r23662: According to simo, check_dos_char is needed

(This used to be commit c195eccefea69c17169c350a13bbfe845fc6fc44)

2 files changed, 52 insertions, 1 deletions

diff --git a/source3/lib/charcnv.c b/source3/lib/charcnv.c
index 7be073fafc..35343b2f0a 100644
--- a/source3/lib/charcnv.c
+++ b/source3/lib/charcnv.c
@@ -179,6 +179,7 @@ void init_iconv(void)
 		 * codepage changes? */
 		/* XXX: Is the did_reload test too strict? */
 		conv_silent = True;
+		init_doschar_table();
 		init_valid_table();
 		conv_silent = False;
 	}
diff --git a/source3/lib/util_unistr.c b/source3/lib/util_unistr.c
index 0221d19dc1..cf040a2dfc 100644
--- a/source3/lib/util_unistr.c
+++ b/source3/lib/util_unistr.c
@@ -36,6 +36,14 @@ static BOOL lowcase_table_use_unmap;
 static BOOL valid_table_use_unmap;
 
 /**
+ * This table says which Unicode characters are valid dos
+ * characters.
+ *
+ * Each value is just a single bit.
+ **/
+static uint8 doschar_table[8192]; /* 65536 characters / 8 bits/byte */
+
+/**
  * Destroy global objects allocated by load_case_tables()
  **/
 void gfree_case_tables(void)
@@ -142,6 +150,21 @@ void load_case_tables(void)
 #endif
 }
 
+/*
+  see if a ucs2 character can be mapped correctly to a dos character
+  and mapped back to the same character in ucs2
+*/
+
+int check_dos_char(smb_ucs2_t c)
+{
+	lazy_initialize_conv();
+	
+	/* Find the right byte, and right bit within the byte; return
+	 * 1 or 0 */
+	return (doschar_table[(c & 0xffff) / 8] & (1 << (c & 7))) != 0;
+}
+
+
 static int check_dos_char_slowly(smb_ucs2_t c)
 {
 	char buf[10];
@@ -159,6 +182,33 @@ static int check_dos_char_slowly(smb_ucs2_t c)
 	return (c == c2);
 }
 
+
+/**
+ * Fill out doschar table the hard way, by examining each character
+ **/
+
+void init_doschar_table(void)
+{
+	int i, j, byteval;
+
+	/* For each byte of packed table */
+	
+	for (i = 0; i <= 0xffff; i += 8) {
+		byteval = 0;
+		for (j = 0; j <= 7; j++) {
+			smb_ucs2_t c;
+
+			c = i + j;
+			
+			if (check_dos_char_slowly(c)) {
+				byteval |= 1 << j;
+			}
+		}
+		doschar_table[i/8] = byteval;
+	}
+}
+
+
 /**
  * Load the valid character map table from <tt>valid.dat</tt> or
  * create from the configured codepage.
@@ -207,7 +257,7 @@ void init_valid_table(void)
 	for (;i<0x10000;i++) {
 		smb_ucs2_t c;
 		SSVAL(&c, 0, i);
-		valid_table[i] = check_dos_char_slowly(c);
+		valid_table[i] = check_dos_char(c);
 	}
 }