| use std::error::Error; | 
 | use std::fmt; | 
 | use std::io; | 
 |  | 
 | use crate::ffi::{self, Backend, Deflate, DeflateBackend, ErrorMessage, Inflate, InflateBackend}; | 
 | use crate::Compression; | 
 |  | 
 | /// Raw in-memory compression stream for blocks of data. | 
 | /// | 
 | /// This type is the building block for the I/O streams in the rest of this | 
 | /// crate. It requires more management than the [`Read`]/[`Write`] API but is | 
 | /// maximally flexible in terms of accepting input from any source and being | 
 | /// able to produce output to any memory location. | 
 | /// | 
 | /// It is recommended to use the I/O stream adaptors over this type as they're | 
 | /// easier to use. | 
 | /// | 
 | /// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html | 
 | /// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html | 
 | #[derive(Debug)] | 
 | pub struct Compress { | 
 |     inner: Deflate, | 
 | } | 
 |  | 
 | /// Raw in-memory decompression stream for blocks of data. | 
 | /// | 
 | /// This type is the building block for the I/O streams in the rest of this | 
 | /// crate. It requires more management than the [`Read`]/[`Write`] API but is | 
 | /// maximally flexible in terms of accepting input from any source and being | 
 | /// able to produce output to any memory location. | 
 | /// | 
 | /// It is recommended to use the I/O stream adaptors over this type as they're | 
 | /// easier to use. | 
 | /// | 
 | /// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html | 
 | /// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html | 
 | #[derive(Debug)] | 
 | pub struct Decompress { | 
 |     inner: Inflate, | 
 | } | 
 |  | 
 | /// Values which indicate the form of flushing to be used when compressing | 
 | /// in-memory data. | 
 | #[derive(Copy, Clone, PartialEq, Eq, Debug)] | 
 | #[non_exhaustive] | 
 | pub enum FlushCompress { | 
 |     /// A typical parameter for passing to compression/decompression functions, | 
 |     /// this indicates that the underlying stream to decide how much data to | 
 |     /// accumulate before producing output in order to maximize compression. | 
 |     None = ffi::MZ_NO_FLUSH as isize, | 
 |  | 
 |     /// All pending output is flushed to the output buffer and the output is | 
 |     /// aligned on a byte boundary so that the decompressor can get all input | 
 |     /// data available so far. | 
 |     /// | 
 |     /// Flushing may degrade compression for some compression algorithms and so | 
 |     /// it should only be used when necessary. This will complete the current | 
 |     /// deflate block and follow it with an empty stored block. | 
 |     Sync = ffi::MZ_SYNC_FLUSH as isize, | 
 |  | 
 |     /// All pending output is flushed to the output buffer, but the output is | 
 |     /// not aligned to a byte boundary. | 
 |     /// | 
 |     /// All of the input data so far will be available to the decompressor (as | 
 |     /// with `Flush::Sync`. This completes the current deflate block and follows | 
 |     /// it with an empty fixed codes block that is 10 bites long, and it assures | 
 |     /// that enough bytes are output in order for the decompressor to finish the | 
 |     /// block before the empty fixed code block. | 
 |     Partial = ffi::MZ_PARTIAL_FLUSH as isize, | 
 |  | 
 |     /// All output is flushed as with `Flush::Sync` and the compression state is | 
 |     /// reset so decompression can restart from this point if previous | 
 |     /// compressed data has been damaged or if random access is desired. | 
 |     /// | 
 |     /// Using this option too often can seriously degrade compression. | 
 |     Full = ffi::MZ_FULL_FLUSH as isize, | 
 |  | 
 |     /// Pending input is processed and pending output is flushed. | 
 |     /// | 
 |     /// The return value may indicate that the stream is not yet done and more | 
 |     /// data has yet to be processed. | 
 |     Finish = ffi::MZ_FINISH as isize, | 
 | } | 
 |  | 
 | /// Values which indicate the form of flushing to be used when | 
 | /// decompressing in-memory data. | 
 | #[derive(Copy, Clone, PartialEq, Eq, Debug)] | 
 | #[non_exhaustive] | 
 | pub enum FlushDecompress { | 
 |     /// A typical parameter for passing to compression/decompression functions, | 
 |     /// this indicates that the underlying stream to decide how much data to | 
 |     /// accumulate before producing output in order to maximize compression. | 
 |     None = ffi::MZ_NO_FLUSH as isize, | 
 |  | 
 |     /// All pending output is flushed to the output buffer and the output is | 
 |     /// aligned on a byte boundary so that the decompressor can get all input | 
 |     /// data available so far. | 
 |     /// | 
 |     /// Flushing may degrade compression for some compression algorithms and so | 
 |     /// it should only be used when necessary. This will complete the current | 
 |     /// deflate block and follow it with an empty stored block. | 
 |     Sync = ffi::MZ_SYNC_FLUSH as isize, | 
 |  | 
 |     /// Pending input is processed and pending output is flushed. | 
 |     /// | 
 |     /// The return value may indicate that the stream is not yet done and more | 
 |     /// data has yet to be processed. | 
 |     Finish = ffi::MZ_FINISH as isize, | 
 | } | 
 |  | 
 | /// The inner state for an error when decompressing | 
 | #[derive(Debug)] | 
 | pub(crate) enum DecompressErrorInner { | 
 |     General { msg: ErrorMessage }, | 
 |     NeedsDictionary(u32), | 
 | } | 
 |  | 
 | /// Error returned when a decompression object finds that the input stream of | 
 | /// bytes was not a valid input stream of bytes. | 
 | #[derive(Debug)] | 
 | pub struct DecompressError(pub(crate) DecompressErrorInner); | 
 |  | 
 | impl DecompressError { | 
 |     /// Indicates whether decompression failed due to requiring a dictionary. | 
 |     /// | 
 |     /// The resulting integer is the Adler-32 checksum of the dictionary | 
 |     /// required. | 
 |     pub fn needs_dictionary(&self) -> Option<u32> { | 
 |         match self.0 { | 
 |             DecompressErrorInner::NeedsDictionary(adler) => Some(adler), | 
 |             _ => None, | 
 |         } | 
 |     } | 
 | } | 
 |  | 
 | #[inline] | 
 | pub(crate) fn decompress_failed<T>(msg: ErrorMessage) -> Result<T, DecompressError> { | 
 |     Err(DecompressError(DecompressErrorInner::General { msg })) | 
 | } | 
 |  | 
 | #[inline] | 
 | pub(crate) fn decompress_need_dict<T>(adler: u32) -> Result<T, DecompressError> { | 
 |     Err(DecompressError(DecompressErrorInner::NeedsDictionary( | 
 |         adler, | 
 |     ))) | 
 | } | 
 |  | 
 | /// Error returned when a compression object is used incorrectly or otherwise | 
 | /// generates an error. | 
 | #[derive(Debug)] | 
 | pub struct CompressError { | 
 |     pub(crate) msg: ErrorMessage, | 
 | } | 
 |  | 
 | #[inline] | 
 | pub(crate) fn compress_failed<T>(msg: ErrorMessage) -> Result<T, CompressError> { | 
 |     Err(CompressError { msg }) | 
 | } | 
 |  | 
 | /// Possible status results of compressing some data or successfully | 
 | /// decompressing a block of data. | 
 | #[derive(Copy, Clone, PartialEq, Eq, Debug)] | 
 | pub enum Status { | 
 |     /// Indicates success. | 
 |     /// | 
 |     /// Means that more input may be needed but isn't available | 
 |     /// and/or there's more output to be written but the output buffer is full. | 
 |     Ok, | 
 |  | 
 |     /// Indicates that forward progress is not possible due to input or output | 
 |     /// buffers being empty. | 
 |     /// | 
 |     /// For compression it means the input buffer needs some more data or the | 
 |     /// output buffer needs to be freed up before trying again. | 
 |     /// | 
 |     /// For decompression this means that more input is needed to continue or | 
 |     /// the output buffer isn't large enough to contain the result. The function | 
 |     /// can be called again after fixing both. | 
 |     BufError, | 
 |  | 
 |     /// Indicates that all input has been consumed and all output bytes have | 
 |     /// been written. Decompression/compression should not be called again. | 
 |     /// | 
 |     /// For decompression with zlib streams the adler-32 of the decompressed | 
 |     /// data has also been verified. | 
 |     StreamEnd, | 
 | } | 
 |  | 
 | impl Compress { | 
 |     /// Creates a new object ready for compressing data that it's given. | 
 |     /// | 
 |     /// The `level` argument here indicates what level of compression is going | 
 |     /// to be performed, and the `zlib_header` argument indicates whether the | 
 |     /// output data should have a zlib header or not. | 
 |     pub fn new(level: Compression, zlib_header: bool) -> Compress { | 
 |         Compress { | 
 |             inner: Deflate::make(level, zlib_header, ffi::MZ_DEFAULT_WINDOW_BITS as u8), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Creates a new object ready for compressing data that it's given. | 
 |     /// | 
 |     /// The `level` argument here indicates what level of compression is going | 
 |     /// to be performed, and the `zlib_header` argument indicates whether the | 
 |     /// output data should have a zlib header or not. The `window_bits` parameter | 
 |     /// indicates the base-2 logarithm of the sliding window size and must be | 
 |     /// between 9 and 15. | 
 |     /// | 
 |     /// # Panics | 
 |     /// | 
 |     /// If `window_bits` does not fall into the range 9 ..= 15, | 
 |     /// `new_with_window_bits` will panic. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn new_with_window_bits( | 
 |         level: Compression, | 
 |         zlib_header: bool, | 
 |         window_bits: u8, | 
 |     ) -> Compress { | 
 |         assert!( | 
 |             window_bits > 8 && window_bits < 16, | 
 |             "window_bits must be within 9 ..= 15" | 
 |         ); | 
 |         Compress { | 
 |             inner: Deflate::make(level, zlib_header, window_bits), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Creates a new object ready for compressing data that it's given. | 
 |     /// | 
 |     /// The `level` argument here indicates what level of compression is going | 
 |     /// to be performed. | 
 |     /// | 
 |     /// The Compress object produced by this constructor outputs gzip headers | 
 |     /// for the compressed data. | 
 |     /// | 
 |     /// # Panics | 
 |     /// | 
 |     /// If `window_bits` does not fall into the range 9 ..= 15, | 
 |     /// `new_with_window_bits` will panic. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn new_gzip(level: Compression, window_bits: u8) -> Compress { | 
 |         assert!( | 
 |             window_bits > 8 && window_bits < 16, | 
 |             "window_bits must be within 9 ..= 15" | 
 |         ); | 
 |         Compress { | 
 |             inner: Deflate::make(level, true, window_bits + 16), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Returns the total number of input bytes which have been processed by | 
 |     /// this compression object. | 
 |     pub fn total_in(&self) -> u64 { | 
 |         self.inner.total_in() | 
 |     } | 
 |  | 
 |     /// Returns the total number of output bytes which have been produced by | 
 |     /// this compression object. | 
 |     pub fn total_out(&self) -> u64 { | 
 |         self.inner.total_out() | 
 |     } | 
 |  | 
 |     /// Specifies the compression dictionary to use. | 
 |     /// | 
 |     /// Returns the Adler-32 checksum of the dictionary. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn set_dictionary(&mut self, dictionary: &[u8]) -> Result<u32, CompressError> { | 
 |         let stream = &mut *self.inner.inner.stream_wrapper; | 
 |         stream.msg = std::ptr::null_mut(); | 
 |         let rc = unsafe { | 
 |             assert!(dictionary.len() < ffi::uInt::MAX as usize); | 
 |             ffi::deflateSetDictionary(stream, dictionary.as_ptr(), dictionary.len() as ffi::uInt) | 
 |         }; | 
 |  | 
 |         match rc { | 
 |             ffi::MZ_STREAM_ERROR => compress_failed(self.inner.inner.msg()), | 
 |             ffi::MZ_OK => Ok(stream.adler as u32), | 
 |             c => panic!("unknown return code: {}", c), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Quickly resets this compressor without having to reallocate anything. | 
 |     /// | 
 |     /// This is equivalent to dropping this object and then creating a new one. | 
 |     pub fn reset(&mut self) { | 
 |         self.inner.reset(); | 
 |     } | 
 |  | 
 |     /// Dynamically updates the compression level. | 
 |     /// | 
 |     /// This can be used to switch between compression levels for different | 
 |     /// kinds of data, or it can be used in conjunction with a call to reset | 
 |     /// to reuse the compressor. | 
 |     /// | 
 |     /// This may return an error if there wasn't enough output space to complete | 
 |     /// the compression of the available input data before changing the | 
 |     /// compression level. Flushing the stream before calling this method | 
 |     /// ensures that the function will succeed on the first call. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn set_level(&mut self, level: Compression) -> Result<(), CompressError> { | 
 |         use std::os::raw::c_int; | 
 |         let stream = &mut *self.inner.inner.stream_wrapper; | 
 |         stream.msg = std::ptr::null_mut(); | 
 |  | 
 |         let rc = unsafe { ffi::deflateParams(stream, level.0 as c_int, ffi::MZ_DEFAULT_STRATEGY) }; | 
 |  | 
 |         match rc { | 
 |             ffi::MZ_OK => Ok(()), | 
 |             ffi::MZ_BUF_ERROR => compress_failed(self.inner.inner.msg()), | 
 |             c => panic!("unknown return code: {}", c), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Compresses the input data into the output, consuming only as much | 
 |     /// input as needed and writing as much output as possible. | 
 |     /// | 
 |     /// The flush option can be any of the available `FlushCompress` parameters. | 
 |     /// | 
 |     /// To learn how much data was consumed or how much output was produced, use | 
 |     /// the `total_in` and `total_out` functions before/after this is called. | 
 |     pub fn compress( | 
 |         &mut self, | 
 |         input: &[u8], | 
 |         output: &mut [u8], | 
 |         flush: FlushCompress, | 
 |     ) -> Result<Status, CompressError> { | 
 |         self.inner.compress(input, output, flush) | 
 |     } | 
 |  | 
 |     /// Compresses the input data into the extra space of the output, consuming | 
 |     /// only as much input as needed and writing as much output as possible. | 
 |     /// | 
 |     /// This function has the same semantics as `compress`, except that the | 
 |     /// length of `vec` is managed by this function. This will not reallocate | 
 |     /// the vector provided or attempt to grow it, so space for the output must | 
 |     /// be reserved in the output vector by the caller before calling this | 
 |     /// function. | 
 |     pub fn compress_vec( | 
 |         &mut self, | 
 |         input: &[u8], | 
 |         output: &mut Vec<u8>, | 
 |         flush: FlushCompress, | 
 |     ) -> Result<Status, CompressError> { | 
 |         write_to_spare_capacity_of_vec(output, |out| { | 
 |             let before = self.total_out(); | 
 |             let ret = self.compress(input, out, flush); | 
 |             let bytes_written = self.total_out() - before; | 
 |             (bytes_written as usize, ret) | 
 |         }) | 
 |     } | 
 | } | 
 |  | 
 | impl Decompress { | 
 |     /// Creates a new object ready for decompressing data that it's given. | 
 |     /// | 
 |     /// The `zlib_header` argument indicates whether the input data is expected | 
 |     /// to have a zlib header or not. | 
 |     pub fn new(zlib_header: bool) -> Decompress { | 
 |         Decompress { | 
 |             inner: Inflate::make(zlib_header, ffi::MZ_DEFAULT_WINDOW_BITS as u8), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Creates a new object ready for decompressing data that it's given. | 
 |     /// | 
 |     /// The `zlib_header` argument indicates whether the input data is expected | 
 |     /// to have a zlib header or not. The `window_bits` parameter indicates the | 
 |     /// base-2 logarithm of the sliding window size and must be between 9 and 15. | 
 |     /// | 
 |     /// # Panics | 
 |     /// | 
 |     /// If `window_bits` does not fall into the range 9 ..= 15, | 
 |     /// `new_with_window_bits` will panic. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn new_with_window_bits(zlib_header: bool, window_bits: u8) -> Decompress { | 
 |         assert!( | 
 |             window_bits > 8 && window_bits < 16, | 
 |             "window_bits must be within 9 ..= 15" | 
 |         ); | 
 |         Decompress { | 
 |             inner: Inflate::make(zlib_header, window_bits), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Creates a new object ready for decompressing data that it's given. | 
 |     /// | 
 |     /// The Decompress object produced by this constructor expects gzip headers | 
 |     /// for the compressed data. | 
 |     /// | 
 |     /// # Panics | 
 |     /// | 
 |     /// If `window_bits` does not fall into the range 9 ..= 15, | 
 |     /// `new_with_window_bits` will panic. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn new_gzip(window_bits: u8) -> Decompress { | 
 |         assert!( | 
 |             window_bits > 8 && window_bits < 16, | 
 |             "window_bits must be within 9 ..= 15" | 
 |         ); | 
 |         Decompress { | 
 |             inner: Inflate::make(true, window_bits + 16), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Returns the total number of input bytes which have been processed by | 
 |     /// this decompression object. | 
 |     pub fn total_in(&self) -> u64 { | 
 |         self.inner.total_in() | 
 |     } | 
 |  | 
 |     /// Returns the total number of output bytes which have been produced by | 
 |     /// this decompression object. | 
 |     pub fn total_out(&self) -> u64 { | 
 |         self.inner.total_out() | 
 |     } | 
 |  | 
 |     /// Decompresses the input data into the output, consuming only as much | 
 |     /// input as needed and writing as much output as possible. | 
 |     /// | 
 |     /// The flush option can be any of the available `FlushDecompress` parameters. | 
 |     /// | 
 |     /// If the first call passes `FlushDecompress::Finish` it is assumed that | 
 |     /// the input and output buffers are both sized large enough to decompress | 
 |     /// the entire stream in a single call. | 
 |     /// | 
 |     /// A flush value of `FlushDecompress::Finish` indicates that there are no | 
 |     /// more source bytes available beside what's already in the input buffer, | 
 |     /// and the output buffer is large enough to hold the rest of the | 
 |     /// decompressed data. | 
 |     /// | 
 |     /// To learn how much data was consumed or how much output was produced, use | 
 |     /// the `total_in` and `total_out` functions before/after this is called. | 
 |     /// | 
 |     /// # Errors | 
 |     /// | 
 |     /// If the input data to this instance of `Decompress` is not a valid | 
 |     /// zlib/deflate stream then this function may return an instance of | 
 |     /// `DecompressError` to indicate that the stream of input bytes is corrupted. | 
 |     pub fn decompress( | 
 |         &mut self, | 
 |         input: &[u8], | 
 |         output: &mut [u8], | 
 |         flush: FlushDecompress, | 
 |     ) -> Result<Status, DecompressError> { | 
 |         self.inner.decompress(input, output, flush) | 
 |     } | 
 |  | 
 |     /// Decompresses the input data into the extra space in the output vector | 
 |     /// specified by `output`. | 
 |     /// | 
 |     /// This function has the same semantics as `decompress`, except that the | 
 |     /// length of `vec` is managed by this function. This will not reallocate | 
 |     /// the vector provided or attempt to grow it, so space for the output must | 
 |     /// be reserved in the output vector by the caller before calling this | 
 |     /// function. | 
 |     /// | 
 |     /// # Errors | 
 |     /// | 
 |     /// If the input data to this instance of `Decompress` is not a valid | 
 |     /// zlib/deflate stream then this function may return an instance of | 
 |     /// `DecompressError` to indicate that the stream of input bytes is corrupted. | 
 |     pub fn decompress_vec( | 
 |         &mut self, | 
 |         input: &[u8], | 
 |         output: &mut Vec<u8>, | 
 |         flush: FlushDecompress, | 
 |     ) -> Result<Status, DecompressError> { | 
 |         write_to_spare_capacity_of_vec(output, |out| { | 
 |             let before = self.total_out(); | 
 |             let ret = self.decompress(input, out, flush); | 
 |             let bytes_written = self.total_out() - before; | 
 |             (bytes_written as usize, ret) | 
 |         }) | 
 |     } | 
 |  | 
 |     /// Specifies the decompression dictionary to use. | 
 |     #[cfg(feature = "any_zlib")] | 
 |     pub fn set_dictionary(&mut self, dictionary: &[u8]) -> Result<u32, DecompressError> { | 
 |         let stream = &mut *self.inner.inner.stream_wrapper; | 
 |         stream.msg = std::ptr::null_mut(); | 
 |         let rc = unsafe { | 
 |             assert!(dictionary.len() < ffi::uInt::MAX as usize); | 
 |             ffi::inflateSetDictionary(stream, dictionary.as_ptr(), dictionary.len() as ffi::uInt) | 
 |         }; | 
 |  | 
 |         match rc { | 
 |             ffi::MZ_STREAM_ERROR => decompress_failed(self.inner.inner.msg()), | 
 |             ffi::MZ_DATA_ERROR => decompress_need_dict(stream.adler as u32), | 
 |             ffi::MZ_OK => Ok(stream.adler as u32), | 
 |             c => panic!("unknown return code: {}", c), | 
 |         } | 
 |     } | 
 |  | 
 |     /// Performs the equivalent of replacing this decompression state with a | 
 |     /// freshly allocated copy. | 
 |     /// | 
 |     /// This function may not allocate memory, though, and attempts to reuse any | 
 |     /// previously existing resources. | 
 |     /// | 
 |     /// The argument provided here indicates whether the reset state will | 
 |     /// attempt to decode a zlib header first or not. | 
 |     pub fn reset(&mut self, zlib_header: bool) { | 
 |         self.inner.reset(zlib_header); | 
 |     } | 
 | } | 
 |  | 
 | impl Error for DecompressError {} | 
 |  | 
 | impl DecompressError { | 
 |     /// Retrieve the implementation's message about why the operation failed, if one exists. | 
 |     pub fn message(&self) -> Option<&str> { | 
 |         match &self.0 { | 
 |             DecompressErrorInner::General { msg } => msg.get(), | 
 |             _ => None, | 
 |         } | 
 |     } | 
 | } | 
 |  | 
 | impl From<DecompressError> for io::Error { | 
 |     fn from(data: DecompressError) -> io::Error { | 
 |         io::Error::new(io::ErrorKind::Other, data) | 
 |     } | 
 | } | 
 |  | 
 | impl fmt::Display for DecompressError { | 
 |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | 
 |         let msg = match &self.0 { | 
 |             DecompressErrorInner::General { msg } => msg.get(), | 
 |             DecompressErrorInner::NeedsDictionary { .. } => Some("requires a dictionary"), | 
 |         }; | 
 |         match msg { | 
 |             Some(msg) => write!(f, "deflate decompression error: {}", msg), | 
 |             None => write!(f, "deflate decompression error"), | 
 |         } | 
 |     } | 
 | } | 
 |  | 
 | impl Error for CompressError {} | 
 |  | 
 | impl CompressError { | 
 |     /// Retrieve the implementation's message about why the operation failed, if one exists. | 
 |     pub fn message(&self) -> Option<&str> { | 
 |         self.msg.get() | 
 |     } | 
 | } | 
 |  | 
 | impl From<CompressError> for io::Error { | 
 |     fn from(data: CompressError) -> io::Error { | 
 |         io::Error::new(io::ErrorKind::Other, data) | 
 |     } | 
 | } | 
 |  | 
 | impl fmt::Display for CompressError { | 
 |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | 
 |         match self.msg.get() { | 
 |             Some(msg) => write!(f, "deflate compression error: {}", msg), | 
 |             None => write!(f, "deflate compression error"), | 
 |         } | 
 |     } | 
 | } | 
 |  | 
 | /// Allows `writer` to write data into the spare capacity of the `output` vector. | 
 | /// This will not reallocate the vector provided or attempt to grow it, so space | 
 | /// for the `output` must be reserved by the caller before calling this | 
 | /// function. | 
 | /// | 
 | /// `writer` needs to return the number of bytes written (and can also return | 
 | /// another arbitrary return value). | 
 | fn write_to_spare_capacity_of_vec<T>( | 
 |     output: &mut Vec<u8>, | 
 |     writer: impl FnOnce(&mut [u8]) -> (usize, T), | 
 | ) -> T { | 
 |     let cap = output.capacity(); | 
 |     let len = output.len(); | 
 |  | 
 |     output.resize(output.capacity(), 0); | 
 |     let (bytes_written, ret) = writer(&mut output[len..]); | 
 |  | 
 |     let new_len = core::cmp::min(len + bytes_written, cap); // Sanitizes `bytes_written`. | 
 |     output.resize(new_len, 0 /* unused */); | 
 |  | 
 |     ret | 
 | } | 
 |  | 
 | #[cfg(test)] | 
 | mod tests { | 
 |     use std::io::Write; | 
 |  | 
 |     use crate::write; | 
 |     use crate::{Compression, Decompress, FlushDecompress}; | 
 |  | 
 |     #[cfg(feature = "any_zlib")] | 
 |     use crate::{Compress, FlushCompress}; | 
 |  | 
 |     #[test] | 
 |     fn issue51() { | 
 |         let data = vec![ | 
 |             0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xb3, 0xc9, 0x28, 0xc9, | 
 |             0xcd, 0xb1, 0xe3, 0xe5, 0xb2, 0xc9, 0x48, 0x4d, 0x4c, 0xb1, 0xb3, 0x29, 0xc9, 0x2c, | 
 |             0xc9, 0x49, 0xb5, 0x33, 0x31, 0x30, 0x51, 0xf0, 0xcb, 0x2f, 0x51, 0x70, 0xcb, 0x2f, | 
 |             0xcd, 0x4b, 0xb1, 0xd1, 0x87, 0x08, 0xda, 0xe8, 0x83, 0x95, 0x00, 0x95, 0x26, 0xe5, | 
 |             0xa7, 0x54, 0x2a, 0x24, 0xa5, 0x27, 0xe7, 0xe7, 0xe4, 0x17, 0xd9, 0x2a, 0x95, 0x67, | 
 |             0x64, 0x96, 0xa4, 0x2a, 0x81, 0x8c, 0x48, 0x4e, 0xcd, 0x2b, 0x49, 0x2d, 0xb2, 0xb3, | 
 |             0xc9, 0x30, 0x44, 0x37, 0x01, 0x28, 0x62, 0xa3, 0x0f, 0x95, 0x06, 0xd9, 0x05, 0x54, | 
 |             0x04, 0xe5, 0xe5, 0xa5, 0x67, 0xe6, 0x55, 0xe8, 0x1b, 0xea, 0x99, 0xe9, 0x19, 0x21, | 
 |             0xab, 0xd0, 0x07, 0xd9, 0x01, 0x32, 0x53, 0x1f, 0xea, 0x3e, 0x00, 0x94, 0x85, 0xeb, | 
 |             0xe4, 0xa8, 0x00, 0x00, 0x00, | 
 |         ]; | 
 |  | 
 |         let mut decoded = Vec::with_capacity(data.len() * 2); | 
 |  | 
 |         let mut d = Decompress::new(false); | 
 |         // decompressed whole deflate stream | 
 |         assert!(d | 
 |             .decompress_vec(&data[10..], &mut decoded, FlushDecompress::Finish) | 
 |             .is_ok()); | 
 |  | 
 |         // decompress data that has nothing to do with the deflate stream (this | 
 |         // used to panic) | 
 |         drop(d.decompress_vec(&[0], &mut decoded, FlushDecompress::None)); | 
 |     } | 
 |  | 
 |     #[test] | 
 |     fn reset() { | 
 |         let string = "hello world".as_bytes(); | 
 |         let mut zlib = Vec::new(); | 
 |         let mut deflate = Vec::new(); | 
 |  | 
 |         let comp = Compression::default(); | 
 |         write::ZlibEncoder::new(&mut zlib, comp) | 
 |             .write_all(string) | 
 |             .unwrap(); | 
 |         write::DeflateEncoder::new(&mut deflate, comp) | 
 |             .write_all(string) | 
 |             .unwrap(); | 
 |  | 
 |         let mut dst = [0; 1024]; | 
 |         let mut decoder = Decompress::new(true); | 
 |         decoder | 
 |             .decompress(&zlib, &mut dst, FlushDecompress::Finish) | 
 |             .unwrap(); | 
 |         assert_eq!(decoder.total_out(), string.len() as u64); | 
 |         assert!(dst.starts_with(string)); | 
 |  | 
 |         decoder.reset(false); | 
 |         decoder | 
 |             .decompress(&deflate, &mut dst, FlushDecompress::Finish) | 
 |             .unwrap(); | 
 |         assert_eq!(decoder.total_out(), string.len() as u64); | 
 |         assert!(dst.starts_with(string)); | 
 |     } | 
 |  | 
 |     #[cfg(feature = "any_zlib")] | 
 |     #[test] | 
 |     fn set_dictionary_with_zlib_header() { | 
 |         let string = "hello, hello!".as_bytes(); | 
 |         let dictionary = "hello".as_bytes(); | 
 |  | 
 |         let mut encoded = Vec::with_capacity(1024); | 
 |  | 
 |         let mut encoder = Compress::new(Compression::default(), true); | 
 |  | 
 |         let dictionary_adler = encoder.set_dictionary(&dictionary).unwrap(); | 
 |  | 
 |         encoder | 
 |             .compress_vec(string, &mut encoded, FlushCompress::Finish) | 
 |             .unwrap(); | 
 |  | 
 |         assert_eq!(encoder.total_in(), string.len() as u64); | 
 |         assert_eq!(encoder.total_out(), encoded.len() as u64); | 
 |  | 
 |         let mut decoder = Decompress::new(true); | 
 |         let mut decoded = [0; 1024]; | 
 |         let decompress_error = decoder | 
 |             .decompress(&encoded, &mut decoded, FlushDecompress::Finish) | 
 |             .expect_err("decompression should fail due to requiring a dictionary"); | 
 |  | 
 |         let required_adler = decompress_error.needs_dictionary() | 
 |             .expect("the first call to decompress should indicate a dictionary is required along with the required Adler-32 checksum"); | 
 |  | 
 |         assert_eq!(required_adler, dictionary_adler, | 
 |             "the Adler-32 checksum should match the value when the dictionary was set on the compressor"); | 
 |  | 
 |         let actual_adler = decoder.set_dictionary(&dictionary).unwrap(); | 
 |  | 
 |         assert_eq!(required_adler, actual_adler); | 
 |  | 
 |         // Decompress the rest of the input to the remainder of the output buffer | 
 |         let total_in = decoder.total_in(); | 
 |         let total_out = decoder.total_out(); | 
 |  | 
 |         let decompress_result = decoder.decompress( | 
 |             &encoded[total_in as usize..], | 
 |             &mut decoded[total_out as usize..], | 
 |             FlushDecompress::Finish, | 
 |         ); | 
 |         assert!(decompress_result.is_ok()); | 
 |  | 
 |         assert_eq!(&decoded[..decoder.total_out() as usize], string); | 
 |     } | 
 |  | 
 |     #[cfg(feature = "any_zlib")] | 
 |     #[test] | 
 |     fn set_dictionary_raw() { | 
 |         let string = "hello, hello!".as_bytes(); | 
 |         let dictionary = "hello".as_bytes(); | 
 |  | 
 |         let mut encoded = Vec::with_capacity(1024); | 
 |  | 
 |         let mut encoder = Compress::new(Compression::default(), false); | 
 |  | 
 |         encoder.set_dictionary(&dictionary).unwrap(); | 
 |  | 
 |         encoder | 
 |             .compress_vec(string, &mut encoded, FlushCompress::Finish) | 
 |             .unwrap(); | 
 |  | 
 |         assert_eq!(encoder.total_in(), string.len() as u64); | 
 |         assert_eq!(encoder.total_out(), encoded.len() as u64); | 
 |  | 
 |         let mut decoder = Decompress::new(false); | 
 |  | 
 |         decoder.set_dictionary(&dictionary).unwrap(); | 
 |  | 
 |         let mut decoded = [0; 1024]; | 
 |         let decompress_result = decoder.decompress(&encoded, &mut decoded, FlushDecompress::Finish); | 
 |  | 
 |         assert!(decompress_result.is_ok()); | 
 |  | 
 |         assert_eq!(&decoded[..decoder.total_out() as usize], string); | 
 |     } | 
 |  | 
 |     #[cfg(feature = "any_zlib")] | 
 |     #[test] | 
 |     fn test_gzip_flate() { | 
 |         let string = "hello, hello!".as_bytes(); | 
 |  | 
 |         let mut encoded = Vec::with_capacity(1024); | 
 |  | 
 |         let mut encoder = Compress::new_gzip(Compression::default(), 9); | 
 |  | 
 |         encoder | 
 |             .compress_vec(string, &mut encoded, FlushCompress::Finish) | 
 |             .unwrap(); | 
 |  | 
 |         assert_eq!(encoder.total_in(), string.len() as u64); | 
 |         assert_eq!(encoder.total_out(), encoded.len() as u64); | 
 |  | 
 |         let mut decoder = Decompress::new_gzip(9); | 
 |  | 
 |         let mut decoded = [0; 1024]; | 
 |         decoder | 
 |             .decompress(&encoded, &mut decoded, FlushDecompress::Finish) | 
 |             .unwrap(); | 
 |  | 
 |         assert_eq!(&decoded[..decoder.total_out() as usize], string); | 
 |     } | 
 |  | 
 |     #[cfg(feature = "any_zlib")] | 
 |     #[test] | 
 |     fn test_error_message() { | 
 |         let mut decoder = Decompress::new(false); | 
 |         let mut decoded = [0; 128]; | 
 |         let garbage = b"xbvxzi"; | 
 |  | 
 |         let err = decoder | 
 |             .decompress(&*garbage, &mut decoded, FlushDecompress::Finish) | 
 |             .unwrap_err(); | 
 |  | 
 |         assert_eq!(err.message(), Some("invalid stored block lengths")); | 
 |     } | 
 | } |