--- /dev/null
+/**
+ * \file lzma/vli.h
+ * \brief Variable-length integer handling
+ *
+ * In the .xz format, most integers are encoded in a variable-length
+ * representation, which is sometimes called little endian base-128 encoding.
+ * This saves space when smaller values are more likely than bigger values.
+ *
+ * The encoding scheme encodes seven bits to every byte, using minimum
+ * number of bytes required to represent the given value. Encodings that use
+ * non-minimum number of bytes are invalid, thus every integer has exactly
+ * one encoded representation. The maximum number of bits in a VLI is 63,
+ * thus the vli argument must be less than or equal to UINT64_MAX / 2. You
+ * should use LZMA_VLI_MAX for clarity.
+ */
+
+/*
+ * 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 Maximum supported value of a variable-length integer
+ */
+#define LZMA_VLI_MAX (UINT64_MAX / 2)
+
+/**
+ * \brief VLI value to denote that the value is unknown
+ */
+#define LZMA_VLI_UNKNOWN UINT64_MAX
+
+/**
+ * \brief Maximum supported encoded length of variable length integers
+ */
+#define LZMA_VLI_BYTES_MAX 9
+
+/**
+ * \brief VLI constant suffix
+ */
+#define LZMA_VLI_C(n) UINT64_C(n)
+
+
+/**
+ * \brief Variable-length integer type
+ *
+ * Valid VLI values are in the range [0, LZMA_VLI_MAX]. Unknown value is
+ * indicated with LZMA_VLI_UNKNOWN, which is the maximum value of the
+ * underlaying integer type.
+ *
+ * lzma_vli will be uint64_t for the foreseeable future. If a bigger size
+ * is needed in the future, it is guaranteed that 2 * LZMA_VLI_MAX will
+ * not overflow lzma_vli. This simplifies integer overflow detection.
+ */
+typedef uint64_t lzma_vli;
+
+
+/**
+ * \brief Validate a variable-length integer
+ *
+ * This is useful to test that application has given acceptable values
+ * for example in the uncompressed_size and compressed_size variables.
+ *
+ * \return True if the integer is representable as VLI or if it
+ * indicates unknown value.
+ */
+#define lzma_vli_is_valid(vli) \
+ ((vli) <= LZMA_VLI_MAX || (vli) == LZMA_VLI_UNKNOWN)
+
+
+/**
+ * \brief Encode a variable-length integer
+ *
+ * This function has two modes: single-call and multi-call. Single-call mode
+ * encodes the whole integer at once; it is an error if the output buffer is
+ * too small. Multi-call mode saves the position in *vli_pos, and thus it is
+ * possible to continue encoding if the buffer becomes full before the whole
+ * integer has been encoded.
+ *
+ * \param vli Integer to be encoded
+ * \param vli_pos How many VLI-encoded bytes have already been written
+ * out. When starting to encode a new integer in
+ * multi-call mode, *vli_pos must be set to zero.
+ * To use single-call encoding, set vli_pos to NULL.
+ * \param out Beginning of the output buffer
+ * \param out_pos The next byte will be written to out[*out_pos].
+ * \param out_size Size of the out buffer; the first byte into
+ * which no data is written to is out[out_size].
+ *
+ * \return Slightly different return values are used in multi-call and
+ * single-call modes.
+ *
+ * Single-call (vli_pos == NULL):
+ * - LZMA_OK: Integer successfully encoded.
+ * - LZMA_PROG_ERROR: Arguments are not sane. This can be due
+ * to too little output space; single-call mode doesn't use
+ * LZMA_BUF_ERROR, since the application should have checked
+ * the encoded size with lzma_vli_size().
+ *
+ * Multi-call (vli_pos != NULL):
+ * - LZMA_OK: So far all OK, but the integer is not
+ * completely written out yet.
+ * - LZMA_STREAM_END: Integer successfully encoded.
+ * - LZMA_BUF_ERROR: No output space was provided.
+ * - LZMA_PROG_ERROR: Arguments are not sane.
+ */
+extern LZMA_API(lzma_ret) lzma_vli_encode(lzma_vli vli, size_t *vli_pos,
+ uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow;
+
+
+/**
+ * \brief Decode a variable-length integer
+ *
+ * Like lzma_vli_encode(), this function has single-call and multi-call modes.
+ *
+ * \param vli Pointer to decoded integer. The decoder will
+ * initialize it to zero when *vli_pos == 0, so
+ * application isn't required to initialize *vli.
+ * \param vli_pos How many bytes have already been decoded. When
+ * starting to decode a new integer in multi-call
+ * mode, *vli_pos must be initialized to zero. To
+ * use single-call decoding, set vli_pos to NULL.
+ * \param in Beginning of the input buffer
+ * \param in_pos The next byte will be read from in[*in_pos].
+ * \param in_size Size of the input buffer; the first byte that
+ * won't be read is in[in_size].
+ *
+ * \return Slightly different return values are used in multi-call and
+ * single-call modes.
+ *
+ * Single-call (vli_pos == NULL):
+ * - LZMA_OK: Integer successfully decoded.
+ * - LZMA_DATA_ERROR: Integer is corrupt. This includes hitting
+ * the end of the input buffer before the whole integer was
+ * decoded; providing no input at all will use LZMA_DATA_ERROR.
+ * - LZMA_PROG_ERROR: Arguments are not sane.
+ *
+ * Multi-call (vli_pos != NULL):
+ * - LZMA_OK: So far all OK, but the integer is not
+ * completely decoded yet.
+ * - LZMA_STREAM_END: Integer successfully decoded.
+ * - LZMA_DATA_ERROR: Integer is corrupt.
+ * - LZMA_BUF_ERROR: No input was provided.
+ * - LZMA_PROG_ERROR: Arguments are not sane.
+ */
+extern LZMA_API(lzma_ret) lzma_vli_decode(lzma_vli *vli, size_t *vli_pos,
+ const uint8_t *in, size_t *in_pos, size_t in_size)
+ lzma_nothrow;
+
+
+/**
+ * \brief Get the number of bytes required to encode a VLI
+ *
+ * \return Number of bytes on success (1-9). If vli isn't valid,
+ * zero is returned.
+ */
+extern LZMA_API(uint32_t) lzma_vli_size(lzma_vli vli)
+ lzma_nothrow lzma_attr_pure;
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