Move more of the simple string functions to the header, to allow inli…

…ning and further optimization.

Before:
   text    data     bss     dec     hex filename
  10374      19    2712   13105    3331 app/config.o
 106854   26720   13344  146918   23de6 memtest_shared
   8734      19    2712   11465    2cc9 app/config.o
 111310   28392  294688  434390   6a0d6 memtest_shared

After:
   text    data     bss     dec     hex filename
  10105      19    2712   12836    3224 app/config.o
 106580   26720   13344  146644   23cd4 memtest_shared
   8653      19    2712   11384    2c78 app/config.o
 110969   28392  294688  434049   69f81 memtest_shared

lib/string.c

@@ -31,18 +31,6 @@ void reverse(char s[])
 // Public Functions
 //------------------------------------------------------------------------------
 
-int memcmp(const void *s1, const void *s2, size_t n)
-{
-    const unsigned char *src1 = s1, *src2 = s2;
-
-    for (size_t i = 0; i < n; i++) {
-        if (src1[i] != src2[i]) {
-            return (int)src1[i] - (int)src2[i];
-        }
-    }
-    return 0;
-}
-
 void *memmove(void *dest, const void *src, size_t n)
 {
     char *d = (char *)dest, *s = (char *)src;
@@ -64,28 +52,6 @@ void *memmove(void *dest, const void *src, size_t n)
     return dest;
 }
 
-size_t strlen(const char *s)
-{
-    size_t len = 0;
-    while (*s++) {
-        len++;
-    }
-    return len;
-}
-
-int strncmp(const char *s1, const char *s2, size_t n)
-{
-    for (size_t i = 0; i < n; i++) {
-        if (s1[i] != s2[i]) {
-            return (int)s1[i] - (int)s2[i];
-        }
-        if (s1[i] == '\0') {
-            return 0;
-        }
-    }
-    return 0;
-}
-
 char *strstr(const char *haystack, const char *needle)
 {
     size_t haystack_len = strlen(haystack);

lib/string.h

@@ -18,7 +18,17 @@
  * between the first mismatching byte in s1 (interpreted as an unsigned
  * value) and the corresponding byte in s2.
  */
-int memcmp(const void *s1, const void *s2, size_t n);
+static inline int memcmp(const void *s1, const void *s2, size_t n)
+{
+    const unsigned char *src1 = s1, *src2 = s2;
+
+    for (size_t i = 0; i < n; i++) {
+        if (src1[i] != src2[i]) {
+            return (int)src1[i] - (int)src2[i];
+        }
+    }
+    return 0;
+}
 
 /**
  * Copies n bytes from the memory area pointed to by src to the memory area
@@ -45,15 +55,33 @@ void *memmove(void *dest, const void *src, size_t n);
 /**
  * Returns the string length, excluding the terminating null character.
  */
-size_t strlen(const char *s);
+static inline size_t strlen(const char *s)
+{
+    size_t len = 0;
+    while (*s++) {
+        len++;
+    }
+    return len;
+}
 
 /**
  * Compares at most the first n characters in the strings s1 and s2 and
  * returns 0 if all characters are the same or the numerical difference
  * between the first mismatching character in s1 (interpreted as a signed
  * value) and the corresponding character in s2.
  */
-int strncmp(const char *s1, const char *s2, size_t n);
+static inline int strncmp(const char *s1, const char *s2, size_t n)
+{
+    for (size_t i = 0; i < n; i++) {
+        if (s1[i] != s2[i]) {
+            return (int)s1[i] - (int)s2[i];
+        }
+        if (s1[i] == '\0') {
+            return 0;
+        }
+    }
+    return 0;
+}
 
 /**
  * Finds the first occurrence of the substring needle in the string haystack