diff options
| author | Christopher Jeffrey <chjjeffrey@gmail.com> | 2016-07-07 07:57:39 +0300 |
|---|---|---|
| committer | Anna Henningsen <anna@addaleax.net> | 2016-07-17 19:21:33 +0300 |
| commit | 151d316b99d56a4614c95cc59ea7a0c9c0f1928b (patch) | |
| tree | 43521487851641f945a3f82d4d7b9bf8dc591a0c /src/string_bytes.cc | |
| parent | 35e8c9481fa515bc6c122a63492def5e598537b4 (diff) | |
buffer: optimize hex_decode
PR-URL: https://github.com/nodejs/node/pull/7602
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Diffstat (limited to 'src/string_bytes.cc')
| -rw-r--r-- | src/string_bytes.cc | 37 |
1 files changed, 24 insertions, 13 deletions
diff --git a/src/string_bytes.cc b/src/string_bytes.cc index 6f15ad48848..668a3b1efe2 100644 --- a/src/string_bytes.cc +++ b/src/string_bytes.cc @@ -143,16 +143,27 @@ const int8_t unbase64_table[256] = }; -template <typename TypeName> -unsigned hex2bin(TypeName c) { - if (c >= '0' && c <= '9') - return c - '0'; - if (c >= 'A' && c <= 'F') - return 10 + (c - 'A'); - if (c >= 'a' && c <= 'f') - return 10 + (c - 'a'); - return static_cast<unsigned>(-1); -} +static const int8_t unhex_table[256] = + { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 + }; + +#define unhex(x) \ + static_cast<unsigned>(unhex_table[static_cast<uint8_t>(x)]) template <typename TypeName> @@ -162,11 +173,11 @@ size_t hex_decode(char* buf, const size_t srcLen) { size_t i; for (i = 0; i < len && i * 2 + 1 < srcLen; ++i) { - unsigned a = hex2bin(src[i * 2 + 0]); - unsigned b = hex2bin(src[i * 2 + 1]); + unsigned a = unhex(src[i * 2 + 0]); + unsigned b = unhex(src[i * 2 + 1]); if (!~a || !~b) return i; - buf[i] = a * 16 + b; + buf[i] = (a << 4) | b; } return i; |