sds: add cfl_sds_snprintf

include/cfl/cfl_sds.h

@@ -61,5 +61,6 @@ cfl_sds_t cfl_sds_create_size(size_t size);
 void cfl_sds_set_len(cfl_sds_t s, size_t len);
 void cfl_sds_cat_safe(cfl_sds_t *buf, const char *str, int len);
 cfl_sds_t cfl_sds_printf(cfl_sds_t *sds, const char *fmt, ...);
+int cfl_sds_snprintf(cfl_sds_t *str, size_t size, const char *fmt, ...);
 
 #endif

src/cfl_sds.c

@@ -234,3 +234,32 @@ cfl_sds_t cfl_sds_printf(cfl_sds_t *sds, const char *fmt, ...)
     return s;
 }
 
+
+/*
+ * cfl_sds_snprintf is a wrapper of snprintf.
+ * The difference is that this function can increase the buffer of cfl_sds_t.
+ */
+int cfl_sds_snprintf(cfl_sds_t *str, size_t size, const char *fmt, ...)
+{
+    va_list va;
+    cfl_sds_t tmp;
+    int ret;
+
+ retry_snprintf:
+    va_start(va, fmt);
+    ret = vsnprintf(*str, size, fmt, va);
+    if (ret > size) {
+        tmp = cfl_sds_increase(*str, ret-size);
+        if (tmp == NULL) {
+            return -1;
+        }
+        *str = tmp;
+        size = ret;
+        va_end(va);
+        goto retry_snprintf;
+    }
+    va_end(va);
+
+    cfl_sds_len_set(*str, ret);
+    return ret;
+}

tests/sds.c

@@ -52,8 +52,109 @@ static void test_sds_printf()
     cfl_sds_destroy(s);
 }
 
+
+static int sds_twice(size_t sds_size, const char *input, const char* expect)
+{
+    int ret;
+    cfl_sds_t s;
+    cfl_sds_t tmp;
+
+    s = cfl_sds_create_size(sds_size);
+    ret = cfl_sds_snprintf(&s, cfl_sds_avail(s), "%s%s", input, input);
+    if (!TEST_CHECK(ret >= 0)) {
+        TEST_MSG("cfl_sds_snprintf failed. ret=%d", ret);
+        return -1;
+    }
+
+    /* check if buffer size is enough */
+    if (ret >= cfl_sds_avail(s)) {
+        tmp = cfl_sds_increase(s, ret - cfl_sds_avail(s) + 1);
+        if (!TEST_CHECK(tmp != NULL)) {
+            TEST_MSG("cfl_sds_increase failed");
+            cfl_sds_destroy(s);
+            return -1;
+        }
+        s = tmp;
+        ret = cfl_sds_snprintf(&s, cfl_sds_avail(s), "%s%s", input, input);
+        if (!TEST_CHECK(ret >= 0)) {
+            TEST_MSG("cfl_sds_snprintf failed. ret=%d", ret);
+            cfl_sds_destroy(s);
+            return -1;
+        }
+        else if (!TEST_CHECK(ret < cfl_sds_avail(s))) {
+            TEST_MSG("buffer is short. avail=%d, ret=%d, sds=%s",cfl_sds_avail(s), ret, s);
+            cfl_sds_destroy(s);
+            return -1;
+        }
+    }
+
+    if (!TEST_CHECK(strcmp(s, expect) == 0)) {
+        TEST_MSG("strcmp failed. \ngot   =%s\nexpect=%s", s, expect);
+    }
+
+    cfl_sds_destroy(s);
+    return 0;
+}
+
+struct sds_snprintf_case {
+    size_t size;
+    const char *input;
+    const char *expect;
+};
+
+static void test_sds_snprintf_simple()
+{
+    int ret;
+    cfl_sds_t buf;
+    size_t buf_size = 256;
+
+    buf = cfl_sds_create_size(buf_size);
+    if (!TEST_CHECK(buf != NULL)) {
+        TEST_MSG("cfl_sds_create_size failed");
+        return;
+    }
+
+    ret = cfl_sds_snprintf(&buf, buf_size, "%d%s%zu", 10, "str", buf_size);
+    if (!TEST_CHECK(ret >= 0)) {
+        TEST_MSG("cfl_sds_snprintf failed. ret=%d", ret);
+        cfl_sds_destroy(buf);
+        return;
+    }
+    else if (!TEST_CHECK(ret < cfl_sds_avail(buf))) {
+        TEST_MSG("buffer size is short");
+        cfl_sds_destroy(buf);
+        return;
+    }
+
+    if (!TEST_CHECK(strcmp(buf, "10str256") == 0)) {
+        TEST_MSG("strcmp failed. \ngot   =%s\nexpect=10str256", buf);
+    }
+
+    cfl_sds_destroy(buf);
+}
+
+static void test_sds_snprintf_cases()
+{
+    int ret;
+    int i;
+    struct sds_snprintf_case cases[] = {
+        {128, "a", "aa"},
+        {10, "0123456789ABCDEF", "0123456789ABCDEF0123456789ABCDEF"},
+        {0, NULL}
+    };
+
+    for (i=0; cases[i].input != NULL; i++) {
+        ret = sds_twice(cases[i].size, cases[i].input, cases[i].expect);
+        if (!TEST_CHECK(ret == 0)) {
+            TEST_MSG("case %d failed", i);
+        }
+    }
+}
+
 TEST_LIST = {
     { "sds_usage" , test_sds_usage},
     { "sds_printf", test_sds_printf},
+    { "sds_snprintf_simple", test_sds_snprintf_simple},
+    { "sds_snprintf_cases", test_sds_snprintf_cases},
     { 0 }
 };