Mercurial > hg
changeset 19718:d69e06724b96
parsers: use a lookup table to convert hex to binary
This is a hotspot for parse_manifest. With this patch, for a 20 MB, 200,000
file manifest, parse_manifest goes down from 0.153 seconds to 0.116.
| author | Siddharth Agarwal <sid0@fb.com> |
|---|---|
| date | Sat, 07 Sep 2013 00:59:24 -0700 |
| parents | 6031fe568cd0 |
| children | 2f9d5c5256ea |
| files | mercurial/parsers.c |
| diffstat | 1 files changed, 23 insertions(+), 7 deletions(-) [+] |
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--- a/mercurial/parsers.c Fri Sep 06 23:05:33 2013 -0700 +++ b/mercurial/parsers.c Sat Sep 07 00:59:24 2013 -0700 @@ -14,16 +14,32 @@ #include "util.h" +static int8_t hextable[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, /* 0-9 */ + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* A-F */ + -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, /* a-f */ + -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 +}; + static inline int hexdigit(const char *p, Py_ssize_t off) { - char c = p[off]; + int8_t val = hextable[(unsigned char)p[off]]; - if (c >= '0' && c <= '9') - return c - '0'; - if (c >= 'a' && c <= 'f') - return c - 'a' + 10; - if (c >= 'A' && c <= 'F') - return c - 'A' + 10; + if (val >= 0) { + return val; + } PyErr_SetString(PyExc_ValueError, "input contains non-hex character"); return 0;