[Qemu-devel] [PATCH RFC 1/4] get rid of signed range

[Hu Tao]

Signed-off-by: Hu Tao <address@hidden>
---
 include/qemu/range.h               | 144 ++++++++++++-------------------------
 qapi/string-input-visitor.c        | 116 +++++++++++++++++-------------
 qapi/string-output-visitor.c       |  97 +++++++++++++------------
 tests/test-string-input-visitor.c  |   4 +-
 tests/test-string-output-visitor.c |   8 +--
 5 files changed, 165 insertions(+), 204 deletions(-)

diff --git a/include/qemu/range.h b/include/qemu/range.h
index 8879f8a..cfa021f 100644
--- a/include/qemu/range.h
+++ b/include/qemu/range.h
@@ -61,127 +61,75 @@ static inline int ranges_overlap(uint64_t first1, uint64_t 
len1,
     return !(last2 < first1 || last1 < first2);
 }
 
-typedef struct SignedRangeList SignedRangeList;
-
-typedef struct SignedRange {
-    int64_t start;
-    int64_t length;
-
-    QTAILQ_ENTRY(SignedRange) entry;
-} SignedRange;
-
-QTAILQ_HEAD(SignedRangeList, SignedRange);
-
-static inline int64_t s_range_end(int64_t start, int64_t length)
-{
-    return start + length - 1;
-}
-
-/* negative length or overflow */
-static inline bool s_range_overflow(int64_t start, int64_t length)
+/* 0,1 can merge with 1,2 but don't overlap */
+static inline bool ranges_can_merge(Range *range1, Range *range2)
 {
-    return s_range_end(start, length) < start;
+    return !(range1->end < range2->begin || range2->end < range1->begin);
 }
 
-static inline SignedRange *s_range_new(int64_t start, int64_t length)
+static inline int range_merge(Range *range1, Range *range2)
 {
-    SignedRange *range = NULL;
-
-    if (s_range_overflow(start, length)) {
-        return NULL;
+    if (ranges_can_merge(range1, range2)) {
+        if (range1->end < range2->end) {
+            range1->end = range2->end;
+        }
+        if (range1->begin > range2->begin) {
+            range1->begin = range2->begin;
+        }
+        return 0;
     }
 
-    range = g_malloc0(sizeof(*range));
-    range->start = start;
-    range->length = length;
-
-    return range;
-}
-
-static inline void s_range_free(SignedRange *range)
-{
-    g_free(range);
+    return -1;
 }
 
-static inline bool s_range_overlap(int64_t start1, int64_t length1,
-                                   int64_t start2, int64_t length2)
+static inline GList *g_list_insert_sorted_merged(GList *list,
+                                                 gpointer data,
+                                                 GCompareFunc func)
 {
-    return !((start1 + length1) < start2 || (start2 + length2) < start1);
-}
+    GList *l, *next = NULL;
+    Range *r, *nextr;
 
-static inline int s_range_join(SignedRange *range,
-                               int64_t start, int64_t length)
-{
-    if (s_range_overflow(start, length)) {
-        return -1;
+    if (!list) {
+        list = g_list_insert_sorted(list, data, func);
+        return list;
     }
 
-    if (s_range_overlap(range->start, range->length, start, length)) {
-        int64_t end = s_range_end(range->start, range->length);
-        if (end < s_range_end(start, length)) {
-            end = s_range_end(start, length);
+    nextr = data;
+    l = list;
+    while (l && l != next && nextr) {
+        r = l->data;
+        if (ranges_can_merge(r, nextr)) {
+            range_merge(r, nextr);
+            l = g_list_remove_link(l, next);
+            next = g_list_next(l);
+            if (next) {
+                nextr = next->data;
+            } else {
+                nextr = NULL;
+            }
+        } else {
+            l = g_list_next(l);
         }
-        if (range->start > start) {
-            range->start = start;
-        }
-        range->length = end - range->start + 1;
-        return 0;
     }
 
-    return -1;
+    if (!l) {
+        list = g_list_insert_sorted(list, data, func);
+    }
+
+    return list;
 }
 
-static inline int s_range_compare(int64_t start1, int64_t length1,
-                                  int64_t start2, int64_t length2)
+static inline gint range_compare(gconstpointer a, gconstpointer b)
 {
-    if (start1 == start2 && length1 == length2) {
+    Range *ra = (Range *)a, *rb = (Range *)b;
+    if (ra->begin == rb->begin && ra->end == rb->end) {
         return 0;
-    } else if (s_range_end(start1, length1) <
-               s_range_end(start2, length2)) {
+    } else if (range_get_last(ra->begin, ra->end) <
+               range_get_last(rb->begin, rb->end)) {
         return -1;
     } else {
         return 1;
     }
 }
 
-/* Add range to list. Keep them sorted, and merge ranges whenever possible */
-static inline bool range_list_add(SignedRangeList *list,
-                                  int64_t start, int64_t length)
-{
-    SignedRange *r, *next, *new_range = NULL, *cur = NULL;
-
-    if (s_range_overflow(start, length)) {
-        return false;
-    }
-
-    QTAILQ_FOREACH_SAFE(r, list, entry, next) {
-        if (s_range_overlap(r->start, r->length, start, length)) {
-            s_range_join(r, start, length);
-            break;
-        } else if (s_range_compare(start, length, r->start, r->length) < 0) {
-            cur = r;
-            break;
-        }
-    }
-
-    if (!r) {
-        new_range = s_range_new(start, length);
-        QTAILQ_INSERT_TAIL(list, new_range, entry);
-    } else if (cur) {
-        new_range = s_range_new(start, length);
-        QTAILQ_INSERT_BEFORE(cur, new_range, entry);
-    } else {
-        SignedRange *next = QTAILQ_NEXT(r, entry);
-        while (next && s_range_overlap(r->start, r->length,
-                                       next->start, next->length)) {
-            s_range_join(r, next->start, next->length);
-            QTAILQ_REMOVE(list, next, entry);
-            s_range_free(next);
-            next = QTAILQ_NEXT(r, entry);
-        }
-    }
-
-    return true;
-}
-
 #endif
diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
index 85ac6a1..0b2490b 100644
--- a/qapi/string-input-visitor.c
+++ b/qapi/string-input-visitor.c
@@ -25,8 +25,8 @@ struct StringInputVisitor
 
     bool head;
 
-    SignedRangeList *ranges;
-    SignedRange *cur_range;
+    GList *ranges;
+    GList *cur_range;
     int64_t cur;
 
     const char *string;
@@ -36,24 +36,25 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
 {
     char *str = (char *) siv->string;
     long long start, end;
-    SignedRange *r, *next;
+    Range *cur;
     char *endptr;
 
     if (siv->ranges) {
         return;
     }
 
-    siv->ranges = g_malloc0(sizeof(*siv->ranges));
-    QTAILQ_INIT(siv->ranges);
     errno = 0;
     do {
         start = strtoll(str, &endptr, 0);
         if (errno == 0 && endptr > str && INT64_MIN <= start &&
             start <= INT64_MAX) {
             if (*endptr == '\0') {
-                if (!range_list_add(siv->ranges, start, 1)) {
-                    goto error;
-                }
+                cur = g_malloc0(sizeof(*cur));
+                cur->begin = start;
+                cur->end = start + 1;
+                siv->ranges = g_list_insert_sorted_merged(siv->ranges, cur,
+                                                          range_compare);
+                cur = NULL;
                 str = NULL;
             } else if (*endptr == '-') {
                 str = endptr + 1;
@@ -63,17 +64,25 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
                     (start > INT64_MAX - 65536 ||
                      end < start + 65536)) {
                     if (*endptr == '\0') {
-                        if (!range_list_add(siv->ranges, start,
-                                            end - start + 1)) {
-                            goto error;
-                        }
+                        cur = g_malloc0(sizeof(*cur));
+                        cur->begin = start;
+                        cur->end = end + 1;
+                        siv->ranges =
+                            g_list_insert_sorted_merged(siv->ranges,
+                                                        cur,
+                                                        range_compare);
+                        cur = NULL;
                         str = NULL;
                     } else if (*endptr == ',') {
                         str = endptr + 1;
-                        if (!range_list_add(siv->ranges, start,
-                                            end - start + 1)) {
-                            goto error;
-                        }
+                        cur = g_malloc0(sizeof(*cur));
+                        cur->begin = start;
+                        cur->end = end + 1;
+                        siv->ranges =
+                            g_list_insert_sorted_merged(siv->ranges,
+                                                        cur,
+                                                        range_compare);
+                        cur = NULL;
                     } else {
                         goto error;
                     }
@@ -82,9 +91,13 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
                 }
             } else if (*endptr == ',') {
                 str = endptr + 1;
-                if (!range_list_add(siv->ranges, start, 1)) {
-                    goto error;
-                }
+                cur = g_malloc0(sizeof(*cur));
+                cur->begin = start;
+                cur->end = start + 1;
+                siv->ranges = g_list_insert_sorted_merged(siv->ranges,
+                                                          cur,
+                                                          range_compare);
+                cur = NULL;
             } else {
                 goto error;
             }
@@ -95,14 +108,8 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
 
     return;
 error:
-    if (siv->ranges) {
-        QTAILQ_FOREACH_SAFE(r, siv->ranges, entry, next) {
-            QTAILQ_REMOVE(siv->ranges, r, entry);
-            g_free(r);
-        }
-        g_free(siv->ranges);
-        siv->ranges = NULL;
-    }
+    g_list_free_full(siv->ranges, g_free);
+    assert(siv->ranges == NULL);
 }
 
 static void
@@ -112,10 +119,11 @@ start_list(Visitor *v, const char *name, Error **errp)
 
     parse_str(siv, errp);
 
-    if (siv->ranges) {
-        siv->cur_range = QTAILQ_FIRST(siv->ranges);
-        if (siv->cur_range) {
-            siv->cur = siv->cur_range->start;
+    siv->cur_range = g_list_first(siv->ranges);
+    if (siv->cur_range) {
+        Range *r = siv->cur_range->data;
+        if (r) {
+            siv->cur = r->begin;
         }
     }
 }
@@ -125,19 +133,27 @@ next_list(Visitor *v, GenericList **list, Error **errp)
 {
     StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
     GenericList **link;
+    Range *r;
 
     if (!siv->ranges || !siv->cur_range) {
         return NULL;
     }
 
-    if (siv->cur < siv->cur_range->start ||
-        siv->cur >= (siv->cur_range->start + siv->cur_range->length)) {
-        siv->cur_range = QTAILQ_NEXT(siv->cur_range, entry);
-        if (siv->cur_range) {
-            siv->cur = siv->cur_range->start;
-        } else {
+    r = siv->cur_range->data;
+    if (!r) {
+        return NULL;
+    }
+
+    if (siv->cur < r->begin || siv->cur >= r->end) {
+        siv->cur_range = g_list_next(siv->cur_range);
+        if (!siv->cur_range) {
             return NULL;
         }
+        r = siv->cur_range->data;
+        if (!r) {
+            return NULL;
+        }
+        siv->cur = r->begin;
     }
 
     if (siv->head) {
@@ -176,12 +192,19 @@ static void parse_type_int(Visitor *v, int64_t *obj, 
const char *name,
     }
 
     if (!siv->cur_range) {
-        siv->cur_range = QTAILQ_FIRST(siv->ranges);
-        if (siv->cur_range) {
-            siv->cur = siv->cur_range->start;
-        } else {
+        Range *r;
+
+        siv->cur_range = g_list_first(siv->ranges);
+        if (!siv->cur_range) {
+            goto error;
+        }
+
+        r = siv->cur_range->data;
+        if (!r) {
             goto error;
         }
+
+        siv->cur = r->begin;
     }
 
     *obj = siv->cur;
@@ -291,16 +314,7 @@ Visitor *string_input_get_visitor(StringInputVisitor *v)
 
 void string_input_visitor_cleanup(StringInputVisitor *v)
 {
-    SignedRange *r, *next;
-
-    if (v->ranges) {
-        QTAILQ_FOREACH_SAFE(r, v->ranges, entry, next) {
-            QTAILQ_REMOVE(v->ranges, r, entry);
-            g_free(r);
-        }
-        g_free(v->ranges);
-    }
-
+    g_list_free_full(v->ranges, g_free);
     g_free(v);
 }
 
diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
index ccebc7a..1c0834a 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -64,7 +64,7 @@ struct StringOutputVisitor
         int64_t s;
         uint64_t u;
     } range_start, range_end;
-    SignedRangeList *ranges;
+    GList *ranges;
 };
 
 static void string_output_set(StringOutputVisitor *sov, char *string)
@@ -78,25 +78,50 @@ static void string_output_set(StringOutputVisitor *sov, 
char *string)
 
 static void string_output_append(StringOutputVisitor *sov, int64_t a)
 {
-    range_list_add(sov->ranges, a, 1);
+    Range *r = g_malloc0(sizeof(*r));
+    r->begin = a;
+    r->end = a + 1;
+    sov->ranges = g_list_insert_sorted_merged(sov->ranges, r, range_compare);
 }
 
 static void string_output_append_range(StringOutputVisitor *sov,
                                        int64_t s, int64_t e)
 {
-    range_list_add(sov->ranges, s, e);
+    Range *r = g_malloc0(sizeof(*r));
+    r->begin = s;
+    r->end = e + 1;
+    sov->ranges = g_list_insert_sorted_merged(sov->ranges, r, range_compare);
+}
+
+static void format_string(StringOutputVisitor *sov, Range *r, bool next,
+                          bool human)
+{
+    if (r->end - r->begin > 1) {
+        if (human) {
+            g_string_append_printf(sov->string, "%" PRIx64 "-%" PRIx64,
+                                   r->begin, r->end - 1);
+
+        } else {
+            g_string_append_printf(sov->string, "%" PRId64 "-%" PRId64,
+                                   r->begin, r->end - 1);
+        }
+    } else {
+        if (human) {
+            g_string_append_printf(sov->string, "%" PRIx64, r->begin);
+        } else {
+            g_string_append_printf(sov->string, "%" PRId64, r->begin);
+        }
+    }
+    if (next) {
+        g_string_append(sov->string, ",");
+    }
 }
 
 static void print_type_int(Visitor *v, int64_t *obj, const char *name,
                            Error **errp)
 {
     StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
-    SignedRange *r;
-
-    if (!sov->ranges) {
-        sov->ranges = g_malloc0(sizeof(*sov->ranges));
-        QTAILQ_INIT(sov->ranges);
-    }
+    GList *l;
 
     switch (sov->list_mode) {
     case LM_NONE:
@@ -118,8 +143,7 @@ static void print_type_int(Visitor *v, int64_t *obj, const 
char *name,
             } else {
                 assert(sov->range_start.s < sov->range_end.s);
                 string_output_append_range(sov, sov->range_start.s,
-                                           sov->range_end.s -
-                                           sov->range_start.s + 1);
+                                           sov->range_end.s);
             }
 
             sov->range_start.s = *obj;
@@ -132,8 +156,7 @@ static void print_type_int(Visitor *v, int64_t *obj, const 
char *name,
             sov->range_end.s++;
             assert(sov->range_start.s < sov->range_end.s);
             string_output_append_range(sov, sov->range_start.s,
-                                       sov->range_end.s -
-                                       sov->range_start.s + 1);
+                                       sov->range_end.s);
         } else {
             if (sov->range_start.s == sov->range_end.s) {
                 string_output_append(sov, sov->range_end.s);
@@ -141,8 +164,7 @@ static void print_type_int(Visitor *v, int64_t *obj, const 
char *name,
                 assert(sov->range_start.s < sov->range_end.s);
 
                 string_output_append_range(sov, sov->range_start.s,
-                                           sov->range_end.s -
-                                           sov->range_start.s + 1);
+                                           sov->range_end.s);
             }
             string_output_append(sov, *obj);
         }
@@ -152,34 +174,20 @@ static void print_type_int(Visitor *v, int64_t *obj, 
const char *name,
         abort();
     }
 
-    QTAILQ_FOREACH(r, sov->ranges, entry) {
-        if (r->length > 1) {
-            g_string_append_printf(sov->string, "%" PRId64 "-%" PRId64,
-                                   r->start,
-                                   s_range_end(r->start, r->length));
-        } else {
-            g_string_append_printf(sov->string, "%" PRId64,
-                                   r->start);
-        }
-        if (r->entry.tqe_next) {
-            g_string_append(sov->string, ",");
-        }
+    l = sov->ranges;
+    while (l) {
+        Range *r = l->data;
+        format_string(sov, r, l->next != NULL, false);
+        l = l->next;
     }
 
     if (sov->human) {
+        l = sov->ranges;
         g_string_append(sov->string, " (");
-        QTAILQ_FOREACH(r, sov->ranges, entry) {
-            if (r->length > 1) {
-                g_string_append_printf(sov->string, "%" PRIx64 "-%" PRIx64,
-                                       r->start,
-                                       s_range_end(r->start, r->length));
-            } else {
-                g_string_append_printf(sov->string, "%" PRIx64,
-                                       r->start);
-            }
-            if (r->entry.tqe_next) {
-                g_string_append(sov->string, ",");
-            }
+        while (l) {
+            Range *r = l->data;
+            format_string(sov, r, l->next != NULL, false);
+            l = l->next;
         }
         g_string_append(sov->string, ")");
     }
@@ -310,20 +318,11 @@ Visitor *string_output_get_visitor(StringOutputVisitor 
*sov)
 
 void string_output_visitor_cleanup(StringOutputVisitor *sov)
 {
-    SignedRange *r, *next;
-
     if (sov->string) {
         g_string_free(sov->string, true);
     }
 
-    if (sov->ranges) {
-        QTAILQ_FOREACH_SAFE(r, sov->ranges, entry, next) {
-            QTAILQ_REMOVE(sov->ranges, r, entry);
-            s_range_free(r);
-        }
-        g_free(sov->ranges);
-    }
-
+    g_list_free_full(sov->ranges, g_free);
     g_free(sov);
 }
 
diff --git a/tests/test-string-input-visitor.c 
b/tests/test-string-input-visitor.c
index b08a7db..b01e2f2 100644
--- a/tests/test-string-input-visitor.c
+++ b/tests/test-string-input-visitor.c
@@ -67,13 +67,13 @@ static void test_visitor_in_int(TestInputVisitorData *data,
 static void test_visitor_in_intList(TestInputVisitorData *data,
                                     const void *unused)
 {
-    int64_t value[] = {-2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 20};
+    int64_t value[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 20};
     int16List *res = NULL, *tmp;
     Error *errp = NULL;
     Visitor *v;
     int i = 0;
 
-    v = visitor_input_test_init(data, "1,2,-2-1,2-4,20,5-9,1-8");
+    v = visitor_input_test_init(data, "1,2,0,2-4,20,5-9,1-8");
 
     visit_type_int16List(v, &res, NULL, &errp);
     g_assert(errp == NULL);
diff --git a/tests/test-string-output-visitor.c 
b/tests/test-string-output-visitor.c
index d2ad580..28e7359 100644
--- a/tests/test-string-output-visitor.c
+++ b/tests/test-string-output-visitor.c
@@ -44,7 +44,7 @@ static void visitor_output_teardown(TestOutputVisitorData 
*data,
 static void test_visitor_out_int(TestOutputVisitorData *data,
                                  const void *unused)
 {
-    int64_t value = -42;
+    int64_t value = 42;
     Error *err = NULL;
     char *str;
 
@@ -53,14 +53,14 @@ static void test_visitor_out_int(TestOutputVisitorData 
*data,
 
     str = string_output_get_string(data->sov);
     g_assert(str != NULL);
-    g_assert_cmpstr(str, ==, "-42");
+    g_assert_cmpstr(str, ==, "42");
     g_free(str);
 }
 
 static void test_visitor_out_intList(TestOutputVisitorData *data,
                                      const void *unused)
 {
-    int64_t value[] = {-10, -7, -2, -1, 0, 1, 9, 10, 16, 15, 14,
+    int64_t value[] = {0, 1, 9, 10, 16, 15, 14,
         3, 4, 5, 6, 11, 12, 13, 21, 22, INT64_MAX - 1, INT64_MAX};
     intList *list = NULL, **tmp = &list;
     int i;
@@ -79,7 +79,7 @@ static void test_visitor_out_intList(TestOutputVisitorData 
*data,
     str = string_output_get_string(data->sov);
     g_assert(str != NULL);
     g_assert_cmpstr(str, ==,
-        "-10,-7,-2-1,3-6,9-16,21-22,9223372036854775806-9223372036854775807");
+        "0-1,3-6,9-16,21-22,9223372036854775806-9223372036854775807");
     g_free(str);
     while (list) {
         intList *tmp2;
-- 
1.9.3