better parity contexts integration for literal length

Cargo.toml

@@ -3,7 +3,8 @@ name = "upkr"
 version = "0.2.0-pre3"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[profile.release]
+strip = "debuginfo"
 
 [dependencies]
 cdivsufsort = "2"

asm_unpackers/Makefile

@@ -39,6 +39,19 @@ 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 $@
 	
+build/unpack_arm32: ../c_unpacker/main.c unpack_arm32.S
+	mkdir -p build
+	arm-linux-gnueabihf-gcc -g -static -o $@ $^
+
+test_arm32: build/unpack_arm32
+	qemu-arm $< test_data.upk /tmp/out.bin
+	cmp test_data.bin /tmp/out.bin
+
+build/unpack_arm32.bin: unpack_arm32.S
+	mkdir -p build
+	arm-none-eabi-gcc -c -o build/unpack_arm32.o $?
+	arm-none-eabi-objcopy -O binary --only-section=.text build/unpack_arm32.o $@
+	
 build/unpack_c: ../c_unpacker/main.c ../c_unpacker/unpack.c
 	mkdir -p build
 	gcc -g -o $@ $^
@@ -47,5 +60,5 @@ test_c: build/unpack_c
 	$< test_data.upk /tmp/out.bin
 	cmp test_data.bin /tmp/out.bin
 
-sizes: build/unpack_armv6m.bin build/unpack_riscv64.bin build/unpack_riscv32.bin
+sizes: build/unpack_armv6m.bin build/unpack_riscv64.bin build/unpack_riscv32.bin build/unpack_arm32.bin
 	ls -l build/*.bin

asm_unpackers/unpack_arm32.S

@@ -0,0 +1,100 @@
+.arm
+
+.section .text
+
+.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 .. context index
+// r6 .. decode_length temp
+// r7 .. probs ptr
+// r8-r11 .. decode_bit temp
+// r12 .. decode_length return address
+upkr_unpack:
+    push { r3-r11, lr }
+
+	mov r2, #384
+    mov r3, #128
+.Lclear:
+    subs r2, r2, #1
+    strb r3, [sp, -r2]
+    bne .Lclear
+
+.Lloop:
+    mov r5, #0
+    bl upkr_decode_bit
+    bcc .Ldata
+.Lmatch:
+	mov r5, #256
+    rsbs r6, r4, #0
+    blcc upkr_decode_bit
+    bcc .Lskip_offset
+
+    bl upkr_decode_length
+    adds r3, r4, #1
+    popeq { r3-r11, pc }
+.Lskip_offset:
+
+	mov r5, #256+64
+    bl upkr_decode_length
+.Lcopy_loop:
+    ldrb r5, [r0, r3]
+.Lstore:
+    strb r5, [r0], #1
+    adds r4, r4, #1
+    blt .Lcopy_loop
+    b .Lloop
+
+.Ldata:
+    mov r5, #1
+
+.Ldata_loop:
+    bl upkr_decode_bit
+    adc r5, r5, r5
+	movs r4, r5, lsr #8
+    beq .Ldata_loop
+	b .Lstore
+
+.type upkr_decode_length, %function
+upkr_decode_length:
+	mov r12, lr
+
+    mov r4, #0
+	mvn r6, #0
+.Lbit_loop:
+    bl upkr_decode_bit_inc
+	addcc r4, r4, r6
+	movcc pc, r12
+
+    bl upkr_decode_bit_inc
+    addcs r4, r4, r6
+	mov r6, r6, lsl #1
+    b .Lbit_loop
+
+.type upkr_decode_bit, %function
+upkr_decode_bit_inc:
+	add r5, r5, #1
+upkr_decode_bit:
+	cmp r2, #4096
+	ldrltb r8, [r1], #1
+	orrlt r2, r8, r2, lsl#8
+	blt upkr_decode_bit
+
+    ldrb r8, [sp, -r5]
+	and r9, r2, #255
+	add r9, r9, #1
+	cmp r8, r9
+	rsbcs r8, r8, #256
+	mvn r9, r2, lsr#8
+	addcs r9, r9, #1
+	mla r2, r8, r9, r2
+	add r9, r8, #8
+	sub r8, r8, r9, lsr#4
+	rsbcs r8, r8, #256
+	strb r8, [sp, -r5]
+	mov pc, r14
+

asm_unpackers/unpack_riscv.S

@@ -1,13 +1,11 @@
 .section .text
 
-#define FRAME_SIZE (256+32*4+4)
-
-// x8 prob array ptr
 // x9 prev was literal
 // x10 out ptr
 // x11 in ptr
 // x12 offset
 // x13 state
+// x14 context index
 
 .global upkr_unpack
 .type upkr_unpack, %function
@@ -15,11 +13,11 @@ upkr_unpack:
 	mv t4, ra
 	mv x17, x8
 	mv t6, x9
-	li x13, FRAME_SIZE
-	li x9, 128
+	li x9, 256 + 128
+	mv x13, x9
 1:
-	addi sp, sp, -1
-	sb x9, 0(sp)
+	sub x8, sp, x13
+	sb x9, 0(x8)
 	addi x13, x13, -1
 	bnez x13, 1b
 	
@@ -35,7 +33,7 @@ upkr_unpack:
 
 .Lfinished_offset:
 	addi x14, x14, 64
-	jal t3, upkr_decode_number
+	jalr ra // jal upkr_decode_number
 1:
 	add x14, x10, t0
 	lbu x14, (x14)
@@ -58,36 +56,14 @@ upkr_unpack:
 .Lread_offset_inc_x14:
 	addi x14, x14, 1
 .Lread_offset:
-	jal t3, upkr_decode_number
+	jalr ra // jal upkr_decode_number
 	addi t0, x9, 1
 	bnez t0, .Lfinished_offset
 .Ldone:
-	addi sp, sp, FRAME_SIZE
 	mv x8, x17
 	mv x9, t6
 	jr t4
 
-// x14 context index
-// return: x9 negtive decoded number 
-upkr_decode_number:
-	mv t5, x14
-	li x9, 0
-	li x8, -1
-1:
-	jal upkr_decode_bit
-	beqz x15, 1f
-	jal upkr_decode_bit
-	beqz x15, 2f
-	add x9, x9, x8
-2:
-	slli x8, x8, 1
-	j 1b
-1:
-	add x9, x9, x8
-	
-	mv x14, t5
-	jr t3
-
 upkr_load_byte:
 	lbu x15, 0(x11)
 	addi x11, x11, 1
@@ -104,39 +80,52 @@ upkr_decode_bit:
 	srli x15, x13, 12
 	beqz x15, upkr_load_byte
 
-	mv t1, x14
-	mv t2, x10
+	addi x14, x14, 1
 	
-	add x14, x14, sp
-	lbu x12, 0(x14)
+	sub t2, sp, x14
+	lbu x12, (t2)
 	
-	andi x10, x13, 255
-	sltu x15, x10, x12
-	srli x13, x13, 8
-	beqz x15, .Lelse
+	andi x8, x13, 255
+	sltu x15, x8, x12
+	beqz x15, 1f
+	xori x12, x12, 255
+	addi x12, x12, 1
+1:
+	srli x8, x13, 8
+	addi x8, x8, 1
+	sub x8, x8, x15
+	mul x8, x8, x12
+	sub x13, x13, x8
 	
-	mul x13, x13, x12
-	add x13, x13, x10
-	li x10, 256 + 8
-	sub x10, x10, x12
-	srli x10, x10, 4
-	add x12, x12, x10
-	j .Lendif
+	addi x8, x12, 8
+	srli x8, x8, 4
+	sub x12, x12, x8
+	beqz x15, 1f
+	sub x12, x0, x12
+1:
 
-.Lelse:
-	li x16, 256
-	sub x16, x16, x12
-	mul x13, x13, x16
-	add x13, x13, x10
-	sub x13, x13, x12
-	addi x10, x12, 8
-	srli x10, x10, 4
-	sub x12, x12, x10
-
-.Lendif:
-
-	sb x12, 0(x14)
+	sb x12, (t2)
 	
-	addi x14, t1, 1
-	mv x10, t2
-	ret
+	jalr ra
+
+// x14 context index
+// return: x9 negtive decoded number 
+upkr_decode_number:
+	mv t3, ra
+	mv t5, x14
+	li x9, 0
+	li t1, -1
+1:
+	jal upkr_decode_bit
+	beqz x15, 1f
+	jal upkr_decode_bit
+	beqz x15, 2f
+	add x9, x9, t1
+2:
+	add t1, t1, t1
+	j 1b
+1:
+	add x9, x9, t1
+	
+	mv x14, t5
+	jr t3

src/greedy_packer.rs

@@ -12,6 +12,8 @@ pub fn pack(
     let mut rans_coder = RansCoder::new(config);
     let mut state = lz::CoderState::new(config);
 
+    let mut literal = vec![];
+
     let mut pos = 0;
     while pos < data.len() {
         if let Some(ref mut cb) = progress_callback {
@@ -22,6 +24,10 @@ pub fn pack(
             let max_offset = config.max_offset.min(1 << (m.length * 3 - 1).min(31));
             let offset = pos - m.pos;
             if offset < max_offset && m.length >= config.min_length() {
+                if !literal.is_empty() {
+                    lz::Op::Literal(literal).encode(&mut rans_coder, &mut state, config);
+                    literal = vec![];
+                }
                 let length = m.length.min(config.max_length);
                 lz::Op::Match {
                     offset: offset as u32,
@@ -43,6 +49,10 @@ pub fn pack(
                     .count()
                     .min(config.max_length);
                 if length >= config.min_length() {
+                    if !literal.is_empty() {
+                        lz::Op::Literal(literal).encode(&mut rans_coder, &mut state, config);
+                        literal = vec![];
+                    }
                     lz::Op::Match {
                         offset: offset as u32,
                         len: length as u32,
@@ -55,11 +65,14 @@ pub fn pack(
         }
 
         if !encoded_match {
-            lz::Op::Literal(data[pos]).encode(&mut rans_coder, &mut state, config);
+            literal.push(data[pos]);
             pos += 1;
         }
     }
 
+    if !literal.is_empty() {
+        lz::Op::Literal(literal).encode(&mut rans_coder, &mut state, config);
+    }
     lz::encode_eof(&mut rans_coder, &mut state, config);
     rans_coder.finish()
 }

src/lz.rs

@@ -3,36 +3,53 @@ use crate::rans::{EntropyCoder, RansDecoder};
 use crate::Config;
 use thiserror::Error;
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Clone, Debug)]
 pub enum Op {
-    Literal(u8),
+    Literal(Vec<u8>),
     Match { offset: u32, len: u32 },
 }
 
 impl Op {
     pub fn encode(&self, coder: &mut dyn EntropyCoder, state: &mut CoderState, config: &Config) {
-        let literal_base = state.pos % state.parity_contexts * 256;
         match self {
-            &Op::Literal(lit) => {
-                encode_bit(coder, state, literal_base, !config.is_match_bit);
-                let mut context_index = 1;
-                for i in (0..8).rev() {
-                    let bit = (lit >> i) & 1 != 0;
-                    encode_bit(coder, state, literal_base + context_index, bit);
-                    context_index = (context_index << 1) | bit as usize;
+            &Op::Literal(ref lit) => {
+                assert!(state.prev_was_match);
+                encode_length(
+                    coder,
+                    state,
+                    256 + state.pos % state.parity_contexts * 320,
+                    lit.len() as u32 + 1,
+                    config,
+                );
+                for lit in lit {
+                    let literal_base = state.pos % state.parity_contexts * 320;
+                    let mut context_index = 1;
+                    for i in (0..8).rev() {
+                        let bit = (lit >> i) & 1 != 0;
+                        encode_bit(coder, state, literal_base + context_index, bit);
+                        context_index = (context_index << 1) | bit as usize;
+                    }
+                    state.pos += 1;
                 }
                 state.prev_was_match = false;
-                state.pos += 1;
             }
             &Op::Match { offset, len } => {
-                encode_bit(coder, state, literal_base, config.is_match_bit);
+                if state.prev_was_match {
+                    encode_length(
+                        coder,
+                        state,
+                        256 + state.pos % state.parity_contexts * 320,
+                        1,
+                        config,
+                    );
+                }
                 let mut new_offset = true;
                 if !state.prev_was_match && !config.no_repeated_offsets {
                     new_offset = offset != state.last_offset;
                     encode_bit(
                         coder,
                         state,
-                        256 * state.parity_contexts,
+                        320 * state.parity_contexts,
                         new_offset == config.new_offset_bit,
                     );
                 }
@@ -41,14 +58,14 @@ impl Op {
                     encode_length(
                         coder,
                         state,
-                        256 * state.parity_contexts + 1,
+                        320 * state.parity_contexts + 1,
                         offset + if config.eof_in_length { 0 } else { 1 },
                         config,
                     );
                     state.last_offset = offset;
                 }
                 assert!(len as usize >= config.min_length() && len as usize <= config.max_length);
-                encode_length(coder, state, 256 * state.parity_contexts + 65, len, config);
+                encode_length(coder, state, 320 * state.parity_contexts + 65, len, config);
                 state.prev_was_match = true;
                 state.pos += len as usize;
             }
@@ -57,25 +74,28 @@ impl Op {
 }
 
 pub fn encode_eof(coder: &mut dyn EntropyCoder, state: &mut CoderState, config: &Config) {
-    encode_bit(
-        coder,
-        state,
-        state.pos % state.parity_contexts * 256,
-        config.is_match_bit,
-    );
+    if state.prev_was_match {
+        encode_length(
+            coder,
+            state,
+            256 + state.pos % state.parity_contexts * 320,
+            1,
+            config,
+        );
+    }
     if !state.prev_was_match && !config.no_repeated_offsets {
         encode_bit(
             coder,
             state,
-            256 * state.parity_contexts,
+            320 * state.parity_contexts,
             config.new_offset_bit ^ config.eof_in_length,
         );
     }
     if !config.eof_in_length || state.prev_was_match || config.no_repeated_offsets {
-        encode_length(coder, state, 256 * state.parity_contexts + 1, 1, config);
+        encode_length(coder, state, 320 * state.parity_contexts + 1, 1, config);
     }
     if config.eof_in_length {
-        encode_length(coder, state, 256 * state.parity_contexts + 65, 1, config);
+        encode_length(coder, state, 320 * state.parity_contexts + 65, 1, config);
     }
 }
 
@@ -119,9 +139,9 @@ pub struct CoderState {
 impl CoderState {
     pub fn new(config: &Config) -> CoderState {
         CoderState {
-            contexts: ContextState::new((1 + 255) * config.parity_contexts + 1 + 64 + 64, config),
+            contexts: ContextState::new((64 + 256) * config.parity_contexts + 1 + 64 + 64, config),
             last_offset: 0,
-            prev_was_match: false,
+            prev_was_match: true,
             pos: 0,
             parity_contexts: config.parity_contexts,
         }
@@ -168,7 +188,8 @@ pub fn unpack_internal(
     max_size: usize,
 ) -> Result<isize, UnpackError> {
     let mut decoder = RansDecoder::new(packed_data, &config);
-    let mut contexts = ContextState::new((1 + 255) * config.parity_contexts + 1 + 64 + 64, &config);
+    let mut contexts =
+        ContextState::new((64 + 256) * config.parity_contexts + 1 + 64 + 64, &config);
     let mut offset = usize::MAX;
     let mut position = 0usize;
     let mut prev_was_match = false;
@@ -199,50 +220,14 @@ pub fn unpack_internal(
 
     loop {
         margin = margin.max(position as isize - decoder.pos() as isize);
-        let literal_base = position % config.parity_contexts * 256;
-        if decoder.decode_with_context(&mut contexts.context_mut(literal_base))?
-            == config.is_match_bit
-        {
-            if config.no_repeated_offsets
-                || prev_was_match
-                || decoder
-                    .decode_with_context(&mut contexts.context_mut(256 * config.parity_contexts))?
-                    == config.new_offset_bit
-            {
-                offset = decode_length(
-                    &mut decoder,
-                    &mut contexts,
-                    256 * config.parity_contexts + 1,
-                    &config,
-                )? - if config.eof_in_length { 0 } else { 1 };
-                if offset == 0 {
-                    break;
-                }
-            }
-            let length = decode_length(
-                &mut decoder,
-                &mut contexts,
-                256 * config.parity_contexts + 65,
-                &config,
-            )?;
-            if config.eof_in_length && length == 1 {
-                break;
-            }
-            if offset > position {
-                return Err(UnpackError::OffsetOutOfRange { offset, position });
-            }
-            if let Some(ref mut result) = result {
-                for _ in 0..length {
-                    if result.len() < max_size {
-                        result.push(result[result.len() - offset]);
-                    } else {
-                        break;
-                    }
-                }
-            }
-            position += length;
-            prev_was_match = true;
-        } else {
+        let literal_length = decode_length(
+            &mut decoder,
+            &mut contexts,
+            256 + position % config.parity_contexts * 320,
+            config,
+        )? - 1;
+        for _ in 0..literal_length {
+            let literal_base = position % config.parity_contexts * 320;
             let mut context_index = 1;
             let mut byte = 0;
             for i in (0..8).rev() {
@@ -259,6 +244,46 @@ pub fn unpack_internal(
             position += 1;
             prev_was_match = false;
         }
+
+        if config.no_repeated_offsets
+            || prev_was_match
+            || decoder
+                .decode_with_context(&mut contexts.context_mut(320 * config.parity_contexts))?
+                == config.new_offset_bit
+        {
+            offset = decode_length(
+                &mut decoder,
+                &mut contexts,
+                320 * config.parity_contexts + 1,
+                &config,
+            )? - if config.eof_in_length { 0 } else { 1 };
+            if offset == 0 {
+                break;
+            }
+        }
+        let length = decode_length(
+            &mut decoder,
+            &mut contexts,
+            320 * config.parity_contexts + 65,
+            &config,
+        )?;
+        if config.eof_in_length && length == 1 {
+            break;
+        }
+        if offset > position {
+            return Err(UnpackError::OffsetOutOfRange { offset, position });
+        }
+        if let Some(ref mut result) = result {
+            for _ in 0..length {
+                if result.len() < max_size {
+                    result.push(result[result.len() - offset]);
+                } else {
+                    break;
+                }
+            }
+        }
+        position += length;
+        prev_was_match = true;
     }
 
     if position > max_size {

src/main.rs

@@ -49,6 +49,12 @@ fn main() -> Result<()> {
                 config.is_match_bit = false;
                 config.new_offset_bit = false;
             }
+            Long("x86b") => {
+                config.use_bitstream = true;
+                config.continue_value_bit = false;
+                config.no_repeated_offsets = true;
+                level = 9;
+            }
 
             Short('u') | Long("unpack") => unpack = true,
             Long("margin") => calculate_margin = true,
@@ -154,6 +160,9 @@ fn print_help(exit_code: i32) -> ! {
     eprintln!(
         " --x86               --bitstream --invert-is-match-bit --invert-continue-value-bit --invert-new-offset-bit"
     );
+    eprintln!(
+        " --x86b              --bitstream --invert-continue-value-bit --no-repeated-offsets -9"
+    );
     eprintln!();
     eprintln!("Config options (need to match when packing/unpacking):");
     eprintln!(" -b, --bitstream     bitstream mode");

src/parsing_packer.rs

@@ -15,7 +15,7 @@ pub fn pack(
     let mut parse = parse(data, Config::from_level(level), config, progress_cb);
     let mut ops = vec![];
     while let Some(link) = parse {
-        ops.push(link.op);
+        ops.push(link.op.clone());
         parse = link.prev.clone();
     }
     let mut state = lz::CoderState::new(config);
@@ -32,9 +32,15 @@ struct Parse {
     op: lz::Op,
 }
 
+struct LiteralPrefix {
+    arrival: Arrival,
+    prefix: Vec<u8>,
+}
+
 struct Arrival {
     parse: Option<Rc<Parse>>,
     state: lz::CoderState,
+    literal_prefix: Option<Box<LiteralPrefix>>,
     cost: f64,
 }
 
@@ -130,6 +136,7 @@ fn parse(
                     op,
                 })),
                 state,
+                literal_prefix: None,
                 cost: arrival.cost + cost_counter.cost(),
             },
             max_arrivals,
@@ -141,6 +148,7 @@ fn parse(
         Arrival {
             parse: None,
             state: lz::CoderState::new(encoding_config),
+            literal_prefix: None,
             cost: 0.0,
         },
         max_arrivals,
@@ -252,19 +260,26 @@ fn parse(
             }
 
             cost_counter.reset();
-            let mut state = arrival.state;
-            let op = lz::Op::Literal(data[pos]);
+            let (arrival, mut prefix) = if let Some(prefix) = arrival.literal_prefix {
+                (prefix.arrival, prefix.prefix)
+            } else {
+                (arrival, vec![])
+            };
+            let mut state = arrival.state.clone();
+            prefix.push(data[pos]);
+            let op = lz::Op::Literal(prefix.clone());
             op.encode(cost_counter, &mut state, encoding_config);
             add_arrival(
                 &mut arrivals,
                 pos + 1,
                 Arrival {
                     parse: Some(Rc::new(Parse {
-                        prev: arrival.parse,
+                        prev: arrival.parse.clone(),
                         op,
                     })),
                     state,
                     cost: arrival.cost + cost_counter.cost(),
+                    literal_prefix: Some(Box::new(LiteralPrefix { arrival, prefix })),
                 },
                 max_arrivals,
             );