1 files changed, 188 insertions, 0 deletions
diff --git a/src/core/ext/transport/chttp2/transport/timeout_encoding.c b/src/core/ext/transport/chttp2/transport/timeout_encoding.c
new file mode 100644
index 0000000000..b7f7912493
--- /dev/null
+++ b/src/core/ext/transport/chttp2/transport/timeout_encoding.c
@@ -0,0 +1,188 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/ext/transport/chttp2/transport/timeout_encoding.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/support/port_platform.h>
+#include "src/core/lib/support/string.h"
+
+static int64_t round_up(int64_t x, int64_t divisor) {
+  return (x / divisor + (x % divisor != 0)) * divisor;
+}
+
+/* round an integer up to the next value with three significant figures */
+static int64_t round_up_to_three_sig_figs(int64_t x) {
+  if (x < 1000) return x;
+  if (x < 10000) return round_up(x, 10);
+  if (x < 100000) return round_up(x, 100);
+  if (x < 1000000) return round_up(x, 1000);
+  if (x < 10000000) return round_up(x, 10000);
+  if (x < 100000000) return round_up(x, 100000);
+  if (x < 1000000000) return round_up(x, 1000000);
+  return round_up(x, 10000000);
+}
+
+/* encode our minimum viable timeout value */
+static void enc_tiny(char *buffer) { memcpy(buffer, "1n", 3); }
+
+static void enc_ext(char *buffer, int64_t value, char ext) {
+  int n = int64_ttoa(value, buffer);
+  buffer[n] = ext;
+  buffer[n + 1] = 0;
+}
+
+static void enc_seconds(char *buffer, int64_t sec) {
+  if (sec % 3600 == 0) {
+    enc_ext(buffer, sec / 3600, 'H');
+  } else if (sec % 60 == 0) {
+    enc_ext(buffer, sec / 60, 'M');
+  } else {
+    enc_ext(buffer, sec, 'S');
+  }
+}
+
+static void enc_nanos(char *buffer, int64_t x) {
+  x = round_up_to_three_sig_figs(x);
+  if (x < 100000) {
+    if (x % 1000 == 0) {
+      enc_ext(buffer, x / 1000, 'u');
+    } else {
+      enc_ext(buffer, x, 'n');
+    }
+  } else if (x < 100000000) {
+    if (x % 1000000 == 0) {
+      enc_ext(buffer, x / 1000000, 'm');
+    } else {
+      enc_ext(buffer, x / 1000, 'u');
+    }
+  } else if (x < 1000000000) {
+    enc_ext(buffer, x / 1000000, 'm');
+  } else {
+    /* note that this is only ever called with times of less than one second,
+       so if we reach here the time must have been rounded up to a whole second
+       (and no more) */
+    memcpy(buffer, "1S", 3);
+  }
+}
+
+static void enc_micros(char *buffer, int64_t x) {
+  x = round_up_to_three_sig_figs(x);
+  if (x < 100000) {
+    if (x % 1000 == 0) {
+      enc_ext(buffer, x / 1000, 'm');
+    } else {
+      enc_ext(buffer, x, 'u');
+    }
+  } else if (x < 100000000) {
+    if (x % 1000000 == 0) {
+      enc_ext(buffer, x / 1000000, 'S');
+    } else {
+      enc_ext(buffer, x / 1000, 'm');
+    }
+  } else {
+    enc_ext(buffer, x / 1000000, 'S');
+  }
+}
+
+void grpc_chttp2_encode_timeout(gpr_timespec timeout, char *buffer) {
+  if (timeout.tv_sec < 0) {
+    enc_tiny(buffer);
+  } else if (timeout.tv_sec == 0) {
+    enc_nanos(buffer, timeout.tv_nsec);
+  } else if (timeout.tv_sec < 1000 && timeout.tv_nsec != 0) {
+    enc_micros(buffer,
+               (int64_t)(timeout.tv_sec * 1000000) +
+                   (timeout.tv_nsec / 1000 + (timeout.tv_nsec % 1000 != 0)));
+  } else {
+    enc_seconds(buffer, timeout.tv_sec + (timeout.tv_nsec != 0));
+  }
+}
+
+static int is_all_whitespace(const char *p) {
+  while (*p == ' ') p++;
+  return *p == 0;
+}
+
+int grpc_chttp2_decode_timeout(const char *buffer, gpr_timespec *timeout) {
+  int32_t x = 0;
+  const uint8_t *p = (const uint8_t *)buffer;
+  int have_digit = 0;
+  /* skip whitespace */
+  for (; *p == ' '; p++)
+    ;
+  /* decode numeric part */
+  for (; *p >= '0' && *p <= '9'; p++) {
+    int32_t digit = (int32_t)(*p - (uint8_t)'0');
+    have_digit = 1;
+    /* spec allows max. 8 digits, but we allow values up to 1,000,000,000 */
+    if (x >= (100 * 1000 * 1000)) {
+      if (x != (100 * 1000 * 1000) || digit != 0) {
+        *timeout = gpr_inf_future(GPR_TIMESPAN);
+        return 1;
+      }
+    }
+    x = x * 10 + digit;
+  }
+  if (!have_digit) return 0;
+  /* skip whitespace */
+  for (; *p == ' '; p++)
+    ;
+  /* decode unit specifier */
+  switch (*p) {
+    case 'n':
+      *timeout = gpr_time_from_nanos(x, GPR_TIMESPAN);
+      break;
+    case 'u':
+      *timeout = gpr_time_from_micros(x, GPR_TIMESPAN);
+      break;
+    case 'm':
+      *timeout = gpr_time_from_millis(x, GPR_TIMESPAN);
+      break;
+    case 'S':
+      *timeout = gpr_time_from_seconds(x, GPR_TIMESPAN);
+      break;
+    case 'M':
+      *timeout = gpr_time_from_minutes(x, GPR_TIMESPAN);
+      break;
+    case 'H':
+      *timeout = gpr_time_from_hours(x, GPR_TIMESPAN);
+      break;
+    default:
+      return 0;
+  }
+  p++;
+  return is_all_whitespace((const char *)p);
+}