node/src/node_encoding.cc

#include "node.h"
#include "env-inl.h"
#include "string_bytes.h"
#include "util-inl.h"
#include "v8.h"

namespace node {

using v8::HandleScope;
using v8::Isolate;
using v8::Local;
using v8::Value;

enum encoding ParseEncoding(const char* encoding,
                            enum encoding default_encoding) {
  switch (encoding[0]) {
    case 'u':
      // utf8, utf16le
      if (encoding[1] == 't' && encoding[2] == 'f') {
        // Skip `-`
        encoding += encoding[3] == '-' ? 4 : 3;
        if (encoding[0] == '8' && encoding[1] == '\0')
          return UTF8;
        if (strncmp(encoding, "16le", 4) == 0)
          return UCS2;

      // ucs2
      } else if (encoding[1] == 'c' && encoding[2] == 's') {
        encoding += encoding[3] == '-' ? 4 : 3;
        if (encoding[0] == '2' && encoding[1] == '\0')
          return UCS2;
      }
      break;
    case 'l':
      // latin1
      if (encoding[1] == 'a') {
        if (strncmp(encoding + 2, "tin1", 4) == 0)
          return LATIN1;
      }
      break;
    case 'b':
      // binary
      if (encoding[1] == 'i') {
        if (strncmp(encoding + 2, "nary", 4) == 0)
          return LATIN1;

      // buffer
      } else if (encoding[1] == 'u') {
        if (strncmp(encoding + 2, "ffer", 4) == 0)
          return BUFFER;
      }
      break;
    case '\0':
      return default_encoding;
    default:
      break;
  }

  if (StringEqualNoCase(encoding, "utf8")) {
    return UTF8;
  } else if (StringEqualNoCase(encoding, "utf-8")) {
    return UTF8;
  } else if (StringEqualNoCase(encoding, "ascii")) {
    return ASCII;
  } else if (StringEqualNoCase(encoding, "base64")) {
    return BASE64;
  } else if (StringEqualNoCase(encoding, "ucs2")) {
    return UCS2;
  } else if (StringEqualNoCase(encoding, "ucs-2")) {
    return UCS2;
  } else if (StringEqualNoCase(encoding, "utf16le")) {
    return UCS2;
  } else if (StringEqualNoCase(encoding, "utf-16le")) {
    return UCS2;
  } else if (StringEqualNoCase(encoding, "latin1")) {
    return LATIN1;
  } else if (StringEqualNoCase(encoding, "binary")) {
    return LATIN1;  // BINARY is a deprecated alias of LATIN1.
  } else if (StringEqualNoCase(encoding, "buffer")) {
    return BUFFER;
  } else if (StringEqualNoCase(encoding, "hex")) {
    return HEX;
  } else {
    return default_encoding;
  }
}


enum encoding ParseEncoding(Isolate* isolate,
                            Local<Value> encoding_v,
                            enum encoding default_encoding) {
  CHECK(!encoding_v.IsEmpty());

  if (!encoding_v->IsString())
    return default_encoding;

  Utf8Value encoding(isolate, encoding_v);

  return ParseEncoding(*encoding, default_encoding);
}

Local<Value> Encode(Isolate* isolate,
                    const char* buf,
                    size_t len,
                    enum encoding encoding) {
  CHECK_NE(encoding, UCS2);
  Local<Value> error;
  return StringBytes::Encode(isolate, buf, len, encoding, &error)
      .ToLocalChecked();
}

Local<Value> Encode(Isolate* isolate, const uint16_t* buf, size_t len) {
  Local<Value> error;
  return StringBytes::Encode(isolate, buf, len, &error)
      .ToLocalChecked();
}

// Returns -1 if the handle was not valid for decoding
ssize_t DecodeBytes(Isolate* isolate,
                    Local<Value> val,
                    enum encoding encoding) {
  HandleScope scope(isolate);

  return StringBytes::Size(isolate, val, encoding).FromMaybe(-1);
}

// Returns number of bytes written.
ssize_t DecodeWrite(Isolate* isolate,
                    char* buf,
                    size_t buflen,
                    Local<Value> val,
                    enum encoding encoding) {
  return StringBytes::Write(isolate, buf, buflen, val, encoding, nullptr);
}

}  // namespace node