diff --git a/scan/scan_8int.c b/scan/scan_8int.c
index 5a6fcaa..5aa7344 100644
--- a/scan/scan_8int.c
+++ b/scan/scan_8int.c
@@ -4,7 +4,7 @@ size_t scan_8int(const char* src,unsigned int* dest) {
   register const char *tmp=src;
   register unsigned int l=0;
   register unsigned char c;
-  while ((c=(char)(*tmp-'0'))<8) {
+  while ((c=(unsigned char)(*tmp-'0'))<8) {
     if (l>>(sizeof(l)*8-3)) break;
     l=l*8+c;
     ++tmp;
diff --git a/scan/scan_8longlong.c b/scan/scan_8longlong.c
index e32db8d..5e660fc 100644
--- a/scan/scan_8longlong.c
+++ b/scan/scan_8longlong.c
@@ -4,11 +4,11 @@ size_t scan_8longlong(const char *src,unsigned long long *dest) {
   register const char *tmp=src;
   register unsigned long long l=0;
   register unsigned char c;
-  while ((c=*tmp-'0')<8) {
+  while ((c=(unsigned char)(*tmp-'0'))<8) {
     if (l>>(sizeof(l)*8-3)) break;
     l=l*8+c;
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/scan/scan_8longn.c b/scan/scan_8longn.c
index 7d500d4..1d51c14 100644
--- a/scan/scan_8longn.c
+++ b/scan/scan_8longn.c
@@ -4,11 +4,11 @@ size_t scan_8longn(const char *src,size_t n,unsigned long *dest) {
   register const char *tmp=src;
   register unsigned long l=0;
   register unsigned char c;
-  while (n-->0 && (c=*tmp-'0')<8) {
+  while (n-->0 && (c=(unsigned char)(*tmp-'0'))<8) {
     if (l>>(sizeof(l)*8-3)) break;
     l=l*8+c;
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/scan/scan_charsetnskip.c b/scan/scan_charsetnskip.c
index 2961732..dd76a54 100644
--- a/scan/scan_charsetnskip.c
+++ b/scan/scan_charsetnskip.c
@@ -11,5 +11,5 @@ size_t scan_charsetnskip(const char *s,const char *charset,size_t limit) {
     if (*i!=*t) break;
     ++t;
   }
-  return t-s;
+  return (size_t)(t-s);
 }
diff --git a/scan/scan_fromhex.c b/scan/scan_fromhex.c
index 62fdfa7..1365b39 100644
--- a/scan/scan_fromhex.c
+++ b/scan/scan_fromhex.c
@@ -1,10 +1,10 @@
 #include "scan.h"
 
 int scan_fromhex(unsigned char c) {
-  c-='0';
+  c=(unsigned char)(c-'0');
   if (c<=9) return c;
-  c&=~0x20;
-  c-='A'-'0';
+  c=(unsigned char)(c&~0x20);
+  c=(unsigned char)(c-('A'-'0'));
   if (c<6) return c+10;
   return -1;
 /* more readable but creates worse code:
diff --git a/scan/scan_httpdate.c b/scan/scan_httpdate.c
index 8d9e508..bcaf6c2 100644
--- a/scan/scan_httpdate.c
+++ b/scan/scan_httpdate.c
@@ -12,11 +12,11 @@ extern char** environ;
 
 static int parsetime(const char*c,struct tm* x) {
   unsigned long tmp;
-  c+=scan_ulong(c,&tmp); x->tm_hour=tmp;
+  c+=scan_ulong(c,&tmp); x->tm_hour=(int)tmp;
   if (*c!=':') return -1; ++c;
-  c+=scan_ulong(c,&tmp); x->tm_min=tmp;
+  c+=scan_ulong(c,&tmp); x->tm_min=(int)tmp;
   if (*c!=':') return -1; ++c;
-  c+=scan_ulong(c,&tmp); x->tm_sec=tmp;
+  c+=scan_ulong(c,&tmp); x->tm_sec=(int)tmp;
   if (*c!=' ') return -1;
   return 0;
 }
@@ -37,14 +37,14 @@ size_t scan_httpdate(const char *in,time_t *t) {
       }
     }
     c+=4; if (*c==' ') ++c;
-    c+=scan_ulong(c,&tmp); x.tm_mday=tmp;
+    c+=scan_ulong(c,&tmp); x.tm_mday=(int)tmp;
     ++c;
     if (parsetime(c,&x)) return 0;
     c+=9;
-    c+=scan_ulong(c,&tmp); x.tm_year=tmp-1900;
+    c+=scan_ulong(c,&tmp); x.tm_year=(int)(tmp-1900);
     goto done;
   }
-  c+=scan_ulong(c,&tmp); x.tm_mday=tmp;
+  c+=scan_ulong(c,&tmp); x.tm_mday=(int)tmp;
   while (*c==' ') ++c; // work around crappy sqlite download httpd
 //  ++c;
   for (i=0; i<12; ++i)
@@ -53,9 +53,9 @@ size_t scan_httpdate(const char *in,time_t *t) {
     }
   c+=4;
   c+=scan_ulong(c,&tmp);
-  if (tmp>1000) x.tm_year=tmp-1900; else
-    if (tmp<70) x.tm_year=tmp+100; else
-                x.tm_year=tmp;
+  if (tmp>1000) x.tm_year=(int)(tmp-1900); else
+    if (tmp<70) x.tm_year=(int)(tmp+100); else
+                x.tm_year=(int)tmp;
   ++c;
   if (parsetime(c,&x)) return 0;
   c+=9;
@@ -86,5 +86,5 @@ done:
 #endif
   }
 #endif
-  return c-in;
+  return (size_t)(c-in);
 }
diff --git a/scan/scan_long.c b/scan/scan_long.c
index 5efcbfe..ae610d9 100644
--- a/scan/scan_long.c
+++ b/scan/scan_long.c
@@ -1,5 +1,5 @@
 #include "scan.h"
 
 size_t scan_long(const char *src,long *dest) {
-  return scan_longn(src,-1,dest);
+  return scan_longn(src,(size_t)(-1),dest);
 }
diff --git a/scan/scan_longlong.c b/scan/scan_longlong.c
index 8aa0537..751733c 100644
--- a/scan/scan_longlong.c
+++ b/scan/scan_longlong.c
@@ -3,17 +3,17 @@
 static const unsigned long maxlong = ((unsigned long)-1)>>1;
 
 size_t scan_longlong(const char* src,signed long long* dest) {
-  unsigned int i,o;
+  size_t i,o;
   unsigned long long l;
   char c=src[0];
-  int neg=c=='-';
+  unsigned int neg=c=='-';
   o=c=='-' || c=='+';
   if ((i=scan_ulonglong(src+o,&l))) {
     if (i>0 && l>maxlong+neg) {
       l/=10;
       --i;
     }
-    if (i+o) *dest=c=='-'?-l:l;
+    if (i+o) *dest=(signed long long)(c=='-'?-l:l);
     return i+o;
   } return 0;
 }
diff --git a/scan/scan_longn.c b/scan/scan_longn.c
index a632904..ae996b3 100644
--- a/scan/scan_longn.c
+++ b/scan/scan_longn.c
@@ -9,7 +9,7 @@ size_t scan_longn(const char *src,size_t n,long *dest) {
   unsigned int neg;
   int ok;
   if (!n--) return 0;
-  tmp=src; l=0; ok=neg=0;
+  tmp=src; l=0; ok=0; neg=0;
   switch (*tmp) {
   case '-': neg=1;
   case '+': ++tmp;
diff --git a/scan/scan_noncharsetnskip.c b/scan/scan_noncharsetnskip.c
index 35acdb1..d280fd5 100644
--- a/scan/scan_noncharsetnskip.c
+++ b/scan/scan_noncharsetnskip.c
@@ -11,5 +11,5 @@ size_t scan_noncharsetnskip(const char *s,const char *charset,size_t limit) {
     if (*i==*t) break;
     ++t;
   }
-  return t-s;
+  return (size_t)(t-s);
 }
diff --git a/scan/scan_short.c b/scan/scan_short.c
index 14051bd..45e5091 100644
--- a/scan/scan_short.c
+++ b/scan/scan_short.c
@@ -1,6 +1,6 @@
 #include "scan.h"
 
-static const unsigned int maxshort = ((unsigned short)-1)>>1;
+static const unsigned short maxshort = ((unsigned short)-1)>>1;
 
 size_t scan_short(const char* src,short* dest) {
   register const char *tmp;
@@ -14,7 +14,7 @@ size_t scan_short(const char* src,short* dest) {
   case '+': ++tmp;
   }
   while ((c=(unsigned char)(*tmp-'0'))<10) {
-    unsigned long int n;
+    unsigned short int n;
     /* we want to do: l=l*10+c
      * but we need to check for integer overflow.
      * to check whether l*10 overflows, we could do
@@ -22,17 +22,17 @@ size_t scan_short(const char* src,short* dest) {
      * however, multiplication and division are expensive.
      * so instead of *10 we do (l<<3) (i.e. *8) + (l<<1) (i.e. *2)
      * and check for overflow on all the intermediate steps */
-    n=(unsigned int)l<<3; if ((n>>3)!=(unsigned int)l) break;
+    n=(unsigned short)(l<<3); if ((n>>3)!=(unsigned short)l) break;
     if (n+(l<<1) < n) break;
-    n+=l<<1;
+    n=(unsigned short)(n+(l<<1));
     if (n+c < n) break;
-    n+=c;
+    n=(unsigned short)(n+c);
     if (n > maxshort+neg) break;
-    l=n;
+    l=(short)n;
     ++tmp;
     ok=1;
   }
   if (!ok) return 0;
-  *dest=(neg?-l:l);
+  *dest=(short)(neg?-l:l);
   return (size_t)(tmp-src);
 }
diff --git a/scan/scan_uint.c b/scan/scan_uint.c
index b3c6962..c166b41 100644
--- a/scan/scan_uint.c
+++ b/scan/scan_uint.c
@@ -14,7 +14,7 @@ size_t scan_uint(const char* src,unsigned int* dest) {
     register const char *tmp=src;
     register unsigned int l=0;
     register unsigned char c;
-    while ((c=(char)(*tmp-'0'))<10) {
+    while ((c=(unsigned char)(*tmp-'0'))<10) {
       unsigned int n;
       /* division is very slow on most architectures */
       n=l<<3; if ((n>>3)!=l) break;
diff --git a/scan/scan_ulonglong.c b/scan/scan_ulonglong.c
index 71c69c6..23cd8eb 100644
--- a/scan/scan_ulonglong.c
+++ b/scan/scan_ulonglong.c
@@ -4,7 +4,7 @@ size_t scan_ulonglong(const char *src,unsigned long long *dest) {
   register const char *tmp=src;
   register unsigned long long l=0;
   register unsigned char c;
-  while ((c=(char)(*tmp-'0'))<10) {
+  while ((c=(unsigned char)(*tmp-'0'))<10) {
     unsigned long long n;
     /* division is very slow on most architectures */
     n=l<<3; if ((n>>3)!=l) break;
diff --git a/scan/scan_ulongn.c b/scan/scan_ulongn.c
index f685114..4011fb4 100644
--- a/scan/scan_ulongn.c
+++ b/scan/scan_ulongn.c
@@ -4,7 +4,7 @@ size_t scan_ulongn(const char* src,size_t n,unsigned long int* dest) {
   register const char *tmp=src;
   register unsigned long int l=0;
   register unsigned char c;
-  while (n-->0 && (c=(char)(*tmp-'0'))<10) {
+  while (n-->0 && (c=(unsigned char)(*tmp-'0'))<10) {
     unsigned long int n;
     /* we want to do: l=l*10+c
      * but we need to check for integer overflow.
diff --git a/scan/scan_ushort.c b/scan/scan_ushort.c
index bdfd4fa..893127a 100644
--- a/scan/scan_ushort.c
+++ b/scan/scan_ushort.c
@@ -14,17 +14,17 @@ size_t scan_ushort(const char* src,unsigned short* dest) {
     register const char *tmp=src;
     register unsigned short int l=0;
     register unsigned char c;
-    while ((c=*tmp-'0')<10) {
+    while ((c=(unsigned char)(*tmp-'0'))<10) {
       unsigned short int n;
       /* division is very slow on most architectures */
-      n=l<<3; if ((n>>3)!=l) break;
+      n=(unsigned short)(l<<3); if ((n>>3)!=l) break;
       if (n+(l<<1) < n) break;
-      n+=l<<1;
+      n=(unsigned short)(n+(l<<1));
       if ((unsigned short)(n+c) < n) break;
-      l=n+c;
+      l=(unsigned short)(n+c);
       ++tmp;
     }
     if (tmp-src) *dest=l;
-    return tmp-src;
+    return (size_t)(tmp-src);
   }
 }
diff --git a/scan/scan_whitenskip.c b/scan/scan_whitenskip.c
index bc50a99..3297f0a 100644
--- a/scan/scan_whitenskip.c
+++ b/scan/scan_whitenskip.c
@@ -5,5 +5,5 @@ size_t scan_whitenskip(const char *s,size_t limit) {
   register const char *t=s;
   register const char *u=t+limit;
   while (t<u && isspace(*t)) ++t;
-  return t-s;
+  return (size_t)(t-s);
 }
diff --git a/scan/scan_xint.c b/scan/scan_xint.c
index 5564a23..316c059 100644
--- a/scan/scan_xint.c
+++ b/scan/scan_xint.c
@@ -4,10 +4,10 @@ size_t scan_xint(const char* src,unsigned int* dest) {
   register const char *tmp=src;
   register unsigned int l=0;
   register unsigned char c;
-  while ((l>>(sizeof(l)*8-4))==0 && (c=scan_fromhex(*tmp))<16) {
+  while ((l>>(sizeof(l)*8-4))==0 && (c=(unsigned char)scan_fromhex((unsigned char)*tmp))<16) {
     l=(l<<4)+c;
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/scan/scan_xlonglong.c b/scan/scan_xlonglong.c
index ccf1e54..350a315 100644
--- a/scan/scan_xlonglong.c
+++ b/scan/scan_xlonglong.c
@@ -2,12 +2,12 @@
 
 size_t scan_xlonglong(const char* src,unsigned long long* dest) {
   register const char *tmp=src;
-  register long long l=0;
+  register unsigned long long l=0;
   register unsigned char c;
-  while ((l>>(sizeof(l)*8-4))==0 && (c=scan_fromhex(*tmp))<16) {
+  while ((l>>(sizeof(l)*8-4))==0 && (c=(unsigned char)scan_fromhex((unsigned char)*tmp))<16) {
     l=(l<<4)+c;
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/scan/scan_xlongn.c b/scan/scan_xlongn.c
index 7618ac5..e29f574 100644
--- a/scan/scan_xlongn.c
+++ b/scan/scan_xlongn.c
@@ -4,10 +4,10 @@ size_t scan_xlongn(const char *src,size_t n,unsigned long *dest) {
   register const char *tmp=src;
   register unsigned long l=0;
   register unsigned char c;
-  while (n-->0 && (l>>(sizeof(l)*8-4))==0 && (c=scan_fromhex(*tmp))<16) {
+  while (n-->0 && (l>>(sizeof(l)*8-4))==0 && (c=(unsigned char)scan_fromhex((unsigned char)*tmp))<16) {
     l=(l<<4)+c;
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/scan/scan_xshort.c b/scan/scan_xshort.c
index 82c3cc6..53b8f95 100644
--- a/scan/scan_xshort.c
+++ b/scan/scan_xshort.c
@@ -4,10 +4,10 @@ size_t scan_xshort(const char* src,unsigned short* dest) {
   register const char *tmp=src;
   register unsigned short l=0;
   register unsigned char c;
-  while ((l>>(sizeof(l)*8-4))==0 && (c=scan_fromhex(*tmp))<16) {
-    l=(l<<4)+c;
+  while ((l>>(sizeof(l)*8-4))==0 && (c=(unsigned char)scan_fromhex((unsigned char)*tmp))<16) {
+    l=(unsigned short)((l<<4)+c);
     ++tmp;
   }
   *dest=l;
-  return tmp-src;
+  return (size_t)(tmp-src);
 }
diff --git a/str/str_chr.c b/str/str_chr.c
index 9338065..3938e79 100644
--- a/str/str_chr.c
+++ b/str/str_chr.c
@@ -9,5 +9,5 @@ size_t str_chr(const char *in, char needle) {
     if (!*t || *t==c) break; ++t;
     if (!*t || *t==c) break; ++t;
   }
-  return t-in;
+  return (size_t)(t-in);
 }
diff --git a/str/str_copy.c b/str/str_copy.c
index 2244267..0a61cea 100644
--- a/str/str_copy.c
+++ b/str/str_copy.c
@@ -9,5 +9,5 @@ size_t str_copy(char *out,const char *in) {
     if (!(*s=*t)) break; ++s; ++t;
     if (!(*s=*t)) break; ++s; ++t;
   }
-  return s-out;
+  return (size_t)(s-out);
 }
diff --git a/str/str_len.c b/str/str_len.c
index b40af18..64a3c4d 100644
--- a/str/str_len.c
+++ b/str/str_len.c
@@ -9,5 +9,5 @@ size_t str_len(const char* in) {
     if (!*t) break; ++t;
     if (!*t) break; ++t;
   }
-  return t-in;
+  return (size_t)(t-in);
 }
diff --git a/str/str_rchr.c b/str/str_rchr.c
index 533f0a4..a0aebf9 100644
--- a/str/str_rchr.c
+++ b/str/str_rchr.c
@@ -10,5 +10,5 @@ size_t str_rchr(const char *in, char needle) {
     if (!*t) break; if (*t==c) found=t; ++t;
     if (!*t) break; if (*t==c) found=t; ++t;
   }
-  return (found?found:t)-in;
+  return (size_t)((found?found:t)-in);
 }