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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 03:10:08 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 03:10:08 +0000
commit5262a872f308b3b584c97d621992fb3877e392b8 (patch)
treeb956c322376141abeafe639bd72cfecdf16954b5 /src/liblzma/simple/simple_coder.c
parentInitial commit. (diff)
downloadxz-utils-5262a872f308b3b584c97d621992fb3877e392b8.tar.xz
xz-utils-5262a872f308b3b584c97d621992fb3877e392b8.zip
Adding upstream version 5.6.1+really5.4.5.upstream/5.6.1+really5.4.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/liblzma/simple/simple_coder.c')
-rw-r--r--src/liblzma/simple/simple_coder.c292
1 files changed, 292 insertions, 0 deletions
diff --git a/src/liblzma/simple/simple_coder.c b/src/liblzma/simple/simple_coder.c
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+++ b/src/liblzma/simple/simple_coder.c
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+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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_simple_coder *coder, const 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.
+ 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_simple_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(void *coder_ptr, const 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)
+{
+ lzma_simple_coder *coder = coder_ptr;
+
+ // 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 || buf_avail == 0) {
+ // 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.
+ //
+ // Do the memcpy() conditionally because out can be NULL
+ // (in which case buf_avail is always 0). Calling memcpy()
+ // with a null-pointer is undefined even if the third
+ // argument is 0.
+ if (buf_avail > 0)
+ 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[] unless there is nothing to filter.
+ // This way we avoid null pointer + 0 (undefined behavior)
+ // when out == NULL.
+ const size_t size = *out_pos - out_start;
+ const size_t filtered = size == 0 ? 0 : 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(void *coder_ptr, const lzma_allocator *allocator)
+{
+ lzma_simple_coder *coder = coder_ptr;
+ lzma_next_end(&coder->next, allocator);
+ lzma_free(coder->simple, allocator);
+ lzma_free(coder, allocator);
+ return;
+}
+
+
+static lzma_ret
+simple_coder_update(void *coder_ptr, const lzma_allocator *allocator,
+ const lzma_filter *filters_null lzma_attribute((__unused__)),
+ const lzma_filter *reversed_filters)
+{
+ lzma_simple_coder *coder = coder_ptr;
+
+ // 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, const lzma_allocator *allocator,
+ const lzma_filter_info *filters,
+ size_t (*filter)(void *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_simple_coder structure if needed.
+ lzma_simple_coder *coder = next->coder;
+ if (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.
+ coder = lzma_alloc(sizeof(lzma_simple_coder)
+ + 2 * unfiltered_max, allocator);
+ if (coder == NULL)
+ return LZMA_MEM_ERROR;
+
+ next->coder = coder;
+ next->code = &simple_code;
+ next->end = &simple_coder_end;
+ next->update = &simple_coder_update;
+
+ coder->next = LZMA_NEXT_CODER_INIT;
+ coder->filter = filter;
+ coder->allocated = 2 * unfiltered_max;
+
+ // Allocate memory for filter-specific data structure.
+ if (simple_size > 0) {
+ coder->simple = lzma_alloc(simple_size, allocator);
+ if (coder->simple == NULL)
+ return LZMA_MEM_ERROR;
+ } else {
+ coder->simple = NULL;
+ }
+ }
+
+ if (filters[0].options != NULL) {
+ const lzma_options_bcj *simple = filters[0].options;
+ coder->now_pos = simple->start_offset;
+ if (coder->now_pos & (alignment - 1))
+ return LZMA_OPTIONS_ERROR;
+ } else {
+ coder->now_pos = 0;
+ }
+
+ // Reset variables.
+ coder->is_encoder = is_encoder;
+ coder->end_was_reached = false;
+ coder->pos = 0;
+ coder->filtered = 0;
+ coder->size = 0;
+
+ return lzma_next_filter_init(&coder->next, allocator, filters + 1);
+}