Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/simple/simple_coder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       simple_coder.c
+/// \brief      Wrapper for simple filters
+///
+/// Simple filters don't change the size of the data i.e. number of bytes
+/// in equals the number of bytes out.
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "simple_private.h"
+
+
+/// Copied or encodes/decodes more data to out[].
+static lzma_ret
+copy_or_code(lzma_coder *coder, lzma_allocator *allocator,
+                const uint8_t *restrict in, size_t *restrict in_pos,
+                size_t in_size, uint8_t *restrict out,
+                size_t *restrict out_pos, size_t out_size, lzma_action action)
+{
+        assert(!coder->end_was_reached);
+
+        if (coder->next.code == NULL) {
+                lzma_bufcpy(in, in_pos, in_size, out, out_pos, out_size);
+
+                // Check if end of stream was reached.
+                if (coder->is_encoder && action == LZMA_FINISH
+                                && *in_pos == in_size)
+                        coder->end_was_reached = true;
+
+        } else {
+                // Call the next coder in the chain to provide us some data.
+                // We don't care about uncompressed_size here, because
+                // the next filter in the chain will do it for us (since
+                // we don't change the size of the data).
+                const lzma_ret ret = coder->next.code(
+                                coder->next.coder, allocator,
+                                in, in_pos, in_size,
+                                out, out_pos, out_size, action);
+
+                if (ret == LZMA_STREAM_END) {
+                        assert(!coder->is_encoder
+                                        || action == LZMA_FINISH);
+                        coder->end_was_reached = true;
+
+                } else if (ret != LZMA_OK) {
+                        return ret;
+                }
+        }
+
+        return LZMA_OK;
+}
+
+
+static size_t
+call_filter(lzma_coder *coder, uint8_t *buffer, size_t size)
+{
+        const size_t filtered = coder->filter(coder->simple,
+                        coder->now_pos, coder->is_encoder,
+                        buffer, size);
+        coder->now_pos += filtered;
+        return filtered;
+}
+
+
+static lzma_ret
+simple_code(lzma_coder *coder, lzma_allocator *allocator,
+                const uint8_t *restrict in, size_t *restrict in_pos,
+                size_t in_size, uint8_t *restrict out,
+                size_t *restrict out_pos, size_t out_size, lzma_action action)
+{
+        // TODO: Add partial support for LZMA_SYNC_FLUSH. We can support it
+        // in cases when the filter is able to filter everything. With most
+        // simple filters it can be done at offset that is a multiple of 2,
+        // 4, or 16. With x86 filter, it needs good luck, and thus cannot
+        // be made to work predictably.
+        if (action == LZMA_SYNC_FLUSH)
+                return LZMA_OPTIONS_ERROR;
+
+        // Flush already filtered data from coder->buffer[] to out[].
+        if (coder->pos < coder->filtered) {
+                lzma_bufcpy(coder->buffer, &coder->pos, coder->filtered,
+                                out, out_pos, out_size);
+
+                // If we couldn't flush all the filtered data, return to
+                // application immediately.
+                if (coder->pos < coder->filtered)
+                        return LZMA_OK;
+
+                if (coder->end_was_reached) {
+                        assert(coder->filtered == coder->size);
+                        return LZMA_STREAM_END;
+                }
+        }
+
+        // If we get here, there is no filtered data left in the buffer.
+        coder->filtered = 0;
+
+        assert(!coder->end_was_reached);
+
+        // If there is more output space left than there is unfiltered data
+        // in coder->buffer[], flush coder->buffer[] to out[], and copy/code
+        // more data to out[] hopefully filling it completely. Then filter
+        // the data in out[]. This step is where most of the data gets
+        // filtered if the buffer sizes used by the application are reasonable.
+        const size_t out_avail = out_size - *out_pos;
+        const size_t buf_avail = coder->size - coder->pos;
+        if (out_avail > buf_avail) {
+                // Store the old position so that we know from which byte
+                // to start filtering.
+                const size_t out_start = *out_pos;
+
+                // Flush data from coder->buffer[] to out[], but don't reset
+                // coder->pos and coder->size yet. This way the coder can be
+                // restarted if the next filter in the chain returns e.g.
+                // LZMA_MEM_ERROR.
+                memcpy(out + *out_pos, coder->buffer + coder->pos, buf_avail);
+                *out_pos += buf_avail;
+
+                // Copy/Encode/Decode more data to out[].
+                {
+                        const lzma_ret ret = copy_or_code(coder, allocator,
+                                        in, in_pos, in_size,
+                                        out, out_pos, out_size, action);
+                        assert(ret != LZMA_STREAM_END);
+                        if (ret != LZMA_OK)
+                                return ret;
+                }
+
+                // Filter out[].
+                const size_t size = *out_pos - out_start;
+                const size_t filtered = call_filter(
+                                coder, out + out_start, size);
+
+                const size_t unfiltered = size - filtered;
+                assert(unfiltered <= coder->allocated / 2);
+
+                // Now we can update coder->pos and coder->size, because
+                // the next coder in the chain (if any) was successful.
+                coder->pos = 0;
+                coder->size = unfiltered;
+
+                if (coder->end_was_reached) {
+                        // The last byte has been copied to out[] already.
+                        // They are left as is.
+                        coder->size = 0;
+
+                } else if (unfiltered > 0) {
+                        // There is unfiltered data left in out[]. Copy it to
+                        // coder->buffer[] and rewind *out_pos appropriately.
+                        *out_pos -= unfiltered;
+                        memcpy(coder->buffer, out + *out_pos, unfiltered);
+                }
+        } else if (coder->pos > 0) {
+                memmove(coder->buffer, coder->buffer + coder->pos, buf_avail);
+                coder->size -= coder->pos;
+                coder->pos = 0;
+        }
+
+        assert(coder->pos == 0);
+
+        // If coder->buffer[] isn't empty, try to fill it by copying/decoding
+        // more data. Then filter coder->buffer[] and copy the successfully
+        // filtered data to out[]. It is probable, that some filtered and
+        // unfiltered data will be left to coder->buffer[].
+        if (coder->size > 0) {
+                {
+                        const lzma_ret ret = copy_or_code(coder, allocator,
+                                        in, in_pos, in_size,
+                                        coder->buffer, &coder->size,
+                                        coder->allocated, action);
+                        assert(ret != LZMA_STREAM_END);
+                        if (ret != LZMA_OK)
+                                return ret;
+                }
+
+                coder->filtered = call_filter(
+                                coder, coder->buffer, coder->size);
+
+                // Everything is considered to be filtered if coder->buffer[]
+                // contains the last bytes of the data.
+                if (coder->end_was_reached)
+                        coder->filtered = coder->size;
+
+                // Flush as much as possible.
+                lzma_bufcpy(coder->buffer, &coder->pos, coder->filtered,
+                                out, out_pos, out_size);
+        }
+
+        // Check if we got everything done.
+        if (coder->end_was_reached && coder->pos == coder->size)
+                return LZMA_STREAM_END;
+
+        return LZMA_OK;
+}
+
+
+static void
+simple_coder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+        lzma_next_end(&coder->next, allocator);
+        lzma_free(coder->simple, allocator);
+        lzma_free(coder, allocator);
+        return;
+}
+
+
+static lzma_ret
+simple_coder_update(lzma_coder *coder, lzma_allocator *allocator,
+                const lzma_filter *filters_null lzma_attribute((unused)),
+                const lzma_filter *reversed_filters)
+{
+        // No update support, just call the next filter in the chain.
+        return lzma_next_filter_update(
+                        &coder->next, allocator, reversed_filters + 1);
+}
+
+
+extern lzma_ret
+lzma_simple_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
+                const lzma_filter_info *filters,
+                size_t (*filter)(lzma_simple *simple, uint32_t now_pos,
+                        bool is_encoder, uint8_t *buffer, size_t size),
+                size_t simple_size, size_t unfiltered_max,
+                uint32_t alignment, bool is_encoder)
+{
+        // Allocate memory for the lzma_coder structure if needed.
+        if (next->coder == NULL) {
+                // Here we allocate space also for the temporary buffer. We
+                // need twice the size of unfiltered_max, because then it
+                // is always possible to filter at least unfiltered_max bytes
+                // more data in coder->buffer[] if it can be filled completely.
+                next->coder = lzma_alloc(sizeof(lzma_coder)
+                                + 2 * unfiltered_max, allocator);
+                if (next->coder == NULL)
+                        return LZMA_MEM_ERROR;
+
+                next->code = &simple_code;
+                next->end = &simple_coder_end;
+                next->update = &simple_coder_update;
+
+                next->coder->next = LZMA_NEXT_CODER_INIT;
+                next->coder->filter = filter;
+                next->coder->allocated = 2 * unfiltered_max;
+
+                // Allocate memory for filter-specific data structure.
+                if (simple_size > 0) {
+                        next->coder->simple = lzma_alloc(
+                                        simple_size, allocator);
+                        if (next->coder->simple == NULL)
+                                return LZMA_MEM_ERROR;
+                } else {
+                        next->coder->simple = NULL;
+                }
+        }
+
+        if (filters[0].options != NULL) {
+                const lzma_options_bcj *simple = filters[0].options;
+                next->coder->now_pos = simple->start_offset;
+                if (next->coder->now_pos & (alignment - 1))
+                        return LZMA_OPTIONS_ERROR;
+        } else {
+                next->coder->now_pos = 0;
+        }
+
+        // Reset variables.
+        next->coder->is_encoder = is_encoder;
+        next->coder->end_was_reached = false;
+        next->coder->pos = 0;
+        next->coder->filtered = 0;
+        next->coder->size = 0;
+
+        return lzma_next_filter_init(
+                        &next->coder->next, allocator, filters + 1);
+}