--- /dev/null
+/**
+ * \file lzma/stream_flags.h
+ * \brief .xz Stream Header and Stream Footer encoder and decoder
+ */
+
+/*
+ * Author: Lasse Collin
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ *
+ * See ../lzma.h for information about liblzma as a whole.
+ */
+
+#ifndef LZMA_H_INTERNAL
+# error Never include this file directly. Use <lzma.h> instead.
+#endif
+
+
+/**
+ * \brief Size of Stream Header and Stream Footer
+ *
+ * Stream Header and Stream Footer have the same size and they are not
+ * going to change even if a newer version of the .xz file format is
+ * developed in future.
+ */
+#define LZMA_STREAM_HEADER_SIZE 12
+
+
+/**
+ * \brief Options for encoding/decoding Stream Header and Stream Footer
+ */
+typedef struct {
+ /**
+ * \brief Stream Flags format version
+ *
+ * To prevent API and ABI breakages if new features are needed in
+ * Stream Header or Stream Footer, a version number is used to
+ * indicate which fields in this structure are in use. For now,
+ * version must always be zero. With non-zero version, the
+ * lzma_stream_header_encode() and lzma_stream_footer_encode()
+ * will return LZMA_OPTIONS_ERROR.
+ *
+ * lzma_stream_header_decode() and lzma_stream_footer_decode()
+ * will always set this to the lowest value that supports all the
+ * features indicated by the Stream Flags field. The application
+ * must check that the version number set by the decoding functions
+ * is supported by the application. Otherwise it is possible that
+ * the application will decode the Stream incorrectly.
+ */
+ uint32_t version;
+
+ /**
+ * \brief Backward Size
+ *
+ * Backward Size must be a multiple of four bytes. In this Stream
+ * format version, Backward Size is the size of the Index field.
+ *
+ * Backward Size isn't actually part of the Stream Flags field, but
+ * it is convenient to include in this structure anyway. Backward
+ * Size is present only in the Stream Footer. There is no need to
+ * initialize backward_size when encoding Stream Header.
+ *
+ * lzma_stream_header_decode() always sets backward_size to
+ * LZMA_VLI_UNKNOWN so that it is convenient to use
+ * lzma_stream_flags_compare() when both Stream Header and Stream
+ * Footer have been decoded.
+ */
+ lzma_vli backward_size;
+# define LZMA_BACKWARD_SIZE_MIN 4
+# define LZMA_BACKWARD_SIZE_MAX (LZMA_VLI_C(1) << 34)
+
+ /**
+ * \brief Check ID
+ *
+ * This indicates the type of the integrity check calculated from
+ * uncompressed data.
+ */
+ lzma_check check;
+
+ /*
+ * Reserved space to allow possible future extensions without
+ * breaking the ABI. You should not touch these, because the
+ * names of these variables may change.
+ *
+ * (We will never be able to use all of these since Stream Flags
+ * is just two bytes plus Backward Size of four bytes. But it's
+ * nice to have the proper types when they are needed.)
+ */
+ lzma_reserved_enum reserved_enum1;
+ lzma_reserved_enum reserved_enum2;
+ lzma_reserved_enum reserved_enum3;
+ lzma_reserved_enum reserved_enum4;
+ lzma_bool reserved_bool1;
+ lzma_bool reserved_bool2;
+ lzma_bool reserved_bool3;
+ lzma_bool reserved_bool4;
+ lzma_bool reserved_bool5;
+ lzma_bool reserved_bool6;
+ lzma_bool reserved_bool7;
+ lzma_bool reserved_bool8;
+ uint32_t reserved_int1;
+ uint32_t reserved_int2;
+
+} lzma_stream_flags;
+
+
+/**
+ * \brief Encode Stream Header
+ *
+ * \param options Stream Header options to be encoded.
+ * options->backward_size is ignored and doesn't
+ * need to be initialized.
+ * \param out Beginning of the output buffer of
+ * LZMA_STREAM_HEADER_SIZE bytes.
+ *
+ * \return - LZMA_OK: Encoding was successful.
+ * - LZMA_OPTIONS_ERROR: options->version is not supported by
+ * this liblzma version.
+ * - LZMA_PROG_ERROR: Invalid options.
+ */
+extern LZMA_API(lzma_ret) lzma_stream_header_encode(
+ const lzma_stream_flags *options, uint8_t *out)
+ lzma_nothrow lzma_attr_warn_unused_result;
+
+
+/**
+ * \brief Encode Stream Footer
+ *
+ * \param options Stream Footer options to be encoded.
+ * \param out Beginning of the output buffer of
+ * LZMA_STREAM_HEADER_SIZE bytes.
+ *
+ * \return - LZMA_OK: Encoding was successful.
+ * - LZMA_OPTIONS_ERROR: options->version is not supported by
+ * this liblzma version.
+ * - LZMA_PROG_ERROR: Invalid options.
+ */
+extern LZMA_API(lzma_ret) lzma_stream_footer_encode(
+ const lzma_stream_flags *options, uint8_t *out)
+ lzma_nothrow lzma_attr_warn_unused_result;
+
+
+/**
+ * \brief Decode Stream Header
+ *
+ * \param options Target for the decoded Stream Header options.
+ * \param in Beginning of the input buffer of
+ * LZMA_STREAM_HEADER_SIZE bytes.
+ *
+ * options->backward_size is always set to LZMA_VLI_UNKNOWN. This is to
+ * help comparing Stream Flags from Stream Header and Stream Footer with
+ * lzma_stream_flags_compare().
+ *
+ * \return - LZMA_OK: Decoding was successful.
+ * - LZMA_FORMAT_ERROR: Magic bytes don't match, thus the given
+ * buffer cannot be Stream Header.
+ * - LZMA_DATA_ERROR: CRC32 doesn't match, thus the header
+ * is corrupt.
+ * - LZMA_OPTIONS_ERROR: Unsupported options are present
+ * in the header.
+ *
+ * \note When decoding .xz files that contain multiple Streams, it may
+ * make sense to print "file format not recognized" only if
+ * decoding of the Stream Header of the _first_ Stream gives
+ * LZMA_FORMAT_ERROR. If non-first Stream Header gives
+ * LZMA_FORMAT_ERROR, the message used for LZMA_DATA_ERROR is
+ * probably more appropriate.
+ *
+ * For example, Stream decoder in liblzma uses LZMA_DATA_ERROR if
+ * LZMA_FORMAT_ERROR is returned by lzma_stream_header_decode()
+ * when decoding non-first Stream.
+ */
+extern LZMA_API(lzma_ret) lzma_stream_header_decode(
+ lzma_stream_flags *options, const uint8_t *in)
+ lzma_nothrow lzma_attr_warn_unused_result;
+
+
+/**
+ * \brief Decode Stream Footer
+ *
+ * \param options Target for the decoded Stream Header options.
+ * \param in Beginning of the input buffer of
+ * LZMA_STREAM_HEADER_SIZE bytes.
+ *
+ * \return - LZMA_OK: Decoding was successful.
+ * - LZMA_FORMAT_ERROR: Magic bytes don't match, thus the given
+ * buffer cannot be Stream Footer.
+ * - LZMA_DATA_ERROR: CRC32 doesn't match, thus the Stream Footer
+ * is corrupt.
+ * - LZMA_OPTIONS_ERROR: Unsupported options are present
+ * in Stream Footer.
+ *
+ * \note If Stream Header was already decoded successfully, but
+ * decoding Stream Footer returns LZMA_FORMAT_ERROR, the
+ * application should probably report some other error message
+ * than "file format not recognized", since the file more likely
+ * is corrupt (possibly truncated). Stream decoder in liblzma
+ * uses LZMA_DATA_ERROR in this situation.
+ */
+extern LZMA_API(lzma_ret) lzma_stream_footer_decode(
+ lzma_stream_flags *options, const uint8_t *in)
+ lzma_nothrow lzma_attr_warn_unused_result;
+
+
+/**
+ * \brief Compare two lzma_stream_flags structures
+ *
+ * backward_size values are compared only if both are not
+ * LZMA_VLI_UNKNOWN.
+ *
+ * \return - LZMA_OK: Both are equal. If either had backward_size set
+ * to LZMA_VLI_UNKNOWN, backward_size values were not
+ * compared or validated.
+ * - LZMA_DATA_ERROR: The structures differ.
+ * - LZMA_OPTIONS_ERROR: version in either structure is greater
+ * than the maximum supported version (currently zero).
+ * - LZMA_PROG_ERROR: Invalid value, e.g. invalid check or
+ * backward_size.
+ */
+extern LZMA_API(lzma_ret) lzma_stream_flags_compare(
+ const lzma_stream_flags *a, const lzma_stream_flags *b)
+ lzma_nothrow lzma_attr_pure;
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