Hex edit for binary columns

Implement the ability to edit binary columns as hex data.
Check input string for valid hex values; if invalid input,
open alert sheet.

Author: Michael Heins

Source/SPDataAdditions.h

@@ -43,6 +43,7 @@ typedef NS_OPTIONS(NSUInteger, SPLineTerminator) {
 - (NSData *)dataEncryptedWithKey:(NSData *)aesKey IV:(NSData *)iv;
 - (NSData *)dataDecryptedWithPassword:(NSString *)password;
 - (NSData *)dataDecryptedWithKey:(NSData *)key;
++ (NSData *)dataWithHexString: (NSString *)hex;
 
 - (NSData *)compress;
 - (NSData *)decompress;

Source/SPDataAdditions.m

@@ -343,6 +343,74 @@ - (NSString *)dataToHexString
 	return hexString;
 }
 
+static int hexval( char c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	if (c >= 'A' && c <= 'F')
+		return c - 'A' + 10;
+	return -1;
+}
+
+//
+// Interpret a string of hex digits in 'hex' as hex data, and return
+// an NSData representation of the data.  Spaces are permitted within
+// the string and an initial '0x' or '0X' will be ignored. If bad input
+// is detected, nil is returned.
+//
++ (NSData *)dataWithHexString: (NSString *)hex 
+{
+	int n = (int)(hex.length + 1);
+	if (n <= 1)
+		return nil;	// no string or empty string
+	char c, *str = (char *)malloc( n), *d = str, *e;
+	const char *s = hex.UTF8String;
+	//
+	// Copy input while removing spaces and tabs.
+	//
+	do {
+		c = *s++;
+		if (c != ' ' && c != '\t')
+			*d++ = c;
+	} while (c);
+	d = str;
+	if (d[0] == '0' && (d[1] == 'x' || d[1] == 'X')) {
+		d += 2;	// bypass initial 0x or 0X
+	}
+	//
+	// Check for non-hex characters
+	//
+	for (e = d; (c = *e); e++) {
+		if (hexval( c) < 0) {
+			break;
+		}
+	}
+	n = (int)(e - d);	// n = # of hex digits
+	if (*e) {
+		//
+		// Bad hex char at e. Return empty data.  Alternative would be to
+		// convert data up to bad point.
+		//
+		free( str);
+		return nil;
+	}
+	int nbytes = (n % 2) ? (n + 1) / 2 : n / 2;
+	unsigned char *bytes = malloc( nbytes), *b = bytes;
+	if (n % 2) {
+		*b++ = hexval( *d++);
+	}
+	while (d < e) {
+		unsigned char v = (hexval( d[0]) << 4) + hexval( d[1]);
+		*b++ = v;
+		d += 2;
+	}
+	NSData *data = [NSData dataWithBytesNoCopy: bytes length: nbytes freeWhenDone: YES];
+	free( str);
+	return data;
+}
+
 /**
  * Returns the hex representation of the given data.
  */

Source/SPTableContentDataSource.m

@@ -33,6 +33,7 @@
 #import "SPDataStorage.h"
 #import "SPCopyTable.h"
 #import "SPTablesList.h"
+#import "SPAlertSheets.h"
 
 #import <pthread.h>
 #import <SPMySQL/SPMySQL.h>
@@ -177,6 +178,11 @@ - (void)tableView:(NSTableView *)tableView setObjectValue:(id)object forTableCol
 			return;
 		}
 
+		NSInteger columnIndex = [[tableColumn identifier] integerValue];
+		NSDictionary *columnDefinition = [[(id <SPDatabaseContentViewDelegate>)[tableContentView delegate] dataColumnDefinitions] objectAtIndex:columnIndex];
+		
+		NSString *columnType = [columnDefinition objectForKey:@"typegrouping"];
+		
 		// Catch editing events in the row and if the row isn't currently being edited,
 		// start an edit.  This allows edits including enum changes to save correctly.
 		if (isEditingRow && [tableContentView selectedRow] != currentlyEditingRow) {
@@ -192,7 +198,28 @@ - (void)tableView:(NSTableView *)tableView setObjectValue:(id)object forTableCol
 
 		NSDictionary *column = NSArrayObjectAtIndex(dataColumns, [[tableColumn identifier] integerValue]);
 
-		if (object) {
+		if ([columnType isEqualToString:@"binary"] && [object isKindOfClass: [NSString class]]) {
+			//
+			// This is a binary object being edited as a hex string. (Is there a better
+			// way to detect this case?)
+			// Convert the string back to binary, checking for errors.
+			//
+			NSData *data = [NSData dataWithHexString: object];
+			if (data) {
+				object = data;
+				[tableValues replaceObjectInRow:rowIndex column:[[tableColumn identifier] integerValue] withObject:object];
+			}
+			else {
+				SPOnewayAlertSheet(
+								   NSLocalizedString(@"Error", @"error"),
+								   [tableDocumentInstance parentWindow],
+								   NSLocalizedString(@"Bad hexadecimal data input.", @"Bad hexadecimal data input.")
+								   );
+				return;
+
+			}
+		}
+		else if (object) {
 			// Restore NULLs if necessary
 			if ([object isEqualToString:[prefs objectForKey:SPNullValue]] && [[column objectForKey:@"null"] boolValue]) {
 				object = [NSNull null];

Source/SPTableContentDelegate.m

@@ -273,13 +273,6 @@ - (BOOL)tableView:(NSTableView *)tableView shouldEditTableColumn:(NSTableColumn
 			// Retrieve the column definition
 			NSDictionary *columnDefinition = [cqColumnDefinition objectAtIndex:[[tableColumn identifier] integerValue]];
 
-			// TODO: Fix editing of "Display as Hex" columns and remove this (also see above)
-			if ([self cellValueIsDisplayedAsHexForColumn:[[tableColumn identifier] integerValue]]) {
-				NSBeep();
-				[SPTooltip showWithObject:NSLocalizedString(@"Disable \"Display Binary Data as Hex\" in the View menu to edit this field.",@"Temporary : Tooltip shown when trying to edit a binary field in table content view while it is displayed using HEX conversion")];
-				return NO;
-			}
-			
 			// Open the editing sheet if required
 			if ([tableContentView shouldUseFieldEditorForRow:rowIndex column:[[tableColumn identifier] integerValue] checkWithLock:NULL]) {