gecko-dev/xpcom/base/nsID.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsID.h"
#include "nsMemory.h"
#include "mozilla/Sprintf.h"

void nsID::Clear()
{
  m0 = 0;
  m1 = 0;
  m2 = 0;
  memset(m3, 0, sizeof(m3));
}

/**
 * Multiplies the_int_var with 16 (0x10) and adds the value of the
 * hexadecimal digit the_char. If it fails it returns false from
 * the function it's used in.
 */

#define ADD_HEX_CHAR_TO_INT_OR_RETURN_FALSE(the_char, the_int_var) \
    the_int_var = (the_int_var << 4) + the_char; \
    if(the_char >= '0' && the_char <= '9') the_int_var -= '0'; \
    else if(the_char >= 'a' && the_char <= 'f') the_int_var -= 'a'-10; \
    else if(the_char >= 'A' && the_char <= 'F') the_int_var -= 'A'-10; \
    else return false


/**
 * Parses number_of_chars characters from the char_pointer pointer and
 * puts the number in the dest_variable. The pointer is moved to point
 * at the first character after the parsed ones. If it fails it returns
 * false from the function the macro is used in.
 */

#define PARSE_CHARS_TO_NUM(char_pointer, dest_variable, number_of_chars) \
  do { int32_t _i=number_of_chars; \
  dest_variable = 0; \
  while(_i) { \
    ADD_HEX_CHAR_TO_INT_OR_RETURN_FALSE(*char_pointer, dest_variable); \
    char_pointer++; \
    _i--; \
  } } while(0)


/**
 * Parses a hyphen from the char_pointer string. If there is no hyphen there
 * the function returns false from the function it's used in. The
 * char_pointer is advanced one step.
 */

#define PARSE_HYPHEN(char_pointer) if (*(char_pointer++) != '-') return false

/*
 * Turns a {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} string into
 * an nsID. It can also handle the old format without the { and }.
 */

bool
nsID::Parse(const char* aIDStr)
{
  /* Optimized for speed */
  if (!aIDStr) {
    return false;
  }

  bool expectFormat1 = (aIDStr[0] == '{');
  if (expectFormat1) {
    ++aIDStr;
  }

  PARSE_CHARS_TO_NUM(aIDStr, m0, 8);
  PARSE_HYPHEN(aIDStr);
  PARSE_CHARS_TO_NUM(aIDStr, m1, 4);
  PARSE_HYPHEN(aIDStr);
  PARSE_CHARS_TO_NUM(aIDStr, m2, 4);
  PARSE_HYPHEN(aIDStr);
  int i;
  for (i = 0; i < 2; ++i) {
    PARSE_CHARS_TO_NUM(aIDStr, m3[i], 2);
  }
  PARSE_HYPHEN(aIDStr);
  while (i < 8) {
    PARSE_CHARS_TO_NUM(aIDStr, m3[i], 2);
    i++;
  }

  return expectFormat1 ? *aIDStr == '}' : true;
}

#ifndef XPCOM_GLUE_AVOID_NSPR

static const char gIDFormat[] =
  "{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}";

/*
 * Returns an allocated string in {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
 * format. The string is allocated with NS_Alloc and should be freed by
 * the caller.
 */

char*
nsID::ToString() const
{
  char* res = (char*)NS_Alloc(NSID_LENGTH);

  if (res) {
    snprintf(res, NSID_LENGTH, gIDFormat,
             m0, (uint32_t)m1, (uint32_t)m2,
             (uint32_t)m3[0], (uint32_t)m3[1], (uint32_t)m3[2],
             (uint32_t)m3[3], (uint32_t)m3[4], (uint32_t)m3[5],
             (uint32_t)m3[6], (uint32_t)m3[7]);
  }
  return res;
}

void
nsID::ToProvidedString(char (&aDest)[NSID_LENGTH]) const
{
  SprintfLiteral(aDest, gIDFormat,
                 m0, (uint32_t)m1, (uint32_t)m2,
                 (uint32_t)m3[0], (uint32_t)m3[1], (uint32_t)m3[2],
                 (uint32_t)m3[3], (uint32_t)m3[4], (uint32_t)m3[5],
                 (uint32_t)m3[6], (uint32_t)m3[7]);
}

#endif // XPCOM_GLUE_AVOID_NSPR