extend duk_lc_nybbles to cover all base-36 digits and rename to duk_lc_digits

12 years ago · 407f09d711
5 changed files with 412 additions and 8 deletions
--- a/src/duk_api_codec.c
+++ b/src/duk_api_codec.c
@ -258,8 +258,8 @@ void duk_hex_encode(duk_context *ctx, int index) {

 	for (i = 0; i < len; i++) {
 		t = data[i];
-		buf[i*2 + 0] = duk_lc_nybbles[t >> 4];
-		buf[i*2 + 1] = duk_lc_nybbles[t & 0x0f];
+		buf[i*2 + 0] = duk_lc_digits[t >> 4];
+		buf[i*2 + 1] = duk_lc_digits[t & 0x0f];
 	}

 	duk_to_string(ctx, -1);
--- a/src/duk_builtin_json.c
+++ b/src/duk_builtin_json.c
@ -627,7 +627,7 @@ static void json_emit_esc(duk_json_enc_ctx *js_ctx, duk_u32 cp, char *esc_str, i
 	while (digits > 0) {
 		digits--;
 		dig = (cp >> (4 * digits)) & 0x0f;
-		duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_nybbles[dig]);
+		duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_digits[dig]);
 	}
 }

@ -1254,8 +1254,8 @@ static void json_enc_value2(duk_json_enc_ctx *js_ctx) {
 			EMIT_1(js_ctx, '|');
 			while (p < p_end) {
 				x = (int) *p++;
-				duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_nybbles[(x >> 4) & 0x0f]);
-				duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_nybbles[x & 0x0f]);
+				duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_digits[(x >> 4) & 0x0f]);
+				duk_hbuffer_append_byte(js_ctx->thr, js_ctx->h_buf, duk_lc_digits[x & 0x0f]);
 			}
 			EMIT_1(js_ctx, '|');
 		} else {
--- a/src/duk_util.h
+++ b/src/duk_util.h
@ -40,7 +40,7 @@ struct duk_bitencoder_ctx {
 *  Externs and prototypes
 */

-extern char duk_lc_nybbles[16];
+extern char duk_lc_digits[36];
 extern char duk_uc_nybbles[16];

 /* Note: assumes that duk_util_probe_steps size is 32 */
--- a/src/duk_util_misc.c
+++ b/src/duk_util_misc.c
@ -4,8 +4,14 @@

 #include "duk_internal.h"

-char duk_lc_nybbles[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
-                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+/* Lowercase digits for radix values 2 to 36.  Also doubles as lowercase
+ * hex nybble table.
+ */
+char duk_lc_digits[36] = { '0', '1', '2', '3', '4', '5', '6', '7',
+                           '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
+                           'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+                           'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+                           'w', 'x', 'y', 'z' };

 char duk_uc_nybbles[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
                            '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
--- a/testcases/test-numconv-tostring-fastpath.js
+++ b/testcases/test-numconv-tostring-fastpath.js
@ -0,0 +1,398 @@
+/*
+ *  Test the 32-bit fast path which applies to integers in the
+ *  range [-2**32-1,2**32-1], in any radix.
+ *
+ *  The test is not exhaustive but has a pretty large (prime)
+ *  skip; both endpoint values are always included though.
+ */
+
+/* FIXME: util */
+/* Trivial string checksum used to summarize brute force output lines
+ * (minimizes test case size).
+ */
+function checkSumString(x) {
+    var i, n;
+    var res = 0;
+    var mult = [ 1, 3, 5, 7, 11, 13, 17, 19, 23 ];
+
+    n = x.length;
+    for (i = 0; i < n; i++) {
+        res += x.charCodeAt(i) * mult[i % mult.length];
+        res = res >>> 0;  // coerce to 32 bits
+    }
+
+    return res;
+}
+
+/*---
+{
+    "custom": true
+}
+---*/
+
+/*===
+radix 2
+179306267
+178417689
+172469437
+158113487
+164522390
+171053804
+173839346
+73212146
+radix 3
+120001562
+116340620
+114838710
+104289556
+107366288
+110915012
+112538566
+49058085
+radix 4
+93996707
+93956672
+93119252
+85264205
+87138494
+90633905
+90749467
+38267839
+radix 5
+85524532
+85420528
+83386734
+75416390
+76399706
+79977948
+80054256
+33672687
+radix 6
+80375401
+79136945
+75214944
+69706448
+69994308
+72423839
+75586644
+31904527
+radix 7
+75660318
+75401474
+70356910
+65459640
+64698752
+68090646
+70718420
+29706955
+radix 8
+70760327
+70625152
+69485827
+61898015
+62283468
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+27580869
+radix 9
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+27476559
+radix 10
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+radix 11
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+radix 12
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+radix 13
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+radix 14
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+radix 15
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+radix 16
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+radix 17
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+radix 18
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+radix 19
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+27150427
+radix 20
+73544332
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+65650006
+27355150
+radix 21
+73704427
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+72906696
+67058764
+27766841
+radix 22
+75433924
+74338906
+67871773
+64092473
+63565508
+66619708
+67094279
+28763924
+radix 23
+73850335
+69301782
+68368528
+64488785
+63024653
+68066056
+66847488
+28551783
+radix 24
+70204641
+70017694
+68737246
+64845718
+63541335
+66918926
+69254539
+29132129
+radix 25
+70855845
+70301783
+69537281
+64991486
+64441155
+65518746
+69378566
+29362760
+radix 26
+71640896
+70461614
+70154774
+65236955
+64792347
+65106858
+68281845
+29798072
+radix 27
+71552515
+71030799
+70959577
+65368358
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+29468067
+radix 28
+71962251
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+radix 29
+72491759
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+72335730
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+28487426
+radix 30
+73411662
+72922686
+72917156
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+67666075
+28850587
+radix 31
+73970452
+73659060
+73152390
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+67311642
+29290105
+radix 32
+74485135
+74394511
+73420892
+64549058
+65141537
+68639239
+68711056
+29925749
+radix 33
+74926889
+74885711
+72847827
+64654882
+65104908
+69566120
+69322629
+27930453
+radix 34
+75281549
+76214857
+72254342
+64501263
+65445833
+68521664
+69218983
+30036608
+radix 35
+75808277
+75869094
+72102173
+64555847
+65319460
+67574813
+71497041
+28178381
+radix 36
+77635113
+75194087
+72176214
+64588163
+65418360
+67316650
+71241876
+30814244
+===*/
+
+function fastPathTest() {
+    var start = -256*256*256*256 + 1;
+    var end = 256*256*256*256 - 1;
+    var step = 115757;  // prime
+    var i;
+    var radix;
+    var tmp = [];
+
+    function flush() {
+        if (tmp.length > 0) {
+            // Note: here we're printing a checksum which is a small integer,
+            // so the checksum will go through the same fast path.
+            print(checkSumString(tmp.join(' ')));
+            tmp.length = 0;
+        }
+    }
+
+    function f(x) {
+        tmp.push(x);
+        if (tmp.length >= 10000) {
+            flush();
+        }
+    }
+
+    for (radix = 2; radix <= 36; radix++) {
+        print('radix', radix);
+        i = start;
+        for (;;) {
+            f(new Number(i).toString(radix));
+
+            if (i >= end) {
+                break;
+            }
+            i += step;
+            if (i >= end) {
+                i = end;  // always include end
+            }
+        }
+        flush();
+    }
+}
+
+try {
+    fastPathTest();
+} catch (e) {
+    print(e);
+}
+