dolphin/Externals/liblzma/common/outqueue.h
2020-04-24 15:18:09 +02:00

157 lines
4.9 KiB
C

///////////////////////////////////////////////////////////////////////////////
//
/// \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;
}