hacked parity context version for arm code

asm_unpackers/.gitignore

@@ -1 +0,0 @@
-/build/

asm_unpackers/Makefile

@@ -1,22 +0,0 @@
-build/unpack_riscv64: ../c_unpacker/main.c ../c_unpacker/unpack.c
-	mkdir -p build
-	riscv64-linux-gnu-gcc -g -static -o $@ $^
-
-test_riscv64: build/unpack_riscv64
-	qemu-riscv64 $< test_data.upk /tmp/out.bin
-	cmp test_data.bin /tmp/out.bin
-
-build/unpack_armv6m: ../c_unpacker/main.c unpack_armv6m.S
-	mkdir -p build
-	arm-linux-gnueabihf-gcc -g -static -o $@ $^
-
-test_armv6m: build/unpack_armv6m
-	qemu-arm $< test_data.upk /tmp/out.bin
-	cmp test_data.bin /tmp/out.bin
-
-build/unpack_armv6m.bin: unpack_armv6m.S
-	arm-none-eabi-gcc -march=armv6-m -c -o build/unpack_armv6m.o $?
-	arm-none-eabi-objcopy -O binary --only-section=.text build/unpack_armv6m.o $@
-
-sizes: build/unpack_armv6m.bin
-	ls -l build/*.bin

asm_unpackers/test_data.bin

@@ -1,99 +0,0 @@
-typedef unsigned char u8;
-typedef unsigned short u16;
-typedef unsigned long u32;
-
-u8* upkr_data_ptr;
-u8 upkr_probs[1 + 255 + 1 + 2*32 + 2*32]; 
-#ifdef UPKR_BITSTREAM
-u16 upkr_state;
-u8 upkr_current_byte;
-int upkr_bits_left;
-#else
-u32 upkr_state;
-#endif
-
-int upkr_decode_bit(int context_index) {
-#ifdef UPKR_BITSTREAM
-    while(upkr_state < 32768) {
-        if(upkr_bits_left == 0) {
-            upkr_current_byte = *upkr_data_ptr++;
-            upkr_bits_left = 8;
-        }
-        upkr_state = (upkr_state << 1) + (upkr_current_byte & 1);
-        upkr_current_byte >>= 1;
-        --upkr_bits_left;
-    }
-#else
-    while(upkr_state < 4096) {
-        upkr_state = (upkr_state << 8) | *upkr_data_ptr++;
-    }
-#endif
-   
-    int prob = upkr_probs[context_index];
-    int bit = (upkr_state & 255) < prob ? 1 : 0;
-    
-    int tmp = prob;
-    if(!bit) {
-        tmp = 256 - tmp;
-    }
-    upkr_state = tmp * (upkr_state >> 8) + (upkr_state & 255);
-    tmp += (256 - tmp + 8) >> 4;
-    if(!bit) {
-        upkr_state -= prob;
-        tmp = 256 - tmp;
-    }
-    upkr_probs[context_index] = tmp;
-
-    return bit;
-}
-
-int upkr_decode_length(int context_index) {
-    int length = 0;
-    int bit_pos = 0;
-    while(upkr_decode_bit(context_index)) {
-        length |= upkr_decode_bit(context_index + 1) << bit_pos++;
-        context_index += 2;
-    }
-    return length | (1 << bit_pos);
-}
-
-void* upkr_unpack(void* destination, void* compressed_data) {
-    upkr_data_ptr = (u8*)compressed_data;
-    upkr_state = 0;
-#ifdef UPKR_BITSTREAM
-    upkr_bits_left = 0;
-#endif
-    for(int i = 0; i < sizeof(upkr_probs); ++i)
-        upkr_probs[i] = 128;
-    
-    u8* write_ptr = (u8*)destination;
-    
-    int prev_was_match = 0;
-    int offset = 0;
-    for(;;) {
-        if(upkr_decode_bit(0)) {
-            if(prev_was_match || upkr_decode_bit(256)) {
-                offset = upkr_decode_length(257) - 1;
-                if(offset == 0) {
-                    break;
-                }
-            }
-            int length = upkr_decode_length(257 + 64);
-            while(length--) {
-                *write_ptr = write_ptr[-offset];
-                ++write_ptr;
-            }
-            prev_was_match = 1;
-        } else {
-            int byte = 1;
-            while(byte < 256) {
-                int bit = upkr_decode_bit(byte);
-                byte = (byte << 1) + bit;
-            }
-            *write_ptr++ = byte;
-            prev_was_match = 0;
-        }
-    }
-    
-    return write_ptr;
-}

asm_unpackers/unpack_armv6m.S

@@ -1,162 +0,0 @@
-// armv6-m upkr unpacker by yrlf
-// some optimizations by exoticorn
-
-.syntax unified
-.thumb
-
-.section .text
-
-#define ALIGNUP(n, align) (((n) + (align) - 1) & ~((align) - 1))
-#define PROB_LEN (1 + 255 + 1 + 2*32 + 2*32)
-#define FRAME_SIZE ALIGNUP(PROB_LEN, 4)
-
-// auto upkr_unpack(uint8_t * out, uint8_t * in) -> tuple<uint8_t *, uint8_t *>
-.global upkr_unpack
-.type upkr_unpack, %function
-// r0 .. out_ptr (returned)
-// r1 .. in_ptr (returned)
-// r2 .. state
-// r3 .. offset
-// r4 .. prev_was_literal / decode_length ret
-// r5 .. subroutine arg (preserved)
-// r6 .. decode_bit ret
-// r7 .. probs ptr
-upkr_unpack:
-    push { r4, r5, r6, r7, lr }
-    sub sp, sp, #FRAME_SIZE
-
-    mov r7, sp
-    movs r2, #255
-    adds r2, r2, #(PROB_LEN - 255)
-    movs r3, #128
-.Lclear:
-    subs r2, r2, #1
-    strb r3, [r7, r2]
-    bne .Lclear
-
-.Lloop:
-    movs r5, #0
-    bl upkr_decode_bit
-    beq .Ldata
-.Lmatch:
-    // r6 = 1
-    lsls r5, r6, #8
-    cmp r4, #0
-    beq 1f
-
-    bl upkr_decode_bit
-    beq 2f
-
-1:
-    bl upkr_decode_length
-    adds r3, r4, #1
-    beq .Lend
-2:
-
-    adds r5, r5, #64
-    bl upkr_decode_length
-.Lcopy_loop:
-    ldrb r5, [r0, r3]
-.Lstore:
-    strb r5, [r0]
-    adds r0, r0, #1
-    adds r4, r4, #1
-    blt .Lcopy_loop
-    b .Lloop
-
-.Ldata:
-    movs r5, #1
-
-.Ldata_loop:
-    bl upkr_decode_bit
-    adcs r5, r5, r5
-    lsrs r4, r5, #8
-    beq .Ldata_loop
-    b .Lstore
-
-.Lend:
-    add sp, sp, #FRAME_SIZE
-    pop { r4, r5, r6, r7, pc }
-
-.type upkr_decode_length, %function
-// r0 .. -length tmp (saved)
-// r1 ..
-// r2 ..
-// r3 ..
-// r4 .. -length (returned)
-// r5 .. context index (saved)
-// r6 .. (saved)
-// r7 ..
-upkr_decode_length:
-    push { r0, r5, r6, lr }
-
-    movs r0, #0
-    subs r4, r0, #1
-.Lbit_loop:
-    adds r5, r5, #1
-    bl upkr_decode_bit
-    beq 1f
-
-    adds r5, r5, #1
-    bl upkr_decode_bit
-    beq 2f
-    adds r0, r0, r4
-2:
-    lsls r4, r4, #1
-    b .Lbit_loop
-1:
-    adds r4, r4, r0
-
-    pop { r0, r5, r6, pc }
-
-.type upkr_decode_bit, %function
-// r0 .. tmp / prob (saved)
-// r1 .. in_ptr (modified)
-// r2 .. state (modified)
-// r3 .. scratch (saved)
-// r4 ..
-// r5 .. context index (preserved)
-// r6 .. bit (returned)
-// r7 .. probs ptr (preserved)
-upkr_fill_state:
-    lsls r2, r2, #8
-    ldrb r6, [r1]
-    adds r1, r1, #1
-    orrs r2, r2, r6
-
-upkr_decode_bit:
-    lsrs r6, r2, #12
-    beq upkr_fill_state
-
-    push { r0, r1, r3, lr }
-
-    ldrb r0, [r7, r5]
-
-    lsrs r3, r2, #8
-    uxtb r1, r2
-
-    subs r6, r1, r0
-    blt 1f
-
-    subs r1, r2, r0
-    rsbs r0, r0, #0
-1:
-
-    muls r3, r3, r0
-    adds r2, r1, r3
-
-    rsbs r3, r0, #0
-    uxtb r3, r3
-    lsrs r3, r3, #4
-    adcs r0, r0, r3
-
-    cmp r6, #0
-    blt 1f
-
-    rsbs r0, r0, #0
-1:
-
-    strb r0, [r7, r5]
-
-    lsrs r6, r6, #31
-    pop { r0, r1, r3, pc }

c_unpacker/.gitignore

@@ -1,5 +0,0 @@
-unpack
-unpack_bitstream
-unpack_debug
-*.upk
-

c_unpacker/Makefile

@@ -1,10 +0,0 @@
-all: unpack unpack_bitstream
-
-unpack: main.c unpack.c
-	cc -O2 -o unpack main.c unpack.c
-
-unpack_bitstream: main.c unpack.c
-	cc -O2 -D UPKR_BITSTREAM -o unpack_bitstream main.c unpack.c
-	
-unpack_debug: main.c unpack.c
-	cc -g -o unpack_debug main.c unpack.c

c_unpacker/main.c

@@ -1,26 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-
-void* upkr_unpack(void* destination, void* compressed_data);
-
-int main(int argn, char** argv) {
-  void* input_buffer = malloc(1024*1024);
-  void* output_buffer = malloc(1024*1024);
-  
-  FILE* in_file = fopen(argv[1], "rb");
-  int in_size = fread(input_buffer, 1, 1024*1024, in_file);
-  fclose(in_file);
-  
-  printf("Compressed size: %d\n", in_size);
-  
-  void* end_ptr = upkr_unpack(output_buffer, input_buffer);
-  int out_size = (char*)end_ptr - (char*)output_buffer;
-  
-  printf("Uncompressed size: %d\n", out_size);
-  
-  FILE* out_file = fopen(argv[2], "wb");
-  fwrite(output_buffer, 1, out_size, out_file);
-  fclose(out_file);
-  
-  return 0;
-}

c_unpacker/readme.txt

@@ -1,4 +0,0 @@
-a very simple unpacker in c, as a reference for people wanting to implement their own unpacker.
-absolutely not production ready, it makes no effort to ensure the output buffer can actually
-hold the uncompressed data.
-!!! Never run on untrusted input !!!

c_unpacker/unpack.c

@@ -1,99 +0,0 @@
-typedef unsigned char u8;
-typedef unsigned short u16;
-typedef unsigned long u32;
-
-u8* upkr_data_ptr;
-u8 upkr_probs[1 + 255 + 1 + 2*32 + 2*32]; 
-#ifdef UPKR_BITSTREAM
-u16 upkr_state;
-u8 upkr_current_byte;
-int upkr_bits_left;
-#else
-u32 upkr_state;
-#endif
-
-int upkr_decode_bit(int context_index) {
-#ifdef UPKR_BITSTREAM
-    while(upkr_state < 32768) {
-        if(upkr_bits_left == 0) {
-            upkr_current_byte = *upkr_data_ptr++;
-            upkr_bits_left = 8;
-        }
-        upkr_state = (upkr_state << 1) + (upkr_current_byte & 1);
-        upkr_current_byte >>= 1;
-        --upkr_bits_left;
-    }
-#else
-    while(upkr_state < 4096) {
-        upkr_state = (upkr_state << 8) | *upkr_data_ptr++;
-    }
-#endif
-   
-    int prob = upkr_probs[context_index];
-    int bit = (upkr_state & 255) < prob ? 1 : 0;
-    
-    int tmp = prob;
-    if(!bit) {
-        tmp = 256 - tmp;
-    }
-    upkr_state = tmp * (upkr_state >> 8) + (upkr_state & 255);
-    tmp += (256 - tmp + 8) >> 4;
-    if(!bit) {
-        upkr_state -= prob;
-        tmp = 256 - tmp;
-    }
-    upkr_probs[context_index] = tmp;
-
-    return bit;
-}
-
-int upkr_decode_length(int context_index) {
-    int length = 0;
-    int bit_pos = 0;
-    while(upkr_decode_bit(context_index)) {
-        length |= upkr_decode_bit(context_index + 1) << bit_pos++;
-        context_index += 2;
-    }
-    return length | (1 << bit_pos);
-}
-
-void* upkr_unpack(void* destination, void* compressed_data) {
-    upkr_data_ptr = (u8*)compressed_data;
-    upkr_state = 0;
-#ifdef UPKR_BITSTREAM
-    upkr_bits_left = 0;
-#endif
-    for(int i = 0; i < sizeof(upkr_probs); ++i)
-        upkr_probs[i] = 128;
-    
-    u8* write_ptr = (u8*)destination;
-    
-    int prev_was_match = 0;
-    int offset = 0;
-    for(;;) {
-        if(upkr_decode_bit(0)) {
-            if(prev_was_match || upkr_decode_bit(256)) {
-                offset = upkr_decode_length(257) - 1;
-                if(offset == 0) {
-                    break;
-                }
-            }
-            int length = upkr_decode_length(257 + 64);
-            while(length--) {
-                *write_ptr = write_ptr[-offset];
-                ++write_ptr;
-            }
-            prev_was_match = 1;
-        } else {
-            int byte = 1;
-            while(byte < 256) {
-                int bit = upkr_decode_bit(byte);
-                byte = (byte << 1) + bit;
-            }
-            *write_ptr++ = byte;
-            prev_was_match = 0;
-        }
-    }
-    
-    return write_ptr;
-}

src/lib.rs

@@ -21,12 +21,3 @@ pub fn pack(
         parsing_packer::pack(data, level, use_bitstream, progress_callback)
     }
 }
-
-pub fn compressed_size(mut data: &[u8]) -> f32 {
-    let mut state = 0;
-    while state < 4096 {
-        state = (state << 8) | data[0] as u32;
-        data = &data[1..];
-    }
-    data.len() as f32 + (state as f32).log2() / 8.
-}

src/lz.rs

@@ -9,29 +9,32 @@ pub enum Op {
 
 impl Op {
     pub fn encode(&self, coder: &mut dyn EntropyCoder, state: &mut CoderState) {
+        let base_context = 256 * (state.pos & 3);
         match self {
             &Op::Literal(lit) => {
-                encode_bit(coder, state, 0, false);
+                encode_bit(coder, state, base_context, false);
                 let mut context_index = 1;
                 for i in (0..8).rev() {
                     let bit = (lit >> i) & 1 != 0;
-                    encode_bit(coder, state, context_index, bit);
+                    encode_bit(coder, state, base_context + context_index, bit);
                     context_index = (context_index << 1) | bit as usize;
                 }
+                state.pos += 1;
                 state.prev_was_match = false;
             }
             &Op::Match { offset, len } => {
-                encode_bit(coder, state, 0, true);
+                encode_bit(coder, state, base_context, true);
                 if !state.prev_was_match {
-                    encode_bit(coder, state, 256, offset != state.last_offset);
+                    encode_bit(coder, state, 1024, offset != state.last_offset);
                 } else {
                     assert!(offset != state.last_offset);
                 }
                 if offset != state.last_offset {
-                    encode_length(coder, state, 257, offset + 1);
+                    encode_length(coder, state, 1025, offset + 1);
                     state.last_offset = offset;
                 }
-                encode_length(coder, state, 257 + 64, len);
+                encode_length(coder, state, 1025 + 64, len);
+                state.pos += len as usize;
                 state.prev_was_match = true;
             }
         }
@@ -39,11 +42,11 @@ impl Op {
 }
 
 pub fn encode_eof(coder: &mut dyn EntropyCoder, state: &mut CoderState) {
-    encode_bit(coder, state, 0, true);
+    encode_bit(coder, state, 256 * (state.pos & 3), true);
     if !state.prev_was_match {
-        encode_bit(coder, state, 256, true);
+        encode_bit(coder, state, 1024, true);
     }
-    encode_length(coder, state, 257, 1);
+    encode_length(coder, state, 1025, 1);
 }
 
 fn encode_bit(
@@ -77,14 +80,16 @@ fn encode_length(
 pub struct CoderState {
     contexts: ContextState,
     last_offset: u32,
+    pos: usize,
     prev_was_match: bool,
 }
 
 impl CoderState {
     pub fn new() -> CoderState {
         CoderState {
-            contexts: ContextState::new(1 + 255 + 1 + 64 + 64),
+            contexts: ContextState::new((1 + 255) * 4 + 1 + 64 + 64),
             last_offset: 0,
+            pos: 0,
             prev_was_match: false,
         }
     }
@@ -96,7 +101,7 @@ impl CoderState {
 
 pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
     let mut decoder = RansDecoder::new(packed_data, use_bitstream);
-    let mut contexts = ContextState::new(1 + 255 + 1 + 64 + 64);
+    let mut contexts = ContextState::new((1 + 255) * 4 + 1 + 64 + 64);
     let mut result = vec![];
     let mut offset = 0;
     let mut prev_was_match = false;
@@ -119,14 +124,15 @@ pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
     }
 
     loop {
-        if decoder.decode_with_context(&mut contexts.context_mut(0)) {
+        let base_context = 256 * (result.len() & 3);
-            if prev_was_match || decoder.decode_with_context(&mut contexts.context_mut(256)) {
+        if decoder.decode_with_context(&mut contexts.context_mut(base_context)) {
-                offset = decode_length(&mut decoder, &mut contexts, 257) - 1;
+            if prev_was_match || decoder.decode_with_context(&mut contexts.context_mut(1024)) {
+                offset = decode_length(&mut decoder, &mut contexts, 1025) - 1;
                 if offset == 0 {
                     break;
                 }
             }
-            let length = decode_length(&mut decoder, &mut contexts, 257 + 64);
+            let length = decode_length(&mut decoder, &mut contexts, 1025 + 64);
             for _ in 0..length {
                 result.push(result[result.len() - offset]);
             }
@@ -135,7 +141,7 @@ pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
             let mut context_index = 1;
             let mut byte = 0;
             for i in (0..8).rev() {
-                let bit = decoder.decode_with_context(&mut contexts.context_mut(context_index));
+                let bit = decoder.decode_with_context(&mut contexts.context_mut(base_context + context_index));
                 context_index = (context_index << 1) | bit as usize;
                 byte |= (bit as u8) << i;
             }

src/main.rs

@@ -16,7 +16,7 @@ fn main() -> Result<()> {
 
             let mut data = vec![];
             File::open(infile)?.read_to_end(&mut data)?;
-
+            
             let mut pb = pbr::ProgressBar::new(data.len() as u64);
             pb.set_units(pbr::Units::Bytes);
             let packed_data = upkr::pack(
@@ -58,10 +58,7 @@ fn main() -> Result<()> {
 
 fn print_help() {
     eprintln!("Usage:");
-    eprintln!("  upkr pack [-b] [-l level(0-9)] <infile> <outfile>");
+    eprintln!("  upkr pack [-l level(0-9)] <infile> <outfile>");
-    eprintln!("  upkr unpack [-b] <infile> <outfile>");
+    eprintln!("  upkr unpack <infile> <outfile>");
-    eprintln!();
-    eprintln!(" -b, --bitstream     bitstream mode");
-    eprintln!(" -l, --level N       compression level 0-9");
     std::process::exit(1);
 }