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Re: [PATCH v14 01/11] util/cutils: Add qemu_strtotime_ns()


From: Tao Xu
Subject: Re: [PATCH v14 01/11] util/cutils: Add qemu_strtotime_ns()
Date: Thu, 7 Nov 2019 09:38:29 +0800
User-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0

On 11/7/2019 3:56 AM, Eduardo Habkost wrote:
On Mon, Oct 28, 2019 at 03:52:10PM +0800, Tao Xu wrote:
To convert strings with time suffixes to numbers, support time unit are
"ns" for nanosecond, "us" for microsecond, "ms" for millisecond or "s"
for second. Add test for qemu_strtotime_ns, test the input of basic,
time suffixes, float, invaild, trailing and overflow.

Signed-off-by: Tao Xu <address@hidden>
---

Changes in v14:
     - Reuse the codes of do_strtosz to build qemu_strtotime_ns
       (Eduardo)
     - Squash patch v13 01/12 and 02/12 together (Daniel and Eduardo)
     - Drop time unit picosecond (Eric)

Suggestion for the next version: if you are refactoring existing
do_strtosz() code, please refactor it in one patch, and add new
functionality in another patch.

Thank you for your suggestions and comments blew. I will improve in next version.

---
  include/qemu/cutils.h |   1 +
  tests/test-cutils.c   | 204 ++++++++++++++++++++++++++++++++++++++++++
  util/cutils.c         |  89 +++++++++++-------
  3 files changed, 262 insertions(+), 32 deletions(-)

diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
index b54c847e0f..ff2b3f4614 100644
--- a/include/qemu/cutils.h
+++ b/include/qemu/cutils.h
@@ -182,5 +182,6 @@ int uleb128_decode_small(const uint8_t *in, uint32_t *n);
   * *str1 is <, == or > than *str2.
   */
  int qemu_pstrcmp0(const char **str1, const char **str2);
+int qemu_strtotime_ns(const char *nptr, const char **end, uint64_t *result);
#endif
diff --git a/tests/test-cutils.c b/tests/test-cutils.c
index 1aa8351520..d6a0824efd 100644
--- a/tests/test-cutils.c
+++ b/tests/test-cutils.c
[...]
+static void test_qemu_strtotime_ns_trailing(void)
+{
+    const char *str;
+    const char *endptr;
+    int err;
+    uint64_t res = 0xbaadf00d;
+
+    str = "123xxx";
+
+    err = qemu_strtotime_ns(str, NULL, &res);
+    g_assert_cmpint(err, ==, -EINVAL);
+
+    str = "1msxxx";
+    err = qemu_strtotime_ns(str, &endptr, &res);
+    g_assert_cmpint(err, ==, 0);
+    g_assert_cmpint(res, ==, 1000000);
+    g_assert(endptr == str + 3);
+
+    err = qemu_strtotime_ns(str, NULL, &res);
+    g_assert_cmpint(err, ==, -EINVAL);
+}

This is better than the test case in v13, where trailing strings
were not handled consistently.  Good.

[...]
diff --git a/util/cutils.c b/util/cutils.c
index fd591cadf0..d83825f8b4 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -181,41 +181,38 @@ int fcntl_setfl(int fd, int flag)
  }
  #endif
-static int64_t suffix_mul(char suffix, int64_t unit)
-{
-    switch (qemu_toupper(suffix)) {
-    case 'B':
-        return 1;
-    case 'K':
-        return unit;
-    case 'M':
-        return unit * unit;
-    case 'G':
-        return unit * unit * unit;
-    case 'T':
-        return unit * unit * unit * unit;
-    case 'P':
-        return unit * unit * unit * unit * unit;
-    case 'E':
-        return unit * unit * unit * unit * unit * unit;
+static int64_t suffix_mul(const char *suffixes[], int num_suffix,
+                          const char *endptr, int *offset, int64_t unit)
+{
+    int i, suffix_len;
+    int64_t mul = 1;
+
+    for (i = 0; i < num_suffix; i++) {
+        suffix_len = strlen(suffixes[i]);
+        if (strlen(endptr) >= suffix_len &&

Is the strlen(endptr) check here really necessary?


+            g_ascii_strncasecmp(suffixes[i], endptr, suffix_len) == 0) {
+            *offset = suffix_len;
+            return mul;
+        }
+        mul *= unit;
      }
+
      return -1;
  }
/*
- * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
- * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
- * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
- * other error.
+ * Convert string according to different suffixes. End pointer will be returned
+ * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on other 
error.
   */
-static int do_strtosz(const char *nptr, const char **end,
-                      const char default_suffix, int64_t unit,
-                      uint64_t *result)
+static int do_strtomul(const char *nptr, const char **end,
+                       const char *suffixes[], int num_suffix,
+                       const char *default_suffix, int64_t unit,
+                       uint64_t *result)
  {
      int retval;
      const char *endptr;
-    unsigned char c;
      int mul_required = 0;
+    int offset = 0;
      double val, mul, integral, fraction;
retval = qemu_strtod_finite(nptr, &endptr, &val);
@@ -226,12 +223,12 @@ static int do_strtosz(const char *nptr, const char **end,
      if (fraction != 0) {
          mul_required = 1;
      }
-    c = *endptr;
-    mul = suffix_mul(c, unit);
+
+    mul = suffix_mul(suffixes, num_suffix, endptr, &offset, unit);
      if (mul >= 0) {
-        endptr++;
+        endptr += offset;
      } else {
-        mul = suffix_mul(default_suffix, unit);
+        mul = suffix_mul(suffixes, num_suffix, default_suffix, &offset, unit);
          assert(mul >= 0);
      }
      if (mul == 1 && mul_required) {
@@ -259,19 +256,47 @@ out:
      return retval;
  }
+/*
+ * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
+ * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
+ * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
+ * other error.
+ */
+static int do_strtosz(const char *nptr, const char **end,
+                      const char *default_suffix, int64_t unit,
+                      uint64_t *result)
+{
+    static const char *suffixes[] = { "B", "K", "M", "G", "T", "P", "E" };
+
+    return do_strtomul(nptr, end, suffixes, 7, default_suffix, unit, result);

[1] You can use ARRAY_SIZE(suffixes) instead of hardcoding the
array size.

+}
+
  int qemu_strtosz(const char *nptr, const char **end, uint64_t *result)
  {
-    return do_strtosz(nptr, end, 'B', 1024, result);
+    return do_strtosz(nptr, end, "B", 1024, result);
  }
int qemu_strtosz_MiB(const char *nptr, const char **end, uint64_t *result)
  {
-    return do_strtosz(nptr, end, 'M', 1024, result);
+    return do_strtosz(nptr, end, "M", 1024, result);
  }
int qemu_strtosz_metric(const char *nptr, const char **end, uint64_t *result)
  {
-    return do_strtosz(nptr, end, 'B', 1000, result);
+    return do_strtosz(nptr, end, "B", 1000, result);
+}
+
+/*
+ * Convert string to time, support time unit are ns for nanosecond, us for
+ * microsecond, ms for millisecond and s for second. End pointer will be
+ * returned in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
+ * other error.
+ */
+int qemu_strtotime_ns(const char *nptr, const char **end, uint64_t *result)
+{
+    static const char *suffixes[] = { "ns", "us", "ms", "s" };
+
+    return do_strtomul(nptr, end, suffixes, 4, "ns", 1000, result);

Same as above[1].

  }
/**
--
2.20.1






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