Polish the streambuffer API a bit
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@@ -237,6 +237,130 @@ public:
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};
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class StreamBuffer {
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public:
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// Construct an empty buffer.
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StreamBuffer();
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// Construct an empty buffer, preallocate the specified amount of space.
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StreamBuffer(int64_t size, bool fixed_size);
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// Construct a streambuffer that reads from an external block of bytes.
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StreamBuffer(const char *s, int64_t len);
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// Delete a StreamBuffer.
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~StreamBuffer();
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// Get the total number of bytes ever read from this buffer.
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int64_t read_count() const;
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// Get the total number of bytes ever written to this buffer.
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int64_t write_count() const;
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// Delete all data and (if not fixed-size) free the buffer.
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// Also resets the read and write counts.
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void clear();
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// Write block of bytes into the buffer.
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//
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// Caution: this function doesn't write the length!
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// It just writes the bytes.
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//
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void write_bytes(const char *bytes, int64_t len);
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// Read a block of bytes from the buffer.
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//
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// May throw StreamEof if the specified number of bytes aren't present.
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//
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const char *read_bytes(int64_t bytes);
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// Write integers and floats into the buffer.
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//
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// Note that integral parameters are all 64 bits. That's so that I can do
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// runtime error checking to verify that the numbers are all in-range.
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//
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void write_int8(int64_t v);
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void write_int16(int64_t v);
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void write_int32(int64_t v);
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void write_int64(int64_t v);
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void write_uint8(uint64_t v);
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void write_uint16(uint64_t v);
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void write_uint32(uint64_t v);
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void write_uint64(uint64_t v);
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void write_float(float f);
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void write_double(double d);
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// Read fixed-size integers from the buffer.
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//
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// May throw StreamEof if the specified number of bytes aren't present.
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//
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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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uint8_t read_uint8() { return read_int8(); }
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uint16_t read_uint16() { return read_int16(); }
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uint32_t read_uint32() { return read_int32(); }
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uint64_t read_uint64() { return read_int64(); }
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float read_float();
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double read_double();
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// Write other types into the buffer.
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//
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// Note that strings are preceded by a length field. Reading
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// a string works by reading the length field, and then reading
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// the correct number of bytes.
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//
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void write_bool(bool b) { write_int8(b ? 1 : 0); }
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void write_hashvalue(const util::HashValue &hv);
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void write_string(const std::string &s);
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// Read other types from the buffer.
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//
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// May throw StreamEof if the specified number of bytes aren't present.
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// Read string with a length limit will throw 'StreamCorruption' if the
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// length is too long.
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//
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bool read_bool() { return read_int8(); }
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util::HashValue read_hashvalue();
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std::string read_string();
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std::string read_string_limit(int64_t max_allowed);
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// Overwrite values previously written to the buffer.
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//
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// See the comment at the top of this file for an explanation.
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//
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void overwrite_int8(int64_t write_count_after, int64_t v);
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void overwrite_int16(int64_t write_count_after, int64_t v);
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void overwrite_int32(int64_t write_count_after, int64_t v);
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void overwrite_int64(int64_t write_count_after, int64_t v);
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void overwrite_uint8(int64_t write_count_after, uint64_t v);
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void overwrite_uint16(int64_t write_count_after, uint64_t v);
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void overwrite_uint32(int64_t write_count_after, uint64_t v);
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void overwrite_uint64(int64_t write_count_after, uint64_t v);
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// Return true if the buffer is empty.
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bool at_eof();
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// Verify that the buffer is empty, if not, throw StreamCorruption.
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void verify_eof();
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// Rewind the read cursor to a previous position.
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void unread_to(int64_t read_count);
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// Rewind the write cursor to a previous position.
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void unwrite_to(int64_t write_count);
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// Calculate a noncryptographic but good hash of what's in the buffer.
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util::HashValue hash() const;
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// Use the stream buffer 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();
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// Use the stream buffer as a lua_Reader.
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static const char *lua_reader(lua_State *L, void *data, size_t *size);
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void *lua_reader_ud(int64_t bytes);
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private:
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// Start and end of the allocated block.
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char *buf_lo_;
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@@ -280,115 +404,10 @@ private:
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// Implementation for the overwrite_int functions.
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char *get_overwrite(int64_t size, int64_t write_count_after);
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// This is mainly for unit testing.
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// This is for unit testing.
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bool layout_is(int64_t a, int64_t b, int64_t c);
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friend int unittests_streambuffer(lua_State *L);
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public:
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// Construct an empty buffer.
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StreamBuffer();
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// Construct an empty buffer, preallocate the specified amount of space.
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StreamBuffer(int64_t size, bool fixed_size);
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// Construct a streambuffer that reads from an external block of bytes.
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StreamBuffer(const char *s, int64_t len);
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// Delete a StreamBuffer.
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~StreamBuffer();
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// Get the total number of bytes ever read from this buffer.
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int64_t read_count() const;
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// Get the total number of bytes ever written to this buffer.
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int64_t write_count() const;
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// Delete all data and (if not fixed-size) free the buffer.
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// Also resets the read and write counts.
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void clear();
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// Alloc_space and wrote_space need to be invoked together.
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char *alloc_space(int64_t bytes);
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void wrote_space(int64_t bytes);
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// Write numbers into the buffer.
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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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void write_float(float f);
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void write_double(double d);
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void write_hashvalue(const util::HashValue &hv);
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void write_uint8(uint8_t v) { write_int8(v); }
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void write_uint16(uint16_t v) { write_int16(v); }
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void write_uint32(uint32_t v) { write_int32(v); }
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void write_uint64(uint64_t v) { write_int64(v); }
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void write_size(size_t sz) { write_int64(sz); }
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void write_bool(bool b) { write_int8(b ? 1 : 0); }
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// Write strings or blocks of bytes into the buffer.
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void write_string(const std::string &s);
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void write_bytes(const char *bytes, int64_t len);
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void write_ztbytes(const char *bytes);
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// Overwrite values previously written to the buffer.
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void overwrite_int8(int64_t write_count_after, int8_t v);
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void overwrite_int16(int64_t write_count_after, int16_t v);
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void overwrite_int32(int64_t write_count_after, int32_t v);
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void overwrite_int64(int64_t write_count_after, int64_t v);
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void overwrite_uint8(int64_t write_count_after, uint8_t v) { overwrite_int8(write_count_after, v); }
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void overwrite_uint16(int64_t write_count_after, uint16_t v) { overwrite_int16(write_count_after, v); }
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void overwrite_uint32(int64_t write_count_after, uint32_t v) { overwrite_int32(write_count_after, v); }
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void overwrite_uint64(int64_t write_count_after, uint64_t v) { overwrite_int64(write_count_after, v); }
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// Read numbers from the buffer. May throw StreamEof.
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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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float read_float();
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double read_double();
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util::HashValue read_hashvalue();
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uint8_t read_uint8() { return read_int8(); }
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uint16_t read_uint16() { return read_int16(); }
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uint32_t read_uint32() { return read_int32(); }
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uint64_t read_uint64() { return read_int64(); }
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bool read_bool() { return read_int8(); }
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// May throw StreamEof or StreamCorruption.
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size_t read_size();
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size_t read_size_limit(size_t limit);
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// Read a string of no more than the specified length.
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// May throw StreamEof or StreamCorruption.
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std::string read_string();
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std::string read_string_limit(int64_t max_allowed);
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// Read a block of bytes. May throw StreamEof.
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const char *read_bytes(int64_t bytes);
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// Return true if the buffer is empty.
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bool at_eof();
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// Verify that the buffer is empty, if not, throw StreamCorruption.
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void verify_eof();
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// Rewind the read cursor to a previous position.
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void unread_to(int64_t read_count);
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// Rewind the write cursor to a previous position.
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void unwrite_to(int64_t write_count);
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// Calculate a noncryptographic but good hash of what's in the buffer.
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util::HashValue hash() const;
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// Use the stream buffer 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();
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// Use the stream buffer as a lua_Reader.
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static const char *lua_reader(lua_State *L, void *data, size_t *size);
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void *lua_reader_ud(int64_t bytes);
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};
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