Add dynstr_strup function.

Thanks to Richard Braakman for suggesting this.

3 files changed, 35 insertions, 0 deletions

diff --git a/dynstr.c b/dynstr.c
index ac276ae..046613e 100644
--- a/dynstr.c
+++ b/dynstr.c
@@ -197,6 +197,19 @@ size_t dynstr_memcpy(void *mem, Dynstr *dynstr, size_t offset, size_t size)
 }
 
 
+char *dynstr_strdup(Dynstr *dynstr)
+{
+    char *mem;
+    
+    mem = alloc(dynstr->size + 1);
+    if (mem == NULL)
+        return NULL;
+    memcpy(mem, dynstr->mem, dynstr->size);
+    mem[dynstr->size] = '\0';
+    return mem;
+}
+
+
 Dynstr *dynstr_substr(Dynstr *dynstr, size_t offset, size_t size)
 {
     if (offset >= dynstr->size) {
diff --git a/dynstr.h b/dynstr.h
index 5a6f7ad..5ae1bc9 100644
--- a/dynstr.h
+++ b/dynstr.h
@@ -136,6 +136,12 @@ int dynstr_byte_at(Dynstr *dynstr, size_t offset);
  * actually copied, which may be less than requested, and may be zero. */
 size_t dynstr_memcpy(void *mem, Dynstr *dynstr, size_t offset, size_t size);
 
+/* Create a dynamically allocated C string copy of the dynamic string.
+ * This is like strdup. If the dynamic string contains NUL bytes, then
+ * that is the caller's problem. Return pointer to the C string. The
+ * caller is responsible for freeing it. Return NULL on error. */
+char *dynstr_strdup(Dynstr *dynstr);
+
 /* Search for first or last byte with a given value in a string, 
  * starting at a given offset and until the end of the string. Return offset 
  * of matching byte, or DYNSTR_NOT_FOUND if not found. Offset is from 
diff --git a/unittests.c b/unittests.c
index fc6b663..61a59bb 100644
--- a/unittests.c
+++ b/unittests.c
@@ -515,6 +515,21 @@ static int test_copies_partial_substring_when_length_too_big(void)
 }
 
 
+static int test_strdup_duplicates_string(void)
+{
+    Dynstr *dynstr;
+    char *cstring;
+    char data[] = "hello, world";
+    
+    dynstr = dynstr_new_from_constant_cstring(data);
+    cstring = dynstr_strdup(dynstr);
+    FAIL_UNLESS_EQUAL(memcmp(data, cstring, sizeof(data)), 0);
+    free(cstring);
+    dynstr_free(dynstr);
+    return true;
+}
+
+
 static int test_cats_ok(void)
 {
     Dynstr *a;
@@ -1233,6 +1248,7 @@ static const struct test tests[] = {
     TEST(test_memcpy_truncates_if_copying_too_much),
     TEST(test_memcpy_copies_whole_string_ok),
     TEST(test_memcpy_copies_substring_ok),
+    TEST(test_strdup_duplicates_string),
     TEST(test_copies_empty_substring_ok),
     TEST(test_copies_single_byte_substring_ok),
     TEST(test_copies_middle_substring_ok),