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#include "Archive.h"
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <memory>
#include <vector>
#include <zlib.h>
namespace Archive
{
using UniqueFileHandle = std::unique_ptr<std::FILE, decltype(&std::fclose)>;
static inline std::size_t BytesToBlocks(std::size_t bytes);
static inline std::size_t ConvertPathSeparator(const char* src, char* dest);
static constexpr std::uint32_t VERSION {0x0010};
static constexpr std::size_t BLOCK_SIZE {1024};
static constexpr std::size_t DIRECTORY_MARGIN {64};
static constexpr int UNUSED_BLOCK {-1};
static constexpr int DIRECTORY_BLOCK {-2};
Archive::Archive(const char* p) :
path {p},
header {},
entries {}
{
UniqueFileHandle file {std::fopen(path, "rb"), &std::fclose};
if (!file)
throw "could not open archive";
std::size_t length = std::fread(&header, sizeof(Header), 1, file.get());
if (1 != length)
throw "could not read";
if (VERSION != header.version)
throw "bad version";
int err = std::fseek(file.get(), sizeof(Header) + header.directory.offset, SEEK_SET);
if (-1 == err)
throw "could not find directory in archive";
std::vector<Bytef> compressed(header.directory.compressed_size);
length = std::fread(compressed.data(), 1, header.directory.compressed_size, file.get());
if (header.directory.compressed_size != length)
throw "could not read compressed directory";
const std::size_t total_entries = header.total_entries + DIRECTORY_MARGIN;
entries.resize(header.total_entries);
entries.reserve(total_entries); // In original impl entries were switched on/off with their uncompressed size value.
uLongf uncompressed_size = sizeof(Entry) * total_entries;
err = uncompress(
reinterpret_cast<Bytef*>(entries.data()),
&uncompressed_size,
compressed.data(),
header.directory.compressed_size);
if (Z_OK != err)
throw "could not uncompress directory";
UpdateBlockMap();
}
int
Archive::Expand(const int index, std::uint8_t*& buffer, const bool null_terminated) const
{
if (0 > index && static_cast<int>(header.total_entries) <= index)
return -1; // Can be replaced by error-checked access to std::vector holding entries.
UniqueFileHandle file {std::fopen(path, "rb"), &std::fclose};
if (!file)
return -1;
const auto& entry = entries[index];
std::vector<Bytef> compressed(entry.compressed_size);
int err = std::fseek(file.get(), sizeof(Header) + entry.offset, SEEK_SET);
if (-1 == err)
return -1;
const std::size_t length = std::fread(compressed.data(), 1, entry.compressed_size, file.get());
if (entry.compressed_size != length)
return -1;
uLongf output_length = entry.original_size + static_cast<uLongf>(null_terminated);
auto uncompressed = std::make_unique<std::uint8_t[]>(output_length);
err = uncompress(uncompressed.get(), &output_length, compressed.data(), entry.compressed_size);
if (Z_OK != err)
return -1;
buffer = uncompressed.release();
if (null_terminated)
buffer[output_length - 1] = 0;
return output_length;
}
int
Archive::Expand(const char* filepath, std::uint8_t*& buffer, const bool null_terminated) const
{
const int index = Find(filepath);
if (-1 == index)
return -1;
return Expand(index, buffer, null_terminated);
}
int
Archive::Find(const char* filepath) const
{
std::vector<char> path(std::strlen(filepath) + 1);
ConvertPathSeparator(filepath, path.data());
for (std::size_t i = 0; i < entries.size(); ++i) {
if (0 == std::strcmp(entries[i].name, path.data()))
return i;
}
return -1;
}
void
Archive::UpdateBlockMap()
{
const std::size_t last_directory_block = header.directory.offset / BLOCK_SIZE + DirectoryBlocks() - 1;
std::size_t last_block = last_directory_block;
for (const auto& entry : entries) {
const std::size_t block = entry.offset / BLOCK_SIZE + BytesToBlocks(entry.compressed_size) - 1;
if (last_block < block)
last_block = block;
}
blocks.clear();
blocks.resize(last_block + 1, UNUSED_BLOCK);
for (std::size_t n = header.directory.offset / BLOCK_SIZE; n <= last_directory_block; ++n)
blocks[n] = DIRECTORY_BLOCK;
for (std::size_t i = 0; i < entries.size(); ++i) {
const std::size_t from = entries[i].offset / BLOCK_SIZE;
const std::size_t exclusive_to = from + BytesToBlocks(entries[i].compressed_size);
for (std::size_t n = from; n < exclusive_to; ++n)
blocks[n] = i;
}
}
void
Archive::PrintNamesOfEntries() const
{
for (const auto& entry : entries)
std::printf("%s\n", entry.name);
}
void
Archive::PrintBlocks() const
{
for (std::size_t i = 0; i < blocks.size(); ++i) {
std::printf("%ld\t", i);
switch (blocks[i]) {
case UNUSED_BLOCK:
std::printf("(unused)\n");
break;
case DIRECTORY_BLOCK:
std::printf("(dir)\n");
break;
default:
std::printf("%s\n", entries[blocks[i]].name);
}
}
}
std::size_t
Archive::DirectoryBlocks() const
{
const std::size_t blocks = BytesToBlocks(header.total_entries * sizeof(Entry));
return blocks == 0 ? 1 : blocks;
}
std::size_t
BytesToBlocks(const std::size_t bytes)
{
const std::size_t full = bytes / BLOCK_SIZE;
const std::size_t partial = (bytes % BLOCK_SIZE) > 0;
return full + partial;
}
std::size_t
ConvertPathSeparator(const char* src, char* dest)
{
std::size_t i;
for (i = 0; 0 != src[i]; ++i) {
if ('\\' == src[i])
dest[i] = '/';
else
dest[i] = src[i];
}
return i;
}
} // namespace Archive
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