From 5262a872f308b3b584c97d621992fb3877e392b8 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 05:10:08 +0200 Subject: Adding upstream version 5.6.1+really5.4.5. Signed-off-by: Daniel Baumann --- src/liblzma/simple/simple_coder.c | 292 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 292 insertions(+) create mode 100644 src/liblzma/simple/simple_coder.c (limited to 'src/liblzma/simple/simple_coder.c') diff --git a/src/liblzma/simple/simple_coder.c b/src/liblzma/simple/simple_coder.c new file mode 100644 index 0000000..ed2d7fb --- /dev/null +++ b/src/liblzma/simple/simple_coder.c @@ -0,0 +1,292 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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); +} -- cgit v1.2.3