Move googleurl into the Chrome repo.

url/url_canon_internal.cc

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <cstdio>
+#include <errno.h>
+#include <stdlib.h>
+#include <string>
+
+#include "googleurl/src/url_canon_internal.h"
+
+namespace url_canon {
+
+namespace {
+
+template<typename CHAR, typename UCHAR>
+void DoAppendStringOfType(const CHAR* source, int length,
+                          SharedCharTypes type,
+                          CanonOutput* output) {
+  for (int i = 0; i < length; i++) {
+    if (static_cast<UCHAR>(source[i]) >= 0x80) {
+      // ReadChar will fill the code point with kUnicodeReplacementCharacter
+      // when the input is invalid, which is what we want.
+      unsigned code_point;
+      ReadUTFChar(source, &i, length, &code_point);
+      AppendUTF8EscapedValue(code_point, output);
+    } else {
+      // Just append the 7-bit character, possibly escaping it.
+      unsigned char uch = static_cast<unsigned char>(source[i]);
+      if (!IsCharOfType(uch, type))
+        AppendEscapedChar(uch, output);
+      else
+        output->push_back(uch);
+    }
+  }
+}
+
+// This function assumes the input values are all contained in 8-bit,
+// although it allows any type. Returns true if input is valid, false if not.
+template<typename CHAR, typename UCHAR>
+void DoAppendInvalidNarrowString(const CHAR* spec, int begin, int end,
+                                 CanonOutput* output) {
+  for (int i = begin; i < end; i++) {
+    UCHAR uch = static_cast<UCHAR>(spec[i]);
+    if (uch >= 0x80) {
+      // Handle UTF-8/16 encodings. This call will correctly handle the error
+      // case by appending the invalid character.
+      AppendUTF8EscapedChar(spec, &i, end, output);
+    } else if (uch <= ' ' || uch == 0x7f) {
+      // This function is for error handling, so we escape all control
+      // characters and spaces, but not anything else since we lack
+      // context to do something more specific.
+      AppendEscapedChar(static_cast<unsigned char>(uch), output);
+    } else {
+      output->push_back(static_cast<char>(uch));
+    }
+  }
+}
+
+// Overrides one component, see the url_canon::Replacements structure for
+// what the various combionations of source pointer and component mean.
+void DoOverrideComponent(const char* override_source,
+                         const url_parse::Component& override_component,
+                         const char** dest,
+                         url_parse::Component* dest_component) {
+  if (override_source) {
+    *dest = override_source;
+    *dest_component = override_component;
+  }
+}
+
+// Similar to DoOverrideComponent except that it takes a UTF-16 input and does
+// not actually set the output character pointer.
+//
+// The input is converted to UTF-8 at the end of the given buffer as a temporary
+// holding place. The component indentifying the portion of the buffer used in
+// the |utf8_buffer| will be specified in |*dest_component|.
+//
+// This will not actually set any |dest| pointer like DoOverrideComponent
+// does because all of the pointers will point into the |utf8_buffer|, which
+// may get resized while we're overriding a subsequent component. Instead, the
+// caller should use the beginning of the |utf8_buffer| as the string pointer
+// for all components once all overrides have been prepared.
+bool PrepareUTF16OverrideComponent(
+    const char16* override_source,
+    const url_parse::Component& override_component,
+    CanonOutput* utf8_buffer,
+    url_parse::Component* dest_component) {
+  bool success = true;
+  if (override_source) {
+    if (!override_component.is_valid()) {
+      // Non-"valid" component (means delete), so we need to preserve that.
+      *dest_component = url_parse::Component();
+    } else {
+      // Convert to UTF-8.
+      dest_component->begin = utf8_buffer->length();
+      success = ConvertUTF16ToUTF8(&override_source[override_component.begin],
+                                   override_component.len, utf8_buffer);
+      dest_component->len = utf8_buffer->length() - dest_component->begin;
+    }
+  }
+  return success;
+}
+
+}  // namespace
+
+// See the header file for this array's declaration.
+const unsigned char kSharedCharTypeTable[0x100] = {
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0x00 - 0x0f
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0x10 - 0x1f
+    0,                           // 0x20  ' ' (escape spaces in queries)
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x21  !
+    0,                           // 0x22  "
+    0,                           // 0x23  #  (invalid in query since it marks the ref)
+    CHAR_QUERY | CHAR_USERINFO,  // 0x24  $
+    CHAR_QUERY | CHAR_USERINFO,  // 0x25  %
+    CHAR_QUERY | CHAR_USERINFO,  // 0x26  &
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x27  '
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x28  (
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x29  )
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x2a  *
+    CHAR_QUERY | CHAR_USERINFO,  // 0x2b  +
+    CHAR_QUERY | CHAR_USERINFO,  // 0x2c  ,
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x2d  -
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_COMPONENT,  // 0x2e  .
+    CHAR_QUERY,                  // 0x2f  /
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x30  0
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x31  1
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x32  2
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x33  3
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x34  4
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x35  5
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x36  6
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_OCT | CHAR_COMPONENT,  // 0x37  7
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_COMPONENT,             // 0x38  8
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_DEC | CHAR_COMPONENT,             // 0x39  9
+    CHAR_QUERY,  // 0x3a  :
+    CHAR_QUERY,  // 0x3b  ;
+    0,           // 0x3c  <  (Try to prevent certain types of XSS.)
+    CHAR_QUERY,  // 0x3d  =
+    0,           // 0x3e  >  (Try to prevent certain types of XSS.)
+    CHAR_QUERY,  // 0x3f  ?
+    CHAR_QUERY,  // 0x40  @
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x41  A
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x42  B
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x43  C
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x44  D
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x45  E
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x46  F
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x47  G
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x48  H
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x49  I
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4a  J
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4b  K
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4c  L
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4d  M
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4e  N
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x4f  O
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x50  P
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x51  Q
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x52  R
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x53  S
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x54  T
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x55  U
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x56  V
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x57  W
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_COMPONENT, // 0x58  X
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x59  Y
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x5a  Z
+    CHAR_QUERY,  // 0x5b  [
+    CHAR_QUERY,  // 0x5c  '\'
+    CHAR_QUERY,  // 0x5d  ]
+    CHAR_QUERY,  // 0x5e  ^
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x5f  _
+    CHAR_QUERY,  // 0x60  `
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x61  a
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x62  b
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x63  c
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x64  d
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x65  e
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_HEX | CHAR_COMPONENT,  // 0x66  f
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x67  g
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x68  h
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x69  i
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6a  j
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6b  k
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6c  l
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6d  m
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6e  n
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x6f  o
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x70  p
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x71  q
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x72  r
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x73  s
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x74  t
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x75  u
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x76  v
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x77  w
+    CHAR_QUERY | CHAR_USERINFO | CHAR_IPV4 | CHAR_COMPONENT,  // 0x78  x
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x79  y
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x7a  z
+    CHAR_QUERY,  // 0x7b  {
+    CHAR_QUERY,  // 0x7c  |
+    CHAR_QUERY,  // 0x7d  }
+    CHAR_QUERY | CHAR_USERINFO | CHAR_COMPONENT,  // 0x7e  ~
+    0,           // 0x7f
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0x80 - 0x8f
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0x90 - 0x9f
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xa0 - 0xaf
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xb0 - 0xbf
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xc0 - 0xcf
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xd0 - 0xdf
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xe0 - 0xef
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // 0xf0 - 0xff
+};
+
+const char kHexCharLookup[0x10] = {
+    '0', '1', '2', '3', '4', '5', '6', '7',
+    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F',
+};
+
+const char kCharToHexLookup[8] = {
+    0,         // 0x00 - 0x1f
+    '0',       // 0x20 - 0x3f: digits 0 - 9 are 0x30 - 0x39
+    'A' - 10,  // 0x40 - 0x5f: letters A - F are 0x41 - 0x46
+    'a' - 10,  // 0x60 - 0x7f: letters a - f are 0x61 - 0x66
+    0,         // 0x80 - 0x9F
+    0,         // 0xA0 - 0xBF
+    0,         // 0xC0 - 0xDF
+    0,         // 0xE0 - 0xFF
+};
+
+const char16 kUnicodeReplacementCharacter = 0xfffd;
+
+void AppendStringOfType(const char* source, int length,
+                        SharedCharTypes type,
+                        CanonOutput* output) {
+  DoAppendStringOfType<char, unsigned char>(source, length, type, output);
+}
+
+void AppendStringOfType(const char16* source, int length,
+                        SharedCharTypes type,
+                        CanonOutput* output) {
+  DoAppendStringOfType<char16, char16>(source, length, type, output);
+}
+
+void AppendInvalidNarrowString(const char* spec, int begin, int end,
+                               CanonOutput* output) {
+  DoAppendInvalidNarrowString<char, unsigned char>(spec, begin, end, output);
+}
+
+void AppendInvalidNarrowString(const char16* spec, int begin, int end,
+                               CanonOutput* output) {
+  DoAppendInvalidNarrowString<char16, char16>(spec, begin, end, output);
+}
+
+bool ConvertUTF16ToUTF8(const char16* input, int input_len,
+                        CanonOutput* output) {
+  bool success = true;
+  for (int i = 0; i < input_len; i++) {
+    unsigned code_point;
+    success &= ReadUTFChar(input, &i, input_len, &code_point);
+    AppendUTF8Value(code_point, output);
+  }
+  return success;
+}
+
+bool ConvertUTF8ToUTF16(const char* input, int input_len,
+                        CanonOutputT<char16>* output) {
+  bool success = true;
+  for (int i = 0; i < input_len; i++) {
+    unsigned code_point;
+    success &= ReadUTFChar(input, &i, input_len, &code_point);
+    AppendUTF16Value(code_point, output);
+  }
+  return success;
+}
+
+void SetupOverrideComponents(const char* base,
+                             const Replacements<char>& repl,
+                             URLComponentSource<char>* source,
+                             url_parse::Parsed* parsed) {
+  // Get the source and parsed structures of the things we are replacing.
+  const URLComponentSource<char>& repl_source = repl.sources();
+  const url_parse::Parsed& repl_parsed = repl.components();
+
+  DoOverrideComponent(repl_source.scheme, repl_parsed.scheme,
+                      &source->scheme, &parsed->scheme);
+  DoOverrideComponent(repl_source.username, repl_parsed.username,
+                      &source->username, &parsed->username);
+  DoOverrideComponent(repl_source.password, repl_parsed.password,
+                      &source->password, &parsed->password);
+
+  // Our host should be empty if not present, so override the default setup.
+  DoOverrideComponent(repl_source.host, repl_parsed.host,
+                      &source->host, &parsed->host);
+  if (parsed->host.len == -1)
+    parsed->host.len = 0;
+
+  DoOverrideComponent(repl_source.port, repl_parsed.port,
+                      &source->port, &parsed->port);
+  DoOverrideComponent(repl_source.path, repl_parsed.path,
+                      &source->path, &parsed->path);
+  DoOverrideComponent(repl_source.query, repl_parsed.query,
+                      &source->query, &parsed->query);
+  DoOverrideComponent(repl_source.ref, repl_parsed.ref,
+                      &source->ref, &parsed->ref);
+}
+
+bool SetupUTF16OverrideComponents(const char* base,
+                                  const Replacements<char16>& repl,
+                                  CanonOutput* utf8_buffer,
+                                  URLComponentSource<char>* source,
+                                  url_parse::Parsed* parsed) {
+  bool success = true;
+
+  // Get the source and parsed structures of the things we are replacing.
+  const URLComponentSource<char16>& repl_source = repl.sources();
+  const url_parse::Parsed& repl_parsed = repl.components();
+
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.scheme, repl_parsed.scheme,
+      utf8_buffer, &parsed->scheme);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.username, repl_parsed.username,
+      utf8_buffer, &parsed->username);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.password, repl_parsed.password,
+      utf8_buffer, &parsed->password);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.host, repl_parsed.host,
+      utf8_buffer, &parsed->host);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.port, repl_parsed.port,
+      utf8_buffer, &parsed->port);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.path, repl_parsed.path,
+      utf8_buffer, &parsed->path);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.query, repl_parsed.query,
+      utf8_buffer, &parsed->query);
+  success &= PrepareUTF16OverrideComponent(
+      repl_source.ref, repl_parsed.ref,
+      utf8_buffer, &parsed->ref);
+
+  // PrepareUTF16OverrideComponent will not have set the data pointer since the
+  // buffer could be resized, invalidating the pointers. We set the data
+  // pointers for affected components now that the buffer is finalized.
+  if (repl_source.scheme)   source->scheme = utf8_buffer->data();
+  if (repl_source.username) source->username = utf8_buffer->data();
+  if (repl_source.password) source->password = utf8_buffer->data();
+  if (repl_source.host)     source->host = utf8_buffer->data();
+  if (repl_source.port)     source->port = utf8_buffer->data();
+  if (repl_source.path)     source->path = utf8_buffer->data();
+  if (repl_source.query)    source->query = utf8_buffer->data();
+  if (repl_source.ref)      source->ref = utf8_buffer->data();
+
+  return success;
+}
+
+#ifndef WIN32
+
+int _itoa_s(int value, char* buffer, size_t size_in_chars, int radix) {
+  const char* format_str;
+  if (radix == 10)
+    format_str = "%d";
+  else if (radix == 16)
+    format_str = "%x";
+  else
+    return EINVAL;
+
+  int written = snprintf(buffer, size_in_chars, format_str, value);
+  if (static_cast<size_t>(written) >= size_in_chars) {
+    // Output was truncated, or written was negative.
+    return EINVAL;
+  }
+  return 0;
+}
+
+int _itow_s(int value, char16* buffer, size_t size_in_chars, int radix) {
+  if (radix != 10)
+    return EINVAL;
+
+  // No more than 12 characters will be required for a 32-bit integer.
+  // Add an extra byte for the terminating null.
+  char temp[13];
+  int written = snprintf(temp, sizeof(temp), "%d", value);
+  if (static_cast<size_t>(written) >= size_in_chars) {
+    // Output was truncated, or written was negative.
+    return EINVAL;
+  }
+
+  for (int i = 0; i < written; ++i) {
+    buffer[i] = static_cast<char16>(temp[i]);
+  }
+  buffer[written] = '\0';
+  return 0;
+}
+
+#endif  // !WIN32
+
+}  // namespace url_canon