1/*!
  2 * ws: a node.js websocket client
  3 * Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
  4 * MIT Licensed
  5 */
  6
  7#include <v8.h>
  8#include <node.h>
  9#include <node_buffer.h>
 10#include <node_object_wrap.h>
 11#include <stdlib.h>
 12#include <wchar.h>
 13#include <stdio.h>
 14#include "nan.h"
 15
 16using namespace v8;
 17using namespace node;
 18
 19#define UNI_SUR_HIGH_START   (uint32_t) 0xD800
 20#define UNI_SUR_LOW_END    (uint32_t) 0xDFFF
 21#define UNI_REPLACEMENT_CHAR (uint32_t) 0x0000FFFD
 22#define UNI_MAX_LEGAL_UTF32  (uint32_t) 0x0010FFFF
 23
 24static const uint8_t trailingBytesForUTF8[256] = {
 25  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 26  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 27  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 28  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 29  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 30  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 31  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 32  2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
 33};
 34
 35static const uint32_t offsetsFromUTF8[6] = {
 36  0x00000000, 0x00003080, 0x000E2080,
 37  0x03C82080, 0xFA082080, 0x82082080
 38};
 39
 40static int isLegalUTF8(const uint8_t *source, const int length)
 41{
 42  uint8_t a;
 43  const uint8_t *srcptr = source+length;
 44  switch (length) {
 45  default: return 0;
 46  /* Everything else falls through when "true"... */
 47  /* RFC3629 makes 5 & 6 bytes UTF-8 illegal
 48  case 6: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0;
 49  case 5: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0; */
 50  case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0;
 51  case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0;
 52  case 2: if ((a = (*--srcptr)) > 0xBF) return 0;
 53    switch (*source) {
 54      /* no fall-through in this inner switch */
 55      case 0xE0: if (a < 0xA0) return 0; break;
 56      case 0xED: if (a > 0x9F) return 0; break;
 57      case 0xF0: if (a < 0x90) return 0; break;
 58      case 0xF4: if (a > 0x8F) return 0; break;
 59      default:   if (a < 0x80) return 0;
 60    }
 61
 62  case 1: if (*source >= 0x80 && *source < 0xC2) return 0;
 63  }
 64  if (*source > 0xF4) return 0;
 65  return 1;
 66}
 67
 68int is_valid_utf8 (size_t len, char *value)
 69{
 70  /* is the string valid UTF-8? */
 71  for (unsigned int i = 0; i < len; i++) {
 72    uint32_t ch = 0;
 73    uint8_t  extrabytes = trailingBytesForUTF8[(uint8_t) value[i]];
 74
 75    if (extrabytes + i >= len)
 76      return 0;
 77
 78    if (isLegalUTF8 ((uint8_t *) (value + i), extrabytes + 1) == 0) return 0;
 79
 80    switch (extrabytes) {
 81      case 5 : ch += (uint8_t) value[i++]; ch <<= 6;
 82      case 4 : ch += (uint8_t) value[i++]; ch <<= 6;
 83      case 3 : ch += (uint8_t) value[i++]; ch <<= 6;
 84      case 2 : ch += (uint8_t) value[i++]; ch <<= 6;
 85      case 1 : ch += (uint8_t) value[i++]; ch <<= 6;
 86      case 0 : ch += (uint8_t) value[i];
 87    }
 88
 89    ch -= offsetsFromUTF8[extrabytes];
 90
 91    if (ch <= UNI_MAX_LEGAL_UTF32) {
 92      if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END)
 93        return 0;
 94    } else {
 95      return 0;
 96    }
 97  }
 98
 99  return 1;
100}
101
102class Validation : public ObjectWrap
103{
104public:
105
106  static void Initialize(v8::Handle<v8::Object> target)
107  {
108    HandleScope scope;
109    Local<FunctionTemplate> t = FunctionTemplate::New(New);
110    t->InstanceTemplate()->SetInternalFieldCount(1);
111    NODE_SET_METHOD(t, "isValidUTF8", Validation::IsValidUTF8);
112    target->Set(String::NewSymbol("Validation"), t->GetFunction());
113  }
114
115protected:
116
117  static NAN_METHOD(New)
118  {
119    NanScope();
120    Validation* validation = new Validation();
121    validation->Wrap(args.This());
122    NanReturnValue(args.This());
123  }
124
125  static NAN_METHOD(IsValidUTF8)
126  {
127    NanScope();
128    if (!Buffer::HasInstance(args[0])) {
129      return NanThrowTypeError("First argument needs to be a buffer");
130    }
131    Local<Object> buffer_obj = args[0]->ToObject();
132    char *buffer_data = Buffer::Data(buffer_obj);
133    size_t buffer_length = Buffer::Length(buffer_obj);
134    NanReturnValue(is_valid_utf8(buffer_length, buffer_data) == 1 ? True() : False());
135  }
136};
137
138extern "C" void init (Handle<Object> target)
139{
140  NanScope();
141  Validation::Initialize(target);
142}
143
144NODE_MODULE(validation, init)
145