diff --git a/include/ucore/dstr.h b/include/ucore/dstr.h
new file mode 100644
index 0000000..083de2f
--- /dev/null
+++ b/include/ucore/dstr.h
@@ -0,0 +1,162 @@
+#ifndef UC_DSTR_H_
+#define UC_DSTR_H_
+
+#include <stddef.h>
+#include <stdarg.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** A managed C-string, using dynalically allocated memory for the string.
+ *
+ * The .str member might not always be nul terminated,
+ * Normally, use uc_dstr_str() to retreive the managed string
+ * instead of accessing ->str directly.
+ *
+ * Normally, let the DSTR manage the nul terminator as  manually adding 
+ * a nul byte and potintially adding more data to the DStr would append 
+ * it after that nul terminator.
+ */
+struct DStr {
+    /** Length of the managed string.*/
+    size_t len;
+
+    //internal fields:
+    size_t allocated;
+    char *str;
+};
+
+#define UC_DSTR_STATIC_INIT {0, 0, NULL}
+
+/** Initialize a DStr.
+ * Note that str->str will be NULL after initialization.
+ *
+ */
+void uc_dstr_init(struct DStr *str);
+
+/** Destroy/free the string. 
+ * (Frees str->str, not str itself)
+ */
+void uc_dstr_destroy(struct DStr *str);
+
+/** Copy a DStr
+ *
+ * @param dest destination string to copy to, must not contain an existing string
+ * @param src DStr to copy
+ *
+ * @return 0 if success, != 0 if allocation fails
+ */
+int uc_dstr_copy(struct DStr *dest, const struct DStr *src);
+
+/**
+ * @return the available/unused tail bytes in the string.
+ */
+size_t uc_dstr_available(const struct DStr *str);
+
+/** Ensure the DStr have room for least 'len' bytes,
+ *  allocating room if needed. 
+ *
+ *  This includes the length of the existing string,
+ *  to ensure e.g an additional 10 bytes can be appended,
+ *  one would do uc_dstr_ensure(str, str->len + 10)
+ *
+ *  @return 0 on success (!= 0 if an allocation fail)
+ */
+int uc_dstr_ensure(struct DStr *str, size_t total);
+
+/** Reset the DStr, setting its length to 0
+ */
+void uc_dstr_reset(struct DStr *str);
+
+/** nul terminate the DStr */
+void uc_dstr_terminate(struct DStr *str);
+
+/** Retreive the managed string, the returned string
+ * is always nul terminated. The DStr will still be managing
+ * the returned char *.
+ */
+char *uc_dstr_str(struct DStr *str);
+
+/** Reserve len bytes for appending to the dstr
+ *  you must fill in a string in the 0-len range of
+ *  the returned pointer.
+ *
+ * @param len bytes to reseve
+ * @return poiinter to the start of the data to append
+ */
+char *uc_dstr_put(struct DStr *str, size_t len);
+
+/** Append a string, filtering out characters.
+ * e.g. pass in the ctype.h isdigit as the is_x function
+ * to append only the digits in the supplied string.
+ *
+ * @param s string to append
+ * @param is_x ctype.h compatible function to use as a filter.
+ * @return number of chars appended
+ */
+size_t uc_dstr_put_str_filter(struct DStr *str, const char *s, int (*is_x)(int c));
+
+/* Append a string of the give size.
+ * (The nul terminator is not appended) 
+ * 
+ * @param s string to append
+ * @param len bytes to append (not including the nul terminator) 
+ * @return 0 on success (!= 0 if an allocation fail)
+ */
+int uc_dstr_put_str_sz(struct DStr *str, const char *s, size_t len);
+
+/* Append a string.
+ * (The nul terminator is not appended) 
+ *
+ *  @return 0 on success (!= 0 if an allocation fail)
+ */
+int uc_dstr_put_str(struct DStr *str, const char *s);
+
+/* Append a single char.
+ *
+ *  @return 0 on success (!= 0 if an allocation fail)
+ */
+int uc_dstr_put_char(struct DStr *str, char c);
+
+/* Make the DStr take ownership of the given dynamically allocated string.
+ * Any existing string in the DStr is freed.
+ */
+void uc_dstr_own(struct DStr *str, char *s);
+
+/** Release the managed string.
+ * The caller is now responsible for managing/free'ing the returned string.
+ * The DStr is considered empty afterwards.
+ *
+ * @return The dynamically allocated string that was managed.
+ */
+char *uc_dstr_steal(struct DStr *str);
+
+/** Swap the A and B DStr */
+void uc_str_swap(struct DStr *a, struct DStr *b);
+
+/** Replace all occurences in the DStr
+ * (This may be used to replace any embedded nul bytes too)
+ *
+ * @param f char to find
+ * @param r char to replace with
+ */
+size_t uc_dstr_replace(struct DStr *str, char f, char r);
+
+/** Remove leading and trailing spaces in the DStr
+ * Spaces are the ascii ones: " \t\r\v\t\n"
+ */
+void uc_dstr_trim(struct DStr *str);
+
+/** Append formatted string (just as sprintf)*/
+int uc_dstr_sprintf(struct DStr *str, const char *fmt, ...) __attribute__((format(printf,2,3)));
+
+/** va_list variant */
+int uc_dstr_vsprintf(struct DStr *str, const char *fmt, va_list ap_)__attribute__((format(printf,2,0)));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
diff --git a/include/ucore/heapsort.h b/include/ucore/heapsort.h
new file mode 100644
index 0000000..fcaf426
--- /dev/null
+++ b/include/ucore/heapsort.h
@@ -0,0 +1,30 @@
+#ifndef UC_HEAPSORT_H_
+#define UC_HEAPSORT_H_
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+///compare function. Needs only to return < 0 if 
+//a is less tan b
+typedef int (*uc_hs_cmp)(const void *a, const void *b, void *cookie);
+//swap function, must swap around element a and b
+typedef void (*uc_hs_swp)(void *a, void *b);
+
+/** Sort an array.
+ * @param base start of array
+ * @param count number of elements in array
+ * @param width size of each element
+ * @param cmp compare function
+ * @param swap swap function
+ * @param cookie user pointer passed back to compare function
+ */
+void uc_heapsort(void *base, size_t count, size_t width,
+                 uc_hs_cmp cmp, uc_hs_swp swap, void *cookie);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/include/ucore/utils.h b/include/ucore/utils.h
index f3bedef..39db850 100644
--- a/include/ucore/utils.h
+++ b/include/ucore/utils.h
@@ -14,15 +14,15 @@
 
 //MAX of a and b
 #define UC_MAX(a,b) \
-   ({ __typeof__ (a) _a = (a); \
-       __typeof__ (b) _b = (b); \
-     _a > _b ? _a : _b; })
+   ({ __typeof__ (a) _amx = (a); \
+       __typeof__ (b) _bmx = (b); \
+     _amx > _bmx ? _amx : _bmx; })
 
 //min of a and b
 #define UC_MIN(a,b) \
-   ({ __typeof__ (a) _a = (a); \
-       __typeof__ (b) _b = (b); \
-     _a < _b ? _a : _b; })
+   ({ __typeof__ (a) _amn = (a); \
+       __typeof__ (b) _bmn = (b); \
+     _amn < _bmn ? _amn : _bmn; })
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*a))
 
diff --git a/src/buffer.c b/src/buffer.c
index e8c96a3..4a27e57 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdarg.h>
 #include "ucore/buffer.h"
+#include "ucore/utils.h"
  
 GBuf*
 uc_new_gbuf(size_t initsz)
@@ -48,7 +49,7 @@ uc_gbuf_append(GBuf *buf,const void *data,size_t len)
     unsigned char *gbuf;
     
     if (buf->len - buf->used < len)
-        if (uc_gbuf_grow(buf, len + len/2))
+        if (uc_gbuf_grow(buf, len + UC_MAX(UC_MIN(8U,len/2),256U)))
             return -1;
 
     gbuf = buf->buf;
diff --git a/src/dstr.c b/src/dstr.c
new file mode 100644
index 0000000..9c64fa2
--- /dev/null
+++ b/src/dstr.c
@@ -0,0 +1,281 @@
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include "ucore/dstr.h"
+#include "ucore/utils.h"
+
+void uc_dstr_init(struct DStr *str)
+{
+    str->len = 0;
+    str->allocated = 0;
+    str->str = NULL;
+}
+
+void uc_dstr_destroy(struct DStr *str)
+{
+    free(str->str);
+}
+
+int uc_dstr_copy(struct DStr *dest, const struct DStr *src)
+{
+    char *s;
+
+    uc_dstr_init(dest);
+    if (src->allocated == 0) {
+        return 0;
+    }
+
+    s = uc_dstr_put(dest, src->len);
+    if (s == NULL) {
+        return -1;
+    }
+
+    //+1 to copy a potential nul terminator, uc_dstr_put 
+    //guarantees we have room for it.
+    memcpy(s, src->str, UC_MIN(src->len + 1, src->allocated));
+
+    return 0;
+}
+
+size_t uc_dstr_available(const struct DStr *str)
+{
+    return str->allocated - str->len;
+}
+
+int uc_dstr_ensure(struct DStr *str, size_t total)
+{
+    if (str->allocated < total) {
+        //allocate a minimum no. of bytes, and one
+        //additional for the common case of nul terminating
+        //the string
+        size_t new_len = UC_MAX(7U, total) + 1;
+        char *new_str = realloc(str->str, new_len);
+
+        if (new_str == NULL) {
+            return -1;
+        }
+        str->str = new_str;
+        str->allocated = new_len;
+    }
+
+    return 0;
+}
+
+void uc_dstr_reset(struct DStr *str)
+{
+    str->len = 0;
+    if (str->str) {
+        str->str[0] = 0;
+    }
+}
+
+void uc_dstr_terminate(struct DStr *str)
+{
+    uc_dstr_ensure(str, str->len + 1);
+    str->str[str->len] = 0;
+}
+
+char *uc_dstr_str(struct DStr *str)
+{
+    uc_dstr_terminate(str);
+
+    return str->str;
+}
+
+char *uc_dstr_put(struct DStr *str, size_t len)
+{
+    char *start;
+
+    if (uc_dstr_ensure(str, str->len + len) != 0) {
+        return NULL;
+    }
+
+    start = str->str + str->len;
+    str->len += len;
+
+    return start;
+}
+
+size_t uc_dstr_put_str_filter(struct DStr *str, const char *s, int (*is_x)(int c))
+{
+    size_t len = strlen(s);
+    size_t i;
+    size_t idx = 0;
+
+    if (uc_dstr_ensure(str, str->len + len) != 0) {
+        return 0;
+    }
+
+    for (i = 0; i < len; i++) {
+        if (is_x(s[i])) {
+            str->str[str->len + idx]= s[i];
+            idx++;
+        }
+    }
+
+    str->len += idx;
+
+    return idx;
+}
+
+int uc_dstr_put_str_sz(struct DStr *str, const char *s, size_t len)
+{
+    char *start = uc_dstr_put(str, len);
+
+    if (start == NULL) {
+        return -1;
+    }
+    memcpy(start, s, len);
+
+    return 0;
+}
+
+int uc_dstr_put_str(struct DStr *str, const char *s)
+{
+    size_t len = strlen(s);
+
+    return uc_dstr_put_str_sz(str, s ,len);
+}
+
+int uc_dstr_put_char(struct DStr *str, char c)
+{
+    char *start = uc_dstr_put(str, 1);
+
+    if (start == NULL) {
+        return -1;
+    }
+    *start = c;
+
+    return 0;
+}
+
+void uc_dstr_own(struct DStr *str, char *s)
+{
+    size_t len = strlen(s);
+
+    if (str->str) {
+        free(str);
+    }
+
+    str->len = len;
+    str->allocated = len + 1;
+    str->str = s;
+}
+
+char *uc_dstr_steal(struct DStr *str)
+{
+    char *s = str->str;
+
+    uc_dstr_init(str);
+
+    return s;
+}
+
+void uc_str_swap(struct DStr *a, struct DStr *b)
+{
+    struct DStr tmp;
+
+    tmp = *a;
+    *a = *b;
+    *b = tmp;
+}
+
+size_t uc_dstr_replace(struct DStr *str, char f, char r)
+{
+    size_t i;
+    size_t count = 0;
+
+    if (str->len == 0) {
+        return 0;
+    }
+
+    for (i = 0; i < str->len; i++) {
+        if (str->str[i] == f) {
+            str->str[i] = r;
+            count++;
+        }
+    }
+
+    return count;
+}
+
+void uc_dstr_trim(struct DStr *str)
+{
+    size_t spaces;
+
+    uc_dstr_terminate(str);
+
+    //spaces at the start
+    spaces = strspn(str->str, " \t\n\v\f\r");
+    if (spaces > 0) {
+        memmove(str->str, str->str + spaces, str->len - spaces);
+        str->len -= spaces;
+    }
+
+    //spaces at the end
+    if (str->len > 0) {
+        size_t idx = str->len - 1;
+        do {
+            if (strchr(" \t\n\v\f\r", str->str[idx]) == NULL) {
+                break;
+            } else {
+                str->len--;
+                idx--;
+            }
+        } while (idx != 0);
+    }
+}
+
+int uc_dstr_sprintf(struct DStr *str, const char *fmt, ...)
+{
+    va_list ap;
+    int rc;
+
+    va_start(ap, fmt);
+    rc = uc_dstr_vsprintf(str, fmt, ap);
+    va_end(ap);
+
+    return rc;
+}
+
+int uc_dstr_vsprintf(struct DStr *str, const char *fmt, va_list ap_)
+{
+    va_list ap;
+    int rc;
+    int available;
+    int needed;
+
+    rc = uc_dstr_ensure(str, str->len + 1);
+    if (rc != 0) {
+        return -1;
+    }
+
+    available = uc_dstr_available(str);
+
+    va_copy(ap, ap_);
+    needed = vsnprintf(str->str + str->len, available, fmt, ap);
+    va_end(ap);
+
+    if (needed <= 0) {
+        return needed;
+    }
+
+    if (needed >= available) {
+        rc = uc_dstr_ensure(str, str->len + needed);
+        if (rc != 0) {
+            return -1;
+        }
+
+        available = uc_dstr_available(str);
+
+        va_copy(ap, ap_);
+        needed = vsnprintf(str->str + str->len, available, fmt, ap);
+        va_end(ap);
+    }
+
+    str->len += needed;
+
+    return needed;
+}
+
diff --git a/src/fd_utils.c b/src/fd_utils.c
index e557f60..e14fb12 100644
--- a/src/fd_utils.c
+++ b/src/fd_utils.c
@@ -89,14 +89,8 @@ int uc_set_ip_dscp(int fd, unsigned int dscp)
     int val;
 
     //only 6 bits for dscp
-    if (dscp > 63) {
-        errno = EINVAL;
-        return -1;
-    }
-
-    val = dscp << 2;
+    val = (dscp & 0x3f) << 2;
 
     return setsockopt(fd, IPPROTO_IP, IP_TOS, &val, sizeof val);
 }
 
-
diff --git a/src/heapsort.c b/src/heapsort.c
new file mode 100644
index 0000000..45a56e5
--- /dev/null
+++ b/src/heapsort.c
@@ -0,0 +1,53 @@
+#include <string.h>
+#include "ucore/heapsort.h"
+
+static void
+uc_sift(unsigned char *base, size_t start, size_t count, size_t width,
+     uc_hs_cmp cmp, uc_hs_swp swap, void *cookie)
+{
+    size_t root = start, child;
+
+    while ((root * 2 + 1) < count) {
+        child = root * 2 + 1;
+        if (child < (count - 1)) {
+            int rc = cmp(&base[child * width], &base[(child + 1) * width], cookie);
+            if (rc < 0) {
+                child++;
+            }
+        }
+
+        if (cmp(&base[root * width], &base[child * width], cookie) < 0) {
+            swap(base + root * width, base + child * width);
+            root = child;
+        } else {
+            return;
+        }
+    }
+}
+
+void
+uc_heapsort(void *base_, size_t count, size_t width,
+     uc_hs_cmp cmp, uc_hs_swp swap, void *cookie)
+{
+    long start;
+    long end;
+    unsigned char *base = base_;
+
+    if (count == 0 || width == 0) {
+        return;
+    }
+
+    start = count / 2 - 1, 
+    end = count - 1;
+
+    while (start >= 0) {
+        uc_sift(base, start, count, width, cmp, swap, cookie);
+        start--;
+    }
+
+    while (end > 0) {
+        swap(base + end * width, base);
+        uc_sift(base, 0, end, width, cmp, swap, cookie);
+        end--;
+    }
+}
diff --git a/test/test_dstr.c b/test/test_dstr.c
new file mode 100644
index 0000000..6168e98
--- /dev/null
+++ b/test/test_dstr.c
@@ -0,0 +1,186 @@
+#include <check.h>
+#include <ctype.h>
+#include <ucore/dstr.h>
+#include <ucore/utils.h>
+
+
+START_TEST (test_dstr_basics)
+    struct DStr str;
+    int rc;
+
+    char *s;
+
+    uc_dstr_init(&str);
+    rc = uc_dstr_put_str(&str, "Hello");
+    ck_assert_int_eq(rc, 0);
+    ck_assert_int_eq(str.len, 5);
+    ck_assert_str_eq(uc_dstr_str(&str), "Hello");
+
+    rc = uc_dstr_put_char(&str, '!');
+    ck_assert_int_eq(rc, 0);
+    ck_assert_int_eq(str.len, 6);
+    ck_assert_str_eq(uc_dstr_str(&str), "Hello!");
+   
+    rc = uc_dstr_put_str_sz(&str, " World 12345678", 13);
+    ck_assert_int_eq(rc, 0);
+    ck_assert_int_eq(str.len, 19);
+    ck_assert_str_eq(uc_dstr_str(&str), "Hello! World 123456");
+
+    uc_dstr_reset(&str);
+    ck_assert_int_eq(str.len, 0);
+    ck_assert_str_eq(uc_dstr_str(&str), "");
+
+    uc_dstr_reset(&str);
+    ck_assert_int_gt(uc_dstr_available(&str), 0);
+
+    s = uc_dstr_put(&str, 2);
+    fail_if(s == NULL);
+    s[0] = '1';
+    s[1] = '2';
+
+    ck_assert_str_eq(uc_dstr_str(&str), "12");
+
+    uc_dstr_destroy(&str);
+
+    //just test that this doesn't crash:
+    uc_dstr_init(&str); 
+    uc_dstr_destroy(&str);
+END_TEST
+
+START_TEST (test_dstr_own_steal)
+    struct DStr str;
+    char *s;
+
+    uc_dstr_init(&str);
+    uc_dstr_own(&str, strdup("Hello !"));
+    ck_assert_int_eq(str.len, 7);
+    ck_assert_str_eq(uc_dstr_str(&str), "Hello !");
+
+    s = uc_dstr_steal(&str);
+    ck_assert_str_eq(s, "Hello !");
+    ck_assert_int_eq(str.len, 0);
+    ck_assert_str_eq(uc_dstr_str(&str), "");
+
+    free(s); 
+    uc_dstr_destroy(&str);
+END_TEST
+
+START_TEST (test_dstr_trim)
+    struct DStr str = UC_DSTR_STATIC_INIT;
+
+    uc_dstr_put_str(&str, " \t  \nHello !\r\n");
+    uc_dstr_trim(&str);
+    ck_assert_str_eq(uc_dstr_str(&str), "Hello !");
+
+    uc_dstr_destroy(&str);
+    uc_dstr_init(&str);
+
+    uc_dstr_put_str(&str, "     ");
+
+    uc_dstr_trim(&str);
+    ck_assert_str_eq(uc_dstr_str(&str), "");
+
+    uc_dstr_destroy(&str);
+    uc_dstr_init(&str);
+
+    uc_dstr_trim(&str);
+    ck_assert_str_eq(uc_dstr_str(&str), "");
+
+    uc_dstr_destroy(&str);
+
+END_TEST
+
+START_TEST (test_dstr_replace)
+    struct DStr str;
+    size_t rc; 
+
+    uc_dstr_init(&str);
+    uc_dstr_put_str(&str, "-1-2-3-4-5-");
+    rc = uc_dstr_replace(&str, '-',' ');
+    ck_assert_int_eq(rc, 6);
+    
+    ck_assert_str_eq(uc_dstr_str(&str), " 1 2 3 4 5 ");
+    rc = uc_dstr_replace(&str, 'X','2');
+    ck_assert_int_eq(rc, 0);
+    ck_assert_str_eq(uc_dstr_str(&str), " 1 2 3 4 5 ");
+
+    uc_dstr_destroy(&str);
+
+END_TEST
+
+START_TEST (test_dstr_filter)
+    struct DStr str;
+    size_t rc; 
+
+    uc_dstr_init(&str);
+    uc_dstr_put_str(&str, "AB:");
+    rc = uc_dstr_put_str_filter(&str, "1:2,3 4 ", isdigit);
+    ck_assert_int_eq(rc, 4);
+    
+    ck_assert_str_eq(uc_dstr_str(&str), "AB:1234");
+
+    uc_dstr_destroy(&str);
+
+END_TEST
+
+START_TEST (test_dstr_sprintf)
+    struct DStr str;
+    size_t rc; 
+
+    uc_dstr_init(&str);
+    rc = uc_dstr_sprintf(&str, "%d-%d-%d", 1, 2, 3);
+    ck_assert_int_gt(rc, 0);
+    ck_assert_str_eq(uc_dstr_str(&str), "1-2-3");
+    
+    rc = uc_dstr_sprintf(&str, " Another, bigger %s.", "string");
+    ck_assert_int_gt(rc, 0);
+    ck_assert_str_eq(uc_dstr_str(&str), "1-2-3 Another, bigger string.");
+
+    uc_dstr_destroy(&str);
+
+END_TEST
+
+START_TEST (test_dstr_copy)
+    struct DStr str;
+    struct DStr copy;
+    size_t rc; 
+
+    uc_dstr_init(&str);
+    rc = uc_dstr_put_str(&str, "123");
+    ck_assert_int_eq(rc, 0);
+    
+    rc = uc_dstr_copy(&copy, &str);
+    ck_assert_int_eq(rc, 0);
+    ck_assert_str_eq(uc_dstr_str(&copy), uc_dstr_str(&str));
+    
+    uc_dstr_destroy(&str);
+    uc_dstr_destroy(&copy);
+    uc_dstr_init(&str);
+    uc_dstr_init(&copy);
+
+    rc = uc_dstr_copy(&copy, &str);
+    ck_assert_int_eq(rc, 0);
+    ck_assert_str_eq(uc_dstr_str(&copy), "");
+
+    uc_dstr_destroy(&str);
+    uc_dstr_destroy(&copy);
+
+END_TEST
+
+Suite *dstr_suite(void)
+{
+    Suite *s = suite_create("dstr");
+    TCase *tc = tcase_create("dstr tests");
+    tcase_add_test(tc, test_dstr_basics);
+    tcase_add_test(tc, test_dstr_own_steal);
+    tcase_add_test(tc, test_dstr_trim);
+    tcase_add_test(tc, test_dstr_replace);
+    tcase_add_test(tc, test_dstr_filter);
+    tcase_add_test(tc, test_dstr_sprintf);
+    tcase_add_test(tc, test_dstr_copy);
+
+    suite_add_tcase(s, tc);
+
+    return s;
+}
+
diff --git a/test/test_heapsort.c b/test/test_heapsort.c
new file mode 100644
index 0000000..9635e56
--- /dev/null
+++ b/test/test_heapsort.c
@@ -0,0 +1,140 @@
+#include <check.h>
+#include <ucore/utils.h>
+#include <ucore/heapsort.h>
+
+struct Stuff {
+    char text[11];
+    int order;
+};
+
+static void swap_stuff(void *a_, void *b_)
+{
+    struct Stuff *a = a_;
+    struct Stuff *b = b_;
+    struct Stuff tmp;
+
+    tmp = *a;
+    *a = *b;
+    *b = tmp;
+}
+
+static int cmp_stuff(const void *a_, const void *b_, void *cookie)
+{
+    const struct Stuff *a = a_;
+    const struct Stuff *b = b_;
+    (void)cookie;
+    if (a->order < b->order)
+        return -1;
+
+    return 1;
+}
+
+void print_stuff(const struct Stuff *s, size_t len)
+{
+    size_t i;
+    for(i = 0; i < len; i++) {
+        printf("%s:%d\n", s[i].text, s[i].order);
+    }
+}
+
+static int cmp_stuff_array(const struct Stuff *a, const struct Stuff *b, size_t len)
+{
+    size_t i;
+    for (i = 0; i < len; i++) {
+        if (strcmp(a[i].text, b[i].text) != 0)
+            return -1;
+        if (a[i].order != b[i].order)
+            return -1;
+    }
+
+    return 0;
+}
+
+START_TEST (test_heapsort_odd)
+    struct Stuff unordered[] = {
+        {"2", 2},
+        {"1", 1},
+        {"4", 4},
+        {"5", 5},
+        {"3", 3},
+    };
+
+    struct Stuff ordered[] = {
+        {"1", 1},
+        {"2", 2},
+        {"3", 3},
+        {"4", 4},
+        {"5", 5},
+    };
+
+    uc_heapsort(unordered, ARRAY_SIZE(unordered), sizeof(struct Stuff), 
+                cmp_stuff, swap_stuff, NULL);
+    print_stuff(unordered, ARRAY_SIZE(unordered));
+    fail_if(cmp_stuff_array(unordered, ordered, ARRAY_SIZE(unordered)) != 0);
+END_TEST
+
+START_TEST (test_heapsort_even)
+    struct Stuff unordered[] = {
+        {"1", 1},
+        {"7", 7},
+        {"3", 3},
+        {"4", 4},
+        {"6", 6},
+        {"2", 2},
+    };
+
+    struct Stuff ordered[] = {
+        {"1", 1},
+        {"2", 2},
+        {"3", 3},
+        {"4", 4},
+        {"6", 6},
+        {"7", 7},
+    };
+
+    uc_heapsort(unordered, ARRAY_SIZE(unordered), sizeof(struct Stuff), 
+                cmp_stuff, swap_stuff, NULL);
+    fail_if(cmp_stuff_array(unordered, ordered, ARRAY_SIZE(unordered)) != 0);
+END_TEST
+
+START_TEST (test_heapsort_zero)
+    struct Stuff unordered[] = {
+        {"1", 1},
+        {"7", 7},
+        {"3", 3},
+        {"4", 4},
+        {"6", 6},
+        {"2", 2},
+    };
+
+    struct Stuff same[] = {
+        {"1", 1},
+        {"7", 7},
+        {"3", 3},
+        {"4", 4},
+        {"6", 6},
+        {"2", 2},
+    };
+
+    uc_heapsort(unordered, 0, sizeof(struct Stuff), 
+                cmp_stuff, swap_stuff, NULL);
+    fail_if(cmp_stuff_array(unordered, same, ARRAY_SIZE(unordered)) != 0);
+
+    uc_heapsort(unordered, ARRAY_SIZE(unordered), 0, 
+                cmp_stuff, swap_stuff, NULL);
+    fail_if(cmp_stuff_array(unordered, same, ARRAY_SIZE(unordered)) != 0);
+END_TEST
+
+Suite *heapsort_suite(void)
+{
+    Suite *s = suite_create("heapsort");
+    TCase *tc = tcase_create("heapsort tests");
+    tcase_add_test(tc, test_heapsort_odd);
+    tcase_add_test(tc, test_heapsort_even);
+    tcase_add_test(tc, test_heapsort_zero);
+
+    suite_add_tcase(s, tc);
+
+    return s;
+}
+
diff --git a/test/test_runner.c b/test/test_runner.c
index a797d5f..5c09bb3 100644
--- a/test/test_runner.c
+++ b/test/test_runner.c
@@ -27,6 +27,8 @@ extern Suite *sprintb_suite(void);
 extern Suite *strv_suite(void);
 extern Suite *ratelimit_suite(void);
 extern Suite *htable_suite(void);
+extern Suite *heapsort_suite(void);
+extern Suite *dstr_suite(void);
 
 static suite_func suites[] = {
     bitvec_suite,
@@ -48,7 +50,9 @@ static suite_func suites[] = {
     ratelimit_suite,
     htable_suite,
     clock_suite,
-    threadqueue_suite
+    threadqueue_suite,
+    heapsort_suite,
+    dstr_suite
 };
 
 int