73 lines
2.0 KiB
C++
73 lines
2.0 KiB
C++
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#ifndef PACKER_HPP
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#define PACKER_HPP
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#include "luastack.hpp"
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#include <cstdint>
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#include <string>
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#include <sstream>
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#include <cassert>
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class Packer {
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private:
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std::ostringstream *oss_;
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// Packer is not copyable.
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Packer(const Packer &other) { assert(false); }
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public:
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using fixhandle = size_t;
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Packer(std::ostringstream *s) : oss_(s) {}
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// Get the current file position.
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size_t tellp() { return oss_->tellp(); }
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void write_int8(int8_t v);
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void write_int16(int16_t v);
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void write_int32(int32_t v);
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void write_int64(int64_t v);
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// Sometimes, you want to write a length followed by a block of data.
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// Sometimes, you don't know the length until after you've written the block
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// of data. To help with this situation, we provide the overwrite_int
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// functions. Here's what you do:
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//
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// 1. write a dummy length into the stream.
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// 2. use 'tellp' to fetch the stream position *after* the dummy length.
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// 3. write the block of data.
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// 4. use an overwrite function below to overwrite the dummy length.
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//
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void overwrite_int8(size_t tell_after, int8_t value);
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void overwrite_int16(size_t tell_after, int16_t value);
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void overwrite_int32(size_t tell_after, int32_t value);
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void overwrite_int64(size_t tell_after, int64_t value);
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// The packer can be used as a lua_Writer.
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static int lua_writer(lua_State *L, const void *p, size_t sz, void *ud);
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void *lua_writer_ud() { return this; }
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};
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class Unpacker {
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private:
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const char *data_;
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size_t size_;
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public:
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Unpacker(const char *d, size_t s);
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const char *data() { return data_; }
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size_t size() { return size_; }
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int8_t read_int8();
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int16_t read_int16();
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int32_t read_int32();
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int64_t read_int64();
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void skip(size_t n);
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Unpacker read_section(size_t n);
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// The unpacker can be used as a lua_Reader
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static const char *lua_reader(lua_State *L, void *ud, size_t *size);
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void *lua_reader_ud() { return this; }
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};
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#endif // PACKER_HPP
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