Vendor in some support code

4 files changed, 1887 insertions, 0 deletions

diff --git a/src/escape.c b/src/escape.c
new file mode 100644
index 0000000..d083da6
--- /dev/null
+++ b/src/escape.c
@@ -0,0 +1,213 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, 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.
+ *
+ ***************************************************************************/
+
+/* Escape and unescape URL encoding in strings. The functions return a new
+ * allocated string or NULL if an error occurred.  */
+#include <ctype.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "escape.h"
+
+/* Portable character check (remember EBCDIC). Do not use isalnum() because
+   its behavior is altered by the current locale.
+   See https://tools.ietf.org/html/rfc3986#section-2.3
+*/
+bool Curl_isunreserved(unsigned char in)
+{
+  switch(in) {
+    case '0': case '1': case '2': case '3': case '4':
+    case '5': case '6': case '7': case '8': case '9':
+    case 'a': case 'b': case 'c': case 'd': case 'e':
+    case 'f': case 'g': case 'h': case 'i': case 'j':
+    case 'k': case 'l': case 'm': case 'n': case 'o':
+    case 'p': case 'q': case 'r': case 's': case 't':
+    case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
+    case 'A': case 'B': case 'C': case 'D': case 'E':
+    case 'F': case 'G': case 'H': case 'I': case 'J':
+    case 'K': case 'L': case 'M': case 'N': case 'O':
+    case 'P': case 'Q': case 'R': case 'S': case 'T':
+    case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
+    case '-': case '.': case '_': case '~':
+      return true;
+    default:
+      break;
+  }
+  return false;
+}
+
+/* for ABI-compatibility with previous versions */
+char *curl_escape(const char *string, int inlength)
+{
+  return curl_easy_escape(string, inlength);
+}
+
+/* for ABI-compatibility with previous versions */
+char *curl_unescape(const char *string, int length)
+{
+  return curl_easy_unescape(string, length, NULL);
+}
+
+char *curl_easy_escape(const char *string, int inlength)
+{
+  size_t alloc;
+  char *ns;
+  char *testing_ptr = NULL;
+  size_t newlen;
+  size_t strindex = 0;
+  size_t length;
+
+  if(inlength < 0)
+    return NULL;
+
+  alloc = (inlength?(size_t)inlength:strlen(string)) + 1;
+  newlen = alloc;
+
+  ns = malloc(alloc);
+  if(!ns)
+    return NULL;
+
+  length = alloc-1;
+  while(length--) {
+    unsigned char in = *string; /* we need to treat the characters unsigned */
+
+    if(Curl_isunreserved(in))
+      /* just copy this */
+      ns[strindex++] = in;
+    else {
+      /* encode it */
+      newlen += 2; /* the size grows with two, since this'll become a %XX */
+      if(newlen > alloc) {
+        alloc *= 2;
+        testing_ptr = realloc(ns, alloc);
+        if(!testing_ptr)
+          return NULL;
+        ns = testing_ptr;
+      }
+
+      snprintf(&ns[strindex], 4, "%%%02X", in);
+
+      strindex += 3;
+    }
+    string++;
+  }
+  ns[strindex] = 0; /* terminate it */
+  return ns;
+}
+
+/*
+ * Curl_urldecode() URL decodes the given string.
+ *
+ * Optionally detects control characters (byte codes lower than 32) in the
+ * data and rejects such data.
+ *
+ * Returns a pointer to a malloced string in *ostring with length given in
+ * *olen. If length == 0, the length is assumed to be strlen(string).
+ */
+CURLcode Curl_urldecode(const char *string, size_t length,
+                        char **ostring, size_t *olen,
+                        bool reject_ctrl)
+{
+  size_t alloc = (length?length:strlen(string)) + 1;
+  char *ns = malloc(alloc);
+  size_t strindex = 0;
+  unsigned long hex;
+
+  if(!ns)
+    return CURLE_OUT_OF_MEMORY;
+
+  while(--alloc > 0) {
+    unsigned char in = *string;
+    if(('%' == in) && (alloc > 2) &&
+       isxdigit(string[1]) && isxdigit(string[2])) {
+      /* this is two hexadecimal digits following a '%' */
+      char hexstr[3];
+      char *ptr;
+      hexstr[0] = string[1];
+      hexstr[1] = string[2];
+      hexstr[2] = 0;
+
+      hex = strtoul(hexstr, &ptr, 16);
+
+      in = (unsigned char)hex; /* this long is never bigger than 255 anyway */
+
+      string += 2;
+      alloc -= 2;
+    }
+
+    if(reject_ctrl && (in < 0x20)) {
+      free(ns);
+      return CURLE_URL_MALFORMAT;
+    }
+
+    ns[strindex++] = in;
+    string++;
+  }
+  ns[strindex] = 0; /* terminate it */
+
+  if(olen)
+    /* store output size */
+    *olen = strindex;
+
+  /* store output string */
+  *ostring = ns;
+
+  return CURLE_OK;
+}
+
+/*
+ * Unescapes the given URL escaped string of given length. Returns a
+ * pointer to a malloced string with length given in *olen.
+ * If length == 0, the length is assumed to be strlen(string).
+ * If olen == NULL, no output length is stored.
+ */
+char *curl_easy_unescape(const char *string, int length, int *olen)
+{
+  char *str = NULL;
+  if(length >= 0) {
+    size_t inputlen = length;
+    size_t outputlen;
+    CURLcode res = Curl_urldecode(string, inputlen, &str, &outputlen, false);
+    if(res)
+      return NULL;
+
+    if(olen) {
+      if(outputlen <= (size_t) INT_MAX)
+        *olen = (int)outputlen;
+      else
+        /* too large to return in an int, fail! */
+        free(str);
+    }
+  }
+  return str;
+}
+
+/* For operating systems/environments that use different malloc/free
+   systems for the app and for this library, we provide a free that uses
+   the library's memory system */
+void curl_free(void *p)
+{
+  free(p);
+}
diff --git a/src/ini.c b/src/ini.c
new file mode 100644
index 0000000..236684e
--- /dev/null
+++ b/src/ini.c
@@ -0,0 +1,194 @@
+/* inih -- simple .INI file parser
+
+inih is released under the New BSD license (see LICENSE.txt). Go to the project
+home page for more info:
+
+https://github.com/benhoyt/inih
+
+*/
+
+#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
+#define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include "ini.h"
+
+#if !INI_USE_STACK
+#include <stdlib.h>
+#endif
+
+#define MAX_SECTION 50
+#define MAX_NAME 50
+
+/* Strip whitespace chars off end of given string, in place. Return s. */
+static char* rstrip(char* s)
+{
+    char* p = s + strlen(s);
+    while (p > s && isspace((unsigned char)(*--p)))
+        *p = '\0';
+    return s;
+}
+
+/* Return pointer to first non-whitespace char in given string. */
+static char* lskip(const char* s)
+{
+    while (*s && isspace((unsigned char)(*s)))
+        s++;
+    return (char*)s;
+}
+
+/* Return pointer to first char (of chars) or inline comment in given string,
+   or pointer to null at end of string if neither found. Inline comment must
+   be prefixed by a whitespace character to register as a comment. */
+static char* find_chars_or_comment(const char* s, const char* chars)
+{
+#if INI_ALLOW_INLINE_COMMENTS
+    int was_space = 0;
+    while (*s && (!chars || !strchr(chars, *s)) &&
+           !(was_space && strchr(INI_INLINE_COMMENT_PREFIXES, *s))) {
+        was_space = isspace((unsigned char)(*s));
+        s++;
+    }
+#else
+    while (*s && (!chars || !strchr(chars, *s))) {
+        s++;
+    }
+#endif
+    return (char*)s;
+}
+
+/* Version of strncpy that ensures dest (size bytes) is null-terminated. */
+static char* strncpy0(char* dest, const char* src, size_t size)
+{
+    strncpy(dest, src, size - 1);
+    dest[size - 1] = '\0';
+    return dest;
+}
+
+/* See documentation in header file. */
+int ini_parse_stream(ini_reader reader, void* stream, ini_handler handler,
+                     void* user)
+{
+    /* Uses a fair bit of stack (use heap instead if you need to) */
+#if INI_USE_STACK
+    char line[INI_MAX_LINE];
+#else
+    char* line;
+#endif
+    char section[MAX_SECTION] = "";
+    char prev_name[MAX_NAME] = "";
+
+    char* start;
+    char* end;
+    char* name;
+    char* value;
+    int lineno = 0;
+    int error = 0;
+
+#if !INI_USE_STACK
+    line = (char*)malloc(INI_MAX_LINE);
+    if (!line) {
+        return -2;
+    }
+#endif
+
+    /* Scan through stream line by line */
+    while (reader(line, INI_MAX_LINE, stream) != NULL) {
+        lineno++;
+
+        start = line;
+#if INI_ALLOW_BOM
+        if (lineno == 1 && (unsigned char)start[0] == 0xEF &&
+                           (unsigned char)start[1] == 0xBB &&
+                           (unsigned char)start[2] == 0xBF) {
+            start += 3;
+        }
+#endif
+        start = lskip(rstrip(start));
+
+        if (*start == ';' || *start == '#') {
+            /* Per Python configparser, allow both ; and # comments at the
+               start of a line */
+        }
+#if INI_ALLOW_MULTILINE
+        else if (*prev_name && *start && start > line) {
+            /* Non-blank line with leading whitespace, treat as continuation
+               of previous name's value (as per Python configparser). */
+            if (!handler(user, section, prev_name, start) && !error)
+                error = lineno;
+        }
+#endif
+        else if (*start == '[') {
+            /* A "[section]" line */
+            end = find_chars_or_comment(start + 1, "]");
+            if (*end == ']') {
+                *end = '\0';
+                strncpy0(section, start + 1, sizeof(section));
+                *prev_name = '\0';
+            }
+            else if (!error) {
+                /* No ']' found on section line */
+                error = lineno;
+            }
+        }
+        else if (*start) {
+            /* Not a comment, must be a name[=:]value pair */
+            end = find_chars_or_comment(start, "=:");
+            if (*end == '=' || *end == ':') {
+                *end = '\0';
+                name = rstrip(start);
+                value = lskip(end + 1);
+#if INI_ALLOW_INLINE_COMMENTS
+                end = find_chars_or_comment(value, NULL);
+                if (*end)
+                    *end = '\0';
+#endif
+                rstrip(value);
+
+                /* Valid name[=:]value pair found, call handler */
+                strncpy0(prev_name, name, sizeof(prev_name));
+                if (!handler(user, section, name, value) && !error)
+                    error = lineno;
+				memset(value, 0, strlen(value));
+            }
+            else if (!error) {
+                /* No '=' or ':' found on name[=:]value line */
+                error = lineno;
+            }
+        }
+
+#if INI_STOP_ON_FIRST_ERROR
+        if (error)
+            break;
+#endif
+    }
+
+#if !INI_USE_STACK
+    free(line);
+#endif
+
+    return error;
+}
+
+/* See documentation in header file. */
+int ini_parse_file(FILE* file, ini_handler handler, void* user)
+{
+    return ini_parse_stream((ini_reader)fgets, file, handler, user);
+}
+
+/* See documentation in header file. */
+int ini_parse(const char* filename, ini_handler handler, void* user)
+{
+    FILE* file;
+    int error;
+
+    file = fopen(filename, "r");
+    if (!file)
+        return -1;
+    error = ini_parse_file(file, handler, user);
+    fclose(file);
+    return error;
+}
diff --git a/src/url.c b/src/url.c
new file mode 100644
index 0000000..dabf45f
--- /dev/null
+++ b/src/url.c
@@ -0,0 +1,1435 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, 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.
+ *
+ ***************************************************************************/
+
+#define MAX_SCHEME_LEN 8
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include "escape.h"
+#include "url.h"
+
+/* Provided by gmni */
+static char *
+aprintf(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	int n = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+
+	char *strp = calloc(n + 1, 1);
+	assert(strp);
+
+	va_start(ap, fmt);
+	n = vsnprintf(strp, n + 1, fmt, ap);
+	va_end(ap);
+	return strp;
+}
+
+/* via lib/dotdot.c */
+char *Curl_dedotdotify(const char *input)
+{
+  size_t inlen = strlen(input);
+  char *clone;
+  size_t clen = inlen; /* the length of the cloned input */
+  char *out = malloc(inlen + 1);
+  char *outptr;
+  char *orgclone;
+  char *queryp;
+  if(!out)
+    return NULL; /* out of memory */
+
+  *out = 0; /* zero terminates, for inputs like "./" */
+
+  /* get a cloned copy of the input */
+  clone = strdup(input);
+  if(!clone) {
+    free(out);
+    return NULL;
+  }
+  orgclone = clone;
+  outptr = out;
+
+  if(!*clone) {
+    /* zero length string, return that */
+    free(out);
+    return clone;
+  }
+
+  /*
+   * To handle query-parts properly, we must find it and remove it during the
+   * dotdot-operation and then append it again at the end to the output
+   * string.
+   */
+  queryp = strchr(clone, '?');
+  if(queryp)
+    *queryp = 0;
+
+  do {
+
+    /*  A.  If the input buffer begins with a prefix of "../" or "./", then
+        remove that prefix from the input buffer; otherwise, */
+
+    if(!strncmp("./", clone, 2)) {
+      clone += 2;
+      clen -= 2;
+    }
+    else if(!strncmp("../", clone, 3)) {
+      clone += 3;
+      clen -= 3;
+    }
+
+    /*  B.  if the input buffer begins with a prefix of "/./" or "/.", where
+        "."  is a complete path segment, then replace that prefix with "/" in
+        the input buffer; otherwise, */
+    else if(!strncmp("/./", clone, 3)) {
+      clone += 2;
+      clen -= 2;
+    }
+    else if(!strcmp("/.", clone)) {
+      clone[1]='/';
+      clone++;
+      clen -= 1;
+    }
+
+    /*  C.  if the input buffer begins with a prefix of "/../" or "/..", where
+        ".." is a complete path segment, then replace that prefix with "/" in
+        the input buffer and remove the last segment and its preceding "/" (if
+        any) from the output buffer; otherwise, */
+
+    else if(!strncmp("/../", clone, 4)) {
+      clone += 3;
+      clen -= 3;
+      /* remove the last segment from the output buffer */
+      while(outptr > out) {
+        outptr--;
+        if(*outptr == '/')
+          break;
+      }
+      *outptr = 0; /* zero-terminate where it stops */
+    }
+    else if(!strcmp("/..", clone)) {
+      clone[2]='/';
+      clone += 2;
+      clen -= 2;
+      /* remove the last segment from the output buffer */
+      while(outptr > out) {
+        outptr--;
+        if(*outptr == '/')
+          break;
+      }
+      *outptr = 0; /* zero-terminate where it stops */
+    }
+
+    /*  D.  if the input buffer consists only of "." or "..", then remove
+        that from the input buffer; otherwise, */
+
+    else if(!strcmp(".", clone) || !strcmp("..", clone)) {
+      *clone = 0;
+      *out = 0;
+    }
+
+    else {
+      /*  E.  move the first path segment in the input buffer to the end of
+          the output buffer, including the initial "/" character (if any) and
+          any subsequent characters up to, but not including, the next "/"
+          character or the end of the input buffer. */
+
+      do {
+        *outptr++ = *clone++;
+        clen--;
+      } while(*clone && (*clone != '/'));
+      *outptr = 0;
+    }
+
+  } while(*clone);
+
+  if(queryp) {
+    size_t qlen;
+    /* There was a query part, append that to the output. The 'clone' string
+       may now have been altered so we copy from the original input string
+       from the correct index. */
+    size_t oindex = queryp - orgclone;
+    qlen = strlen(&input[oindex]);
+    memcpy(outptr, &input[oindex], qlen + 1); /* include the end zero byte */
+  }
+
+  free(orgclone);
+  return out;
+}
+
+/* via lib/url.c */
+CURLcode Curl_parse_login_details(const char *login, const size_t len,
+                                  char **userp, char **passwdp,
+                                  char **optionsp)
+{
+  CURLcode result = CURLE_OK;
+  char *ubuf = NULL;
+  char *pbuf = NULL;
+  char *obuf = NULL;
+  const char *psep = NULL;
+  const char *osep = NULL;
+  size_t ulen;
+  size_t plen;
+  size_t olen;
+
+  /* Attempt to find the password separator */
+  if(passwdp) {
+    psep = strchr(login, ':');
+
+    /* Within the constraint of the login string */
+    if(psep >= login + len)
+      psep = NULL;
+  }
+
+  /* Attempt to find the options separator */
+  if(optionsp) {
+    osep = strchr(login, ';');
+
+    /* Within the constraint of the login string */
+    if(osep >= login + len)
+      osep = NULL;
+  }
+
+  /* Calculate the portion lengths */
+  ulen = (psep ?
+          (size_t)(osep && psep > osep ? osep - login : psep - login) :
+          (osep ? (size_t)(osep - login) : len));
+  plen = (psep ?
+          (osep && osep > psep ? (size_t)(osep - psep) :
+                                 (size_t)(login + len - psep)) - 1 : 0);
+  olen = (osep ?
+          (psep && psep > osep ? (size_t)(psep - osep) :
+                                 (size_t)(login + len - osep)) - 1 : 0);
+
+  /* Allocate the user portion buffer */
+  if(userp && ulen) {
+    ubuf = malloc(ulen + 1);
+    if(!ubuf)
+      result = CURLE_OUT_OF_MEMORY;
+  }
+
+  /* Allocate the password portion buffer */
+  if(!result && passwdp && plen) {
+    pbuf = malloc(plen + 1);
+    if(!pbuf) {
+      free(ubuf);
+      result = CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* Allocate the options portion buffer */
+  if(!result && optionsp && olen) {
+    obuf = malloc(olen + 1);
+    if(!obuf) {
+      free(pbuf);
+      free(ubuf);
+      result = CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  if(!result) {
+    /* Store the user portion if necessary */
+    if(ubuf) {
+      memcpy(ubuf, login, ulen);
+      ubuf[ulen] = '\0';
+      free(*userp);
+      *userp = ubuf;
+    }
+
+    /* Store the password portion if necessary */
+    if(pbuf) {
+      memcpy(pbuf, psep + 1, plen);
+      pbuf[plen] = '\0';
+      free(*passwdp);
+      *passwdp = pbuf;
+    }
+
+    /* Store the options portion if necessary */
+    if(obuf) {
+      memcpy(obuf, osep + 1, olen);
+      obuf[olen] = '\0';
+      free(*optionsp);
+      *optionsp = obuf;
+    }
+  }
+
+  return result;
+}
+
+/* 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 *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->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.
+ */
+size_t Curl_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.
+ */
+void Curl_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)) {
+        snprintf(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;
+  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).
+ */
+char *Curl_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 = Curl_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 */
+  Curl_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,
+                                      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, 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;
+}
+
+static CURLUcode parse_port(struct Curl_URL *u, char *hostname)
+{
+  char *portptr;
+  char endbracket;
+  int len;
+
+  if((1 == sscanf(hostname, "[%*45[0123456789abcdefABCDEF:.%%]%c%n",
+                  &endbracket, &len)) &&
+     (']' == endbracket)) {
+    /* this is a RFC2732-style specified IP-address */
+    portptr = &hostname[len];
+    if(*portptr) {
+      if(*portptr != ':')
+        return CURLUE_MALFORMED_INPUT;
+    }
+    else
+      portptr = NULL;
+  }
+  else
+    portptr = strchr(hostname, ':');
+
+  if(portptr) {
+    char *rest;
+    long port;
+    char portbuf[7];
+
+    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;
+
+    if(rest != &portptr[1]) {
+      *portptr++ = '\0'; /* cut off the name there */
+      *rest = 0;
+      /* generate a new to get rid of leading zeroes etc */
+      snprintf(portbuf, sizeof(portbuf), "%ld", port);
+      u->portnum = port;
+      u->port = strdup(portbuf);
+      if(!u->port)
+        return CURLUE_OUT_OF_MEMORY;
+    }
+    else {
+      /* 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 and Chrome both do that. */
+      *portptr = '\0';
+    }
+  }
+
+  return CURLUE_OK;
+}
+
+/* scan for byte values < 31 or 127 */
+static CURLUcode junkscan(char *part)
+{
+  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 */
+  };
+  if(part) {
+    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(char *hostname, unsigned int flags)
+{
+  const char *l = NULL; /* accepted characters */
+  size_t len;
+  size_t hlen = strlen(hostname);
+  (void)flags;
+
+  if(hostname[0] == '[') {
+    hostname++;
+    l = "0123456789abcdefABCDEF::.%";
+    hlen -= 2;
+  }
+
+  if(l) {
+    /* only valid letters are ok */
+    len = strspn(hostname, l);
+    if(hlen != len)
+      /* hostname with bad content */
+      return CURLUE_MALFORMED_INPUT;
+  }
+  else {
+    /* letters from the second string is not ok */
+    len = strcspn(hostname, " ");
+    if(hlen != len)
+      /* hostname with bad content */
+      return CURLUE_MALFORMED_INPUT;
+  }
+  return CURLUE_OK;
+}
+
+#define HOSTNAME_END(x) (((x) == '/') || ((x) == '?') || ((x) == '#'))
+
+static CURLUcode seturl(const char *url, struct Curl_URL *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];
+  char *schemep = NULL;
+  size_t schemelen = 0;
+  size_t urllen;
+
+  if(!url)
+    return CURLUE_MALFORMED_INPUT;
+
+  /*************************************************************
+   * Parse the URL.
+   ************************************************************/
+  /* allocate scratch area */
+  urllen = strlen(url);
+  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 && strcasecmp(schemebuf, "file") == 0) {
+    /* 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];
+      path = ptr;
+    }
+  }
+  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(junkscan(schemep))
+        return CURLUE_MALFORMED_INPUT;
+    }
+    else {
+      /* no scheme! */
+      return CURLUE_MALFORMED_INPUT;
+    }
+    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;
+
+    len = strlen(p);
+    memcpy(path, p, len);
+    path[len] = 0;
+
+    u->scheme = strdup(schemep);
+    if(!u->scheme)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  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, &hostname, flags);
+    if(result)
+      return result;
+
+    result = parse_port(u, hostname);
+    if(result)
+      return result;
+
+    result = hostname_check(hostname, flags);
+    if(result)
+      return result;
+
+    u->host = strdup(hostname);
+    if(!u->host)
+      return CURLUE_OUT_OF_MEMORY;
+  }
+
+  if(query && query[0]) {
+    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, struct Curl_URL *u, unsigned int flags)
+{
+  CURLUcode result = seturl(url, u, flags);
+  if(result) {
+    free_urlhandle(u);
+    memset(u, 0, sizeof(struct Curl_URL));
+  }
+  return result;
+}
+
+/*
+ */
+struct Curl_URL *curl_url(void)
+{
+  return calloc(sizeof(struct Curl_URL), 1);
+}
+
+void curl_url_cleanup(struct Curl_URL *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;                     \
+  }
+
+struct Curl_URL *curl_url_dup(struct Curl_URL *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(struct Curl_URL *u, CURLUPart what,
+                       char **part, unsigned int flags)
+{
+  char *ptr;
+  CURLUcode ifmissing = CURLUE_UNKNOWN_PART;
+  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_PORT:
+    ptr = u->port;
+    ifmissing = CURLUE_NO_PORT;
+    urldecode = false; /* never for port */
+    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;
+    if(u->scheme && strcasecmp("file", u->scheme) == 0) {
+      url = aprintf("file://%s%s%s",
+                    u->path,
+                    u->fragment? "#": "",
+                    u->fragment? u->fragment : "");
+    }
+    else if(!u->host)
+      return CURLUE_NO_HOST;
+    else {
+      if(u->scheme)
+        scheme = u->scheme;
+      else
+        return CURLUE_NO_SCHEME;
+
+      options = NULL;
+
+      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) ? "@": "",
+                    u->host,
+                    port ? ":": "",
+                    port ? port : "",
+                    (u->path && (u->path[0] != '/')) ? "/": "",
+                    u->path ? u->path : "/",
+                    u->query? "?": "",
+                    u->query? u->query : "",
+                    u->fragment? "#": "",
+                    u->fragment? u->fragment : "");
+    }
+    if(!url)
+      return CURLUE_OUT_OF_MEMORY;
+    *part = url;
+    return CURLUE_OK;
+    break;
+  }
+  default:
+    ptr = NULL;
+  }
+  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(*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(struct Curl_URL *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_PORT:
+      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:
+    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;
+    break;
+  case CURLUPART_PORT:
+    urlencode = false; /* never */
+    port = strtol(part, NULL, 10);  /* Port number must be decimal */
+    if((port <= 0) || (port > 0xffff))
+      return CURLUE_BAD_PORT_NUMBER;
+    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;
+    struct Curl_URL *handle2;
+
+    if(Curl_is_absolute_url(part, NULL, MAX_SCHEME_LEN)) {
+      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 = Curl_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(urlencode) {
+      const char *i;
+      char *o;
+      bool free_part = false;
+      char *enc = malloc(nalloc * 3 + 1); /* for worst case! */
+      if(!enc)
+        return CURLUE_OUT_OF_MEMORY;
+      for(i = 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 {
+          snprintf(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;
+      }
+    }
+
+    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;
+}
diff --git a/src/util.c b/src/util.c
new file mode 100644
index 0000000..93c6e91
--- /dev/null
+++ b/src/util.c
@@ -0,0 +1,45 @@
+#include <assert.h>
+#include <errno.h>
+#include <libgen.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include "util.h"
+
+static void
+posix_dirname(char *path, char *dname)
+{
+	char p[PATH_MAX+1];
+	char *t;
+
+	assert(strlen(path) <= PATH_MAX);
+
+	strcpy(p, path);
+	t = dirname(path);
+	memmove(dname, t, strlen(t) + 1);
+
+	/* restore the path if dirname worked in-place */
+	if (t == path && path != dname) {
+		strcpy(path, p);
+	}
+}
+
+/** Make directory and all of its parents */
+int
+mkdirs(char *path, mode_t mode)
+{
+	char dname[PATH_MAX + 1];
+	posix_dirname(path, dname);
+	if (strcmp(dname, "/") == 0) {
+		return 0;
+	}
+	if (mkdirs(dname, mode) != 0) {
+		return -1;
+	}
+	if (mkdir(path, mode) != 0 && errno != EEXIST) {
+		return -1;
+	}
+	errno = 0;
+	return 0;
+}