = FALSE; /* never */
+    port = strtol(part, &endp, 10);  /* Port number must be decimal */
+    if((port <= 0) || (port > 0xffff))
+      return CURLUE_BAD_PORT_NUMBER;
+    if(*endp)
+      /* weirdly provided number, not good! */
+      return CURLUE_MALFORMED_INPUT;
+    storep = &u->port;
+  }
+  break;
+  case CURLUPART_PATH:
+    urlskipslash = TRUE;
+    storep = &u->path;
+    break;
+  case CURLUPART_QUERY:
+    plusencode = urlencode;
+    appendquery = (flags & CURLU_APPENDQUERY)?1:0;
+    equalsencode = appendquery;
+    storep = &u->query;
+    break;
+  case CURLUPART_FRAGMENT:
+    storep = &u->fragment;
+    break;
+  case CURLUPART_URL: {
+    /*
+     * Allow a new URL to replace the existing (if any) contents.
+     *
+     * If the existing contents is enough for a URL, allow a relative URL to
+     * replace it.
+     */
+    CURLUcode result;
+    char *oldurl;
+    char *redired_url;
+    CURLU *handle2;
+
+    if(Curl_is_absolute_url(part, NULL, MAX_SCHEME_LEN + 1)) {
+      handle2 = curl_url();
+      if(!handle2)
+        return CURLUE_OUT_OF_MEMORY;
+      result = parseurl(part, handle2, flags);
+      if(!result)
+        mv_urlhandle(handle2, u);
+      else
+        curl_url_cleanup(handle2);
+      return result;
+    }
+    /* extract the full "old" URL to do the redirect on */
+    result = curl_url_get(u, CURLUPART_URL, &oldurl, flags);
+    if(result) {
+      /* couldn't get the old URL, just use the new! */
+      handle2 = curl_url();
+      if(!handle2)
+        return CURLUE_OUT_OF_MEMORY;
+      result = parseurl(part, handle2, flags);
+      if(!result)
+        mv_urlhandle(handle2, u);
+      else
+        curl_url_cleanup(handle2);
+      return result;
+    }
+
+    /* apply the relative part to create a new URL */
+    redired_url = concat_url(oldurl, part);
+    free(oldurl);
+    if(!redired_url)
+      return CURLUE_OUT_OF_MEMORY;
+
+    /* now parse the new URL */
+    handle2 = curl_url();
+    if(!handle2) {
+      free(redired_url);
+      return CURLUE_OUT_OF_MEMORY;
+    }
+    result = parseurl(redired_url, handle2, flags);
+    free(redired_url);
+    if(!result)
+      mv_urlhandle(handle2, u);
+    else
+      curl_url_cleanup(handle2);
+    return result;
+  }
+  default:
+    return CURLUE_UNKNOWN_PART;
+  }
+  if(storep) {
+    const char *newp = part;
+    size_t nalloc = strlen(part);
+
+    if(nalloc > CURL_MAX_INPUT_LENGTH)
+      /* excessive input length */
+      return CURLUE_MALFORMED_INPUT;
+
+    if(urlencode) {
+      const unsigned char *i;
+      char *o;
+      bool free_part = FALSE;
+      char *enc = malloc(nalloc * 3 + 1); /* for worst case! */
+      if(!enc)
+        return CURLUE_OUT_OF_MEMORY;
+      if(plusencode) {
+        /* space to plus */
+        i = (const unsigned char *)part;
+        for(o = enc; *i; ++o, ++i)
+          *o = (*i == ' ') ? '+' : *i;
+        *o = 0; /* zero terminate */
+        part = strdup(enc);
+        if(!part) {
+          free(enc);
+          return CURLUE_OUT_OF_MEMORY;
+        }
+        free_part = TRUE;
+      }
+      for(i = (const unsigned char *)part, o = enc; *i; i++) {
+        if(Curl_isunreserved(*i) ||
+           ((*i == '/') && urlskipslash) ||
+           ((*i == '=') && equalsencode) ||
+           ((*i == '+') && plusencode)) {
+          if((*i == '=') && equalsencode)
+            /* only skip the first equals sign */
+            equalsencode = FALSE;
+          *o = *i;
+          o++;
+        }
+        else {
+          msnprintf(o, 4, "%%%02x", *i);
+          o += 3;
+        }
+      }
+      *o = 0; /* zero terminate */
+      newp = enc;
+      if(free_part)
+        free((char *)part);
+    }
+    else {
+      char *p;
+      newp = strdup(part);
+      if(!newp)
+        return CURLUE_OUT_OF_MEMORY;
+      p = (char *)newp;
+      while(*p) {
+        /* make sure percent encoded are lower case */
+        if((*p == '%') && ISXDIGIT(p[1]) && ISXDIGIT(p[2]) &&
+           (ISUPPER(p[1]) || ISUPPER(p[2]))) {
+          p[1] = (char)TOLOWER(p[1]);
+          p[2] = (char)TOLOWER(p[2]);
+          p += 3;
+        }
+        else
+          p++;
+      }
+    }
+
+    if(appendquery) {
+      /* Append the string onto the old query. Add a '&' separator if none is
+         present at the end of the exsting query already */
+      size_t querylen = u->query ? strlen(u->query) : 0;
+      bool addamperand = querylen && (u->query[querylen -1] != '&');
+      if(querylen) {
+        size_t newplen = strlen(newp);
+        char *p = malloc(querylen + addamperand + newplen + 1);
+        if(!p) {
+          free((char *)newp);
+          return CURLUE_OUT_OF_MEMORY;
+        }
+        strcpy(p, u->query); /* original query */
+        if(addamperand)
+          p[querylen] = '&'; /* ampersand */
+        strcpy(&p[querylen + addamperand], newp); /* new suffix */
+        free((char *)newp);
+        free(*storep);
+        *storep = p;
+        return CURLUE_OK;
+      }
+    }
+
+    if(what == CURLUPART_HOST) {
+      if(hostname_check(u, (char *)newp)) {
+        free((char *)newp);
+        return CURLUE_MALFORMED_INPUT;
+      }
+    }
+
+    free(*storep);
+    *storep = (char *)newp;
+  }
+  /* set after the string, to make it not assigned if the allocation above
+     fails */
+  if(port)
+    u->portnum = port;
+  return CURLUE_OK;
+}