diff --git a/convert/convert.c b/convert/convert.c
index 5cfd8ce..439d656 100644
--- a/convert/convert.c
+++ b/convert/convert.c
@@ -24,12 +24,12 @@ int ConverterBuild(struct Converter *c, Handle data, Size datasz,
 	}
 	engine = (UInt8)(**data) - 1;
 	if (engine < 0 || (int)(sizeof(kEngines) / sizeof(*kEngines)) <= engine) {
-		/* Invalid engine. */
+		// Invalid engine.
 		return kErrorBadData;
 	}
 	funcs = &kEngines[engine][direction];
 	if (funcs->build == NULL || funcs->run == NULL) {
-		/* Invalid engine. */
+		// Invalid engine.
 		return kErrorBadData;
 	}
 	err = funcs->build(&out, data, datasz);
diff --git a/convert/convert.h b/convert/convert.h
index 3f23f9e..0e7b698 100644
--- a/convert/convert.h
+++ b/convert/convert.h
@@ -3,68 +3,71 @@
 // Mozilla Public License, version 2.0. See LICENSE.txt for details.
 #ifndef CONVERT_CONVERT_H
 #define CONVERT_CONVERT_H
-/* convert.h - character set conversion routines. */
+// convert.h - character set conversion routines.
 
 #include "lib/defs.h"
 #include "lib/error.h"
 
 enum {
-	/* Constants for CR and LF. Note that we should not use '\n' or '\r'
-	   anywhere, because these character constants may have unexpected values on
-	   certain old Mac OS compilers, depending on the compiler settings. In
-	   particular, the values of '\n' and '\r' will be swapped. */
+	// Constants for CR and LF. Note that we should not use '\n' or '\r'
+	// anywhere, because these character constants may have unexpected values on
+	// certain old Mac OS compilers, depending on the compiler settings. In
+	// particular, the values of '\n' and '\r' will be swapped.
 	kCharLF = 10,
 	kCharCR = 13,
 
-	/* Constant for substitution character: '?'. */
+	// Constant for substitution character: '?'.
 	kCharSubstitute = 63
 };
 
 typedef enum {
-	/* Don't translite line breaks. */
+	// Don't translite line breaks.
 	kLineBreakKeep,
 
-	/* Convert line breaks to LF. */
+	// Convert line breaks to LF.
 	kLineBreakLF,
 
-	/* Convert line breaks to CR. */
+	// Convert line breaks to CR.
 	kLineBreakCR,
 
-	/* Convert line breaks to CR LF. */
+	// Convert line breaks to CR LF.
 	kLineBreakCRLF
 } LineBreakConversion;
 
-/* Directions that the converter runs in. */
-typedef enum { kToUTF8, kFromUTF8 } ConvertDirection;
+// Directions that the converter runs in.
+typedef enum {
+	kToUTF8,
+	kFromUTF8,
+} ConvertDirection;
 
-/* Get the character map used for the given Mac OS script and region codes.
-   Return -1 if no known character map exists. */
+// Get the character map used for the given Mac OS script and region codes.
+// Return -1 if no known character map exists.
 int GetCharmap(int script, int region);
 
-/* The state of a converter. Must be zeroed prior to first conversion. */
+// The state of a converter. Must be zeroed prior to first conversion.
 struct ConverterState {
 	UInt32 data;
 };
 
-/* Implementation function for building a converter. */
+// Implementation function for building a converter.
 typedef ErrorCode (*ConvertBuildf)(Handle *out, Handle data, Size datasz);
 
-/* Implementation function for running a converter. */
+// Implementation function for running a converter.
 typedef void (*ConvertRunf)(const void *cvtptr, LineBreakConversion lc,
                             struct ConverterState *stateptr, UInt8 **optr,
                             UInt8 *oend, const UInt8 **iptr, const UInt8 *iend);
 
-/* A converter. The converter can be freed by disposing the handle. */
+// A converter. The converter can be freed by disposing the handle.
 struct Converter {
 	Handle data;
 	ConvertRunf run;
 };
 
-/* Build a converter from the given conversion table data. */
+// Build a converter from the given conversion table data.
 int ConverterBuild(struct Converter *c, Handle data, Size datasz,
                    ConvertDirection direction);
 
-/* Engine 1: extended ASCII */
+// Engine 1: extended ASCII.
 
 ErrorCode Convert1fBuild(Handle *out, Handle data, Size datasz);
 void Convert1fRun(const void *cvtptr, LineBreakConversion lc,
diff --git a/convert/convert_1f.c b/convert/convert_1f.c
index 81be063..ce3f169 100644
--- a/convert/convert_1f.c
+++ b/convert/convert_1f.c
@@ -1,13 +1,14 @@
 // Copyright 2022 Dietrich Epp.
 // This file is part of SyncFiles. SyncFiles is licensed under the terms of the
 // Mozilla Public License, version 2.0. See LICENSE.txt for details.
-/* convert_1f.c - Forward conversion from extended ASCII to UTF-8. */
+
+// convert_1f.c - Forward conversion from extended ASCII to UTF-8.
 #include "convert/convert.h"
 #include "lib/defs.h"
 
 struct Convert1fData {
-	/* Unicode characters, encoded in UTF-8, and packed MSB first. Always either
-	   2 bytes or 3 bytes. */
+	// Unicode characters, encoded in UTF-8, and packed MSB first. Always either
+	// 2 bytes or 3 bytes.
 	UInt32 chars[128];
 };
 
@@ -81,7 +82,7 @@ void Convert1fRun(const void *cvtptr, LineBreakConversion lc,
 		ch = *ipos++;
 		if (ch < 128) {
 			if (ch == kCharLF || ch == kCharCR) {
-				/* Line breaks. */
+				// Line breaks.
 				if (ch == kCharLF && lastch == kCharCR) {
 					if (lc == kLineBreakKeep) {
 						*opos++ = ch;
@@ -104,11 +105,11 @@ void Convert1fRun(const void *cvtptr, LineBreakConversion lc,
 					}
 				}
 			} else {
-				/* ASCII characters. */
+				// ASCII characters.
 				*opos++ = ch;
 			}
 		} else {
-			/* Unicode characters. */
+			// Unicode characters.
 			uch = cvt->chars[ch - 128];
 			if (uch > 0xffff) {
 				opos[0] = uch >> 16;
diff --git a/convert/convert_1r.c b/convert/convert_1r.c
index 9ed81ce..672900b 100644
--- a/convert/convert_1r.c
+++ b/convert/convert_1r.c
@@ -1,26 +1,27 @@
 // Copyright 2022 Dietrich Epp.
 // This file is part of SyncFiles. SyncFiles is licensed under the terms of the
 // Mozilla Public License, version 2.0. See LICENSE.txt for details.
-/* convert_1r.c - Reverse conversion from UTF-8 to extended ASCII. */
+
+// convert_1r.c - Reverse conversion from UTF-8 to extended ASCII.
 #include "convert/convert.h"
 #include "lib/defs.h"
 
 enum {
-	/* Maximum length of encoded character. */
+	// Maximum length of encoded character.
 	kMaxEncodedLength = 8,
 
-	/* Initial number of nodes to allocate when building the tree. */
+	// Initial number of nodes to allocate when building the tree.
 	kInitialTableAlloc = 8
 };
 
 struct TEntry {
-	/* The output character, or zero if no output. */
+	// The output character, or zero if no output.
 	UInt8 output;
-	/* The next node, or zero if no next node. */
+	// The next node, or zero if no next node.
 	UInt8 next;
 };
 
-/* A node for building the converter. */
+// A node for building the converter.
 struct TNode {
 	struct TEntry entries[256];
 };
@@ -36,10 +37,10 @@ static ErrorCode CreateTree(struct TTree *tree, Handle data, Size datasz)
 	int i, j, dpos, enclen, encend, state, cur, nodecount, nodealloc;
 	unsigned ch;
 
-	/* Create a tree with a root node mapping all the ASCII characters except
-	   NUL, CR, and LF. NUL won't map because an output of 0 is interpreted as
-	   no output. CR and LF are removed so they can be handled specially be the
-	   decoder. */
+	// Create a tree with a root node mapping all the ASCII characters except
+	// NUL, CR, and LF. NUL won't map because an output of 0 is interpreted as
+	// no output. CR and LF are removed so they can be handled specially be the
+	// decoder.
 	nodes =
 		(struct TNode **)NewHandle(kInitialTableAlloc * sizeof(struct TNode));
 	if (nodes == NULL) {
@@ -55,11 +56,11 @@ static ErrorCode CreateTree(struct TTree *tree, Handle data, Size datasz)
 	node->entries[kCharLF].output = 0;
 	node->entries[kCharCR].output = 0;
 
-	/* Parse the table data and build up a tree of TNode. */
+	// Parse the table data and build up a tree of TNode.
 	dpos = 1;
-	/* For each high character (128..255). */
+	// For each high character (128..255).
 	for (i = 0; i < 128; i++) {
-		/* For each encoding of that character. */
+		// For each encoding of that character.
 		for (j = 0; j < 2; j++) {
 			if (dpos >= datasz) {
 				goto bad_table;
@@ -70,8 +71,8 @@ static ErrorCode CreateTree(struct TTree *tree, Handle data, Size datasz)
 				    enclen > kMaxEncodedLength) {
 					goto bad_table;
 				}
-				/* Iterate over all but last byte in encoding, to find the node
-				   which will produce the decoded byte as output. */
+				// Iterate over all but last byte in encoding, to find the node
+				// which will produce the decoded byte as output.
 				state = 0;
 				node = *nodes;
 				for (encend = dpos + enclen - 1; dpos < encend; dpos++) {
@@ -129,11 +130,11 @@ struct CEntry {
 	UInt16 next;
 };
 
-/* A compressed table node. Followed by an array of centry. */
+// A compressed table node. Followed by an array of centry.
 struct CNode {
-	/* First byte in table. */
+	// First byte in table.
 	UInt8 base;
-	/* Number of entries in table, minus one. */
+	// Number of entries in table, minus one.
 	UInt8 span;
 };
 
@@ -147,7 +148,7 @@ static ErrorCode CompactTree(Handle *out, struct TNode **nodes, int nodecount)
 	int i, j, min, max, count, next;
 	unsigned offset;
 
-	/* Figure out where each compacted node will go. */
+	// Figure out where each compacted node will go.
 	infos = (struct NodeInfo **)NewHandle(sizeof(struct NodeInfo) * nodecount);
 	if (infos == NULL) {
 		return kErrorNoMemory;
@@ -171,7 +172,7 @@ static ErrorCode CompactTree(Handle *out, struct TNode **nodes, int nodecount)
 		offset += sizeof(struct CNode) + count * sizeof(struct CEntry);
 	}
 
-	/* Create the compacted tree. */
+	// Create the compacted tree.
 	ctree = NewHandle(offset);
 	if (ctree == NULL) {
 		DisposeHandle((Handle)infos);
@@ -249,7 +250,7 @@ next_out:
 		goto done;
 	}
 
-	/* Follow state machine to the end. */
+	// Follow state machine to the end.
 	savein = ipos;
 	saveout = 0;
 	toffset = 0;
@@ -274,7 +275,7 @@ resume:
 		output = entry->output;
 		toffset = entry->next;
 		if (toffset == 0) {
-			/* Reached end of tree. */
+			// Reached end of tree.
 			if (output == 0) {
 				goto bad_char;
 			}
@@ -282,9 +283,8 @@ resume:
 			goto next_out;
 		}
 		if (output != 0) {
-			/* Can produce output here, or can consume more input. We try
-			    consuming more input, but save the state to rewind if that
-			    fails. */
+			// Can produce output here, or can consume more input. We try
+			// consuming more input, but save the state to rewind if that fails.
 			savein = ipos;
 			saveout = output;
 			savetoffset = toffset;
@@ -292,20 +292,19 @@ resume:
 	}
 
 bad_char:
-	/* Bad character. Back up and try again. */
+	// Bad character. Back up and try again.
 	ipos = savein;
 	if (saveout != 0) {
-		/* Produce saved output. */
+		// Produce saved output.
 		*opos++ = saveout;
 		ch = 0;
 	} else {
-		/* No saved output, this really is a bad character. Consume one
-		   UTF-8 character, emit it as a fallback, and continue. */
+		// No saved output, this really is a bad character. Consume one UTF-8
+		// character, emit it as a fallback, and continue.
 		ch = *ipos++;
 		if ((ch & 0x80) == 0) {
-			/* ASCII character: either NUL, CR, or LF, because only
-			   these
-			   characters will result in a transition to state 0. */
+			// ASCII character: either NUL, CR, or LF, because only these
+			// characters will result in a transition to state 0.
 			if (ch == 0) {
 				*opos++ = ch;
 			} else if (ch == kCharLF && lastch == kCharCR) {
diff --git a/convert/convert_test.c b/convert/convert_test.c
index fdadbac..c3dc103 100644
--- a/convert/convert_test.c
+++ b/convert/convert_test.c
@@ -112,7 +112,7 @@ static void TestConverter(const char *name, struct CharmapData data)
 
 	SetTestName(name);
 
-	/* Load the converter into memory and build the conversion table. */
+	// Load the converter into memory and build the conversion table.
 	datap = (void *)data.ptr;
 	datah = &datap;
 	err = ConverterBuild(&cf, datah, data.size, kToUTF8);
@@ -126,7 +126,7 @@ static void TestConverter(const char *name, struct CharmapData data)
 		goto done;
 	}
 
-	/* Create sample data to convert: 0-255, followed by 0. */
+	// Create sample data to convert: 0-255, followed by 0.
 	len0 = 257;
 	ptr = gBuffer[0];
 	for (i = 0; i < 256; i++) {
@@ -134,7 +134,7 @@ static void TestConverter(const char *name, struct CharmapData data)
 	}
 	ptr[256] = 0;
 
-	/* Convert sample data. */
+	// Convert sample data.
 	iptr = gBuffer[0];
 	iend = iptr + 257;
 	optr = gBuffer[1];
@@ -147,8 +147,8 @@ static void TestConverter(const char *name, struct CharmapData data)
 	}
 	len1 = optr - gBuffer[1];
 
-	/* Convert back, in three calls. The middle call will be to a 1-4 byte slice
-	   in the middle. */
+	// Convert back, in three calls. The middle call will be to a 1-4 byte slice
+	// in the middle.
 	for (i = 1; i < len1 - 2; i++) {
 		jmax = len1 - i;
 		if (jmax > 4) {
@@ -182,8 +182,8 @@ static void TestConverter(const char *name, struct CharmapData data)
 	for (k = 0; k < 2; k++) {
 		cc = k == 0 ? cf : cr;
 		for (i = 0; i < 4; i++) {
-			len1 = lblen[0]; /* Input data */
-			len0 = lblen[i]; /* Expected output */
+			len1 = lblen[0]; // Input data
+			len0 = lblen[i]; // Expected output
 			for (j = 1; j < len1; j++) {
 				SetTestNamef("%s %s linebreak %s split=%d", name,
 				             k == 0 ? "forward" : "backward", kLineBreakName[i],
diff --git a/convert/data.h b/convert/data.h
index 851f3ee..3aca9ab 100644
--- a/convert/data.h
+++ b/convert/data.h
@@ -3,26 +3,26 @@
 // Mozilla Public License, version 2.0. See LICENSE.txt for details.
 #ifndef CONVERT_DATA_H
 #define CONVERT_DATA_H
-/* data.h - charmap data, not used for classic Mac OS builds */
+// data.h - charmap data, not used for classic Mac OS builds
 #include "lib/defs.h"
 
-/* Get the ID of the given character map. Return NULL if no such character map
-   exists. */
+// Get the ID of the given character map. Return NULL if no such character map
+// exists.
 const char *CharmapID(int cmap);
 
-/* Get the human-readable name fo the given character map. Return NULL if no
-   such character map exists. */
+// Get the human-readable name fo the given character map. Return NULL if no
+// such character map exists.
 const char *CharmapName(int cmap);
 
-/* Conversion table data. */
+// Conversion table data.
 struct CharmapData {
 	const UInt8 *ptr;
 	Size size;
 };
 
-/* Get the conversion table data for the given charmap. Returns an empty buffer
-   with a NULL pointer if the character map does not exist or if no conversion
-   table exists for that character map. */
+// Get the conversion table data for the given charmap. Returns an empty buffer
+// with a NULL pointer if the character map does not exist or if no conversion
+// table exists for that character map.
 struct CharmapData CharmapData(int cmap);
 
 #endif