size_t ZipFile::findCentralDirectoryEnd(SeekableReadStream &zip) {
const size_t uSizeFile = zip.size();
const size_t uMaxBack = MIN<size_t>(0xFFFF, uSizeFile); // Maximum size of global comment
byte buf[BUFREADCOMMENT + 4];
size_t uPosFound = 0;
size_t uBackRead = 4;
while ((uPosFound == 0) && (uBackRead < uMaxBack)) {
uBackRead = MIN<size_t>(uMaxBack, uBackRead + BUFREADCOMMENT);
const size_t uReadPos = uSizeFile - uBackRead;
const size_t uReadSize = MIN<size_t>(BUFREADCOMMENT + 4, uSizeFile - uReadPos);
try {
zip.seek(uReadPos);
} catch (...) {
return 0;
}
if (zip.read(buf, uReadSize) != uReadSize) {
uPosFound = 0;
break;
}
for (size_t i = (uReadSize - 3); i-- > 0; )
if (READ_LE_UINT32(buf + i) == 0x06054B50) {
uPosFound = uReadPos + i;
break;
}
}
return uPosFound;
}
void printDataHex(SeekableReadStream &stream, size_t size) {
size_t pos = stream.pos();
size = MIN<size_t>(stream.size() - pos, size);
if (size == 0)
return;
uint32 offset = 0;
byte rowData[16];
while (size > 0) {
// At max 16 bytes printed per row
uint32 n = MIN<size_t>(size, 16);
if (stream.read(rowData, n) != n)
throw Exception(kReadError);
// Print an offset
std::fprintf(stderr, "%08X ", offset);
// 2 "blobs" of each 8 bytes per row
for (uint32 i = 0; i < 2; i++) {
for (uint32 j = 0; j < 8; j++) {
uint32 m = i * 8 + j;
if (m < n)
// Print the data
std::fprintf(stderr, "%02X ", rowData[m]);
else
// Last row, data count not aligned to 16
std::fprintf(stderr, " ");
}
// Separate the blobs by an extra space
std::fprintf(stderr, " ");
}
std::fprintf(stderr, "|");
// If the data byte is a printable character, print it. If not, substitute a '.'
for (uint32 i = 0; i < n; i++)
std::fprintf(stderr, "%c", std::isprint(rowData[i]) ? rowData[i] : '.');
std::fprintf(stderr, "|\n");
size -= n;
offset += n;
}
// Seek back
stream.seek(pos);
}
void StreamTokenizer::nextChunk(SeekableReadStream &stream) {
skipChunk(stream);
byte c = stream.readByte();
if (stream.eos() || stream.err())
return;
if (!isIn(c, _chunkEnds))
stream.seek(-1, SEEK_CUR);
else
if (stream.pos() == stream.size())
// This actually the last character, read one more byte to properly set the EOS state
stream.readByte();
}
size_t searchBackwards(SeekableReadStream &haystack, const byte *needle, size_t needleSize,
size_t maxReadBack) {
if (needleSize == 0 || maxReadBack == 0)
return SIZE_MAX;
assert(maxReadBack >= needleSize);
static const size_t kReadBufferSize = 0x400;
const size_t sizeFile = haystack.size();
const size_t maxBack = MIN<size_t>(maxReadBack, sizeFile);
ScopedArray<byte> buf(new byte[kReadBufferSize + needleSize]);
size_t backRead = needleSize;
while (backRead < maxBack) {
backRead = MIN<size_t>(maxBack, backRead + kReadBufferSize);
const size_t readPos = sizeFile - backRead;
const size_t readSize = MIN<size_t>(kReadBufferSize + needleSize, sizeFile - readPos);
try {
haystack.seek(readPos);
} catch (...) {
break;
}
if (haystack.read(buf.get(), readSize) != readSize)
break;
for (size_t i = (readSize - (needleSize - 1)); i-- > 0; )
if (!memcmp(buf.get() + i, needle, needleSize))
return readPos + i;
}
return SIZE_MAX;
}
