--- a/src/utils/base64.cpp
+++ b/src/utils/base64.cpp
@@ -23,65 +23,115 @@
using std::string;
#endif /* NO_NAMESPACES */
-//#define DEBUG_BASE64
+#undef DEBUG_BASE64
#ifdef DEBUG_BASE64
#define DPRINT(X) fprintf X
#else
#define DPRINT(X)
#endif
-// This is adapted from FreeBSD's code.
+// This is adapted from FreeBSD's code, quite modified for performance.
+// Tests on a Mac pro 2.1G with a 166MB base64 file
+//
+// The original version used strchr to lookup the base64 value from
+// the input code:
+// real 0m13.053s user 0m12.574s sys 0m0.471s
+// Using a direct access, 256 entries table:
+// real 0m3.073s user 0m2.600s sys 0m0.439s
+// Using a variable to hold the array length (instead of in.length()):
+// real 0m2.972s user 0m2.527s sys 0m0.433s
+// Using values from the table instead of isspace() (final)
+// real 0m2.513s user 0m2.059s sys 0m0.439s
+//
+// The table has one entry per char value (0-256). Invalid base64
+// chars take value 256, whitespace 255, Pad ('=') 254.
+// Valid char points contain their base64 value (0-63)
+static const int b64values[] = {
+/* 0 */ 256,/* 1 */ 256,/* 2 */ 256,/* 3 */ 256,/* 4 */ 256,
+/* 5 */ 256,/* 6 */ 256,/* 7 */ 256,/* 8 */ 256,
+/*9 ht */ 255,/* 10 nl */ 255,/* 11 vt */ 255,/* 12 np/ff*/ 255,/* 13 cr */ 255,
+/* 14 */ 256,/* 15 */ 256,/* 16 */ 256,/* 17 */ 256,/* 18 */ 256,/* 19 */ 256,
+/* 20 */ 256,/* 21 */ 256,/* 22 */ 256,/* 23 */ 256,/* 24 */ 256,/* 25 */ 256,
+/* 26 */ 256,/* 27 */ 256,/* 28 */ 256,/* 29 */ 256,/* 30 */ 256,/* 31 */ 256,
+/* 32 sp */ 255,
+/* ! */ 256,/* " */ 256,/* # */ 256,/* $ */ 256,/* % */ 256,
+/* & */ 256,/* ' */ 256,/* ( */ 256,/* ) */ 256,/* * */ 256,
+/* + */ 62,
+/* , */ 256,/* - */ 256,/* . */ 256,
+/* / */ 63,
+/* 0 */ 52,/* 1 */ 53,/* 2 */ 54,/* 3 */ 55,/* 4 */ 56,/* 5 */ 57,/* 6 */ 58,
+/* 7 */ 59,/* 8 */ 60,/* 9 */ 61,
+/* : */ 256,/* ; */ 256,/* < */ 256,
+/* = */ 254,
+/* > */ 256,/* ? */ 256,/* @ */ 256,
+/* A */ 0,/* B */ 1,/* C */ 2,/* D */ 3,/* E */ 4,/* F */ 5,/* G */ 6,/* H */ 7,
+/* I */ 8,/* J */ 9,/* K */ 10,/* L */ 11,/* M */ 12,/* N */ 13,/* O */ 14,
+/* P */ 15,/* Q */ 16,/* R */ 17,/* S */ 18,/* T */ 19,/* U */ 20,/* V */ 21,
+/* W */ 22,/* X */ 23,/* Y */ 24,/* Z */ 25,
+/* [ */ 256,/* \ */ 256,/* ] */ 256,/* ^ */ 256,/* _ */ 256,/* ` */ 256,
+/* a */ 26,/* b */ 27,/* c */ 28,/* d */ 29,/* e */ 30,/* f */ 31,/* g */ 32,
+/* h */ 33,/* i */ 34,/* j */ 35,/* k */ 36,/* l */ 37,/* m */ 38,/* n */ 39,
+/* o */ 40,/* p */ 41,/* q */ 42,/* r */ 43,/* s */ 44,/* t */ 45,/* u */ 46,
+/* v */ 47,/* w */ 48,/* x */ 49,/* y */ 50,/* z */ 51,
+/* { */ 256,/* | */ 256,/* } */ 256,/* ~ */ 256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,
+256,256,256,256,256,256,256,256,
+};
static const char Base64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char Pad64 = '=';
+
bool base64_decode(const string& in, string& out)
{
int io = 0, state = 0, ch = 0;
- const char *pos;
unsigned int ii = 0;
out.erase();
- out.reserve(in.length());
-
- for (ii = 0; ii < in.length(); ii++) {
- ch = in[ii];
- if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */
+ size_t ilen = in.length();
+ out.reserve(ilen);
+
+ for (ii = 0; ii < ilen; ii++) {
+ ch = (unsigned char)in[ii];
+ int value = b64values[ch];
+
+ if (value == 255) /* Skip whitespace anywhere. */
continue;
-
if (ch == Pad64)
break;
-
- pos = strchr(Base64, ch);
- if (pos == 0) {
+ if (value == 256) {
/* A non-base64 character. */
DPRINT((stderr, "base64_dec: non-base64 char at pos %d\n", ii));
return false;
}
-
switch (state) {
case 0:
- out += (pos - Base64) << 2;
+ out += value << 2;
state = 1;
break;
case 1:
- out[io] |= (pos - Base64) >> 4;
- out += ((pos - Base64) & 0x0f) << 4 ;
+ out[io] |= value >> 4;
+ out += (value & 0x0f) << 4 ;
io++;
state = 2;
break;
case 2:
- out[io] |= (pos - Base64) >> 2;
- out += ((pos - Base64) & 0x03) << 6;
+ out[io] |= value >> 2;
+ out += (value & 0x03) << 6;
io++;
state = 3;
break;
case 3:
- out[io] |= (pos - Base64);
+ out[io] |= value;
io++;
state = 0;
break;
default:
- DPRINT((stderr, "base64_dec: internal!bad state!\n"));
+ fprintf(stderr, "base64_dec: internal!bad state!\n");
return false;
}
}
@@ -154,7 +204,7 @@
}
DPRINT((stderr, "base64_dec: ret ok, io %d sz %d len %d value [%s]\n",
- io, out.size(), out.length(), out.c_str()));
+ io, (int)out.size(), (int)out.length(), out.c_str()));
return true;
}