Fix, IBitView::set() fails with ranges within a single byte.

gknowles · gknowles · commit dbcb66ea7a0f · 2025-12-20T00:42:29.000-08:00
diff --git a/libs/basic/bitspan.cpp b/libs/basic/bitspan.cpp
@@ -479,7 +479,7 @@ static void set(void * vdst, size_t dpos, size_t dcnt) {
     dpos = dpos % 8;
     if (dpos) {
         if (dpos + dcnt <= 8) {
-            auto mask = (unsigned char) (255 << (8 - dcnt) >> dpos);
+            unsigned char mask = UCHAR_MAX >> (8 - dcnt) << (8 - dpos - dcnt);
             apply<Op, unsigned char>(dst, nullptr, mask);
             return;
         }
@@ -502,7 +502,7 @@ static void set(void * vdst, size_t dpos, size_t dcnt) {
             return;
         dst += bytes;
     }
-    auto mask = (unsigned char) (255 << (8 - dcnt));
+    unsigned char mask = UCHAR_MAX << (8 - dcnt);
     apply<Op, unsigned char>(dst, nullptr, mask);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -479,7 +479,7 @@ static void set(void * vdst, size_t dpos, size_t dcnt) {`
`479`	`479`	`dpos = dpos % 8;`
`480`	`480`	`if (dpos) {`
`481`	`481`	`if (dpos + dcnt <= 8) {`
`482`		`- auto mask = (unsigned char) (255 << (8 - dcnt) >> dpos);`
	`482`	`+ unsigned char mask = UCHAR_MAX >> (8 - dcnt) << (8 - dpos - dcnt);`
`483`	`483`	`apply<Op, unsigned char>(dst, nullptr, mask);`
`484`	`484`	`return;`
`485`	`485`	`}`
`@@ -502,7 +502,7 @@ static void set(void * vdst, size_t dpos, size_t dcnt) {`
`502`	`502`	`return;`
`503`	`503`	`dst += bytes;`
`504`	`504`	`}`
`505`		`- auto mask = (unsigned char) (255 << (8 - dcnt));`
	`505`	`+ unsigned char mask = UCHAR_MAX << (8 - dcnt);`
`506`	`506`	`apply<Op, unsigned char>(dst, nullptr, mask);`
`507`	`507`	`}`
`508`	`508`