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-rw-r--r--src/liblzma/common/outqueue.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/src/liblzma/common/outqueue.c b/src/liblzma/common/outqueue.c
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+++ b/src/liblzma/common/outqueue.c
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+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file outqueue.c
+/// \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 "outqueue.h"
+
+
+/// This is to ease integer overflow checking: We may allocate up to
+/// 2 * LZMA_THREADS_MAX buffers and we need some extra memory for other
+/// data structures (that's the second /2).
+#define BUF_SIZE_MAX (UINT64_MAX / LZMA_THREADS_MAX / 2 / 2)
+
+
+static lzma_ret
+get_options(uint64_t *bufs_alloc_size, uint32_t *bufs_count,
+ uint64_t buf_size_max, uint32_t threads)
+{
+ if (threads > LZMA_THREADS_MAX || buf_size_max > BUF_SIZE_MAX)
+ return LZMA_OPTIONS_ERROR;
+
+ // The number of buffers is twice the number of threads.
+ // This wastes RAM but keeps the threads busy when buffers
+ // finish out of order.
+ //
+ // NOTE: If this is changed, update BUF_SIZE_MAX too.
+ *bufs_count = threads * 2;
+ *bufs_alloc_size = *bufs_count * buf_size_max;
+
+ return LZMA_OK;
+}
+
+
+extern uint64_t
+lzma_outq_memusage(uint64_t buf_size_max, uint32_t threads)
+{
+ uint64_t bufs_alloc_size;
+ uint32_t bufs_count;
+
+ if (get_options(&bufs_alloc_size, &bufs_count, buf_size_max, threads)
+ != LZMA_OK)
+ return UINT64_MAX;
+
+ return sizeof(lzma_outq) + bufs_count * sizeof(lzma_outbuf)
+ + bufs_alloc_size;
+}
+
+
+extern lzma_ret
+lzma_outq_init(lzma_outq *outq, lzma_allocator *allocator,
+ uint64_t buf_size_max, uint32_t threads)
+{
+ uint64_t bufs_alloc_size;
+ uint32_t bufs_count;
+
+ // Set bufs_count and bufs_alloc_size.
+ return_if_error(get_options(&bufs_alloc_size, &bufs_count,
+ buf_size_max, threads));
+
+ // Allocate memory if needed.
+ if (outq->buf_size_max != buf_size_max
+ || outq->bufs_allocated != bufs_count) {
+ lzma_outq_end(outq, allocator);
+
+#if SIZE_MAX < UINT64_MAX
+ if (bufs_alloc_size > SIZE_MAX)
+ return LZMA_MEM_ERROR;
+#endif
+
+ outq->bufs = lzma_alloc(bufs_count * sizeof(lzma_outbuf),
+ allocator);
+ outq->bufs_mem = lzma_alloc((size_t)(bufs_alloc_size),
+ allocator);
+
+ if (outq->bufs == NULL || outq->bufs_mem == NULL) {
+ lzma_outq_end(outq, allocator);
+ return LZMA_MEM_ERROR;
+ }
+ }
+
+ // Initialize the rest of the main structure. Initialization of
+ // outq->bufs[] is done when they are actually needed.
+ outq->buf_size_max = (size_t)(buf_size_max);
+ outq->bufs_allocated = bufs_count;
+ outq->bufs_pos = 0;
+ outq->bufs_used = 0;
+ outq->read_pos = 0;
+
+ return LZMA_OK;
+}
+
+
+extern void
+lzma_outq_end(lzma_outq *outq, lzma_allocator *allocator)
+{
+ lzma_free(outq->bufs, allocator);
+ lzma_free(outq->bufs_mem, allocator);
+ return;
+}
+
+
+extern lzma_outbuf *
+lzma_outq_get_buf(lzma_outq *outq)
+{
+ // Caller must have checked it with lzma_outq_has_buf().
+ assert(outq->bufs_used < outq->bufs_allocated);
+
+ // Initialize the new buffer.
+ lzma_outbuf *buf = &outq->bufs[outq->bufs_pos];
+ buf->buf = outq->bufs_mem + outq->bufs_pos * outq->buf_size_max;
+ buf->size = 0;
+ buf->finished = false;
+
+ // Update the queue state.
+ if (++outq->bufs_pos == outq->bufs_allocated)
+ outq->bufs_pos = 0;
+
+ ++outq->bufs_used;
+
+ return buf;
+}
+
+
+extern bool
+lzma_outq_is_readable(const lzma_outq *outq)
+{
+ uint32_t i = outq->bufs_pos - outq->bufs_used;
+ if (outq->bufs_pos < outq->bufs_used)
+ i += outq->bufs_allocated;
+
+ return outq->bufs[i].finished;
+}
+
+
+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)
+{
+ // There must be at least one buffer from which to read.
+ if (outq->bufs_used == 0)
+ return LZMA_OK;
+
+ // Get the buffer.
+ uint32_t i = outq->bufs_pos - outq->bufs_used;
+ if (outq->bufs_pos < outq->bufs_used)
+ i += outq->bufs_allocated;
+
+ lzma_outbuf *buf = &outq->bufs[i];
+
+ // If it isn't finished yet, we cannot read from it.
+ if (!buf->finished)
+ return LZMA_OK;
+
+ // Copy from the buffer to output.
+ lzma_bufcpy(buf->buf, &outq->read_pos, buf->size,
+ out, out_pos, out_size);
+
+ // Return if we didn't get all the data from the buffer.
+ if (outq->read_pos < buf->size)
+ return LZMA_OK;
+
+ // The buffer was finished. Tell the caller its size information.
+ *unpadded_size = buf->unpadded_size;
+ *uncompressed_size = buf->uncompressed_size;
+
+ // Free this buffer for further use.
+ --outq->bufs_used;
+ outq->read_pos = 0;
+
+ return LZMA_STREAM_END;
+}