search in utils

decompals · Dec 5, 2023 · 7f37e35 · 7f37e35
1 parent 0b4360c
commit 7f37e35
Show file tree

Hide file tree

Showing 3 changed files with 66 additions and 133 deletions.
diff --git a/src/utils.rs b/src/utils.rs
@@ -1,3 +1,5 @@
+use std::cmp;
+
 pub fn read_u32(bytes: &[u8], offset: usize) -> u32 {
     if offset % 4 != 0 {
         panic!("Unaligned offset");
@@ -6,20 +8,62 @@ pub fn read_u32(bytes: &[u8], offset: usize) -> u32 {
     u32::from_be_bytes(bytes[offset..offset + 4].try_into().unwrap())
 }
 
-fn initskip(pattern: &[u8], len: i32, skip: &mut [u16; 256]) {
-    skip.fill(len as u16);
+pub(crate) fn search(
+    input_pos: usize,
+    input_size: usize,
+    pos_out: &mut i32,
+    size_out: &mut u32,
+    data_in: &[u8],
+) {
+    let mut cur_size: usize = 3;
+    let mut found_pos: isize = 0;
+    let mut search_pos: usize = cmp::max(input_pos as isize - 0x1000, 0) as usize;
+    let search_size = cmp::min(input_size - input_pos, 0x111);
 
-    for i in 0..len {
-        skip[pattern[i as usize] as usize] = (len - i - 1) as u16;
+    if search_size >= 3 {
+        while search_pos < input_pos {
+            let found_offset = mischarsearch(
+                &data_in[input_pos..],
+                cur_size,
+                &data_in[search_pos..],
+                cur_size + input_pos - search_pos,
+            );
+
+            if found_offset >= input_pos - search_pos {
+                break;
+            }
+
+            while cur_size < search_size {
+                if data_in[cur_size + search_pos + found_offset] != data_in[cur_size + input_pos] {
+                    break;
+                }
+                cur_size += 1;
+            }
+
+            if search_size == cur_size {
+                *pos_out = (found_offset + search_pos) as i32;
+                *size_out = cur_size as u32;
+                return;
+            }
+
+            found_pos = (search_pos + found_offset) as isize;
+            search_pos = (found_pos + 1) as usize;
+            cur_size += 1;
+        }
+
+        *pos_out = found_pos as i32;
+        if cur_size > 3 {
+            cur_size -= 1;
+            *size_out = cur_size as u32;
+            return;
+        }
+    } else {
+        *pos_out = 0;
     }
+    *size_out = 0;
 }
 
-pub(crate) fn mischarsearch(
-    pattern: &[u8],
-    pattern_len: usize,
-    data: &[u8],
-    data_len: usize,
-) -> usize {
+fn mischarsearch(pattern: &[u8], pattern_len: usize, data: &[u8], data_len: usize) -> usize {
     let mut skip_table = [0u16; 256];
     let mut i: isize;
     //let mut k: usize;
@@ -60,3 +104,11 @@ pub(crate) fn mischarsearch(
     }
     data_len
 }
+
+fn initskip(pattern: &[u8], len: i32, skip: &mut [u16; 256]) {
+    skip.fill(len as u16);
+
+    for i in 0..len {
+        skip[pattern[i as usize] as usize] = (len - i - 1) as u16;
+    }
+}
diff --git a/src/yay0.rs b/src/yay0.rs
@@ -86,14 +86,14 @@ pub fn compress_yay0(bytes: &[u8]) -> Box<[u8]> {
         if v6 < v0 as u32 {
             v6 += 1024;
         }
-        search(v0, insize, &mut a3, &mut a4, bytes);
+        utils::search(v0, insize, &mut a3, &mut a4, bytes);
 
         if a4 <= 2 {
             cmd[cp] |= v1;
             def.push(bytes[v0]);
             v0 += 1;
         } else {
-            search(v0 + 1, insize, &mut v8, &mut v7, bytes);
+            utils::search(v0 + 1, insize, &mut v8, &mut v7, bytes);
             if v7 > a4 + 1 {
                 cmd[cp] |= v1;
                 def.push(bytes[v0]);
@@ -162,70 +162,6 @@ pub fn compress_yay0(bytes: &[u8]) -> Box<[u8]> {
     ret.into_boxed_slice()
 }
 
-fn search(
-    input_pos: usize,
-    input_size: usize,
-    pos_out: &mut i32,
-    size_out: &mut u32,
-    data_in: &[u8],
-) {
-    let mut cur_size: usize = 3;
-    let mut found_pos: isize = 0;
-    let mut search_pos: usize = 0;
-
-    if input_pos > 0x1000 {
-        search_pos = input_pos - 0x1000;
-    }
-
-    let mut search_size = 273;
-
-    if input_size - input_pos <= 273 {
-        search_size = input_size - input_pos;
-    }
-
-    if search_size >= 3 {
-        while search_pos < input_pos {
-            let found_offset = utils::mischarsearch(
-                &data_in[input_pos..],
-                cur_size,
-                &data_in[search_pos..],
-                cur_size + input_pos - search_pos,
-            );
-
-            if found_offset >= input_pos - search_pos {
-                break;
-            }
-
-            while cur_size < search_size {
-                if data_in[cur_size + search_pos + found_offset] != data_in[cur_size + input_pos] {
-                    break;
-                }
-                cur_size += 1;
-            }
-
-            if search_size == cur_size {
-                *pos_out = (found_offset + search_pos) as i32;
-                *size_out = cur_size as u32;
-                return;
-            }
-
-            found_pos = (search_pos + found_offset) as isize;
-            search_pos = (found_pos + 1) as usize;
-            cur_size += 1;
-        }
-
-        *pos_out = found_pos as i32;
-        if cur_size > 3 {
-            cur_size -= 1;
-            *size_out = cur_size as u32;
-            return;
-        }
-    } else {
-        *pos_out = 0;
-    }
-    *size_out = 0;
-}
-
 #[cfg(test)]
 mod tests {
     use core::panic;

diff --git a/src/yaz0.rs b/src/yaz0.rs
@@ -89,7 +89,7 @@ pub fn compress_yaz0(bytes: &[u8]) -> Box<[u8]> {
         let mut group_pos: i32 = 0;
         let mut group_size: u32 = 0;
 
-        search(
+        utils::search(
             input_pos,
             input_size,
             &mut group_pos,
@@ -109,7 +109,7 @@ pub fn compress_yaz0(bytes: &[u8]) -> Box<[u8]> {
             let mut new_position: i32 = 0;
 
             // Search for a new group after one position after the current one
-            search(
+            utils::search(
                 input_pos + 1,
                 input_size,
                 &mut new_position,
@@ -179,61 +179,6 @@ pub fn compress_yaz0(bytes: &[u8]) -> Box<[u8]> {
     output.into_boxed_slice()
 }
 
-fn search(
-    input_pos: usize,
-    input_size: usize,
-    pos_out: &mut i32,
-    size_out: &mut u32,
-    data_in: &[u8],
-) {
-    let mut cur_size: usize = 3;
-    let mut found_pos: isize = 0;
-    let mut search_pos: usize = cmp::max(input_pos as isize - 0x1000, 0) as usize;
-    let search_size = cmp::min(input_size - input_pos, 0x111);
-
-    if search_size >= 3 {
-        while search_pos < input_pos {
-            let found_offset = utils::mischarsearch(
-                &data_in[input_pos..],
-                cur_size,
-                &data_in[search_pos..],
-                cur_size + input_pos - search_pos,
-            );
-
-            if found_offset >= input_pos - search_pos {
-                break;
-            }
-
-            while cur_size < search_size {
-                if data_in[cur_size + search_pos + found_offset] != data_in[cur_size + input_pos] {
-                    break;
-                }
-                cur_size += 1;
-            }
-
-            if search_size == cur_size {
-                *pos_out = (found_offset + search_pos) as i32;
-                *size_out = cur_size as u32;
-                return;
-            }
-
-            found_pos = (search_pos + found_offset) as isize;
-            search_pos = (found_pos + 1) as usize;
-            cur_size += 1;
-        }
-
-        *pos_out = found_pos as i32;
-        if cur_size > 3 {
-            cur_size -= 1;
-            *size_out = cur_size as u32;
-            return;
-        }
-    } else {
-        *pos_out = 0;
-    }
-    *size_out = 0;
-}
-
 #[cfg(test)]
 mod tests {
     #[test]