* src/integer/conv/cl_I_from_digits.cc: Made input of all numbers in

non-power-of-two base much faster.
        * tests/test_I_io.cc: New file...
        * tests/Makefile.in, tests/test_I.cc: ...used here.

ChangeLog

@@ -1,4 +1,11 @@
-2004-10-22  Richard B. Kreckel  <kreckel@ginac.de>
+2005-11-02  Richard B. Kreckel  <kreckel@ginac.de>
+
+	* src/integer/conv/cl_I_from_digits.cc: Made input of all numbers in
+	non-power-of-two base much faster.
+	* tests/test_I_io.cc: New file...
+	* tests/Makefile.in, tests/test_I.cc: ...used here.
+
+2005-10-22  Richard B. Kreckel  <kreckel@ginac.de>
 
 	* Version 1.1.10 released.
 

src/integer/conv/cl_I_from_digits.cc

@@ -13,116 +13,184 @@
 
 namespace cln {
 
+static const cl_I digits_to_I_base2 (const char * MSBptr, uintL len, uintD base)
+{
+	// base is a power of two: write the digits from least significant
+	// to most significant into the result NUDS. Result needs
+	// 1+ceiling(len*log(base)/(intDsize*log(2))) or some more digits
+	CL_ALLOCA_STACK;
+	var uintD* erg_MSDptr;
+	var uintC erg_len;
+	var uintD* erg_LSDptr;
+	var int b = (base==2 ? 1 : base==4 ? 2 : base==8 ? 3 : base==16 ? 4 : /*base==32*/ 5);
+	num_stack_alloc(1+(len*b)/intDsize,,erg_LSDptr=);
+	erg_MSDptr = erg_LSDptr; erg_len = 0;
+	var uintD d = 0;  // resulting digit
+	var int ch_where = 0;  // position of ch inside d
+	while (len > 0) {
+		var uintB ch = *(const uintB *)(MSBptr+len-1); // next character
+		if (ch!='.') { // skip decimal point
+			// Compute value of ch ('0'-'9','A'-'Z','a'-'z'):
+			ch = ch - '0';
+			if (ch > '9'-'0') { // not a digit?
+				ch = ch+'0'-'A'+10;
+				if (ch > 'Z'-'A'+10) {// not an uppercase letter?
+					ch = ch+'A'-'a'; // must be lowercase!
+				}
+			}
+			d = d | (uintD)ch<<ch_where;
+			ch_where = ch_where+b;
+			if (ch_where >= intDsize) {
+			    // d is ready to be written into the NUDS:
+			    lsprefnext(erg_MSDptr) = d;
+			    ch_where = ch_where-intDsize;
+			    d = (uintD)ch >> b-ch_where;  // carry
+			    erg_len++;
+			}
+		}
+		len--;
+	}
+	if (d != 0) {  // is there anything left over?
+		lsprefnext(erg_MSDptr) = d;
+		++erg_len;
+	}
+	return NUDS_to_I(erg_MSDptr,erg_len);
+}
+
+// For each base b in [2..36], power_table[b-2] contains the largest exponent e
+// such that b^e<2^intDsize, i.e. floor(log(2^intDsize-1,b)).
+static const uintC power_table [36-2+1] = {
+#if (intDsize==8)
+	/* base  2..7  */           7,  5,  3,  3,  3,  2,
+	/* base  8..15 */   2,  2,  2,  2,  2,  2,  2,  2,
+	/* base 16..23 */   1,  1,  1,  1,  1,  1,  1,  1,
+	/* base 24..31 */   1,  1,  1,  1,  1,  1,  1,  1,
+	/* base 32..36 */   1,  1,  1,  1,  1
+#endif
+#if (intDsize==16)
+	/* base  2..7  */          15, 10,  7,  6,  6,  5,
+	/* base  8..15 */   5,  5,  4,  4,  4,  4,  4,  4,
+	/* base 16..23 */   3,  3,  3,  3,  3,  3,  3,  3,
+	/* base 24..31 */   3,  3,  3,  3,  3,  3,  3,  3,
+	/* base 32..36 */   3,  3,  3,  3,  3
+#endif
+#if (intDsize==32)
+	/* base  2..7  */          31, 20, 15, 13, 12, 11,
+	/* base  8..15 */  10, 10,  9,  9,  8,  8,  8,  8,
+	/* base 16..23 */   7,  7,  7,  7,  7,  7,  7,  7,
+	/* base 24..31 */   6,  6,  6,  6,  6,  6,  6,  6,
+	/* base 32..36 */   6,  6,  6,  6,  6
+#endif
+#if (intDsize==64)
+	/* base  2..7  */          63, 40, 31, 27, 24, 22,
+	/* base  8..15 */  21, 20, 19, 18, 17, 17, 16, 16,
+	/* base 16..23 */  15, 15, 15, 15, 14, 14, 14, 14,
+	/* base 24..31 */  13, 13, 13, 13, 13, 13, 13, 12,
+	/* base 32..36 */  12, 12, 12, 12, 12
+#endif
+};
+
+static const cl_I digits_to_I_baseN (const char * MSBptr, uintL len, uintD base)
+{
+	// base is not a power of two: Add digits one by one. Result nees
+	// 1+ceiling(len*log(base)/(intDsize*log(2))) or some more digits.
+	CL_ALLOCA_STACK;
+	var uintD* erg_MSDptr;
+	var uintC erg_len;
+	var uintD* erg_LSDptr;
+	var uintL need = 1+floor(len,intDsize*256); // > len/(intDsize*256) >=0
+	switch (base) { // multiply need with ceiling(256*log(base)/log(2)):
+		case 2: need = 256*need; break;
+		case 3: need = 406*need; break;
+		case 4: need = 512*need; break;
+		case 5: need = 595*need; break;
+		case 6: need = 662*need; break;
+		case 7: need = 719*need; break;
+		case 8: need = 768*need; break;
+		case 9: need = 812*need; break;
+		case 10: need = 851*need; break;
+		case 11: need = 886*need; break;
+		case 12: need = 918*need; break;
+		case 13: need = 948*need; break;
+		case 14: need = 975*need; break;
+		case 15: need = 1001*need; break;
+		case 16: need = 1024*need; break;
+		case 17: need = 1047*need; break;
+		case 18: need = 1068*need; break;
+		case 19: need = 1088*need; break;
+		case 20: need = 1107*need; break;
+		case 21: need = 1125*need; break;
+		case 22: need = 1142*need; break;
+		case 23: need = 1159*need; break;
+		case 24: need = 1174*need; break;
+		case 25: need = 1189*need; break;
+		case 26: need = 1204*need; break;
+		case 27: need = 1218*need; break;
+		case 28: need = 1231*need; break;
+		case 29: need = 1244*need; break;
+		case 30: need = 1257*need; break;
+		case 31: need = 1269*need; break;
+		case 32: need = 1280*need; break;
+		case 33: need = 1292*need; break;
+		case 34: need = 1303*need; break;
+		case 35: need = 1314*need; break;
+		case 36: need = 1324*need; break;
+		default: NOTREACHED
+	}
+	// Now we have need >= len*log(base)/(intDsize*log(2)).
+	need += 1;
+	// Add digits one by one:
+	num_stack_alloc(need,,erg_LSDptr=);
+	// erg_MSDptr/erg_len/erg_LSDptr is a NUDS, erg_len < need.
+	erg_MSDptr = erg_LSDptr; erg_len = 0;
+	while (len > 0) {
+		var uintD newdigit = 0;
+		var uintC chx = 0;
+		var uintD factor = 1;
+		while (chx < power_table[base-2] && len > 0) {
+			var uintB ch = *(const uintB *)MSBptr; MSBptr++; // next character
+			if (ch!='.') { // skip decimal point
+				// Compute value of ('0'-'9','A'-'Z','a'-'z'):
+				ch = ch-'0';
+				if (ch > '9'-'0') { // not a digit?
+					ch = ch+'0'-'A'+10;
+					if (ch > 'Z'-'A'+10) {// not an uppercase letter?
+						ch = ch+'A'-'a';  // must be lowercase!
+					}
+				}
+				factor = factor*base;
+				newdigit = base*newdigit+ch;
+				chx++;
+			}
+			len--;
+		}
+		var uintD carry = mulusmall_loop_lsp(factor,erg_LSDptr,erg_len,newdigit);
+		if (carry!=0) {
+			// need to extend NUDS:
+			lsprefnext(erg_MSDptr) = carry;
+			erg_len++;
+		}
+	}
+	return NUDS_to_I(erg_MSDptr,erg_len);
+}
+
 const cl_I digits_to_I (const char * MSBptr, uintL len, uintD base)
 {
-      CL_ALLOCA_STACK;
-      var uintD* erg_MSDptr;
-      var uintC erg_len;
-      var uintD* erg_LSDptr;
-      if ((base & (base-1)) == 0) {
-        // Fast path for powers of two: write the digits from least
-        // significant to most significant into the result NUDS.
-        var int b = (base==2 ? 1 : base==4 ? 2 : base==8 ? 3 : base==16 ? 4 : /*base==32*/ 5);
-        num_stack_alloc(1+(len*b)/intDsize,,erg_LSDptr=);
-        erg_MSDptr = erg_LSDptr; erg_len = 0;
-        var uintD d = 0;  // resulting digit
-        var int ch_where = 0;  // position of ch inside d
-        while (len > 0)
-          { var uintB ch = *(const uintB *)(MSBptr+len-1); // next character
-            if (!(ch=='.')) // skip decimal point
-              { // Compute value of ch ('0'-'9','A'-'Z','a'-'z'):
-                ch = ch - '0';
-                if (ch > '9'-'0') // not a digit?
-                  { ch = ch+'0'-'A'+10;
-                    if (ch > 'Z'-'A'+10) // not an uppercase letter?
-                      { ch = ch+'A'-'a'; } // must be lowercase!
-                  }
-                d = d | (uintD)ch<<ch_where;
-                ch_where = ch_where+b;
-                if (ch_where >= intDsize) {
-                  // d is ready to be written into the NUDS:
-                  lsprefnext(erg_MSDptr) = d;
-                  ch_where = ch_where-intDsize;
-                  d = (uintD)ch >> b-ch_where;  // carry
-                  erg_len++;
-                }
-              }
-            len--;
-          }
-        if (d != 0) {  // is there anything left over?
-          lsprefnext(erg_MSDptr) = d;
-          ++erg_len;
-        }
-      } else {
-        // Slow path: Add digits one by one for non-powers of two.
-        // Platz fürs Ergebnis:
-        // 1+ceiling(len*log(base)/(intDsize*log(2))) or some more digits
-        var uintL need = 1+floor(len,intDsize*256); // > len/(intDsize*256) >=0
-        switch (base) // multiply need with ceiling(256*log(base)/log(2)):
-          {
-          //case 2: need = 256*need; break;
-            case 3: need = 406*need; break;
-          //case 4: need = 512*need; break;
-            case 5: need = 595*need; break;
-            case 6: need = 662*need; break;
-            case 7: need = 719*need; break;
-          //case 8: need = 768*need; break;
-            case 9: need = 812*need; break;
-            case 10: need = 851*need; break;
-            case 11: need = 886*need; break;
-            case 12: need = 918*need; break;
-            case 13: need = 948*need; break;
-            case 14: need = 975*need; break;
-            case 15: need = 1001*need; break;
-          //case 16: need = 1024*need; break;
-            case 17: need = 1047*need; break;
-            case 18: need = 1068*need; break;
-            case 19: need = 1088*need; break;
-            case 20: need = 1107*need; break;
-            case 21: need = 1125*need; break;
-            case 22: need = 1142*need; break;
-            case 23: need = 1159*need; break;
-            case 24: need = 1174*need; break;
-            case 25: need = 1189*need; break;
-            case 26: need = 1204*need; break;
-            case 27: need = 1218*need; break;
-            case 28: need = 1231*need; break;
-            case 29: need = 1244*need; break;
-            case 30: need = 1257*need; break;
-            case 31: need = 1269*need; break;
-          //case 32: need = 1280*need; break;
-            case 33: need = 1292*need; break;
-            case 34: need = 1303*need; break;
-            case 35: need = 1314*need; break;
-            case 36: need = 1324*need; break;
-            default: NOTREACHED
-          }
-        // Now we have need >= len*log(base)/(intDsize*log(2)).
-        need += 1;
-        // Add digits one by one:
-        num_stack_alloc(need,,erg_LSDptr=);
-        erg_MSDptr = erg_LSDptr; erg_len = 0;
-        while (len > 0)
-          { // erg_MSDptr/erg_len/erg_LSDptr is a NUDS, erg_len < need.
-            var uintB ch = *(const uintB *)MSBptr; MSBptr++; // next character
-            if (!(ch=='.')) // skip decimal point
-              { // Compute value of ('0'-'9','A'-'Z','a'-'z'):
-                ch = ch - '0';
-                if (ch > '9'-'0') // not a digit?
-                  { ch = ch+'0'-'A'+10;
-                    if (ch > 'Z'-'A'+10) // not an uppercase letter?
-                      { ch = ch+'A'-'a'; } // must be lowercase!
-                  }
-                // multiply erg with base and add ch:
-               {var uintD carry = mulusmall_loop_lsp(base,erg_LSDptr,erg_len,ch);
-                if (!(carry==0))
-                  // need to extend NUDS:
-                  { lsprefnext(erg_MSDptr) = carry; erg_len++; }
-              }}
-            len--;
-          }
-      }
-      return NUDS_to_I(erg_MSDptr,erg_len);
+	if ((base & (base-1)) == 0) {
+		return digits_to_I_base2(MSBptr, len, base);
+	} else {
+		// This is quite insensitive to the breakeven point.
+		// On a 1GHz Athlon I get approximately:
+		//   base  3: breakeven == 15000
+		//   base 10: breakeven ==  5000
+		//   base 36: breakeven ==  2000
+		if (len>50000/base)
+			// Divide-and-conquer:
+			return digits_to_I(MSBptr,len/2,base)*expt_pos(base,len-len/2)
+			      +digits_to_I(MSBptr+len/2,len-len/2,base);
+		else
+			return digits_to_I_baseN(MSBptr, len, base);
+	}
 }
 
 }  // namespace cln

tests/Makefile.in

@@ -56,7 +56,7 @@ MODULES_tests = tests \
                 test_I_gcd test_I_xgcd \
                 test_I_ash test_I_evenp test_I_oddp test_I_lognot test_I_logand test_I_logandc1 test_I_logandc2 test_I_logior test_I_logorc1 test_I_logorc2 test_I_logxor test_I_lognand test_I_lognor test_I_logeqv test_I_boole test_I_logbitp test_I_logtest test_I_ldb test_I_ldbtest test_I_mkf test_I_dpb test_I_dpf test_I_logcount test_I_ilength test_I_ord2 test_I_power2p \
                 test_I_isqrt test_I_sqrtp \
-                test_I_GV \
+                test_I_io test_I_GV \
                 test_MI \
                 test_MI_canonhom test_MI_plus test_MI_minus test_MI_mul test_MI_recip test_MI_div test_MI_expt \
                 test_nt \

tests/test_I.cc

@@ -43,6 +43,7 @@ extern int test_I_power2p (int iterations);
 extern int test_I_isqrt (int iterations);
 extern int test_I_sqrtp (int iterations);
 // Miscellaneous.
+extern int test_I_io (int iterations);
 extern int test_I_GV (int iterations);
 
 #define RUN(tester,iterations)  \
@@ -96,6 +97,7 @@ int test_I (int iterations)
 	RUN(test_I_isqrt,iterations);
 	RUN(test_I_sqrtp,iterations);
 	// Miscellaneous.
+	RUN(test_I_io,iterations);
 	RUN(test_I_GV,iterations);
 	return error;
 }

tests/test_I_io.cc

@@ -0,0 +1,17 @@
+#include "test_I.h"
+#include <cln/input.h>
+#include <sstream>
+
+int test_I_io (int iterations)
+{
+	int error = 0;
+	for (int i = iterations; i > 0; i--) {
+		cl_I a = testrandom_I();
+		int base = iterations % (36-1) + 2;
+		cl_read_flags rflags = {syntax_integer, lsyntax_standard, base};
+		stringstream buf;
+		print_integer(buf, base, a);
+		ASSERT1(a == read_integer(buf, rflags), a);
+	}
+	return error;
+}