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Diffstat (limited to 'contrib/xz/src/liblzma/common/outqueue.h')
| -rw-r--r-- | contrib/xz/src/liblzma/common/outqueue.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/contrib/xz/src/liblzma/common/outqueue.h b/contrib/xz/src/liblzma/common/outqueue.h new file mode 100644 index 000000000000..079634de4587 --- /dev/null +++ b/contrib/xz/src/liblzma/common/outqueue.h @@ -0,0 +1,156 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file outqueue.h +/// \brief Output queue handling in multithreaded coding +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "common.h" + + +/// Output buffer for a single thread +typedef struct { + /// Pointer to the output buffer of lzma_outq.buf_size_max bytes + uint8_t *buf; + + /// Amount of data written to buf + size_t size; + + /// Additional size information + lzma_vli unpadded_size; + lzma_vli uncompressed_size; + + /// True when no more data will be written into this buffer. + /// + /// \note This is read by another thread and thus access + /// to this variable needs a mutex. + bool finished; + +} lzma_outbuf; + + +typedef struct { + /// Array of buffers that are used cyclically. + lzma_outbuf *bufs; + + /// Memory allocated for all the buffers + uint8_t *bufs_mem; + + /// Amount of buffer space available in each buffer + size_t buf_size_max; + + /// Number of buffers allocated + uint32_t bufs_allocated; + + /// Position in the bufs array. The next buffer to be taken + /// into use is bufs[bufs_pos]. + uint32_t bufs_pos; + + /// Number of buffers in use + uint32_t bufs_used; + + /// Position in the buffer in lzma_outq_read() + size_t read_pos; + +} lzma_outq; + + +/** + * \brief Calculate the memory usage of an output queue + * + * \return Approximate memory usage in bytes or UINT64_MAX on error. + */ +extern uint64_t lzma_outq_memusage(uint64_t buf_size_max, uint32_t threads); + + +/// \brief Initialize an output queue +/// +/// \param outq Pointer to an output queue. Before calling +/// this function the first time, *outq should +/// have been zeroed with memzero() so that this +/// function knows that there are no previous +/// allocations to free. +/// \param allocator Pointer to allocator or NULL +/// \param buf_size_max Maximum amount of data that a single buffer +/// in the queue may need to store. +/// \param threads Number of buffers that may be in use +/// concurrently. Note that more than this number +/// of buffers will actually get allocated to +/// improve performance when buffers finish +/// out of order. +/// +/// \return - LZMA_OK +/// - LZMA_MEM_ERROR +/// +extern lzma_ret lzma_outq_init( + lzma_outq *outq, const lzma_allocator *allocator, + uint64_t buf_size_max, uint32_t threads); + + +/// \brief Free the memory associated with the output queue +extern void lzma_outq_end(lzma_outq *outq, const lzma_allocator *allocator); + + +/// \brief Get a new buffer +/// +/// lzma_outq_has_buf() must be used to check that there is a buffer +/// available before calling lzma_outq_get_buf(). +/// +extern lzma_outbuf *lzma_outq_get_buf(lzma_outq *outq); + + +/// \brief Test if there is data ready to be read +/// +/// Call to this function must be protected with the same mutex that +/// is used to protect lzma_outbuf.finished. +/// +extern bool lzma_outq_is_readable(const lzma_outq *outq); + + +/// \brief Read finished data +/// +/// \param outq Pointer to an output queue +/// \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]. +/// \param unpadded_size Unpadded Size from the Block encoder +/// \param uncompressed_size Uncompressed Size from the Block encoder +/// +/// \return - LZMA: All OK. Either no data was available or the buffer +/// being read didn't become empty yet. +/// - LZMA_STREAM_END: The buffer being read was finished. +/// *unpadded_size and *uncompressed_size were set. +/// +/// \note This reads lzma_outbuf.finished variables and thus call +/// to this function needs to be protected with a mutex. +/// +extern lzma_ret lzma_outq_read(lzma_outq *restrict outq, + uint8_t *restrict out, size_t *restrict out_pos, + size_t out_size, lzma_vli *restrict unpadded_size, + lzma_vli *restrict uncompressed_size); + + +/// \brief Test if there is at least one buffer free +/// +/// This must be used before getting a new buffer with lzma_outq_get_buf(). +/// +static inline bool +lzma_outq_has_buf(const lzma_outq *outq) +{ + return outq->bufs_used < outq->bufs_allocated; +} + + +/// \brief Test if the queue is completely empty +static inline bool +lzma_outq_is_empty(const lzma_outq *outq) +{ + return outq->bufs_used == 0; +} |