mirror of
https://github.com/WerWolv/ImHex-Patterns.git
synced 2026-03-28 07:47:02 -05:00
1cd7f92a5d
* Add `current_bit_offset()` and `read_bits(...)` to `std::mem` * Replace deprecated BitfieldOrder enum values with new clearer names This adds new options named `MostToLeastSignificant` and `LeastToMostSignificant` to replace the old `LeftToRight` and `RightToLeft` names. These names should be much clearer about what they affect and how. * Throw errors when `std::core::(get|set)_bitfield_order()` are called * Update all patterns to work with the new bitfield behaviors
119 lines
3.0 KiB
Rust
119 lines
3.0 KiB
Rust
// https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md
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#pragma MIME application/zstd
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#include <std/core.pat>
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#include <std/io.pat>
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#include <std/mem.pat>
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#include <std/sys.pat>
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using BitfieldOrder = std::core::BitfieldOrder;
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#define ZSTD_MAGIC_NUMBER 0xFD2FB528
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bitfield frame_header_descriptor_t {
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frame_content_size_flag : 2;
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single_segment_flag : 1;
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unused_bit : 1;
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reserved_bit : 1;
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content_checksum_flag : 1;
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dictionary_id_flag : 2;
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} [[bitfield_order(BitfieldOrder::MostToLeastSignificant, 8)]];
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bitfield window_descriptor_t {
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exponent : 5;
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mantissa : 3;
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} [[bitfield_order(BitfieldOrder::MostToLeastSignificant, 8)]];
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fn window_size(window_descriptor_t window_descriptor) {
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u64 window_log = 10 + window_descriptor.exponent;
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u64 window_base = 1 << window_log;
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u64 window_add = (window_base / 8) * window_descriptor.mantissa;
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u64 window_size = window_base + window_add;
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return window_size;
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};
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struct frame_header_t {
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frame_header_descriptor_t frame_header_descriptor;
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if (!frame_header_descriptor.single_segment_flag){
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window_descriptor_t window_descriptor;
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}
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if (frame_header_descriptor.dictionary_id_flag == 1) {
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le u8 dictionary_id;
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}
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else if (frame_header_descriptor.dictionary_id_flag == 2) {
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le u16 dictionary_id;
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}
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else if (frame_header_descriptor.dictionary_id_flag == 3) {
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le u32 dictionary_id;
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}
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if (frame_header_descriptor.frame_content_size_flag == 0) { // 0
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if (frame_header_descriptor.single_segment_flag) {
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le u8 content_size;
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}
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}
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else if (frame_header_descriptor.frame_content_size_flag == 1) {
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le u16 content_size;
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}
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else if (frame_header_descriptor.frame_content_size_flag == 2) {
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le u32 content_size;
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}
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else {
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le u64 content_size;
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}
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};
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bitfield block_header_t {
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last_block : 1;
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block_type : 2;
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block_size : 21;
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};
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enum block_type : u8 {
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raw_block = 0,
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rle_block = 1,
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compressed_block = 2,
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reserved = 3
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};
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struct data_block_t {
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block_header_t block_header;
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if (block_header.last_block) {
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last_block_flag = true;
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}
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if (block_header.block_type == block_type::raw_block) {
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le u8 block_content[block_header.block_size];
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}
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else if (block_header.block_type == block_type::rle_block) {
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le u8 block_content[1];
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}
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else if (block_header.block_type == block_type::compressed_block) {
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le u8 block_content[block_header.block_size];
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}
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else {
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std::error("The data block seems to be corrupted!");
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}
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};
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struct content_checksum_t {
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le u32 xxh64_hash;
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};
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struct zstd_frame_t {
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le u32 magic_number;
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std::assert(magic_number == ZSTD_MAGIC_NUMBER, "Invalid magic number!");
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frame_header_t frame_header;
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data_block_t data_block[while(!last_block_flag)];
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if (frame_header.frame_header_descriptor.content_checksum_flag) {
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content_checksum_t content_checksum;
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}
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};
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bool last_block_flag = false;
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zstd_frame_t zstd_frame @ 0x00;
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