pike.git/ src/ builtin.cmod

2011-11-04

2011-11-04 13:06:16 by Per Hedbor <ph@opera.com>

• b2f5ff9bb0a7021285407dad7cc3bff6c4cb8a2b (52 lines) (+38/-14) ^{[ Show | Annotate ]}
  Branch: 7.9

Faster hex2string and string2hex sacrificing 260 or so bytes of memory

The performance increase is significant for longer strings.

297:   }       - static INLINE int hexchar( int v ) - { -  return v<10 ? v+'0' : (v-10)+'a'; - } -  +    /*! @decl string string2hex(string data)    *! @appears String.string2hex    *!
310:    *! @seealso    *! @[hex2string()]    */ +  + static const char hexchar[] = { +  '0','1','2','3','4','5','6','7','8','9', +  'a','b','c','d','e','f' + }; +  + static const unsigned char hexdecode[256] = + { +  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, +  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, +  +  /* '0' - '9' */ +  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, +  +  0,0,0,0,0,0,0, +  +  /* 'A' - 'F' */ +  10, 11, 12, 13, 14, 15, +  +  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, +  /* 'a' - 'f' */ +  10, 11, 12, 13, 14, 15, + }; +    PMOD_EXPORT   PIKEFUN string string2hex(string s)    errname String.string2hex;    optflags OPT_TRY_OPTIMIZE;   {    struct pike_string *hex; -  unsigned char *st = (unsigned char *)s->str; -  int i; +  unsigned char *p,*st = (unsigned char *)s->str; +  int i, l;       if (s->size_shift)    Pike_error("Bad argument 1 to string2hex(), expected 8-bit string.\n");       hex = begin_shared_string(2 * s->len); -  +  p = (unsigned char *)hex->str; +  l = s->len;    -  for (i=0; i<s->len; i++) { -  hex->str[i<<1] = hexchar(st[i]>>4); -  hex->str[i<<1|1] = hexchar(st[i]&15); +  for (i=0; i<l; i++) { +  *p++ = hexchar[*st>>4]; +  *p++ = hexchar[*st&15]; +  st++;    }       RETURN end_shared_string(hex);
346:    optflags OPT_TRY_OPTIMIZE;   {    struct pike_string *s; -  int i, o=0; -  unsigned char *q = (unsigned char *)hex->str; +  int tmp, i; +  unsigned char *p, *q = (unsigned char *)hex->str;    int l = hex->len>>1;    if(hex->size_shift) Pike_error("Only hex digits allowed.\n");    if(hex->len&1) Pike_error("Can't have odd number of digits.\n");       s = begin_shared_string(l); -  +  p = (unsigned char *)s->str;    for (i=0; i<l; i++)    { -  s->str[i] = (q[o]<='9' ? q[o]-'0' :((q[o]+9)&15))<<4; o++; -  s->str[i] |= (q[o]<='9' ? q[o]-'0': ((q[o]+9)&15)); o++; +  tmp = hexdecode[*q++]; +  *p++ = (tmp<<4) | hexdecode[*q++];    }    RETURN end_shared_string(s);   }