src/lib/trace-ir/utils.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
   5  */
   6
   7 #ifndef BABELTRACE_TRACE_IR_UTILS_INTERNAL_H
   8 #define BABELTRACE_TRACE_IR_UTILS_INTERNAL_H
   9
  10 #include <babeltrace2/trace-ir/field-class.h>
  11 #include <stdbool.h>
  12 #include <stdint.h>
  13
  14 #include "clock-class.h"
  15
  16 struct search_query {
  17         gpointer value;
  18         int found;
  19 };
  20
  21 static inline
  22 uint64_t bt_util_ns_from_value(uint64_t frequency, uint64_t value_cycles)
  23 {
  24         uint64_t ns;
  25
  26         if (frequency == UINT64_C(1000000000)) {
  27                 ns = value_cycles;
  28         } else {
  29                 double dblres = ((1e9 * (double) value_cycles) / (double) frequency);
  30
  31                 if (dblres >= (double) UINT64_MAX) {
  32                         /* Overflows uint64_t */
  33                         ns = UINT64_C(-1);
  34                 } else {
  35                         ns = (uint64_t) dblres;
  36                 }
  37         }
  38
  39         return ns;
  40 }
  41
  42 static inline
  43 bool bt_util_get_base_offset_ns(int64_t offset_seconds, uint64_t offset_cycles,
  44                 uint64_t frequency, int64_t *base_offset_ns)
  45 {
  46         bool overflows = false;
  47         uint64_t offset_cycles_ns;
  48
  49         BT_ASSERT_DBG(base_offset_ns);
  50
  51         /* Initialize nanosecond timestamp to clock's offset in seconds */
  52         if (offset_seconds <= (INT64_MIN / INT64_C(1000000000) - 1) ||
  53                         offset_seconds >= (INT64_MAX / INT64_C(1000000000)) - 1) {
  54                 /*
  55                  * Overflow: offset in seconds converted to nanoseconds
  56                  * is outside the int64_t range. We also subtract 1 here
  57                  * to leave "space" for the offset in cycles converted
  58                  * to nanoseconds (which is always less than 1 second by
  59                  * contract).
  60                  */
  61                 overflows = true;
  62                 goto end;
  63         }
  64
  65         /* Offset (seconds) to nanoseconds */
  66         *base_offset_ns = offset_seconds * INT64_C(1000000000);
  67
  68         /* Add offset in cycles */
  69         BT_ASSERT_DBG(offset_cycles < frequency);
  70         offset_cycles_ns = bt_util_ns_from_value(frequency,
  71                 offset_cycles);
  72         BT_ASSERT_DBG(offset_cycles_ns < 1000000000);
  73         *base_offset_ns += (int64_t) offset_cycles_ns;
  74
  75 end:
  76         return overflows;
  77 }
  78
  79 static inline
  80 int bt_util_ns_from_origin_inline(int64_t base_offset_ns,
  81                 uint64_t frequency, uint64_t value, int64_t *ns_from_origin)
  82 {
  83         int ret = 0;
  84         uint64_t value_ns_unsigned;
  85         int64_t value_ns_signed;
  86
  87         /* Initialize to clock class's base offset */
  88         *ns_from_origin = base_offset_ns;
  89
  90         /* Add given value in cycles */
  91         value_ns_unsigned = bt_util_ns_from_value(frequency, value);
  92         if (value_ns_unsigned >= (uint64_t) INT64_MAX) {
  93                 /*
  94                  * FIXME: `value_ns_unsigned` could be greater than
  95                  * `INT64_MAX` in fact: in this case, we need to
  96                  * subtract `INT64_MAX` from `value_ns_unsigned`, make
  97                  * sure that the difference is less than `INT64_MAX`,
  98                  * and try to add them one after the other to
  99                  * `*ns_from_origin`.
 100                  */
 101                 ret = -1;
 102                 goto end;
 103         }
 104
 105         value_ns_signed = (int64_t) value_ns_unsigned;
 106         BT_ASSERT_DBG(value_ns_signed >= 0);
 107
 108         if (*ns_from_origin <= 0) {
 109                 goto add_value;
 110         }
 111
 112         if (value_ns_signed > INT64_MAX - *ns_from_origin) {
 113                 ret = -1;
 114                 goto end;
 115         }
 116
 117 add_value:
 118         *ns_from_origin += value_ns_signed;
 119
 120 end:
 121         return ret;
 122 }
 123
 124 static inline
 125 int bt_util_ns_from_origin_clock_class(const struct bt_clock_class *clock_class,
 126                 uint64_t value, int64_t *ns_from_origin)
 127 {
 128         int ret = 0;
 129
 130         if (clock_class->base_offset.overflows) {
 131                 ret = -1;
 132                 goto end;
 133         }
 134
 135         ret = bt_util_ns_from_origin_inline(clock_class->base_offset.value_ns,
 136                 clock_class->frequency, value, ns_from_origin);
 137
 138 end:
 139         return ret;
 140 }
 141
 142 static inline
 143 bool bt_util_value_is_in_range_signed(uint64_t size, int64_t value)
 144 {
 145         int64_t min_value = UINT64_C(-1) << (size - 1);
 146         int64_t max_value = (UINT64_C(1) << (size - 1)) - 1;
 147         return value >= min_value && value <= max_value;
 148 }
 149
 150 static inline
 151 bool bt_util_value_is_in_range_unsigned(unsigned int size, uint64_t value)
 152 {
 153         uint64_t max_value = (size == 64) ? UINT64_MAX :
 154                 (UINT64_C(1) << size) - 1;
 155         return value <= max_value;
 156 }
 157
 158 #endif /* BABELTRACE_TRACE_IR_UTILS_INTERNAL_H */