//========================================================================
//
// FoFiBase.cc
//
// Copyright 1999-2003 Glyph & Cog, LLC
//
//========================================================================

//========================================================================
//
// Modified under the Poppler project - http://poppler.freedesktop.org
//
// All changes made under the Poppler project to this file are licensed
// under GPL version 2 or later
//
// Copyright (C) 2008 Ed Avis <eda@waniasset.com>
// Copyright (C) 2011 Jim Meyering <jim@meyering.net>
// Copyright (C) 2016, 2018 Albert Astals Cid <aacid@kde.org>
// Copyright (C) 2019 Christian Persch <chpe@src.gnome.org>
//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
//
//========================================================================

#include <config.h>

#include <stdio.h>
#include <limits.h>
#include "goo/gfile.h"
#include "goo/gmem.h"
#include "poppler/Error.h"
#include "FoFiBase.h"

//------------------------------------------------------------------------
// FoFiBase
//------------------------------------------------------------------------

FoFiBase::FoFiBase(const char *fileA, int lenA, bool freeFileDataA) {
  file = (const unsigned char *)fileA;
  len = lenA;
  freeFileData = freeFileDataA;
}

FoFiBase::~FoFiBase() {
  if (freeFileData) {
    gfree((char*)file);
  }
}

char *FoFiBase::readFile(const char *fileName, int *fileLen) {
  FILE *f;
  char *buf;
  int n;

  if (!(f = openFile(fileName, "rb"))) {
    error(errIO, -1, "Cannot open '{0:s}'", fileName);
    return nullptr;
  }
  if (fseek(f, 0, SEEK_END) != 0) {
    error(errIO, -1, "Cannot seek to end of '{0:s}'", fileName);
    fclose(f);
    return nullptr;
  }
  n = (int)ftell(f);
  if (n < 0) {
    error(errIO, -1, "Cannot determine length of '{0:s}'", fileName);
    fclose(f);
    return nullptr;
  }
  if (fseek(f, 0, SEEK_SET) != 0) {
    error(errIO, -1, "Cannot seek to start of '{0:s}'", fileName);
    fclose(f);
    return nullptr;
  }
  buf = (char *)gmalloc(n);
  if ((int)fread(buf, 1, n, f) != n) {
    gfree(buf);
    fclose(f);
    return nullptr;
  }
  fclose(f);
  *fileLen = n;
  return buf;
}

int FoFiBase::getS8(int pos, bool *ok) const {
  int x;

  if (pos < 0 || pos >= len) {
    *ok = false;
    return 0;
  }
  x = file[pos];
  if (x & 0x80) {
    x |= ~0xff;
  }
  return x;
}

int FoFiBase::getU8(int pos, bool *ok) const {
  if (pos < 0 || pos >= len) {
    *ok = false;
    return 0;
  }
  return file[pos];
}

int FoFiBase::getS16BE(int pos, bool *ok) const {
  int x;

  if (pos < 0 || pos+1 >= len || pos > INT_MAX - 1) {
    *ok = false;
    return 0;
  }
  x = file[pos];
  x = (x << 8) + file[pos+1];
  if (x & 0x8000) {
    x |= ~0xffff;
  }
  return x;
}

int FoFiBase::getU16BE(int pos, bool *ok) const {
  int x;

  if (pos < 0 || pos+1 >= len || pos > INT_MAX - 1) {
    *ok = false;
    return 0;
  }
  x = file[pos];
  x = (x << 8) + file[pos+1];
  return x;
}

int FoFiBase::getS32BE(int pos, bool *ok) const {
  int x;

  if (pos < 0 || pos+3 >= len || pos > INT_MAX - 3) {
    *ok = false;
    return 0;
  }
  x = file[pos];
  x = (x << 8) + file[pos+1];
  x = (x << 8) + file[pos+2];
  x = (x << 8) + file[pos+3];
  if (x & 0x80000000) {
    x |= ~0xffffffff;
  }
  return x;
}

unsigned int FoFiBase::getU32BE(int pos, bool *ok) const {
  unsigned int x;

  if (pos < 0 || pos+3 >= len || pos > INT_MAX - 3) {
    *ok = false;
    return 0;
  }
  x = file[pos];
  x = (x << 8) + file[pos+1];
  x = (x << 8) + file[pos+2];
  x = (x << 8) + file[pos+3];
  return x;
}

unsigned int FoFiBase::getU32LE(int pos, bool *ok) const {
  unsigned int x;

  if (pos < 0 || pos+3 >= len || pos > INT_MAX - 3) {
    *ok = false;
    return 0;
  }
  x = file[pos+3];
  x = (x << 8) + file[pos+2];
  x = (x << 8) + file[pos+1];
  x = (x << 8) + file[pos];
  return x;
}

unsigned int FoFiBase::getUVarBE(int pos, int size, bool *ok) const {
  unsigned int x;
  int i;

  if (pos < 0 || pos + size > len || pos > INT_MAX - size) {
    *ok = false;
    return 0;
  }
  x = 0;
  for (i = 0; i < size; ++i) {
    x = (x << 8) + file[pos + i];
  }
  return x;
}

bool FoFiBase::checkRegion(int pos, int size) const {
  return pos >= 0 &&
         pos < INT_MAX - size &&
         size < INT_MAX - pos &&
         pos + size >= pos &&
         pos + size <= len;
}