[liba] implement strlcpy

Change-Id: I083129b31cbb070e8c1d87d7e3db91f8134e3540

liba/Makefile

@@ -2,8 +2,8 @@ SFLAGS += -Iliba/include
 
 liba/src/external/sqlite/mem5.o: CFLAGS += -w
 
-objs += $(addprefix liba/src/, assert.o errno.o malloc.o memcpy.o memset.o powf.o strcmp.o strlen.o external/sqlite/mem5.o)
-tests += $(addprefix liba/test/, stdint.c)
+objs += $(addprefix liba/src/, assert.o errno.o malloc.o memcpy.o memset.o powf.o strcmp.o strlcpy.o strlen.o external/sqlite/mem5.o)
+tests += $(addprefix liba/test/, stdint.c strlcpy.c)
 
 # The use of aeabi-rt could be made conditional to an AEABI target.
 # In practice we're always using liba on such a target.

liba/include/string.h

@@ -10,6 +10,7 @@ void * memcpy(void * dst, const void * src, size_t n);
 void * memset(void * b, int c, size_t len);
 size_t strlen(const char * s);
 int strcmp(const char *s1, const char *s2);
+size_t strlcpy(char * dst, const char * src, size_t len);
 
 LIBA_END_DECLS
 

liba/src/strlcpy.c

@@ -0,0 +1,14 @@
+#include <string.h>
+
+size_t strlcpy(char * dst, const char * src, size_t len) {
+  if (len == 0) {
+    return 0;
+  }
+  const char * cur = src;
+  const char * end = src+len-1;
+  while (*cur != 0 && cur < end) {
+    *dst++ = *cur++;
+  }
+  *dst = 0;
+  return cur-src;
+}

liba/test/strlcpy.c

@@ -0,0 +1,12 @@
+#include <quiz.h>
+#include <string.h>
+#include <assert.h>
+
+QUIZ_CASE(liba_strlcpy) {
+  char * t = "Hello";
+  char buffer[16];
+  size_t result = strlcpy(buffer, t, 2);
+  assert(result == 1);
+  assert(buffer[0] == 'H');
+  assert(buffer[1] == NULL);
+}