Index: xz/src/liblzma/simple/simple_coder.c |
=================================================================== |
--- xz/src/liblzma/simple/simple_coder.c (revision 0) |
+++ xz/src/liblzma/simple/simple_coder.c (revision 0) |
@@ -0,0 +1,280 @@ |
+/////////////////////////////////////////////////////////////////////////////// |
+// |
+/// \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); |
+} |
Property changes on: xz/src/liblzma/simple/simple_coder.c |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |