diff --git a/buffer.h b/buffer.h
index 54bed5c..e51f394 100644
--- a/buffer.h
+++ b/buffer.h
@@ -13,6 +13,13 @@
 extern "C" {
 #endif
 
+/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
+#ifndef __writememsz__
+#define __writememsz__(a,b)
+#define __readmemsz__(a,b)
+#define __readmem__(a)
+#endif
+
 typedef struct buffer {
   char *x;		/* actual buffer space */
   size_t p;		/* current position */
@@ -30,7 +37,9 @@ typedef struct buffer {
 #define BUFFER_INSIZE 8192
 #define BUFFER_OUTSIZE 8192
 
+__writememsz__(4,5)
 void buffer_init(buffer* b,ssize_t (*op)(),int fd,char* y,size_t ylen);
+__writememsz__(4,5)
 void buffer_init_free(buffer* b,ssize_t (*op)(),int fd,char* y,size_t ylen);
 void buffer_free(void* buf);
 void buffer_munmap(void* buf);
@@ -38,11 +47,17 @@ int buffer_mmapread(buffer* b,const char* filename);
 void buffer_close(buffer* b);
 
 int buffer_flush(buffer* b);
+__readmemsz__(2,3)
 int buffer_put(buffer* b,const char* x,size_t len);
+__readmemsz__(2,3)
 int buffer_putalign(buffer* b,const char* x,size_t len);
+__readmemsz__(2,3)
 int buffer_putflush(buffer* b,const char* x,size_t len);
+__readmem__(2)
 int buffer_puts(buffer* b,const char* x);
+__readmem__(2)
 int buffer_putsalign(buffer* b,const char* x);
+__readmem__(2)
 int buffer_putsflush(buffer* b,const char* x);
 
 #if defined(__GNUC__) && !defined(__LIBOWFAT_INTERNAL)
@@ -53,8 +68,8 @@ int buffer_putsflush(buffer* b,const char* x);
 #define buffer_putsflush(b,s) (__builtin_constant_p(s) ? buffer_putflush(b,s,strlen(s)) : buffer_putsflush(b,s))
 #endif
 
-int buffer_putm_internal(buffer*b,...);
-int buffer_putm_internal_flush(buffer*b,...);
+int buffer_putm_internal(buffer* b,...);
+int buffer_putm_internal_flush(buffer* b,...);
 #define buffer_putm(b,...) buffer_putm_internal(b,__VA_ARGS__,(char*)0)
 #define buffer_putmflush(b,...) buffer_putm_internal_flush(b,__VA_ARGS__,(char*)0)
 
@@ -67,16 +82,21 @@ int buffer_putnlflush(buffer* b); /* put \n and flush */
     : buffer_put((s),&(c),1) \
   )
 
+__writememsz__(2,3)
 ssize_t buffer_get(buffer* b,char* x,size_t len);
 ssize_t buffer_feed(buffer* b);
 ssize_t buffer_getc(buffer* b,char* x);
+__writememsz__(2,3)
 ssize_t buffer_getn(buffer* b,char* x,size_t len);
 
 /* read bytes until the destination buffer is full (len bytes), end of
  * file is reached or the read char is in charset (setlen bytes).  An
  * empty line when looking for \n will write '\n' to x and return 0.  If
  * EOF is reached, \0 is written to the buffer */
+__writememsz__(2,3)
+__readmemsz__(4,5)
 ssize_t buffer_get_token(buffer* b,char* x,size_t len,const char* charset,size_t setlen);
+__writememsz__(2,3)
 ssize_t buffer_getline(buffer* b,char* x,size_t len);
 
 /* this predicate is given the string as currently read from the buffer
@@ -84,6 +104,7 @@ ssize_t buffer_getline(buffer* b,char* x,size_t len);
 typedef int (*string_predicate)(const char* x,size_t len);
 
 /* like buffer_get_token but the token ends when your predicate says so */
+__writememsz__(2,3)
 ssize_t buffer_get_token_pred(buffer* b,char* x,size_t len,string_predicate p);
 
 char *buffer_peek(buffer* b);
@@ -133,11 +154,13 @@ int buffer_putsaflush(buffer* b,const stralloc* sa);
  * data is available. */
 
 /* read token from buffer to stralloc */
+__readmemsz__(3,4)
 int buffer_get_token_sa(buffer* b,stralloc* sa,const char* charset,size_t setlen);
 /* read line from buffer to stralloc */
 int buffer_getline_sa(buffer* b,stralloc* sa);
 
 /* same as buffer_get_token_sa but empty sa first */
+__readmemsz__(3,4)
 int buffer_get_new_token_sa(buffer* b,stralloc* sa,const char* charset,size_t setlen);
 /* same as buffer_getline_sa but empty sa first */
 int buffer_getnewline_sa(buffer* b,stralloc* sa);
@@ -155,6 +178,7 @@ void buffer_fromsa(buffer* b,const stralloc* sa);	/* read from sa */
 int buffer_tosa(buffer*b,stralloc* sa);		/* write to sa, auto-growing it */
 #endif
 
+__readmemsz__(2,3)
 void buffer_frombuf(buffer* b,const char* x,size_t l);	/* buffer reads from static buffer */
 
 #ifdef ARRAY_H
diff --git a/byte.h b/byte.h
index 0568164..9e9ba04 100644
--- a/byte.h
+++ b/byte.h
@@ -9,24 +9,36 @@
 extern "C" {
 #endif
 
+/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
 #ifndef __pure__
 #define __pure__
 #endif
 
+#ifndef __writememsz__
+#define __writememsz__(a,b)
+#define __readmemsz__(a,b)
+#endif
+
 /* byte_chr returns the smallest integer i between 0 and len-1
  * inclusive such that one[i] equals needle, or len if not found. */
+__readmemsz__(1,2)
 size_t byte_chr(const void* haystack, size_t len, char needle) __pure__;
 
 /* byte_rchr returns the largest integer i between 0 and len-1 inclusive
  * such that one[i] equals needle, or len if not found. */
+__readmemsz__(1,2)
 size_t byte_rchr(const void* haystack,size_t len,char needle) __pure__;
 
 /* byte_copy copies in[0] to out[0], in[1] to out[1], ... and in[len-1]
  * to out[len-1]. */
+__writememsz__(1,2)
+__readmemsz__(3,2)
 void byte_copy(void* out, size_t len, const void* in);
 
 /* byte_copyr copies in[len-1] to out[len-1], in[len-2] to out[len-2],
  * ... and in[0] to out[0] */
+__writememsz__(1,2)
+__readmemsz__(3,2)
 void byte_copyr(void* out, size_t len, const void* in);
 
 /* byte_diff returns negative, 0, or positive, depending on whether the
@@ -34,13 +46,18 @@ void byte_copyr(void* out, size_t len, const void* in);
  * than, equal to, or greater than the string b[0], b[1], ...,
  * b[len-1]. When the strings are different, byte_diff does not read
  * bytes past the first difference. */
+__readmemsz__(1,2)
+__readmemsz__(3,2)
 int byte_diff(const void* a, size_t len, const void* b) __pure__;
 
 /* byte_zero sets the bytes out[0], out[1], ..., out[len-1] to 0 */
+__writememsz__(1,2)
 void byte_zero(void* out, size_t len);
 
 #define byte_equal(s,n,t) (!byte_diff((s),(n),(t)))
 
+__readmemsz__(1,2)
+__readmemsz__(3,2)
 int byte_equal_notimingattack(const void* a, size_t len,const void* b) __pure__;
 
 #if defined(__i386__) || defined(__x86_64__)
diff --git a/scan.h b/scan.h
index bcd4365..2458bfb 100644
--- a/scan.h
+++ b/scan.h
@@ -15,10 +15,16 @@
 extern "C" {
 #endif
 
+/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
 #ifndef __pure__
 #define __pure__
 #endif
 
+#ifndef __writememsz__
+#define __writememsz__(a,b)
+#define __readmemsz__(a,b)
+#endif
+
 /* This file declared functions used to decode / scan / unmarshal
  * integer or string values from a buffer.
  * The first argument is always the source buffer, the second argument
@@ -39,24 +45,28 @@ extern "C" {
  * values, i.e. on a 32-bit system:
  * scan_ulong("4294967296",&i" -> i=429496729, return 9 */
 size_t scan_ulong(const char *src,unsigned long *dest);
+__readmemsz__(1,2)
 size_t scan_ulongn(const char* src,size_t n,unsigned long* dest);
 
 /* Interpret src as ASCII hexadecimal number, write number to dest and
  * return the number of bytes that were parsed.
  * Note: leading '+' or '-' not accepted! */
 size_t scan_xlong(const char *src,unsigned long *dest);
+__readmemsz__(1,2)
 size_t scan_xlongn(const char *src,size_t n,unsigned long *dest);
 
 /* interpret src as ASCII octal number, write number to dest and
  * return the number of bytes that were parsed.
  * Note: leading '+' or '-' not accepted! */
 size_t scan_8long(const char *src,unsigned long *dest);
+__readmemsz__(1,2)
 size_t scan_8longn(const char *src,size_t n,unsigned long *dest);
 
 /* interpret src as signed ASCII decimal number, write number to dest
  * and return the number of bytes that were parsed.
  * Note: leading spaces not accepted! */
 size_t scan_long(const char *src,signed long *dest);
+__readmemsz__(1,2)
 size_t scan_longn(const char *src,size_t n,signed long *dest);
 
 size_t scan_longlong(const char *src,signed long long *dest);
@@ -84,17 +94,21 @@ size_t scan_double(const char *in, double *dest);
 size_t scan_plusminus(const char *src,signed int *dest);
 
 /* return the highest integer n<=limit so that isspace(in[i]) for all 0<=i<=n */
+__readmemsz__(1,2)
 size_t scan_whitenskip(const char *in,size_t limit) __pure__;
 
 /* return the highest integer n<=limit so that !isspace(in[i]) for all 0<=i<=n */
+__readmemsz__(1,2)
 size_t scan_nonwhitenskip(const char *in,size_t limit) __pure__;
 
 /* return the highest integer n<=limit so that in[i] is element of
  * charset (ASCIIZ string) for all 0<=i<=n */
+__readmemsz__(1,3)
 size_t scan_charsetnskip(const char *in,const char *charset,size_t limit) __pure__;
 
 /* return the highest integer n<=limit so that in[i] is not element of
  * charset (ASCIIZ string) for all 0<=i<=n */
+__readmemsz__(1,3)
 size_t scan_noncharsetnskip(const char *in,const char *charset,size_t limit) __pure__;
 
 /* try to parse ASCII GMT date; does not understand time zones. */
@@ -153,6 +167,7 @@ size_t scan_pb_type5_fixed32(const char* in,size_t len,uint32_t* b) __pure__;
  *   return 0
  * Note: *dest will point inside the input buffer!
  */
+__readmemsz__(1,2)
 size_t scan_netstring(const char* in,size_t len,char** dest,size_t* slen) __pure__;
 
 /* internal function that might be useful independently */
diff --git a/scan/scan_8long.c b/scan/scan_8long.c
index d44c750..46b6ff6 100644
--- a/scan/scan_8long.c
+++ b/scan/scan_8long.c
@@ -7,7 +7,7 @@
 #endif
 
 size_t scan_8long(const char *src,unsigned long *dest) {
-  return scan_8longn(src,(size_t)-1,dest);
+  return scan_8longn(src,((size_t)-1)/2,dest);
 }
 
 #ifdef UNITTEST
diff --git a/scan/scan_long.c b/scan/scan_long.c
index 308721d..0a7a7a8 100644
--- a/scan/scan_long.c
+++ b/scan/scan_long.c
@@ -7,7 +7,7 @@
 #endif
 
 size_t scan_long(const char *src,long *dest) {
-  return scan_longn(src,(size_t)(-1),dest);
+  return scan_longn(src,((size_t)-1)/2,dest);
 }
 
 #ifdef UNITTEST
diff --git a/scan/scan_ulong.c b/scan/scan_ulong.c
index 9323d35..d69f2a9 100644
--- a/scan/scan_ulong.c
+++ b/scan/scan_ulong.c
@@ -1,5 +1,5 @@
 #include "scan.h"
 
 size_t scan_ulong(const char* src,unsigned long int* dest) {
-  return scan_ulongn(src,(size_t)-1,dest);
+  return scan_ulongn(src,((size_t)-1)/2,dest);
 }
diff --git a/scan/scan_xlong.c b/scan/scan_xlong.c
index 8cda884..314ba06 100644
--- a/scan/scan_xlong.c
+++ b/scan/scan_xlong.c
@@ -1,7 +1,7 @@
 #include "scan.h"
 
 size_t scan_xlong(const char *src,unsigned long *dest) {
-  return scan_xlongn(src,(size_t)-1,dest);
+  return scan_xlongn(src,((size_t)-1)/2,dest);
 }
 
 /* unit tested via scan_xlongn */
diff --git a/stralloc.h b/stralloc.h
index b328667..18a3f8b 100644
--- a/stralloc.h
+++ b/stralloc.h
@@ -8,10 +8,16 @@
 extern "C" {
 #endif
 
+/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
 #ifndef __pure__
 #define __pure__
 #endif
 
+#ifndef __writememsz__
+#define __writememsz__(a,b)
+#define __readmemsz__(a,b)
+#endif
+
 /* stralloc is the internal data structure all functions are working on.
  * s is the string.
  * len is the used length of the string.
@@ -46,6 +52,7 @@ int stralloc_readyplus(stralloc* sa,size_t len);
 /* stralloc_copyb copies the string buf[0], buf[1], ..., buf[len-1] into
  * sa, allocating space if necessary, and returns 1. If it runs out of
  * memory, stralloc_copyb leaves sa alone and returns 0. */
+__readmemsz__(2,3)
 int stralloc_copyb(stralloc* sa,const char* buf,size_t len);
 
 /* stralloc_copys copies a \0-terminated string from buf into sa,
@@ -62,6 +69,7 @@ int stralloc_copy(stralloc* sa,const stralloc* sa2);
  * returns 1. If sa is unallocated, stralloc_catb is the same as
  * stralloc_copyb. If it runs out of memory, stralloc_catb leaves sa
  * alone and returns 0. */
+__readmemsz__(2,3)
 int stralloc_catb(stralloc* sa,const char* in,size_t len);
 
 /* stralloc_cats is analogous to stralloc_copys */
@@ -161,11 +169,13 @@ int buffer_putsaflush(buffer* b,const stralloc* sa);
  * data is available. */
 
 /* read token from buffer to stralloc */
+__readmemsz__(3,4)
 int buffer_get_token_sa(buffer* b,stralloc* sa,const char* charset,size_t setlen);
 /* read line from buffer to stralloc */
 int buffer_getline_sa(buffer* b,stralloc* sa);
 
 /* same as buffer_get_token_sa but empty sa first */
+__readmemsz__(3,4)
 int buffer_get_new_token_sa(buffer* b,stralloc* sa,const char* charset,size_t setlen);
 /* same as buffer_getline_sa but empty sa first */
 int buffer_getnewline_sa(buffer* b,stralloc* sa);
diff --git a/textcode.h b/textcode.h
index beb296e..a09eff9 100644
--- a/textcode.h
+++ b/textcode.h
@@ -11,48 +11,72 @@ extern "C" {
 /* These take len bytes from src and write them in encoded form to
  * dest (if dest != NULL), returning the number of bytes written. */
 
+/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
+#ifndef __writememsz__
+#define __readmemsz__(a,b)
+#endif
+
 /* Needs len/3*4 bytes */
+__readmemsz__(2,3)
 size_t fmt_uuencoded(char* dest,const char* src,size_t len);
 /* Needs len/3*4 bytes */
+__readmemsz__(2,3)
 size_t fmt_base64(char* dest,const char* src,size_t len);
+__readmemsz__(2,3)
 size_t fmt_base64url(char* dest,const char* src,size_t len);
 /* Worst case: len*3 */
+__readmemsz__(2,3)
 size_t fmt_quotedprintable(char* dest,const char* src,size_t len);
 /* Worst case: len*3 */
+__readmemsz__(2,3)
 size_t fmt_quotedprintable2(char* dest,const char* src,size_t len,const char* escapeme);
 /* Worst case: len*3 */
+__readmemsz__(2,3)
 size_t fmt_urlencoded(char* dest,const char* src,size_t len);
 /* Worst case: len*3 */
+__readmemsz__(2,3)
 size_t fmt_urlencoded2(char* dest,const char* src,size_t len,const char* escapeme);
 /* Worst case: len*2 */
+__readmemsz__(2,3)
 size_t fmt_yenc(char* dest,const char* src,size_t len);
 /* Needs len*2 bytes */
+__readmemsz__(2,3)
 size_t fmt_hexdump(char* dest,const char* src,size_t len);
 /* Change '<' to '&lt;' and '&' to '&amp;' and '\n' to '<br>'; worst case: len*5 */
 /* This is meant for outputting text that goes between tags */
+__readmemsz__(2,3)
 size_t fmt_html(char* dest,const char* src,size_t len);
 /* Change '<' to '&lt;' and '&' to '&amp;' and '"' to '&quot;'; worst case: len*6 */
 /* This is meant for outputting text that goes in a tag argument between double quotes*/
+__readmemsz__(2,3)
 size_t fmt_html_tagarg(char* dest,const char* src,size_t len);
 /* Change '<' to '&lt;' and '&' to '&amp;'; worst case: len*5 */
+__readmemsz__(2,3)
 size_t fmt_xml(char* dest,const char* src,size_t len);
 
 /* Change '\' to "\\", '\n' to "\n", ^A to "\x01" etc; worst case: len*4 */
+__readmemsz__(2,3)
 size_t fmt_cescape(char* dest,const char* src,size_t len);
 /* Worst case: len*4 */
+__readmemsz__(2,3)
 size_t fmt_cescape2(char* dest,const char* src,size_t len,const char* escapeme);
 /* Fold whitespace to '_'; this is great for writing fields with
  * white spaces to a log file and still allow awk to do log analysis */
 /* Worst case: same size */
+__readmemsz__(2,3)
 size_t fmt_foldwhitespace(char* dest,const char* src,size_t len);
 /* Worst case: len*3 */
+__readmemsz__(2,3)
 size_t fmt_ldapescape(char* dest,const char* src,size_t len);
+__readmemsz__(2,3)
 size_t fmt_ldapescape2(char* dest,const char* src,size_t len,const char* escapeme);
 /* Encode JSON string from UTF-8; will backslash-escape the bare minimum.
  * Invalid UTF-8 in input will output as valid UTF-8 for each byte
  * Worst case: len*6 */
+__readmemsz__(2,3)
 size_t fmt_jsonescape(char* dest,const char* src,size_t len);
 
+__readmemsz__(2,3)
 size_t fmt_base85(char* dest,const char* src,size_t len);
 
 /* These read one line from src, decode it, and write the result to