Allow skipping the version checks when using the version guessing sys…

…tem. The files will simply not decode if the version information is not correct.

psistega3-cli/src/main.rs

@@ -89,6 +89,7 @@ fn main() {
     // Attempt to extract the codec version number.
     // No default codec needs to be implemented here as the statement below
     //   will always yield a valid codec.
+    let mut skip_version_checks = false;
     let mut codec: Box<dyn Codec>;
     if needs_codec {
         let mut codec_version: Option<Version> = None;
@@ -106,6 +107,8 @@ fn main() {
                 } else {
                     show_abort_message(Error::VersionGuessingFailed);
                 }
+
+                skip_version_checks = true;
             }
 
             if let Ok(v) = version.parse::<u8>() {
@@ -129,6 +132,9 @@ fn main() {
         codec = Box::<StegaV2>::default();
     }
 
+    // When using the version guessing system, the checks are skipped.
+    codec.set_config_state(Config::SkipVersionChecks, skip_version_checks);
+
     // Execute the requested action with the provided arguments.
     let result = match action.as_str() {
         "-e" | "-encrypt" => handle_encode(&args[4..], &mut codec),

psistega3-core/src/codecs/codec.rs

@@ -89,22 +89,26 @@ pub trait Codec {
 pub enum Config {
     /// Enable or disable the noise map.
     ///
-    /// Applicable to: v1.
+    /// Applicable to: v1, v2.
     NoiseLayer,
     /// Enable or disable verbose mode.
     ///
-    /// Applicable to: v1.
+    /// Applicable to: v1, v2.
     Verbose,
     /// Enable or disable the saving of files when encoding or decoding.
     ///
-    /// Applicable to: v1.
+    /// Applicable to: v1, v2.
     OutputFiles,
     /// Enable or disable the file access locking system for this file.
     ///
-    /// Applicable to: v1.
+    /// Applicable to: v1, v2.
     Locker,
     /// Enable or disable the single-read locker system.
     ///
-    /// Applicable to: v1.
+    /// Applicable to: v1, v2.
     ReadOnce,
+    /// Enable or disable version checking.
+    ///
+    /// Applicable to: v2. This is not applicable to v1 as checks are never performed.
+    SkipVersionChecks,
 }

psistega3-core/src/codecs/v1.rs

@@ -881,6 +881,7 @@ impl Codec for StegaV1 {
             Config::ReadOnce => {
                 self.set_feature_flag_state(1, state);
             }
+            Config::SkipVersionChecks => {}
         }
     }
 }

psistega3-core/src/codecs/v2.rs

@@ -39,6 +39,8 @@ pub struct StegaV2 {
     noise_layer: bool,
     /// If the resulting image file should be saved when encoding.
     output_files: bool,
+    /// Should we skip version checks?
+    skip_version_checks: bool,
     /// Flags for use when encoding and decoding.
     /// Bit 0 indicates that the file locker is to be used with this file.
     /// Bit 1 indicates that the file is read-once.
@@ -65,6 +67,7 @@ impl StegaV2 {
             data_cell_map: HashMap::new(),
             noise_layer: true,
             output_files: true,
+            skip_version_checks: false,
             flags: 0,
             locker,
             logger: Logger::new(false),
@@ -597,6 +600,11 @@ impl StegaV2 {
             return false;
         }
 
+        if !self.skip_version_checks && data[5] != CODED_VERSION {
+            // The codec version does not match.
+            return false;
+        }
+
         // The 1st bit are be stored in byte 1.
         // Bit 1 stores the flag indicating whether the file locker should be
         //   used with this file.
@@ -881,6 +889,9 @@ impl Codec for StegaV2 {
             Config::ReadOnce => {
                 self.set_feature_flag_state(1, state);
             }
+            Config::SkipVersionChecks => {
+                self.skip_version_checks = state;
+            }
         }
     }
 }
@@ -1149,6 +1160,7 @@ mod tests_encode_decode {
             data_cell_map: HashMap::new(),
             noise_layer: false, // We do not need this here.
             output_files: true,
+            skip_version_checks: false,
             flags: 0,
             locker,
             logger: Logger::new(false),