dohertj2/lmxopcua
1
0
Fork 0
Code Issues 1 Pull Requests 1 Actions Packages Projects Releases Wiki Activity

fix(driver-ablegacy): resolve Medium code-review finding (Driver.AbLegacy-004)

Browse Source 
DecodeValue for Bit with no bitIndex now reads the full 16-bit word via
GetInt16(0) and tests bit 0 instead of GetInt8(0), which only covered the
low byte and silently misread any bit in positions 8..15. The comment
explains the two decode paths (suffix-present vs suffix-absent).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Joseph Doherty
2026-05-22 09:24:19 -04:00
parent 7d30009dc8
commit 47eac2d84f
2 changed files with 7 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/LibplctagLegacyTagRuntime.cs
View File

@@ -33,9 +33,13 @@ internal sealed class LibplctagLegacyTagRuntime : IAbLegacyTagRuntime
public object? DecodeValue(AbLegacyDataType type, int? bitIndex) => type switch
{
// When a bit suffix is present (e.g. B3:0/5) libplctag resolves the individual bit and
// GetBit returns it directly. When there is no suffix the caller addressed a Bit-typed
// tag without an explicit bit index; read the full 16-bit word and test bit 0 — GetInt8
// only covers the low byte and silently misses any bit set in bits 8..15.
AbLegacyDataType.Bit => bitIndex is int bit
? _tag.GetBit(bit)
: _tag.GetInt8(0) != 0,
: (_tag.GetInt16(0) & 1) != 0,
AbLegacyDataType.Int or AbLegacyDataType.AnalogInt => (int)_tag.GetInt16(0),
AbLegacyDataType.Long => _tag.GetInt32(0),
AbLegacyDataType.Float => _tag.GetFloat32(0),