Changeset 492 in code for trunk

Timestamp:

Apr 13, 2021, 10:48:46 AM (4 years ago)

Author:

hubert

Message:

Make casemapping work over bytes instead of runes

Fixes a panic in partialCasemap when the input string was invalid UTF-8.

File:

• trunk/irc.go (modified) (4 diffs)

trunk/irc.go

@@ -430 +430 @@
 // ascii casemapping.
 func casemapASCII(name string) string {
-        var sb strings.Builder
-        sb.Grow(len(name))
-        for _, r := range name {
+        nameBytes := []byte(name)
+        for i, r := range nameBytes {
                 if 'A' <= r && r <= 'Z' {
-                        r += 'a' - 'A'
-                }
-                sb.WriteRune(r)
-        }
-        return sb.String()
+                        nameBytes[i] = r + 'a' - 'A'
+                }
+        }
+        return string(nameBytes)
 }
 
@@ -444 +442 @@
 // rfc1459 casemapping.
 func casemapRFC1459(name string) string {
-        var sb strings.Builder
-        sb.Grow(len(name))
-        for _, r := range name {
+        nameBytes := []byte(name)
+        for i, r := range nameBytes {
                 if 'A' <= r && r <= 'Z' {
-                        r += 'a' - 'A'
+                        nameBytes[i] = r + 'a' - 'A'
                 } else if r == '{' {
-                        r = '['
+                        nameBytes[i] = '['
                 } else if r == '}' {
-                        r = ']'
+                        nameBytes[i] = ']'
                 } else if r == '\\' {
-                        r = '|'
+                        nameBytes[i] = '|'
                 } else if r == '~' {
-                        r = '^'
-                }
-                sb.WriteRune(r)
-        }
-        return sb.String()
+                        nameBytes[i] = '^'
+                }
+        }
+        return string(nameBytes)
 }
 
@@ -466 +462 @@
 // according to the rfc1459-strict casemapping.
 func casemapRFC1459Strict(name string) string {
-        var sb strings.Builder
-        sb.Grow(len(name))
-        for _, r := range name {
+        nameBytes := []byte(name)
+        for i, r := range nameBytes {
                 if 'A' <= r && r <= 'Z' {
-                        r += 'a' - 'A'
+                        nameBytes[i] = r + 'a' - 'A'
                 } else if r == '{' {
-                        r = '['
+                        nameBytes[i] = '['
                 } else if r == '}' {
-                        r = ']'
+                        nameBytes[i] = ']'
                 } else if r == '\\' {
-                        r = '|'
-                }
-                sb.WriteRune(r)
-        }
-        return sb.String()
+                        nameBytes[i] = '|'
+                }
+        }
+        return string(nameBytes)
 }
 
@@ -498 +492 @@
 
 func partialCasemap(higher casemapping, name string) string {
-        nameFullyCM := higher(name)
-        var sb strings.Builder
-        sb.Grow(len(name))
-        for i, r := range nameFullyCM {
-                if 'a' <= r && r <= 'z' {
-                        r = rune(name[i])
-                }
-                sb.WriteRune(r)
-        }
-        return sb.String()
+        nameFullyCM := []byte(higher(name))
+        nameBytes := []byte(name)
+        for i, r := range nameBytes {
+                if !('A' <= r && r <= 'Z') && !('a' <= r && r <= 'z') {
+                        nameBytes[i] = nameFullyCM[i]
+                }
+        }
+        return string(nameBytes)
 }