Merge pull request #56 from nwellnhof/bufsize_t

Safer handling of string buffer sizes and indices

23 files changed, 344 insertions, 321 deletions

diff --git a/api_test/main.c b/api_test/main.c
index 01df51d..132d48c 100644
--- a/api_test/main.c
+++ b/api_test/main.c
@@ -643,16 +643,16 @@ test_incomplete_char(test_batch_runner *runner, const char *utf8,
 static void
 test_continuation_byte(test_batch_runner *runner, const char *utf8)
 {
-	int len = strlen(utf8);
+	size_t len = strlen(utf8);
 
-	for (int pos = 1; pos < len; ++pos) {
+	for (size_t pos = 1; pos < len; ++pos) {
 		char buf[20];
 		sprintf(buf, "((((%s))))", utf8);
 		buf[4+pos] = '\x20';
 
 		char expected[50];
 		strcpy(expected, "<p>((((" UTF8_REPL "\x20");
-		for (int i = pos + 1; i < len; ++i) {
+		for (size_t i = pos + 1; i < len; ++i) {
 			strcat(expected, UTF8_REPL);
 		}
 		strcat(expected, "))))</p>\n");
diff --git a/man/man3/cmark.3 b/man/man3/cmark.3
index 5b68ecb..82c34cd 100644
--- a/man/man3/cmark.3
+++ b/man/man3/cmark.3
@@ -1,4 +1,4 @@
-.TH cmark 3 "March 21, 2015" "LOCAL" "Library Functions Manual"
+.TH cmark 3 "June 07, 2015" "LOCAL" "Library Functions Manual"
 .SH
 NAME
 .PP
@@ -10,7 +10,7 @@ DESCRIPTION
 Simple Interface
 
 .PP
-\fIchar *\f[] \fBcmark_markdown_to_html\f[](\fIconst char *text\f[], \fIint len\f[], \fIint options\f[])
+\fIchar *\f[] \fBcmark_markdown_to_html\f[](\fIconst char *text\f[], \fIsize_t len\f[], \fIint options\f[])
 
 .PP
 Convert \f[I]text\f[] (assumed to be a UTF\-8 encoded string with length
diff --git a/src/blocks.c b/src/blocks.c
index b72c256..a3ac712 100644
--- a/src/blocks.c
+++ b/src/blocks.c
@@ -30,7 +30,7 @@ S_parser_feed(cmark_parser *parser, const unsigned char *buffer, size_t len,
 
 static void
 S_process_line(cmark_parser *parser, const unsigned char *buffer,
-               size_t bytes);
+               bufsize_t bytes);
 
 static cmark_node* make_block(cmark_node_type tag, int start_line, int start_column)
 {
@@ -95,7 +95,7 @@ static cmark_node*
 finalize(cmark_parser *parser, cmark_node* b);
 
 // Returns true if line has only space characters, else false.
-static bool is_blank(cmark_strbuf *s, int offset)
+static bool is_blank(cmark_strbuf *s, bufsize_t offset)
 {
 	while (offset < s->size) {
 		switch (s->ptr[offset]) {
@@ -128,7 +128,7 @@ static inline bool accepts_lines(cmark_node_type block_type)
 	        block_type == NODE_CODE_BLOCK);
 }
 
-static void add_line(cmark_node* node, cmark_chunk *ch, int offset)
+static void add_line(cmark_node* node, cmark_chunk *ch, bufsize_t offset)
 {
 	assert(node->open);
 	cmark_strbuf_put(&node->string_content, ch->data + offset, ch->len - offset);
@@ -136,7 +136,7 @@ static void add_line(cmark_node* node, cmark_chunk *ch, int offset)
 
 static void remove_trailing_blank_lines(cmark_strbuf *ln)
 {
-	int i;
+	bufsize_t i;
 	unsigned char c;
 
 	for (i = ln->size - 1; i >= 0; --i) {
@@ -204,7 +204,7 @@ static int break_out_of_lists(cmark_parser *parser, cmark_node ** bptr)
 static cmark_node*
 finalize(cmark_parser *parser, cmark_node* b)
 {
-	int pos;
+	bufsize_t pos;
 	cmark_node* item;
 	cmark_node* subitem;
 	cmark_node* parent;
@@ -367,10 +367,10 @@ static void process_inlines(cmark_node* root, cmark_reference_map *refmap, int o
 // Attempts to parse a list item marker (bullet or enumerated).
 // On success, returns length of the marker, and populates
 // data with the details.  On failure, returns 0.
-static int parse_list_marker(cmark_chunk *input, int pos, cmark_list **dataptr)
+static bufsize_t parse_list_marker(cmark_chunk *input, bufsize_t pos, cmark_list **dataptr)
 {
 	unsigned char c;
-	int startpos;
+	bufsize_t startpos;
 	cmark_list *data;
 
 	startpos = pos;
@@ -497,6 +497,7 @@ S_parser_feed(cmark_parser *parser, const unsigned char *buffer, size_t len,
 	while (buffer < end) {
 		const unsigned char *eol;
 		size_t line_len;
+		bufsize_t bufsize;
 
 		for (eol = buffer; eol < end; ++eol) {
 			if (S_is_line_end_char(*eol))
@@ -514,17 +515,19 @@ S_parser_feed(cmark_parser *parser, const unsigned char *buffer, size_t len,
 		} else if (eof) {
 			line_len = end - buffer;
 		} else {
-			cmark_strbuf_put(parser->linebuf, buffer, end - buffer);
+			bufsize = cmark_strbuf_check_bufsize(end - buffer);
+			cmark_strbuf_put(parser->linebuf, buffer, bufsize);
 			break;
 		}
 
+		bufsize = cmark_strbuf_check_bufsize(line_len);
 		if (parser->linebuf->size > 0) {
-			cmark_strbuf_put(parser->linebuf, buffer, line_len);
+			cmark_strbuf_put(parser->linebuf, buffer, bufsize);
 			S_process_line(parser, parser->linebuf->ptr,
 			               parser->linebuf->size);
 			cmark_strbuf_clear(parser->linebuf);
 		} else {
-			S_process_line(parser, buffer, line_len);
+			S_process_line(parser, buffer, bufsize);
 		}
 
 		buffer += line_len;
@@ -533,7 +536,7 @@ S_parser_feed(cmark_parser *parser, const unsigned char *buffer, size_t len,
 
 static void chop_trailing_hashtags(cmark_chunk *ch)
 {
-	int n, orig_n;
+	bufsize_t n, orig_n;
 
 	cmark_chunk_rtrim(ch);
 	orig_n = n = ch->len - 1;
@@ -562,10 +565,10 @@ S_find_first_nonspace(cmark_parser *parser, cmark_chunk *input)
 }
 
 static void
-S_process_line(cmark_parser *parser, const unsigned char *buffer, size_t bytes)
+S_process_line(cmark_parser *parser, const unsigned char *buffer, bufsize_t bytes)
 {
 	cmark_node* last_matched_container;
-	int matched = 0;
+	bufsize_t matched = 0;
 	int lev = 0;
 	int i;
 	cmark_list *data = NULL;
@@ -712,7 +715,7 @@ S_process_line(cmark_parser *parser, const unsigned char *buffer, size_t bytes)
 			parser->offset = parser->first_nonspace + matched;
 			container = add_child(parser, container, NODE_HEADER, parser->offset + 1);
 
-			int hashpos = cmark_chunk_strchr(&input, '#', parser->first_nonspace);
+			bufsize_t hashpos = cmark_chunk_strchr(&input, '#', parser->first_nonspace);
 			int level = 0;
 
 			while (peek_at(&input, hashpos) == '#') {
diff --git a/src/buffer.c b/src/buffer.c
index e2ebc02..7d16af8 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4,6 +4,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 
 #include "config.h"
 #include "cmark_ctype.h"
@@ -14,48 +15,75 @@
  */
 unsigned char cmark_strbuf__initbuf[1];
 
-#define ENSURE_SIZE(b, d)			\
-	if ((d) > b->asize)			\
-		cmark_strbuf_grow(b, (d));	\
-
 #ifndef MIN
 #define MIN(x,y)  ((x<y) ? x : y)
 #endif
 
-void cmark_strbuf_init(cmark_strbuf *buf, int initial_size)
+void cmark_strbuf_init(cmark_strbuf *buf, bufsize_t initial_size)
 {
 	buf->asize = 0;
 	buf->size = 0;
 	buf->ptr = cmark_strbuf__initbuf;
 
-	if (initial_size)
+	if (initial_size > 0)
 		cmark_strbuf_grow(buf, initial_size);
 }
 
-void cmark_strbuf_grow(cmark_strbuf *buf, int target_size)
+void cmark_strbuf_overflow_err() {
+	fprintf(stderr, "String buffer overflow");
+	abort();
+}
+
+static inline void
+S_strbuf_grow_by(cmark_strbuf *buf, size_t add) {
+	size_t target_size = (size_t)buf->size + add;
+
+	if (target_size < add             /* Integer overflow. */
+	    || target_size > BUFSIZE_MAX  /* Truncation overflow. */
+	) {
+		cmark_strbuf_overflow_err();
+		return; /* unreachable */
+	}
+
+	if ((bufsize_t)target_size >= buf->asize)
+		cmark_strbuf_grow(buf, (bufsize_t)target_size);
+}
+
+void cmark_strbuf_grow(cmark_strbuf *buf, bufsize_t target_size)
 {
 	unsigned char *new_ptr;
-	int new_size;
 
-	if (target_size <= buf->asize)
+	if (target_size < buf->asize)
 		return;
 
 	if (buf->asize == 0) {
-		new_size = target_size;
 		new_ptr = NULL;
 	} else {
-		new_size = buf->asize;
 		new_ptr = buf->ptr;
 	}
 
-	/* grow the buffer size by 1.5, until it's big enough
-	 * to fit our target size */
-	while (new_size < target_size)
-		new_size = (new_size << 1) - (new_size >> 1);
+	/* Oversize the buffer by 50% to guarantee amortized linear time
+	 * complexity on append operations. */
+	size_t new_size = (size_t)target_size + (size_t)target_size / 2;
+
+	/* Account for terminating null byte. */
+	new_size += 1;
 
 	/* round allocation up to multiple of 8 */
 	new_size = (new_size + 7) & ~7;
 
+	if (new_size < (size_t)target_size  /* Integer overflow. */
+	    || new_size > BUFSIZE_MAX       /* Truncation overflow. */
+	) {
+		if (target_size >= BUFSIZE_MAX) {
+			/* No space for terminating null byte. */
+			cmark_strbuf_overflow_err();
+			return; /* unreachable */
+		}
+		/* Oversize by the maximum possible amount. */
+		new_size = BUFSIZE_MAX;
+	}
+
 	new_ptr = (unsigned char *)realloc(new_ptr, new_size);
 
 	if (!new_ptr) {
@@ -63,16 +91,11 @@ void cmark_strbuf_grow(cmark_strbuf *buf, int target_size)
 		abort();
 	}
 
-	buf->asize = new_size;
+	buf->asize = (bufsize_t)new_size;
 	buf->ptr   = new_ptr;
-
-	/* truncate the existing buffer size if necessary */
-	if (buf->size >= buf->asize)
-		buf->size = buf->asize - 1;
-	buf->ptr[buf->size] = '\0';
 }
 
-size_t cmark_strbuf_len(const cmark_strbuf *buf)
+bufsize_t cmark_strbuf_len(const cmark_strbuf *buf)
 {
 	return buf->size;
 }
@@ -95,13 +118,14 @@ void cmark_strbuf_clear(cmark_strbuf *buf)
 		buf->ptr[0] = '\0';
 }
 
-void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, int len)
+void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, bufsize_t len)
 {
 	if (len <= 0 || data == NULL) {
 		cmark_strbuf_clear(buf);
 	} else {
 		if (data != buf->ptr) {
-			ENSURE_SIZE(buf, len + 1);
+			if (len >= buf->asize)
+				cmark_strbuf_grow(buf, len);
 			memmove(buf->ptr, data, len);
 		}
 		buf->size = len;
@@ -112,22 +136,22 @@ void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, int len)
 void cmark_strbuf_sets(cmark_strbuf *buf, const char *string)
 {
 	cmark_strbuf_set(buf, (const unsigned char *)string,
-	                 string ? strlen(string) : 0);
+	                 string ? cmark_strbuf_safe_strlen(string) : 0);
 }
 
 void cmark_strbuf_putc(cmark_strbuf *buf, int c)
 {
-	ENSURE_SIZE(buf, buf->size + 2);
+	S_strbuf_grow_by(buf, 1);
 	buf->ptr[buf->size++] = c;
 	buf->ptr[buf->size] = '\0';
 }
 
-void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, int len)
+void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, bufsize_t len)
 {
 	if (len <= 0)
 		return;
 
-	ENSURE_SIZE(buf, buf->size + len + 1);
+	S_strbuf_grow_by(buf, len);
 	memmove(buf->ptr + buf->size, data, len);
 	buf->size += len;
 	buf->ptr[buf->size] = '\0';
@@ -135,21 +159,22 @@ void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, int len)
 
 void cmark_strbuf_puts(cmark_strbuf *buf, const char *string)
 {
-	cmark_strbuf_put(buf, (const unsigned char *)string, strlen(string));
+	cmark_strbuf_put(buf, (const unsigned char *)string,
+			 cmark_strbuf_safe_strlen(string));
 }
 
 void cmark_strbuf_vprintf(cmark_strbuf *buf, const char *format, va_list ap)
 {
-	const int expected_size = buf->size + (strlen(format) * 2);
-	int len;
-
-	ENSURE_SIZE(buf, expected_size);
+	size_t expected_size = strlen(format);
+	if (expected_size <= SIZE_MAX / 2)
+		expected_size *= 2;
+	S_strbuf_grow_by(buf, expected_size);
 
 	while (1) {
 		va_list args;
 		va_copy(args, ap);
 
-		len = vsnprintf(
+		int len = vsnprintf(
 		          (char *)buf->ptr + buf->size,
 		          buf->asize - buf->size,
 		          format, args
@@ -168,12 +193,12 @@ void cmark_strbuf_vprintf(cmark_strbuf *buf, const char *format, va_list ap)
 			abort();
 		}
 
-		if (len + 1 <= buf->asize - buf->size) {
+		if ((size_t)len < (size_t)(buf->asize - buf->size)) {
 			buf->size += len;
 			break;
 		}
 
-		ENSURE_SIZE(buf, buf->size + len + 1);
+		S_strbuf_grow_by(buf, len);
 	}
 }
 
@@ -186,11 +211,13 @@ void cmark_strbuf_printf(cmark_strbuf *buf, const char *format, ...)
 	va_end(ap);
 }
 
-void cmark_strbuf_copy_cstr(char *data, int datasize, const cmark_strbuf *buf)
+void cmark_strbuf_copy_cstr(char *data, bufsize_t datasize, const cmark_strbuf *buf)
 {
-	int copylen;
+	bufsize_t copylen;
 
-	assert(data && datasize && buf);
+	assert(buf);
+	if (!data || datasize <= 0)
+		return;
 
 	data[0] = '\0';
 
@@ -224,22 +251,6 @@ unsigned char *cmark_strbuf_detach(cmark_strbuf *buf)
 	return data;
 }
 
-void cmark_strbuf_attach(cmark_strbuf *buf, unsigned char *ptr, int asize)
-{
-	cmark_strbuf_free(buf);
-
-	if (ptr) {
-		buf->ptr = ptr;
-		buf->size = strlen((char *)ptr);
-		if (asize)
-			buf->asize = (asize < buf->size) ? buf->size + 1 : asize;
-		else /* pass 0 to fall back on strlen + 1 */
-			buf->asize = buf->size + 1;
-	} else {
-		cmark_strbuf_grow(buf, asize);
-	}
-}
-
 int cmark_strbuf_cmp(const cmark_strbuf *a, const cmark_strbuf *b)
 {
 	int result = memcmp(a->ptr, b->ptr, MIN(a->size, b->size));
@@ -247,20 +258,28 @@ int cmark_strbuf_cmp(const cmark_strbuf *a, const cmark_strbuf *b)
 	       (a->size < b->size) ? -1 : (a->size > b->size) ? 1 : 0;
 }
 
-int cmark_strbuf_strchr(const cmark_strbuf *buf, int c, int pos)
+bufsize_t cmark_strbuf_strchr(const cmark_strbuf *buf, int c, bufsize_t pos)
 {
+	if (pos >= buf->size)
+		return -1;
+	if (pos < 0)
+		pos = 0;
+
 	const unsigned char *p = (unsigned char *)memchr(buf->ptr + pos, c, buf->size - pos);
 	if (!p)
 		return -1;
 
-	return (int)(p - (const unsigned char *)buf->ptr);
+	return (bufsize_t)(p - (const unsigned char *)buf->ptr);
 }
 
-int cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, int pos)
+bufsize_t cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, bufsize_t pos)
 {
-	int i;
+	if (pos < 0 || buf->size == 0)
+		return -1;
+	if (pos >= buf->size)
+		pos = buf->size - 1;
 
-	for (i = pos; i >= 0; i--) {
+	for (bufsize_t i = pos; i >= 0; i--) {
 		if (buf->ptr[i] == (unsigned char) c)
 			return i;
 	}
@@ -268,17 +287,22 @@ int cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, int pos)
 	return -1;
 }
 
-void cmark_strbuf_truncate(cmark_strbuf *buf, int len)
+void cmark_strbuf_truncate(cmark_strbuf *buf, bufsize_t len)
 {
+	if (len < 0)
+		len = 0;
+
 	if (len < buf->size) {
 		buf->size = len;
 		buf->ptr[buf->size] = '\0';
 	}
 }
 
-void cmark_strbuf_drop(cmark_strbuf *buf, int n)
+void cmark_strbuf_drop(cmark_strbuf *buf, bufsize_t n)
 {
 	if (n > 0) {
+		if (n > buf->size)
+			n = buf->size;
 		buf->size = buf->size - n;
 		if (buf->size)
 			memmove(buf->ptr, buf->ptr + n, buf->size);
@@ -304,7 +328,7 @@ void cmark_strbuf_rtrim(cmark_strbuf *buf)
 
 void cmark_strbuf_trim(cmark_strbuf *buf)
 {
-	int i = 0;
+	bufsize_t i = 0;
 
 	if (!buf->size)
 		return;
@@ -322,7 +346,7 @@ void cmark_strbuf_trim(cmark_strbuf *buf)
 void cmark_strbuf_normalize_whitespace(cmark_strbuf *s)
 {
 	bool last_char_was_space = false;
-	int r, w;
+	bufsize_t r, w;
 
 	for (r = 0, w = 0; r < s->size; ++r) {
 		switch (s->ptr[r]) {
@@ -347,7 +371,7 @@ void cmark_strbuf_normalize_whitespace(cmark_strbuf *s)
 // Destructively unescape a string: remove backslashes before punctuation chars.
 extern void cmark_strbuf_unescape(cmark_strbuf *buf)
 {
-	int r, w;
+	bufsize_t r, w;
 
 	for (r = 0, w = 0; r < buf->size; ++r) {
 		if (buf->ptr[r] == '\\' && cmark_ispunct(buf->ptr[r + 1]))
diff --git a/src/buffer.h b/src/buffer.h
index 417df26..babd051 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -3,20 +3,25 @@
 
 #include <stddef.h>
 #include <stdarg.h>
+#include <string.h>
+#include <limits.h>
 #include "config.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+typedef int bufsize_t;
+
 typedef struct {
 	unsigned char *ptr;
-	int asize, size;
+	bufsize_t asize, size;
 } cmark_strbuf;
 
 extern unsigned char cmark_strbuf__initbuf[];
 
 #define GH_BUF_INIT { cmark_strbuf__initbuf, 0, 0 }
+#define BUFSIZE_MAX INT_MAX
 
 /**
  * Initialize a cmark_strbuf structure.
@@ -24,23 +29,22 @@ extern unsigned char cmark_strbuf__initbuf[];
  * For the cases where GH_BUF_INIT cannot be used to do static
  * initialization.
  */
-void cmark_strbuf_init(cmark_strbuf *buf, int initial_size);
+void cmark_strbuf_init(cmark_strbuf *buf, bufsize_t initial_size);
 
 /**
  * Grow the buffer to hold at least `target_size` bytes.
  */
-void cmark_strbuf_grow(cmark_strbuf *buf, int target_size);
+void cmark_strbuf_grow(cmark_strbuf *buf, bufsize_t target_size);
 
 void cmark_strbuf_free(cmark_strbuf *buf);
 void cmark_strbuf_swap(cmark_strbuf *buf_a, cmark_strbuf *buf_b);
 
-size_t cmark_strbuf_len(const cmark_strbuf *buf);
+bufsize_t cmark_strbuf_len(const cmark_strbuf *buf);
 
 int cmark_strbuf_cmp(const cmark_strbuf *a, const cmark_strbuf *b);
 
-void cmark_strbuf_attach(cmark_strbuf *buf, unsigned char *ptr, int asize);
 unsigned char *cmark_strbuf_detach(cmark_strbuf *buf);
-void cmark_strbuf_copy_cstr(char *data, int datasize, const cmark_strbuf *buf);
+void cmark_strbuf_copy_cstr(char *data, bufsize_t datasize, const cmark_strbuf *buf);
 
 static inline const char *cmark_strbuf_cstr(const cmark_strbuf *buf)
 {
@@ -49,25 +53,41 @@ static inline const char *cmark_strbuf_cstr(const cmark_strbuf *buf)
 
 #define cmark_strbuf_at(buf, n) ((buf)->ptr[n])
 
-void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, int len);
+void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, bufsize_t len);
 void cmark_strbuf_sets(cmark_strbuf *buf, const char *string);
 void cmark_strbuf_putc(cmark_strbuf *buf, int c);
-void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, int len);
+void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, bufsize_t len);
 void cmark_strbuf_puts(cmark_strbuf *buf, const char *string);
 void cmark_strbuf_printf(cmark_strbuf *buf, const char *format, ...)
 	CMARK_ATTRIBUTE((format (printf, 2, 3)));
 void cmark_strbuf_vprintf(cmark_strbuf *buf, const char *format, va_list ap);
 void cmark_strbuf_clear(cmark_strbuf *buf);
 
-int cmark_strbuf_strchr(const cmark_strbuf *buf, int c, int pos);
-int cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, int pos);
-void cmark_strbuf_drop(cmark_strbuf *buf, int n);
-void cmark_strbuf_truncate(cmark_strbuf *buf, int len);
+bufsize_t cmark_strbuf_strchr(const cmark_strbuf *buf, int c, bufsize_t pos);
+bufsize_t cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, bufsize_t pos);
+void cmark_strbuf_drop(cmark_strbuf *buf, bufsize_t n);
+void cmark_strbuf_truncate(cmark_strbuf *buf, bufsize_t len);
 void cmark_strbuf_rtrim(cmark_strbuf *buf);
 void cmark_strbuf_trim(cmark_strbuf *buf);
 void cmark_strbuf_normalize_whitespace(cmark_strbuf *s);
 void cmark_strbuf_unescape(cmark_strbuf *s);
 
+/* Print error and abort. */
+void cmark_strbuf_overflow_err(void);
+
+static inline bufsize_t
+cmark_strbuf_check_bufsize(size_t size) {
+	if (size > BUFSIZE_MAX) {
+		cmark_strbuf_overflow_err();
+	}
+	return (bufsize_t)size;
+}
+
+static inline bufsize_t
+cmark_strbuf_safe_strlen(const char *str) {
+	return cmark_strbuf_check_bufsize(strlen(str));
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/chunk.h b/src/chunk.h
index a246a9d..f23a02d 100644
--- a/src/chunk.h
+++ b/src/chunk.h
@@ -11,8 +11,8 @@
 
 typedef struct {
 	unsigned char *data;
-	int len;
-	int alloc;  // also implies a NULL-terminated string
+	bufsize_t len;
+	bufsize_t alloc;  // also implies a NULL-terminated string
 } cmark_chunk;
 
 static inline void cmark_chunk_free(cmark_chunk *c)
@@ -51,10 +51,10 @@ static inline void cmark_chunk_trim(cmark_chunk *c)
 	cmark_chunk_rtrim(c);
 }
 
-static inline int cmark_chunk_strchr(cmark_chunk *ch, int c, int offset)
+static inline bufsize_t cmark_chunk_strchr(cmark_chunk *ch, int c, bufsize_t offset)
 {
 	const unsigned char *p = (unsigned char *)memchr(ch->data + offset, c, ch->len - offset);
-	return p ? (int)(p - ch->data) : ch->len;
+	return p ? (bufsize_t)(p - ch->data) : ch->len;
 }
 
 static inline const char *cmark_chunk_to_cstr(cmark_chunk *c)
@@ -87,7 +87,7 @@ static inline void cmark_chunk_set_cstr(cmark_chunk *c, const char *str)
 		c->data  = NULL;
 		c->alloc = 0;
 	} else {
-		c->len   = strlen(str);
+		c->len   = cmark_strbuf_safe_strlen(str);
 		c->data  = (unsigned char *)malloc(c->len + 1);
 		c->alloc = 1;
 		memcpy(c->data, str, c->len + 1);
@@ -96,11 +96,12 @@ static inline void cmark_chunk_set_cstr(cmark_chunk *c, const char *str)
 
 static inline cmark_chunk cmark_chunk_literal(const char *data)
 {
-	cmark_chunk c = {(unsigned char *)data, data ? strlen(data) : 0, 0};
+	bufsize_t len = data ? cmark_strbuf_safe_strlen(data) : 0;
+	cmark_chunk c = {(unsigned char *)data, len, 0};
 	return c;
 }
 
-static inline cmark_chunk cmark_chunk_dup(const cmark_chunk *ch, int pos, int len)
+static inline cmark_chunk cmark_chunk_dup(const cmark_chunk *ch, bufsize_t pos, bufsize_t len)
 {
 	cmark_chunk c = {ch->data + pos, len, 0};
 	return c;
diff --git a/src/cmark.c b/src/cmark.c
index 79ceabf..35765b1 100644
--- a/src/cmark.c
+++ b/src/cmark.c
@@ -9,7 +9,7 @@
 const int cmark_version = CMARK_VERSION;
 const char cmark_version_string[] = CMARK_VERSION_STRING;
 
-char *cmark_markdown_to_html(const char *text, int len, int options)
+char *cmark_markdown_to_html(const char *text, size_t len, int options)
 {
 	cmark_node *doc;
 	char *result;
diff --git a/src/cmark.h b/src/cmark.h
index 84c6f76..d86e13e 100644
--- a/src/cmark.h
+++ b/src/cmark.h
@@ -24,7 +24,7 @@ extern "C" {
  * UTF-8-encoded string.
  */
 CMARK_EXPORT
-char *cmark_markdown_to_html(const char *text, int len, int options);
+char *cmark_markdown_to_html(const char *text, size_t len, int options);
 
 /** ## Node Structure
  */
diff --git a/src/commonmark.c b/src/commonmark.c
index dba1fcf..4594748 100644
--- a/src/commonmark.c
+++ b/src/commonmark.c
@@ -20,7 +20,7 @@ struct render_state {
 	int column;
 	int width;
 	int need_cr;
-	int last_breakable;
+	bufsize_t last_breakable;
 	bool begin_line;
 	bool no_wrap;
 	bool in_tight_list_item;
@@ -237,30 +237,29 @@ shortest_unused_backtick_sequence(cmark_chunk *code)
 static bool
 is_autolink(cmark_node *node)
 {
-	const char *title;
-	const char *url;
+	cmark_chunk *title;
+	cmark_chunk *url;
 	cmark_node *link_text;
 
 	if (node->type != CMARK_NODE_LINK) {
 		return false;
 	}
 
-	url = cmark_node_get_url(node);
-	if (url == NULL ||
-	    _scan_scheme((unsigned char *)url) == 0) {
+	url = &node->as.link.url;
+	if (url->len == 0 || scan_scheme(url, 0) == 0) {
 		return false;
 	}
 
-	title = cmark_node_get_title(node);
+	title = &node->as.link.title;
 	// if it has a title, we can't treat it as an autolink:
-	if (title != NULL && strlen(title) > 0) {
+	if (title->len > 0) {
 		return false;
 	}
 
 	link_text = node->first_child;
 	cmark_consolidate_text_nodes(link_text);
-	return ((int)strlen(url) == link_text->as.literal.len &&
-	        strncmp(url,
+	return (url->len == link_text->as.literal.len &&
+	        strncmp((char*)url->data,
 	                (char*)link_text->as.literal.data,
 	                link_text->as.literal.len) == 0);
 }
@@ -289,11 +288,11 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 	int numticks;
 	int i;
 	bool entering = (ev_type == CMARK_EVENT_ENTER);
-	const char *info;
-	const char *title;
+	cmark_chunk *info;
+	cmark_chunk *title;
 	cmark_strbuf listmarker = GH_BUF_INIT;
 	char *emph_delim;
-	int marker_width;
+	bufsize_t marker_width;
 
 	// Don't adjust tight list status til we've started the list.
 	// Otherwise we loose the blank line between a paragraph and
@@ -396,12 +395,12 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 
 	case CMARK_NODE_CODE_BLOCK:
 		blankline(state);
-		info = cmark_node_get_fence_info(node);
+		info = &node->as.code.info;
 		code = &node->as.code.literal;
 		// use indented form if no info, and code doesn't
 		// begin or end with a blank line, and code isn't
 		// first thing in a list item
-		if ((info == NULL || strlen(info) == 0) &&
+		if (info->len == 0 &&
 		    (code->len > 2 &&
 		     !isspace(code->data[0]) &&
 		     !(isspace(code->data[code->len - 1]) &&
@@ -422,7 +421,7 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 				lit(state, "`", false);
 			}
 			lit(state, " ", false);
-			out(state, cmark_chunk_literal(info), false, LITERAL);
+			out(state, *info, false, LITERAL);
 			cr(state);
 			out(state, node->as.code.literal, false, LITERAL);
 			cr(state);
@@ -542,11 +541,10 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 				out(state,
 				    cmark_chunk_literal(cmark_node_get_url(node)),
 				    false, URL);
-				title = cmark_node_get_title(node);
-				if (title && strlen(title) > 0) {
+				title = &node->as.link.title;
+				if (title->len > 0) {
 					lit(state, " \"", true);
-					out(state, cmark_chunk_literal(title),
-					    false, TITLE);
+					out(state, *title, false, TITLE);
 					lit(state, "\"", false);
 				}
 				lit(state, ")", false);
@@ -560,10 +558,10 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 		} else {
 			lit(state, "](", false);
 			out(state, cmark_chunk_literal(cmark_node_get_url(node)), false, URL);
-			title = cmark_node_get_title(node);
-			if (title && strlen(title) > 0) {
+			title = &node->as.link.title;
+			if (title->len > 0) {
 				lit(state, " \"", true);
-				out(state, cmark_chunk_literal(title), false, TITLE);
+				out(state, *title, false, TITLE);
 				lit(state, "\"", false);
 			}
 			lit(state, ")", false);
diff --git a/src/houdini.h b/src/houdini.h
index 9f00f6d..b926cf3 100644
--- a/src/houdini.h
+++ b/src/houdini.h
@@ -31,19 +31,12 @@ extern "C" {
 #define HOUDINI_ESCAPED_SIZE(x) (((x) * 12) / 10)
 #define HOUDINI_UNESCAPED_SIZE(x) (x)
 
-extern size_t houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_html(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_html0(cmark_strbuf *ob, const uint8_t *src, size_t size, int secure);
-extern int houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_xml(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_uri(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_url(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_href(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_unescape_uri(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_unescape_url(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_escape_js(cmark_strbuf *ob, const uint8_t *src, size_t size);
-extern int houdini_unescape_js(cmark_strbuf *ob, const uint8_t *src, size_t size);
+extern bufsize_t houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, bufsize_t size);
+extern int houdini_escape_html(cmark_strbuf *ob, const uint8_t *src, bufsize_t size);
+extern int houdini_escape_html0(cmark_strbuf *ob, const uint8_t *src, bufsize_t size, int secure);
+extern int houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, bufsize_t size);
+extern void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src, bufsize_t size);
+extern int houdini_escape_href(cmark_strbuf *ob, const uint8_t *src, bufsize_t size);
 
 #ifdef __cplusplus
 }
diff --git a/src/houdini_href_e.c b/src/houdini_href_e.c
index 7527780..7fb958a 100644
--- a/src/houdini_href_e.c
+++ b/src/houdini_href_e.c
@@ -49,10 +49,10 @@ static const char HREF_SAFE[] = {
 };
 
 int
-houdini_escape_href(cmark_strbuf *ob, const uint8_t *src, size_t size)
+houdini_escape_href(cmark_strbuf *ob, const uint8_t *src, bufsize_t size)
 {
 	static const uint8_t hex_chars[] = "0123456789ABCDEF";
-	size_t  i = 0, org;
+	bufsize_t i = 0, org;
 	uint8_t hex_str[3];
 
 	hex_str[0] = '%';
diff --git a/src/houdini_html_e.c b/src/houdini_html_e.c
index 1a4c3e1..7f4b91f 100644
--- a/src/houdini_html_e.c
+++ b/src/houdini_html_e.c
@@ -45,9 +45,9 @@ static const char *HTML_ESCAPES[] = {
 };
 
 int
-houdini_escape_html0(cmark_strbuf *ob, const uint8_t *src, size_t size, int secure)
+houdini_escape_html0(cmark_strbuf *ob, const uint8_t *src, bufsize_t size, int secure)
 {
-	size_t  i = 0, org, esc = 0;
+	bufsize_t i = 0, org, esc = 0;
 
 	while (i < size) {
 		org = i;
@@ -75,7 +75,7 @@ houdini_escape_html0(cmark_strbuf *ob, const uint8_t *src, size_t size, int secu
 }
 
 int
-houdini_escape_html(cmark_strbuf *ob, const uint8_t *src, size_t size)
+houdini_escape_html(cmark_strbuf *ob, const uint8_t *src, bufsize_t size)
 {
 	return houdini_escape_html0(ob, src, size, 1);
 }
diff --git a/src/houdini_html_u.c b/src/houdini_html_u.c
index eaf295e..e57894d 100644
--- a/src/houdini_html_u.c
+++ b/src/houdini_html_u.c
@@ -7,10 +7,10 @@
 #include "utf8.h"
 #include "html_unescape.h"
 
-size_t
-houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, size_t size)
+bufsize_t
+houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, bufsize_t size)
 {
-	size_t i = 0;
+	bufsize_t i = 0;
 
 	if (size >= 3 && src[0] == '#') {
 		int codepoint  = 0;
@@ -68,7 +68,7 @@ houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, size_t size)
 				const struct html_ent *entity = find_entity((char *)src, i);
 
 				if (entity != NULL) {
-					int len = 0;
+					bufsize_t len = 0;
 					while (len < 4 && entity->utf8[len] != '\0') {
 						++len;
 					}
@@ -85,9 +85,9 @@ houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, size_t size)
 }
 
 int
-houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, size_t size)
+houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, bufsize_t size)
 {
-	size_t  i = 0, org, ent;
+	bufsize_t i = 0, org, ent;
 
 	while (i < size) {
 		org = i;
@@ -122,7 +122,7 @@ houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, size_t size)
 	return 1;
 }
 
-void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src, size_t size)
+void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src, bufsize_t size)
 {
 	if (!houdini_unescape_html(ob, src, size))
 		cmark_strbuf_put(ob, src, size);
diff --git a/src/html.c b/src/html.c
index d3f9fc7..a30bbca 100644
--- a/src/html.c
+++ b/src/html.c
@@ -11,20 +11,9 @@
 
 // Functions to convert cmark_nodes to HTML strings.
 
-static void escape_html(cmark_strbuf *dest, const unsigned char *source, int length)
+static void escape_html(cmark_strbuf *dest, const unsigned char *source, bufsize_t length)
 {
-	if (length < 0)
-		length = strlen((char *)source);
-
-	houdini_escape_html0(dest, source, (size_t)length, 0);
-}
-
-static void escape_href(cmark_strbuf *dest, const unsigned char *source, int length)
-{
-	if (length < 0)
-		length = strlen((char *)source);
-
-	houdini_escape_href(dest, source, (size_t)length);
+	houdini_escape_html0(dest, source, length, 0);
 }
 
 static inline void cr(cmark_strbuf *html)
@@ -165,7 +154,7 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 			S_render_sourcepos(node, html, options);
 			cmark_strbuf_puts(html, "><code>");
 		} else {
-			int first_tag = 0;
+			bufsize_t first_tag = 0;
 			while (first_tag < node->as.code.info.len &&
 			       node->as.code.info.data[first_tag] != ' ') {
 				first_tag += 1;
@@ -261,8 +250,8 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 	case CMARK_NODE_LINK:
 		if (entering) {
 			cmark_strbuf_puts(html, "<a href=\"");
-			escape_href(html, node->as.link.url.data,
-			            node->as.link.url.len);
+			houdini_escape_href(html, node->as.link.url.data,
+	                                    node->as.link.url.len);
 
 			if (node->as.link.title.len) {
 				cmark_strbuf_puts(html, "\" title=\"");
@@ -279,8 +268,8 @@ S_render_node(cmark_node *node, cmark_event_type ev_type,
 	case CMARK_NODE_IMAGE:
 		if (entering) {
 			cmark_strbuf_puts(html, "<img src=\"");
-			escape_href(html, node->as.link.url.data,
-			            node->as.link.url.len);
+			houdini_escape_href(html, node->as.link.url.data,
+		                            node->as.link.url.len);
 
 			cmark_strbuf_puts(html, "\" alt=\"");
 			state->plain = node;
diff --git a/src/inlines.c b/src/inlines.c
index 8a1ee44..7e8f806 100644
--- a/src/inlines.c
+++ b/src/inlines.c
@@ -36,7 +36,7 @@ typedef struct delimiter {
 	struct delimiter *previous;
 	struct delimiter *next;
 	cmark_node *inl_text;
-	int position;
+	bufsize_t position;
 	unsigned char delim_char;
 	bool can_open;
 	bool can_close;
@@ -45,7 +45,7 @@ typedef struct delimiter {
 
 typedef struct {
 	cmark_chunk input;
-	int pos;
+	bufsize_t pos;
 	cmark_reference_map *refmap;
 	delimiter *last_delim;
 } subject;
@@ -57,7 +57,7 @@ static int parse_inline(subject* subj, cmark_node * parent, int options);
 
 static void subject_from_buf(subject *e, cmark_strbuf *buffer,
                              cmark_reference_map *refmap);
-static int subject_find_special_char(subject *subj, int options);
+static bufsize_t subject_find_special_char(subject *subj, int options);
 
 static cmark_chunk cmark_clean_autolink(cmark_chunk *url, int is_email)
 {
@@ -143,7 +143,7 @@ static inline cmark_node* make_simple(cmark_node_type t)
 static cmark_chunk chunk_clone(cmark_chunk *src)
 {
 	cmark_chunk c;
-	int len = src->len;
+	bufsize_t len = src->len;
 
 	c.len   = len;
 	c.data  = (unsigned char *)malloc(len + 1);
@@ -177,7 +177,7 @@ static inline unsigned char peek_char(subject *subj)
 	return (subj->pos < subj->input.len) ? subj->input.data[subj->pos] : 0;
 }
 
-static inline unsigned char peek_at(subject *subj, int pos)
+static inline unsigned char peek_at(subject *subj, bufsize_t pos)
 {
 	return subj->input.data[pos];
 }
@@ -195,8 +195,8 @@ static inline int is_eof(subject* subj)
 static inline cmark_chunk take_while(subject* subj, int (*f)(int))
 {
 	unsigned char c;
-	int startpos = subj->pos;
-	int len = 0;
+	bufsize_t startpos = subj->pos;
+	bufsize_t len = 0;
 
 	while ((c = peek_char(subj)) && (*f)(c)) {
 		advance(subj);
@@ -211,7 +211,7 @@ static inline cmark_chunk take_while(subject* subj, int (*f)(int))
 // parsed).  Return 0 if you don't find matching closing
 // backticks, otherwise return the position in the subject
 // after the closing backticks.
-static int scan_to_closing_backticks(subject* subj, int openticklength)
+static bufsize_t scan_to_closing_backticks(subject* subj, bufsize_t openticklength)
 {
 	// read non backticks
 	unsigned char c;
@@ -221,7 +221,7 @@ static int scan_to_closing_backticks(subject* subj, int openticklength)
 	if (is_eof(subj)) {
 		return 0;  // did not find closing ticks, return 0
 	}
-	int numticks = 0;
+	bufsize_t numticks = 0;
 	while (peek_char(subj) == '`') {
 		advance(subj);
 		numticks++;
@@ -237,8 +237,8 @@ static int scan_to_closing_backticks(subject* subj, int openticklength)
 static cmark_node* handle_backticks(subject *subj)
 {
 	cmark_chunk openticks = take_while(subj, isbacktick);
-	int startpos = subj->pos;
-	int endpos = scan_to_closing_backticks(subj, openticks.len);
+	bufsize_t startpos = subj->pos;
+	bufsize_t endpos = scan_to_closing_backticks(subj, openticks.len);
 
 	if (endpos == 0) { // not found
 		subj->pos = startpos; // rewind
@@ -260,7 +260,7 @@ static int
 scan_delims(subject* subj, unsigned char c, bool * can_open, bool * can_close)
 {
 	int numdelims = 0;
-	int before_char_pos;
+	bufsize_t before_char_pos;
 	int32_t after_char = 0;
 	int32_t before_char = 0;
 	int len;
@@ -376,7 +376,7 @@ static void push_delimiter(subject *subj, unsigned char c, bool can_open,
 // Assumes the subject has a c at the current position.
 static cmark_node* handle_delim(subject* subj, unsigned char c, bool smart)
 {
-	int numdelims;
+	bufsize_t numdelims;
 	cmark_node * inl_text;
 	bool can_open, can_close;
 	cmark_chunk contents;
@@ -500,11 +500,11 @@ static delimiter*
 S_insert_emph(subject *subj, delimiter *opener, delimiter *closer)
 {
 	delimiter *delim, *tmp_delim;
-	int use_delims;
+	bufsize_t use_delims;
 	cmark_node *opener_inl = opener->inl_text;
 	cmark_node *closer_inl = closer->inl_text;
-	int opener_num_chars = opener_inl->as.literal.len;
-	int closer_num_chars = closer_inl->as.literal.len;
+	bufsize_t opener_num_chars = opener_inl->as.literal.len;
+	bufsize_t closer_num_chars = closer_inl->as.literal.len;
 	cmark_node *tmp, *emph, *first_child, *last_child;
 
 	// calculate the actual number of characters used from this closer
@@ -596,7 +596,7 @@ static cmark_node* handle_backslash(subject *subj)
 static cmark_node* handle_entity(subject* subj)
 {
 	cmark_strbuf ent = GH_BUF_INIT;
-	size_t len;
+	bufsize_t len;
 
 	advance(subj);
 
@@ -618,7 +618,7 @@ static cmark_node *make_str_with_entities(cmark_chunk *content)
 {
 	cmark_strbuf unescaped = GH_BUF_INIT;
 
-	if (houdini_unescape_html(&unescaped, content->data, (size_t)content->len)) {
+	if (houdini_unescape_html(&unescaped, content->data, content->len)) {
 		return make_str(cmark_chunk_buf_detach(&unescaped));
 	} else {
 		return make_str(*content);
@@ -678,7 +678,7 @@ cmark_chunk cmark_clean_title(cmark_chunk *title)
 // Assumes the subject has a '<' character at the current position.
 static cmark_node* handle_pointy_brace(subject* subj)
 {
-	int matchlen = 0;
+	bufsize_t matchlen = 0;
 	cmark_chunk contents;
 
 	advance(subj);  // advance past first <
@@ -725,7 +725,7 @@ static cmark_node* handle_pointy_brace(subject* subj)
 // encountered.  Backticks in labels do not start code spans.
 static int link_label(subject* subj, cmark_chunk *raw_label)
 {
-	int startpos = subj->pos;
+	bufsize_t startpos = subj->pos;
 	int length = 0;
 	unsigned char c;
 
@@ -769,10 +769,10 @@ noMatch:
 // Return a link, an image, or a literal close bracket.
 static cmark_node* handle_close_bracket(subject* subj, cmark_node *parent)
 {
-	int initial_pos;
-	int starturl, endurl, starttitle, endtitle, endall;
-	int n;
-	int sps;
+	bufsize_t initial_pos;
+	bufsize_t starturl, endurl, starttitle, endtitle, endall;
+	bufsize_t n;
+	bufsize_t sps;
 	cmark_reference *ref;
 	bool is_image = false;
 	cmark_chunk url_chunk, title_chunk;
@@ -922,7 +922,7 @@ match:
 // Assumes the subject has a newline at the current position.
 static cmark_node* handle_newline(subject *subj)
 {
-	int nlpos = subj->pos;
+	bufsize_t nlpos = subj->pos;
 	// skip over newline
 	advance(subj);
 	// skip spaces at beginning of line
@@ -938,7 +938,7 @@ static cmark_node* handle_newline(subject *subj)
 	}
 }
 
-static int subject_find_special_char(subject *subj, int options)
+static bufsize_t subject_find_special_char(subject *subj, int options)
 {
 	// "\r\n\\`&_*[]<!"
 	static const int8_t SPECIAL_CHARS[256] = {
@@ -980,7 +980,7 @@ static int subject_find_special_char(subject *subj, int options)
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	};
 
-	int n = subj->pos + 1;
+	bufsize_t n = subj->pos + 1;
 
 	while (n < subj->input.len) {
 		if (SPECIAL_CHARS[subj->input.data[n]])
@@ -1001,7 +1001,7 @@ static int parse_inline(subject* subj, cmark_node * parent, int options)
 	cmark_node* new_inl = NULL;
 	cmark_chunk contents;
 	unsigned char c;
-	int endpos;
+	bufsize_t endpos;
 	c = peek_char(subj);
 	if (c == 0) {
 		return 0;
@@ -1098,7 +1098,7 @@ static void spnl(subject* subj)
 // Modify refmap if a reference is encountered.
 // Return 0 if no reference found, otherwise position of subject
 // after reference is parsed.
-int cmark_parse_reference_inline(cmark_strbuf *input, cmark_reference_map *refmap)
+bufsize_t cmark_parse_reference_inline(cmark_strbuf *input, cmark_reference_map *refmap)
 {
 	subject subj;
 
@@ -1106,8 +1106,8 @@ int cmark_parse_reference_inline(cmark_strbuf *input, cmark_reference_map *refma
 	cmark_chunk url;
 	cmark_chunk title;
 
-	int matchlen = 0;
-	int beforetitle;
+	bufsize_t matchlen = 0;
+	bufsize_t beforetitle;
 
 	subject_from_buf(&subj, input, NULL);
 
diff --git a/src/inlines.h b/src/inlines.h
index 534588e..f8847fc 100644
--- a/src/inlines.h
+++ b/src/inlines.h
@@ -10,7 +10,7 @@ cmark_chunk cmark_clean_title(cmark_chunk *title);
 
 void cmark_parse_inlines(cmark_node* parent, cmark_reference_map *refmap, int options);
 
-int cmark_parse_reference_inline(cmark_strbuf *input, cmark_reference_map *refmap);
+bufsize_t cmark_parse_reference_inline(cmark_strbuf *input, cmark_reference_map *refmap);
 
 #ifdef __cplusplus
 }
diff --git a/src/parser.h b/src/parser.h
index ccdf84b..6e18c67 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -16,12 +16,12 @@ struct cmark_parser {
 	struct cmark_node* root;
 	struct cmark_node* current;
 	int line_number;
-	int offset;
-	int first_nonspace;
+	bufsize_t offset;
+	bufsize_t first_nonspace;
 	int indent;
 	bool blank;
 	cmark_strbuf *curline;
-	int last_line_length;
+	bufsize_t last_line_length;
 	cmark_strbuf *linebuf;
 	int options;
 };
diff --git a/src/scanners.c b/src/scanners.c
index 7f9ed2e..3f4ddac 100644
--- a/src/scanners.c
+++ b/src/scanners.c
@@ -1,11 +1,11 @@
-/* Generated by re2c 0.13.6 */
+/* Generated by re2c 0.13.5 */
 #include <stdlib.h>
 #include "chunk.h"
 #include "scanners.h"
 
-int _scan_at(int (*scanner)(const unsigned char *), cmark_chunk *c, int offset)
+bufsize_t _scan_at(bufsize_t (*scanner)(const unsigned char *), cmark_chunk *c, bufsize_t offset)
 {
-	int res;
+	bufsize_t res;
 	unsigned char *ptr = (unsigned char *)c->data;
 	unsigned char lim = ptr[c->len];
 
@@ -19,7 +19,7 @@ int _scan_at(int (*scanner)(const unsigned char *), cmark_chunk *c, int offset)
 
 
 // Try to match a scheme including colon.
-int _scan_scheme(const unsigned char *p)
+bufsize_t _scan_scheme(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -578,7 +578,7 @@ yy34:
 	if (yych != ':') goto yy31;
 yy35:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy37:
 	yych = *++p;
 	if (yych == 'E') goto yy38;
@@ -2919,7 +2919,7 @@ yy484:
 }
 
 // Try to match URI autolink after first <, returning number of chars matched.
-int _scan_autolink_uri(const unsigned char *p)
+bufsize_t _scan_autolink_uri(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -3517,7 +3517,7 @@ yy520:
 	}
 	if (yych <= '=') goto yy516;
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy524:
 	yych = *++p;
 	if (yych == 'E') goto yy525;
@@ -5858,7 +5858,7 @@ yy971:
 }
 
 // Try to match email autolink after first <, returning num of chars matched.
-int _scan_autolink_email(const unsigned char *p)
+bufsize_t _scan_autolink_email(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -6060,7 +6060,7 @@ yy984:
 	}
 yy985:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy987:
 	++p;
 	yych = *p;
@@ -10803,7 +10803,7 @@ yy1230:
 }
 
 // Try to match an HTML tag after first <, returning num of chars matched.
-int _scan_html_tag(const unsigned char *p)
+bufsize_t _scan_html_tag(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -10964,7 +10964,7 @@ yy1242:
 	if (yych != '>') goto yy1239;
 yy1243:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1245:
 	yych = *++p;
 	if (yych == 'C') goto yy1260;
@@ -11455,7 +11455,7 @@ yy1297:
 
 // Try to match an HTML block tag including first <,
 // returning num of chars matched.
-int _scan_html_block_tag(const unsigned char *p)
+bufsize_t _scan_html_block_tag(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -11513,7 +11513,7 @@ yy1303:
 	goto yy1301;
 yy1304:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1306:
 	yych = *++p;
 	if (yych <= '/') {
@@ -12022,7 +12022,7 @@ yy1343:
 	}
 yy1344:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1346:
 	yych = *++p;
 	if (yych <= 'R') {
@@ -12639,7 +12639,7 @@ yy1466:
 	}
 yy1467:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1469:
 	yych = *++p;
 	if (yych <= 'R') {
@@ -13243,7 +13243,7 @@ yy1585:
 // This may optionally be contained in <..>; otherwise
 // whitespace and unbalanced right parentheses aren't allowed.
 // Newlines aren't ever allowed.
-int _scan_link_url(const unsigned char *p)
+bufsize_t _scan_link_url(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -13308,7 +13308,7 @@ int _scan_link_url(const unsigned char *p)
 		}
 	}
 yy1588:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1589:
 	yyaccept = 0;
 	marker = ++p;
@@ -13402,7 +13402,7 @@ yy1599:
 yy1600:
 	p = marker;
 	if (yyaccept <= 1) {
-		if (yyaccept == 0) {
+		if (yyaccept <= 0) {
 			goto yy1588;
 		} else {
 			goto yy1595;
@@ -13490,7 +13490,7 @@ yy1607:
 	if (yych <= ' ') goto yy1608;
 	if (yych != ')') goto yy1603;
 yy1608:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1609:
 	++p;
 	yych = *p;
@@ -13732,7 +13732,7 @@ yy1623:
 // Try to match a link title (in single quotes, in double quotes, or
 // in parentheses), returning number of chars matched.  Allow one
 // level of internal nesting (quotes within quotes).
-int _scan_link_title(const unsigned char *p)
+bufsize_t _scan_link_title(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -13818,13 +13818,13 @@ yy1632:
 yy1633:
 	p = marker;
 	if (yyaccept <= 1) {
-		if (yyaccept == 0) {
+		if (yyaccept <= 0) {
 			goto yy1626;
 		} else {
 			goto yy1637;
 		}
 	} else {
-		if (yyaccept == 2) {
+		if (yyaccept <= 2) {
 			goto yy1644;
 		} else {
 			goto yy1651;
@@ -13842,7 +13842,7 @@ yy1634:
 yy1636:
 	++p;
 yy1637:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1638:
 	yyaccept = 1;
 	marker = ++p;
@@ -13874,7 +13874,7 @@ yy1641:
 yy1643:
 	++p;
 yy1644:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1645:
 	yyaccept = 2;
 	marker = ++p;
@@ -13906,7 +13906,7 @@ yy1648:
 yy1650:
 	++p;
 yy1651:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1652:
 	yyaccept = 3;
 	marker = ++p;
@@ -13922,7 +13922,7 @@ yy1652:
 }
 
 // Match space characters, including newlines.
-int _scan_spacechars(const unsigned char *p)
+bufsize_t _scan_spacechars(const unsigned char *p)
 {
   const unsigned char *start = p; \
 
@@ -13973,7 +13973,7 @@ int _scan_spacechars(const unsigned char *p)
 		goto yy1659;
 	}
 yy1655:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1656:
 	yych = *++p;
 	goto yy1658;
@@ -13993,7 +13993,7 @@ yy1659:
 }
 
 // Match ATX header start.
-int _scan_atx_header_start(const unsigned char *p)
+bufsize_t _scan_atx_header_start(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -14059,7 +14059,7 @@ yy1665:
 yy1666:
 	++p;
 yy1667:
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1668:
 	++p;
 	yych = *p;
@@ -14128,7 +14128,7 @@ yy1672:
 
 // Match setext header line.  Return 1 for level-1 header,
 // 2 for level-2, 0 for no match.
-int _scan_setext_header_line(const unsigned char *p)
+bufsize_t _scan_setext_header_line(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
 
@@ -14269,7 +14269,7 @@ yy1693:
 // Scan a horizontal rule line: "...three or more hyphens, asterisks,
 // or underscores on a line by themselves. If you wish, you may use
 // spaces between the hyphens or asterisks."
-int _scan_hrule(const unsigned char *p)
+bufsize_t _scan_hrule(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -14384,7 +14384,7 @@ yy1709:
 	if (yych != '\r') goto yy1704;
 yy1711:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1713:
 	++p;
 	yych = *p;
@@ -14422,7 +14422,7 @@ yy1719:
 	}
 yy1721:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1723:
 	++p;
 	yych = *p;
@@ -14460,13 +14460,13 @@ yy1729:
 	}
 yy1731:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 }
 
 }
 
 // Scan an opening code fence.
-int _scan_open_code_fence(const unsigned char *p)
+bufsize_t _scan_open_code_fence(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -14557,7 +14557,7 @@ yy1743:
 yy1745:
 	++p;
 	p = marker;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1747:
 	yych = *++p;
 	if (yybm[0+yych] & 64) {
@@ -14585,13 +14585,13 @@ yy1750:
 yy1752:
 	++p;
 	p = marker;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 }
 
 }
 
 // Scan a closing code fence with length at least len.
-int _scan_close_code_fence(const unsigned char *p)
+bufsize_t _scan_close_code_fence(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -14687,7 +14687,7 @@ yy1764:
 yy1766:
 	++p;
 	p = marker;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1768:
 	yych = *++p;
 	if (yybm[0+yych] & 128) {
@@ -14725,14 +14725,14 @@ yy1771:
 yy1773:
 	++p;
 	p = marker;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 }
 
 }
 
 // Scans an entity.
 // Returns number of chars matched.
-int _scan_entity(const unsigned char *p)
+bufsize_t _scan_entity(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -14799,7 +14799,7 @@ yy1783:
 	}
 yy1784:
 	++p;
-	{ return (p - start); }
+	{ return (bufsize_t)(p - start); }
 yy1786:
 	yych = *++p;
 	if (yych <= ';') {
diff --git a/src/scanners.h b/src/scanners.h
index 1353f3b..bc5134e 100644
--- a/src/scanners.h
+++ b/src/scanners.h
@@ -5,21 +5,21 @@
 extern "C" {
 #endif
 
-int _scan_at(int (*scanner)(const unsigned char *), cmark_chunk *c, int offset);
-int _scan_scheme(const unsigned char *p);
-int _scan_autolink_uri(const unsigned char *p);
-int _scan_autolink_email(const unsigned char *p);
-int _scan_html_tag(const unsigned char *p);
-int _scan_html_block_tag(const unsigned char *p);
-int _scan_link_url(const unsigned char *p);
-int _scan_link_title(const unsigned char *p);
-int _scan_spacechars(const unsigned char *p);
-int _scan_atx_header_start(const unsigned char *p);
-int _scan_setext_header_line(const unsigned char *p);
-int _scan_hrule(const unsigned char *p);
-int _scan_open_code_fence(const unsigned char *p);
-int _scan_close_code_fence(const unsigned char *p);
-int _scan_entity(const unsigned char *p);
+bufsize_t _scan_at(bufsize_t (*scanner)(const unsigned char *), cmark_chunk *c, bufsize_t offset);
+bufsize_t _scan_scheme(const unsigned char *p);
+bufsize_t _scan_autolink_uri(const unsigned char *p);
+bufsize_t _scan_autolink_email(const unsigned char *p);
+bufsize_t _scan_html_tag(const unsigned char *p);
+bufsize_t _scan_html_block_tag(const unsigned char *p);
+bufsize_t _scan_link_url(const unsigned char *p);
+bufsize_t _scan_link_title(const unsigned char *p);
+bufsize_t _scan_spacechars(const unsigned char *p);
+bufsize_t _scan_atx_header_start(const unsigned char *p);
+bufsize_t _scan_setext_header_line(const unsigned char *p);
+bufsize_t _scan_hrule(const unsigned char *p);
+bufsize_t _scan_open_code_fence(const unsigned char *p);
+bufsize_t _scan_close_code_fence(const unsigned char *p);
+bufsize_t _scan_entity(const unsigned char *p);
 
 #define scan_scheme(c, n) _scan_at(&_scan_scheme, c, n)
 #define scan_autolink_uri(c, n) _scan_at(&_scan_autolink_uri, c, n)
diff --git a/src/scanners.re b/src/scanners.re
index 9411018..3722a99 100644
--- a/src/scanners.re
+++ b/src/scanners.re
@@ -2,9 +2,9 @@
 #include "chunk.h"
 #include "scanners.h"
 
-int _scan_at(int (*scanner)(const unsigned char *), cmark_chunk *c, int offset)
+bufsize_t _scan_at(bufsize_t (*scanner)(const unsigned char *), cmark_chunk *c, bufsize_t offset)
 {
-	int res;
+	bufsize_t res;
 	unsigned char *ptr = (unsigned char *)c->data;
 	unsigned char lim = ptr[c->len];
 
@@ -70,29 +70,29 @@ int _scan_at(int (*scanner)(const unsigned char *), cmark_chunk *c, int offset)
 */
 
 // Try to match a scheme including colon.
-int _scan_scheme(const unsigned char *p)
+bufsize_t _scan_scheme(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  scheme [:] { return (p - start); }
+  scheme [:] { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Try to match URI autolink after first <, returning number of chars matched.
-int _scan_autolink_uri(const unsigned char *p)
+bufsize_t _scan_autolink_uri(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  scheme [:][^\x00-\x20<>]*[>]  { return (p - start); }
+  scheme [:][^\x00-\x20<>]*[>]  { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Try to match email autolink after first <, returning num of chars matched.
-int _scan_autolink_email(const unsigned char *p)
+bufsize_t _scan_autolink_email(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
@@ -101,32 +101,32 @@ int _scan_autolink_email(const unsigned char *p)
     [@]
     [a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?
     ([.][a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*
-    [>] { return (p - start); }
+    [>] { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Try to match an HTML tag after first <, returning num of chars matched.
-int _scan_html_tag(const unsigned char *p)
+bufsize_t _scan_html_tag(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  htmltag { return (p - start); }
+  htmltag { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Try to match an HTML block tag including first <,
 // returning num of chars matched.
-int _scan_html_block_tag(const unsigned char *p)
+bufsize_t _scan_html_block_tag(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  [<] [/] blocktagname (spacechar | [>])  { return (p - start); }
-  [<] blocktagname (spacechar | [/>]) { return (p - start); }
-  [<] [!?] { return (p - start); }
+  [<] [/] blocktagname (spacechar | [>])  { return (bufsize_t)(p - start); }
+  [<] blocktagname (spacechar | [/>]) { return (bufsize_t)(p - start); }
+  [<] [!?] { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
@@ -135,13 +135,13 @@ int _scan_html_block_tag(const unsigned char *p)
 // This may optionally be contained in <..>; otherwise
 // whitespace and unbalanced right parentheses aren't allowed.
 // Newlines aren't ever allowed.
-int _scan_link_url(const unsigned char *p)
+bufsize_t _scan_link_url(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  [ \r\n]* [<] ([^<>\r\n\\\x00] | escaped_char | [\\])* [>] { return (p - start); }
-  [ \r\n]* (reg_char+ | escaped_char | in_parens_nosp)* { return (p - start); }
+  [ \r\n]* [<] ([^<>\r\n\\\x00] | escaped_char | [\\])* [>] { return (bufsize_t)(p - start); }
+  [ \r\n]* (reg_char+ | escaped_char | in_parens_nosp)* { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
@@ -149,42 +149,42 @@ int _scan_link_url(const unsigned char *p)
 // Try to match a link title (in single quotes, in double quotes, or
 // in parentheses), returning number of chars matched.  Allow one
 // level of internal nesting (quotes within quotes).
-int _scan_link_title(const unsigned char *p)
+bufsize_t _scan_link_title(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  ["] (escaped_char|[^"\x00])* ["]   { return (p - start); }
-  ['] (escaped_char|[^'\x00])* ['] { return (p - start); }
-  [(] (escaped_char|[^)\x00])* [)]  { return (p - start); }
+  ["] (escaped_char|[^"\x00])* ["]   { return (bufsize_t)(p - start); }
+  ['] (escaped_char|[^'\x00])* ['] { return (bufsize_t)(p - start); }
+  [(] (escaped_char|[^)\x00])* [)]  { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Match space characters, including newlines.
-int _scan_spacechars(const unsigned char *p)
+bufsize_t _scan_spacechars(const unsigned char *p)
 {
   const unsigned char *start = p; \
 /*!re2c
-  [ \t\v\f\r\n]* { return (p - start); }
+  [ \t\v\f\r\n]* { return (bufsize_t)(p - start); }
   . { return 0; }
 */
 }
 
 // Match ATX header start.
-int _scan_atx_header_start(const unsigned char *p)
+bufsize_t _scan_atx_header_start(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  [#]{1,6} ([ ]+|[\r\n])  { return (p - start); }
+  [#]{1,6} ([ ]+|[\r\n])  { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Match setext header line.  Return 1 for level-1 header,
 // 2 for level-2, 0 for no match.
-int _scan_setext_header_line(const unsigned char *p)
+bufsize_t _scan_setext_header_line(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
 /*!re2c
@@ -197,51 +197,51 @@ int _scan_setext_header_line(const unsigned char *p)
 // Scan a horizontal rule line: "...three or more hyphens, asterisks,
 // or underscores on a line by themselves. If you wish, you may use
 // spaces between the hyphens or asterisks."
-int _scan_hrule(const unsigned char *p)
+bufsize_t _scan_hrule(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  ([*][ ]*){3,} [ \t]* [\r\n] { return (p - start); }
-  ([_][ ]*){3,} [ \t]* [\r\n] { return (p - start); }
-  ([-][ ]*){3,} [ \t]* [\r\n] { return (p - start); }
+  ([*][ ]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
+  ([_][ ]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
+  ([-][ ]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Scan an opening code fence.
-int _scan_open_code_fence(const unsigned char *p)
+bufsize_t _scan_open_code_fence(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  [`]{3,} / [^`\r\n\x00]*[\r\n] { return (p - start); }
-  [~]{3,} / [^~\r\n\x00]*[\r\n] { return (p - start); }
+  [`]{3,} / [^`\r\n\x00]*[\r\n] { return (bufsize_t)(p - start); }
+  [~]{3,} / [^~\r\n\x00]*[\r\n] { return (bufsize_t)(p - start); }
   .?                        { return 0; }
 */
 }
 
 // Scan a closing code fence with length at least len.
-int _scan_close_code_fence(const unsigned char *p)
+bufsize_t _scan_close_code_fence(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
-  [`]{3,} / [ \t]*[\r\n] { return (p - start); }
-  [~]{3,} / [ \t]*[\r\n] { return (p - start); }
+  [`]{3,} / [ \t]*[\r\n] { return (bufsize_t)(p - start); }
+  [~]{3,} / [ \t]*[\r\n] { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
 
 // Scans an entity.
 // Returns number of chars matched.
-int _scan_entity(const unsigned char *p)
+bufsize_t _scan_entity(const unsigned char *p)
 {
   const unsigned char *marker = NULL;
   const unsigned char *start = p;
 /*!re2c
   [&] ([#] ([Xx][A-Fa-f0-9]{1,8}|[0-9]{1,8}) |[A-Za-z][A-Za-z0-9]{1,31} ) [;]
-     { return (p - start); }
+     { return (bufsize_t)(p - start); }
   .? { return 0; }
 */
 }
diff --git a/src/utf8.c b/src/utf8.c
index b83c2a5..ba1d873 100644
--- a/src/utf8.c
+++ b/src/utf8.c
@@ -30,7 +30,7 @@ static void encode_unknown(cmark_strbuf *buf)
 	cmark_strbuf_put(buf, repl, 3);
 }
 
-static int utf8proc_charlen(const uint8_t *str, int str_len)
+static int utf8proc_charlen(const uint8_t *str, bufsize_t str_len)
 {
 	int length, i;
 
@@ -42,7 +42,7 @@ static int utf8proc_charlen(const uint8_t *str, int str_len)
 	if (!length)
 		return -1;
 
-	if (str_len >= 0 && length > str_len)
+	if (str_len >= 0 && (bufsize_t)length > str_len)
 		return -str_len;
 
 	for (i = 1; i < length; i++) {
@@ -54,7 +54,7 @@ static int utf8proc_charlen(const uint8_t *str, int str_len)
 }
 
 // Validate a single UTF-8 character according to RFC 3629.
-static int utf8proc_valid(const uint8_t *str, int str_len)
+static int utf8proc_valid(const uint8_t *str, bufsize_t str_len)
 {
 	int length = utf8proc_charlen(str, str_len);
 
@@ -109,14 +109,14 @@ static int utf8proc_valid(const uint8_t *str, int str_len)
 	return length;
 }
 
-void utf8proc_detab(cmark_strbuf *ob, const uint8_t *line, size_t size)
+void utf8proc_detab(cmark_strbuf *ob, const uint8_t *line, bufsize_t size)
 {
 	static const uint8_t whitespace[] = "    ";
 
-	size_t i = 0, tab = 0;
+	bufsize_t i = 0, tab = 0;
 
 	while (i < size) {
-		size_t org = i;
+		bufsize_t org = i;
 
 		while (i < size && line[i] != '\t' && line[i] != '\0'
 		       && line[i] < 0x80) {
@@ -151,7 +151,7 @@ void utf8proc_detab(cmark_strbuf *ob, const uint8_t *line, size_t size)
 	}
 }
 
-int utf8proc_iterate(const uint8_t *str, int str_len, int32_t *dst)
+int utf8proc_iterate(const uint8_t *str, bufsize_t str_len, int32_t *dst)
 {
 	int length;
 	int32_t uc = -1;
@@ -191,7 +191,7 @@ int utf8proc_iterate(const uint8_t *str, int str_len, int32_t *dst)
 void utf8proc_encode_char(int32_t uc, cmark_strbuf *buf)
 {
 	uint8_t dst[4];
-	int len = 0;
+	bufsize_t len = 0;
 
 	assert(uc >= 0);
 
@@ -227,7 +227,7 @@ void utf8proc_encode_char(int32_t uc, cmark_strbuf *buf)
 	cmark_strbuf_put(buf, dst, len);
 }
 
-void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, int len)
+void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, bufsize_t len)
 {
 	int32_t c;
 
@@ -235,7 +235,7 @@ void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, int len)
 	utf8proc_encode_char(x, dest)
 
 	while (len > 0) {
-		int char_len = utf8proc_iterate(str, len, &c);
+		bufsize_t char_len = utf8proc_iterate(str, len, &c);
 
 		if (char_len >= 0) {
 #include "case_fold_switch.inc"
diff --git a/src/utf8.h b/src/utf8.h
index 7df1573..ed1d7ee 100644
--- a/src/utf8.h
+++ b/src/utf8.h
@@ -8,10 +8,10 @@
 extern "C" {
 #endif
 
-void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, int len);
+void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, bufsize_t len);
 void utf8proc_encode_char(int32_t uc, cmark_strbuf *buf);
-int utf8proc_iterate(const uint8_t *str, int str_len, int32_t *dst);
-void utf8proc_detab(cmark_strbuf *dest, const uint8_t *line, size_t size);
+int utf8proc_iterate(const uint8_t *str, bufsize_t str_len, int32_t *dst);
+void utf8proc_detab(cmark_strbuf *dest, const uint8_t *line, bufsize_t size);
 int utf8proc_is_space(int32_t uc);
 int utf8proc_is_punctuation(int32_t uc);
 
diff --git a/src/xml.c b/src/xml.c
index 14f6d67..7eec5a6 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -11,14 +11,9 @@
 
 // Functions to convert cmark_nodes to XML strings.
 
-static void escape_xml(cmark_strbuf *dest, const unsigned char *source, int length)
+static void escape_xml(cmark_strbuf *dest, const unsigned char *source, bufsize_t length)
 {
-	if (source != NULL) {
-		if (length < 0)
-			length = strlen((char *)source);
-
-		houdini_escape_html0(dest, source, (size_t)length, 0);
-	}
+	houdini_escape_html0(dest, source, length, 0);
 }
 
 struct render_state {