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Fix for last block is not multiple of blocksize #84

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Fix for last block is not multiple of blocksize #84

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27 changes: 22 additions & 5 deletions src/zsmake.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -102,16 +102,18 @@ namespace zsync2 {
bool writeBlockSums(const buffer_t& buffer, size_t bytesRead) {
buffer_t checksum(CHECKSUM_SIZE);

// add padding to last block
if (bytesRead < blockSize)
std::fill(checksum.begin() + bytesRead, checksum.end(), 0);
// Create a copy of the buffer for processing, padding it to blockSize if needed
buffer_t padded_buffer(buffer.begin(), buffer.begin() + bytesRead);
if (bytesRead < blockSize) {
padded_buffer.resize(blockSize, 0); // pad with zeros to reach blockSize
}

// sometimes, the inconsistent use of char and unsigned char within the old zsync code base can get
// annoying...
auto r = rcksum_calc_rsum_block(reinterpret_cast<const unsigned char*>(buffer.data()), blockSize);
auto r = rcksum_calc_rsum_block(reinterpret_cast<const unsigned char*>(padded_buffer.data()), blockSize);
rcksum_calc_checksum(
reinterpret_cast<unsigned char*>(checksum.data()),
reinterpret_cast<const unsigned char*>(buffer.data()),
reinterpret_cast<const unsigned char*>(padded_buffer.data()),
blockSize
);
r.a = htons(r.a);
Expand Down Expand Up @@ -152,6 +154,21 @@ namespace zsync2 {
}
}

// Handle the last partial block if any data was read but stream hit EOF
if (inFile.eof()) {
auto bytesRead = (size_t) inFile.gcount();
if (bytesRead > 0) {
SHA1Update(&sha1Ctx, reinterpret_cast<const uint8_t*>(buffer.data()), bytesRead);
writeBlockSums(buffer, bytesRead);
length += bytesRead;
}
} else if (inFile.fail() || inFile.bad()) {
auto error = errno;
std::string messagePrefix = "Failed to calculate block sums: ";
logMessage(messagePrefix + strerror(error));
return false;
}

return true;
}

Expand Down