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Diffstat (limited to 'lib/kaitai/kaitaistream.h')
-rwxr-xr-x | lib/kaitai/kaitaistream.h | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/lib/kaitai/kaitaistream.h b/lib/kaitai/kaitaistream.h new file mode 100755 index 0000000000..9592771db0 --- /dev/null +++ b/lib/kaitai/kaitaistream.h @@ -0,0 +1,250 @@ +#ifndef KAITAI_STREAM_H +#define KAITAI_STREAM_H + +// Kaitai Struct runtime API version: x.y.z = 'xxxyyyzzz' decimal +#define KAITAI_STRUCT_VERSION 7000L + +#include <istream> +#include <sstream> +#include <stdint.h> +#include <sys/types.h> + +namespace kaitai { + +/** + * Kaitai Stream class (kaitai::kstream) is an implementation of + * <a href="https://github.com/kaitai-io/kaitai_struct/wiki/Kaitai-Struct-stream-API">Kaitai Struct stream API</a> + * for C++/STL. It's implemented as a wrapper over generic STL std::istream. + * + * It provides a wide variety of simple methods to read (parse) binary + * representations of primitive types, such as integer and floating + * point numbers, byte arrays and strings, and also provides stream + * positioning / navigation methods with unified cross-language and + * cross-toolkit semantics. + * + * Typically, end users won't access Kaitai Stream class manually, but would + * describe a binary structure format using .ksy language and then would use + * Kaitai Struct compiler to generate source code in desired target language. + * That code, in turn, would use this class and API to do the actual parsing + * job. + */ +class kstream { +public: + /** + * Constructs new Kaitai Stream object, wrapping a given std::istream. + * \param io istream object to use for this Kaitai Stream + */ + kstream(std::istream* io); + + /** + * Constructs new Kaitai Stream object, wrapping a given in-memory data + * buffer. + * \param data data buffer to use for this Kaitai Stream + */ + kstream(std::string& data); + + void close(); + + /** @name Stream positioning */ + //@{ + /** + * Check if stream pointer is at the end of stream. Note that the semantics + * are different from traditional STL semantics: one does *not* need to do a + * read (which will fail) after the actual end of the stream to trigger EOF + * flag, which can be accessed after that read. It is sufficient to just be + * at the end of the stream for this method to return true. + * \return "true" if we are located at the end of the stream. + */ + bool is_eof() const; + + /** + * Set stream pointer to designated position. + * \param pos new position (offset in bytes from the beginning of the stream) + */ + void seek(uint64_t pos); + + /** + * Get current position of a stream pointer. + * \return pointer position, number of bytes from the beginning of the stream + */ + uint64_t pos(); + + /** + * Get total size of the stream in bytes. + * \return size of the stream in bytes + */ + uint64_t size(); + //@} + + /** @name Integer numbers */ + //@{ + + // ------------------------------------------------------------------------ + // Signed + // ------------------------------------------------------------------------ + + int8_t read_s1(); + + // ........................................................................ + // Big-endian + // ........................................................................ + + int16_t read_s2be(); + int32_t read_s4be(); + int64_t read_s8be(); + + // ........................................................................ + // Little-endian + // ........................................................................ + + int16_t read_s2le(); + int32_t read_s4le(); + int64_t read_s8le(); + + // ------------------------------------------------------------------------ + // Unsigned + // ------------------------------------------------------------------------ + + uint8_t read_u1(); + + // ........................................................................ + // Big-endian + // ........................................................................ + + uint16_t read_u2be(); + uint32_t read_u4be(); + uint64_t read_u8be(); + + // ........................................................................ + // Little-endian + // ........................................................................ + + uint16_t read_u2le(); + uint32_t read_u4le(); + uint64_t read_u8le(); + + //@} + + /** @name Floating point numbers */ + //@{ + + // ........................................................................ + // Big-endian + // ........................................................................ + + float read_f4be(); + double read_f8be(); + + // ........................................................................ + // Little-endian + // ........................................................................ + + float read_f4le(); + double read_f8le(); + + //@} + + /** @name Unaligned bit values */ + //@{ + + void align_to_byte(); + uint64_t read_bits_int(int n); + + //@} + + /** @name Byte arrays */ + //@{ + + std::string read_bytes(std::streamsize len); + std::string read_bytes_full(); + std::string read_bytes_term(char term, bool include, bool consume, bool eos_error); + std::string ensure_fixed_contents(std::string expected); + + static std::string bytes_strip_right(std::string src, char pad_byte); + static std::string bytes_terminate(std::string src, char term, bool include); + static std::string bytes_to_str(std::string src, std::string src_enc); + + //@} + + /** @name Byte array processing */ + //@{ + + /** + * Performs a XOR processing with given data, XORing every byte of input with a single + * given value. + * @param data data to process + * @param key value to XOR with + * @return processed data + */ + static std::string process_xor_one(std::string data, uint8_t key); + + /** + * Performs a XOR processing with given data, XORing every byte of input with a key + * array, repeating key array many times, if necessary (i.e. if data array is longer + * than key array). + * @param data data to process + * @param key array of bytes to XOR with + * @return processed data + */ + static std::string process_xor_many(std::string data, std::string key); + + /** + * Performs a circular left rotation shift for a given buffer by a given amount of bits, + * using groups of 1 bytes each time. Right circular rotation should be performed + * using this procedure with corrected amount. + * @param data source data to process + * @param amount number of bits to shift by + * @return copy of source array with requested shift applied + */ + static std::string process_rotate_left(std::string data, int amount); + +#ifdef KS_ZLIB + /** + * Performs an unpacking ("inflation") of zlib-compressed data with usual zlib headers. + * @param data data to unpack + * @return unpacked data + * @throws IOException + */ + static std::string process_zlib(std::string data); +#endif + + //@} + + /** + * Performs modulo operation between two integers: dividend `a` + * and divisor `b`. Divisor `b` is expected to be positive. The + * result is always 0 <= x <= b - 1. + */ + static int mod(int a, int b); + + /** + * Converts given integer `val` to a decimal string representation. + * Should be used in place of std::to_string() (which is available only + * since C++11) in older C++ implementations. + */ + static std::string to_string(int val); + + /** + * Reverses given string `val`, so that the first character becomes the + * last and the last one becomes the first. This should be used to avoid + * the need of local variables at the caller. + */ + static std::string reverse(std::string val); + +private: + std::istream* m_io; + std::istringstream m_io_str; + int m_bits_left; + uint64_t m_bits; + + void init(); + void exceptions_enable() const; + + static uint64_t get_mask_ones(int n); + + static const int ZLIB_BUF_SIZE = 128 * 1024; +}; + +} + +#endif |