Mostly tiny changes, with one optimization to fallback for number parsing. (#1265)

* Mostly tiny changes, with one optimization to fallback for number parsing.

* Missed an update.

include/simdjson/arm64/numberparsing.h

@@ -9,7 +9,7 @@ namespace {
 // credit: https://johnnylee-sde.github.io/Fast-numeric-string-to-int/
 static simdjson_really_inline uint32_t parse_eight_digits_unrolled(const uint8_t *chars) {
   uint64_t val;
-  memcpy(&val, chars, sizeof(uint64_t));
+  std::memcpy(&val, chars, sizeof(uint64_t));
   val = (val & 0x0F0F0F0F0F0F0F0F) * 2561 >> 8;
   val = (val & 0x00FF00FF00FF00FF) * 6553601 >> 16;
   return uint32_t((val & 0x0000FFFF0000FFFF) * 42949672960001 >> 32);

include/simdjson/fallback/numberparsing.h

@@ -11,12 +11,13 @@ void found_float(double result, const uint8_t *buf);
 namespace simdjson {
 namespace SIMDJSON_IMPLEMENTATION {
 namespace {
+// credit: https://johnnylee-sde.github.io/Fast-numeric-string-to-int/
 static simdjson_really_inline uint32_t parse_eight_digits_unrolled(const char *chars) {
-  uint32_t result = 0;
-  for (int i=0;i<8;i++) {
-    result = result*10 + (chars[i] - '0');
-  }
-  return result;
+  uint64_t val;
+  memcpy(&val, chars, sizeof(uint64_t));
+  val = (val & 0x0F0F0F0F0F0F0F0F) * 2561 >> 8;
+  val = (val & 0x00FF00FF00FF00FF) * 6553601 >> 16;
+  return uint32_t((val & 0x0000FFFF0000FFFF) * 42949672960001 >> 32);
 }
 static simdjson_really_inline uint32_t parse_eight_digits_unrolled(const uint8_t *chars) {
   return parse_eight_digits_unrolled((const char *)chars);

include/simdjson/generic/numberparsing.h

@@ -31,7 +31,7 @@ simdjson_really_inline double to_double(uint64_t mantissa, uint64_t real_exponen
     mantissa &= ~(1ULL << 52);
     mantissa |= real_exponent << 52;
     mantissa |= (((uint64_t)negative) << 63);
-    memcpy(&d, &mantissa, sizeof(d));
+    std::memcpy(&d, &mantissa, sizeof(d));
     return d;
 }
 }
@@ -307,7 +307,7 @@ simdjson_really_inline bool is_made_of_eight_digits_fast(const uint8_t *chars) {
   // this can read up to 7 bytes beyond the buffer size, but we require
   // SIMDJSON_PADDING of padding
   static_assert(7 <= SIMDJSON_PADDING, "SIMDJSON_PADDING must be bigger than 7");
-  memcpy(&val, chars, 8);
+  std::memcpy(&val, chars, 8);
   // a branchy method might be faster:
   // return (( val & 0xF0F0F0F0F0F0F0F0 ) == 0x3030303030303030)
   //  && (( (val + 0x0606060606060606) & 0xF0F0F0F0F0F0F0F0 ) ==

include/simdjson/generic/ondemand/json_iterator-inl.h

@@ -204,7 +204,7 @@ simdjson_warn_unused simdjson_really_inline bool json_iterator::copy_to_buffer(c
   }
 
   // Copy to the buffer.
-  memcpy(tmpbuf, json, len);
+  std::memcpy(tmpbuf, json, len);
   tmpbuf[len] = ' ';
   return true;
 }

include/simdjson/ppc64/numberparsing.h

@@ -7,12 +7,12 @@ namespace simdjson {
 namespace SIMDJSON_IMPLEMENTATION {
 namespace {
 
-// we don't have appropriate, so let us use a scalar function
+// we don't have appropriate instructions, so let us use a scalar function
 // credit: https://johnnylee-sde.github.io/Fast-numeric-string-to-int/
 static simdjson_really_inline uint32_t
 parse_eight_digits_unrolled(const uint8_t *chars) {
   uint64_t val;
-  memcpy(&val, chars, sizeof(uint64_t));
+  std::memcpy(&val, chars, sizeof(uint64_t));
 #ifdef __BIG_ENDIAN__
   val = bswap_64(val);
 #endif