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// Copyright 2002 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Author: Neal Cardwell
//
#include "sparse_matmul/zlib_wrapper/gzipheader.h"
#include <algorithm>
#include "absl/base/macros.h"
#include "glog/logging.h"
#include "zlib.h" // for Z_DEFAULT_COMPRESSION
namespace csrblocksparse {
const uint8_t GZipHeader::magic[] = {0x1f, 0x8b};
// ----------------------------------------------------------------------
// GZipHeader::ReadMore()
// Attempt to parse the beginning of the given buffer as a gzip
// header. If these bytes do not constitute a complete gzip header,
// return INCOMPLETE_HEADER. If these bytes do not constitute a
// *valid* gzip header, return INVALID_HEADER. If we find a
// complete header, return COMPLETE_HEADER and set the pointer
// pointed to by header_end to the first byte beyond the gzip header.
// ----------------------------------------------------------------------
GZipHeader::Status GZipHeader::ReadMore(const char* inbuf, int inbuf_len,
const char** header_end) {
CHECK_GE(inbuf_len, 0);
const uint8_t* pos = reinterpret_cast<const uint8_t*>(inbuf);
const uint8_t* const end = pos + inbuf_len;
while (pos < end) {
switch (state_) {
case IN_HEADER_ID1:
if (*pos != magic[0]) return INVALID_HEADER;
pos++;
state_++;
break;
case IN_HEADER_ID2:
if (*pos != magic[1]) return INVALID_HEADER;
pos++;
state_++;
break;
case IN_HEADER_CM:
if (*pos != Z_DEFLATED) return INVALID_HEADER;
pos++;
state_++;
break;
case IN_HEADER_FLG:
flags_ =
(*pos) & (FLAG_FHCRC | FLAG_FEXTRA | FLAG_FNAME | FLAG_FCOMMENT);
pos++;
state_++;
break;
case IN_HEADER_MTIME_BYTE_0:
pos++;
state_++;
break;
case IN_HEADER_MTIME_BYTE_1:
pos++;
state_++;
break;
case IN_HEADER_MTIME_BYTE_2:
pos++;
state_++;
break;
case IN_HEADER_MTIME_BYTE_3:
pos++;
state_++;
break;
case IN_HEADER_XFL:
pos++;
state_++;
break;
case IN_HEADER_OS:
pos++;
state_++;
break;
case IN_XLEN_BYTE_0:
if (!(flags_ & FLAG_FEXTRA)) {
state_ = IN_FNAME;
break;
}
// We have a two-byte little-endian length, followed by a
// field of that length.
extra_length_ = *pos;
pos++;
state_++;
break;
case IN_XLEN_BYTE_1:
extra_length_ += *pos << 8;
pos++;
state_++;
// If we have a zero-length FEXTRA, we want to check to notice that
// we're done reading the FEXTRA before we exit this loop...
ABSL_FALLTHROUGH_INTENDED;
case IN_FEXTRA: {
// Grab the rest of the bytes in the extra field, or as many
// of them as are actually present so far.
const int num_extra_bytes = std::min<int>(extra_length_, (end - pos));
pos += num_extra_bytes;
extra_length_ -= num_extra_bytes;
if (extra_length_ == 0) {
state_ = IN_FNAME; // advance when we've seen extra_length_ bytes
flags_ &= ~FLAG_FEXTRA; // we're done with the FEXTRA stuff
}
break;
}
case IN_FNAME:
if (!(flags_ & FLAG_FNAME)) {
state_ = IN_FCOMMENT;
break;
}
// See if we can find the end of the \0-terminated FNAME field.
pos = reinterpret_cast<const uint8_t*>(memchr(pos, '\0', (end - pos)));
if (pos != nullptr) {
pos++; // advance past the '\0'
flags_ &= ~FLAG_FNAME; // we're done with the FNAME stuff
state_ = IN_FCOMMENT;
} else {
pos = end; // everything we have so far is part of the FNAME
}
break;
case IN_FCOMMENT:
if (!(flags_ & FLAG_FCOMMENT)) {
state_ = IN_FHCRC_BYTE_0;
break;
}
// See if we can find the end of the \0-terminated FCOMMENT field.
pos = reinterpret_cast<const uint8_t*>(memchr(pos, '\0', (end - pos)));
if (pos != nullptr) {
pos++; // advance past the '\0'
flags_ &= ~FLAG_FCOMMENT; // we're done with the FCOMMENT stuff
state_ = IN_FHCRC_BYTE_0;
} else {
pos = end; // everything we have so far is part of the FNAME
}
break;
case IN_FHCRC_BYTE_0:
if (!(flags_ & FLAG_FHCRC)) {
state_ = IN_DONE;
break;
}
pos++;
state_++;
break;
case IN_FHCRC_BYTE_1:
pos++;
flags_ &= ~FLAG_FHCRC; // we're done with the FHCRC stuff
state_++;
break;
case IN_DONE:
*header_end = reinterpret_cast<const char*>(pos);
return COMPLETE_HEADER;
}
}
if ((state_ > IN_HEADER_OS) && (flags_ == 0)) {
*header_end = reinterpret_cast<const char*>(pos);
return COMPLETE_HEADER;
} else {
return INCOMPLETE_HEADER;
}
}
} // namespace csrblocksparse
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