Added more streamlined interfaces for converting rendezvous ids

to/from strings and used these in the rendezvous code.  Improves
performance for ptb_word_lm slightly (saves several allocations and an
sscanf per CPU <-> GPU transfer).
Change: 115852277

1 files changed, 33 insertions, 0 deletions

diff --git a/tensorflow/core/lib/strings/numbers.cc b/tensorflow/core/lib/strings/numbers.cc
index 778545b44b..a60de543cc 100644
--- a/tensorflow/core/lib/strings/numbers.cc
+++ b/tensorflow/core/lib/strings/numbers.cc
@@ -15,6 +15,7 @@ limitations under the License.
 
 #include "tensorflow/core/lib/strings/numbers.h"
 
+#include <ctype.h>
 #include <float.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -237,6 +238,38 @@ bool StringToFp(const string& s, Fprint* fp) {
   }
 }
 
+StringPiece Uint64ToHexString(uint64 v, char* buf) {
+  static const char* hexdigits = "0123456789abcdef";
+  const int num_byte = 16;
+  buf[num_byte] = '\0';
+  for (int i = num_byte - 1; i >= 0; i--) {
+    buf[i] = hexdigits[v & 0xf];
+    v >>= 4;
+  }
+  return StringPiece(buf, num_byte);
+}
+
+bool HexStringToUint64(const StringPiece& s, uint64* result) {
+  uint64 v = 0;
+  if (s.empty()) {
+    return false;
+  }
+  for (int i = 0; i < s.size(); i++) {
+    char c = s[i];
+    if (c >= '0' && c <= '9') {
+      v = (v << 4) + (c - '0');
+    } else if (c >= 'a' && c <= 'f') {
+      v = (v << 4) + 10 + (c - 'a');
+    } else if (c >= 'A' && c <= 'F') {
+      v = (v << 4) + 10 + (c - 'A');
+    } else {
+      return false;
+    }
+  }
+  *result = v;
+  return true;
+}
+
 string HumanReadableNumBytes(int64 num_bytes) {
   if (num_bytes == kint64min) {
     // Special case for number with not representable negation.