Optimize the speed of ldouble algorithm

lengjingzju · lengjingzju · commit 02b98f3546e6 · 2024-02-27T12:00:56.000+08:00
diff --git a/Makefile b/Makefile
@@ -12,8 +12,8 @@ testedbin       = ljson
 testednum       = jnum_test
 
 INSTALL_HEADERS = json.h jnum.h
+FMUL           ?= 1
 DTOA           ?= 0
-RBIT           ?= 11
 TCMP           ?= 2
 
 libsrcs        := json.c jnum.c
@@ -24,8 +24,8 @@ ifeq ($(DTOA),3)
 libsrcs        += dragonbox.c
 endif
 
+CPFLAGS        += -DUSING_FLOAT_MUL=$(FMUL)
 CPFLAGS        += -DJSON_DTOA_ALGORITHM=$(DTOA) # 0:ldouble 1:sprintf 2:grisu2 3:dragonbox
-CPFLAGS        += -DLSHIFT_RESERVED_BIT=$(RBIT) # 2 <= RBIT <= 11
 CPFLAGS        += -DAPPROX_TAIL_CMP_VAL=$(TCMP) # 0 <= TCMP <= 4
 
 .PHONY: all clean install
@@ -40,7 +40,7 @@ $(eval $(call add-liba-build,$(staticlib),$(libsrcs)))
 $(eval $(call add-libso-build,$(sharedlib),$(libsrcs)))
 $(eval $(call add-bin-build,$(testedbin),json_test.c,-L $(OBJ_PREFIX) $(call set_links,ljson),,$(OBJ_PREFIX)/$(staticlib)))
 
-numsrcs        := json.c jnum.c grisu2.c dragonbox.c jnum_test.c
+numsrcs        := jnum.c grisu2.c dragonbox.c jnum_test.c
 $(eval $(call add-bin-build,$(testednum),$(numsrcs)))
 
 all: $(BIN_TARGETS) $(LIB_TARGETS)
diff --git a/README.md b/README.md
@@ -20,7 +20,7 @@ By default, LJSON uses the personally developed ldouble algorithm to print doubl
 * Compile directly
 
 ```sh
-gcc -o ljson json.c json_test.c -O2 -ffunction-sections -fdata-sections -W -Wall
+gcc -o ljson json.c -jnum.c json_test.c -O2 -ffunction-sections -fdata-sections -W -Wall
 ```
 
 * Compile with [IMAKE](https://github.com/lengjingzju/cbuild-ng)
diff --git a/README_zh-cn.md b/README_zh-cn.md
@@ -20,7 +20,7 @@ LJSON 默认使用个人开发的 ldouble 算法打印浮点数，和标准库
 * 直接编译
 
 ```sh
-gcc -o ljson json.c json_test.c -O2 -ffunction-sections -fdata-sections -W -Wall
+gcc -o ljson json.c jnum.c json_test.c -O2 -ffunction-sections -fdata-sections -W -Wall
 ```
 
 * [IMAKE](https://github.com/lengjingzju/cbuild-ng) 编译
diff --git a/dragonbox.c b/dragonbox.c
@@ -1201,7 +1201,7 @@ int dragonbox_dtoa(double num, char *buffer)
         break;
 
     case 0:
-        if (!significand) {
+        if (significand) {
             /* no-normalized double */
             v.f = significand; /* Non-normalized double doesn't have a extra integer bit for Mantissa */
             v.e = 1 - DP_EXPONENT_OFFSET - DP_SIGNIFICAND_SIZE; /* Fixed Exponent: -1022, divisor of Mantissa: pow(2,52) */
diff --git a/jnum.c b/jnum.c
diff --git a/jnum_test.c b/jnum_test.c
@@ -1,10 +1,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include <time.h>
+#include "jnum.h"
 
-extern int jnum_dtoa(double num, char *buffer);
 extern int grisu2_dtoa(double num, char *buffer);
 extern int dragonbox_dtoa(double num, char *buffer);
 
@@ -17,71 +16,107 @@ static unsigned int _system_ms_get(void)
 
 int main(int argc, char *argv[])
 {
+    char buf[64] = {0};
+
     if (argc != 2 && argc != 3) {
         printf("Usage: %s <num>\n", argv[0]);
         printf("Usage: %s <num> <cnt>\n", argv[0]);
+        printf("Usage: %s <i/l/h/L/d> <num>\n", argv[0]);
         return -1;
     }
 
-    char *tmp = NULL;
-    double d = strtod(argv[1], &tmp);
-    char buf[64] = {0};
-
-    if (argc == 2) {
-#if 1
-        printf("original  : %s\nprintf    : %0.15g\n", argv[1], d);
-        jnum_dtoa(d, buf);
-        printf("ldouble   : %s\n", buf);
-        grisu2_dtoa(d, buf);
-        printf("grisu2    : %s\n", buf);
-        dragonbox_dtoa(d, buf);
-        printf("dragonbox : %s\n", buf);
-#else
-        char buf2[64] = {0};
-
-        sprintf(buf2, "%0.15g", d);
-        jnum_dtoa(d, buf);
-        if (strcmp(buf, buf2)) {
-            printf("original  : %s\nprintf    : %0.15g\n", argv[1], d);
+    switch (*argv[1]) {
+    case 'i':
+        {
+            int32_t d = jnum_atoi(argv[2]);
+            jnum_itoa(d, buf);
+            printf("original  : %s\nprintf    : %d\njnum      : %s\n", argv[2], d, buf);
+            break;
+        }
+    case 'l':
+        {
+            int64_t d = jnum_atol(argv[2]);
+            jnum_ltoa(d, buf);
+            printf("original  : %s\nprintf    : %ld\njnum      : %s\n", argv[2], d, buf);
+            break;
+        }
+    case 'h':
+        {
+            uint32_t d = jnum_atoh(argv[2]);
+            jnum_htoa(d, buf);
+            printf("original  : %s\nprintf    : 0x%x\njnum      : %s\n", argv[2], d, buf);
+            break;
+        }
+    case 'L':
+        {
+            uint64_t d = jnum_atolh(argv[2]);
+            jnum_lhtoa(d, buf);
+            printf("original  : %s\nprintf    : 0x%lx\njnum      : %s\n", argv[2], d, buf);
+            break;
+        }
+    case 'd':
+        {
+            double d = jnum_atod(argv[2]);
+            printf("original  : %s\nprintf    : %0.15g\n", argv[2], d);
+            jnum_dtoa(d, buf);
             printf("ldouble   : %s\n", buf);
+            grisu2_dtoa(d, buf);
+            printf("grisu2    : %s\n", buf);
+            dragonbox_dtoa(d, buf);
+            printf("dragonbox : %s\n", buf);
+            break;
         }
-#endif
-    } else {
-        int i;
-        int cnt = atoi(argv[2]);
-        unsigned int ms, ms1, ms2, ms3;
 
-        ms1 = _system_ms_get();
-        for (i = 0; i < cnt; ++i) {
-            sprintf(buf, "%0.15g", d);
-        }
-        ms2 = _system_ms_get();
-        ms = ms2 - ms1;
-        printf("original  : %s\nprintf    : %0.15g\t%ums\n", argv[1], d, ms);
+    default:
+        if (argc == 2) {
+            double d = jnum_atod(argv[1]);
+            char tmp[64] = {0};
 
-        ms1 = _system_ms_get();
-        for (i = 0; i < cnt; ++i) {
+            sprintf(tmp, "%0.15g", d);
             jnum_dtoa(d, buf);
-        }
-        ms2 = _system_ms_get();
-        ms3 = ms2 - ms1;
-        printf("ldouble   : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
+            if (strcmp(buf, tmp)) {
+                printf("original  : %s\nprintf    : %s\n", argv[1], tmp);
+                printf("ldouble   : %s\n", buf);
+            }
+        } else {
+            int i;
+            double d = jnum_atod(argv[1]);
+            int cnt = atoi(argv[2]);
+            unsigned int ms, ms1, ms2, ms3;
 
-        ms1 = _system_ms_get();
-        for (i = 0; i < cnt; ++i) {
-            grisu2_dtoa(d, buf);
-        }
-        ms2 = _system_ms_get();
-        ms3 = ms2 - ms1;
-        printf("grisu2    : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
+            ms1 = _system_ms_get();
+            for (i = 0; i < cnt; ++i) {
+                sprintf(buf, "%0.15g", d);
+            }
+            ms2 = _system_ms_get();
+            ms = ms2 - ms1;
+            printf("original  : %s\nprintf    : %0.15g\t%ums\n", argv[1], d, ms);
 
-        ms1 = _system_ms_get();
-        for (i = 0; i < cnt; ++i) {
-            dragonbox_dtoa(d, buf);
+            ms1 = _system_ms_get();
+            for (i = 0; i < cnt; ++i) {
+                jnum_dtoa(d, buf);
+            }
+            ms2 = _system_ms_get();
+            ms3 = ms2 - ms1;
+            printf("ldouble   : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
+
+            ms1 = _system_ms_get();
+            for (i = 0; i < cnt; ++i) {
+                grisu2_dtoa(d, buf);
+            }
+            ms2 = _system_ms_get();
+            ms3 = ms2 - ms1;
+            printf("grisu2    : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
+
+            ms1 = _system_ms_get();
+            for (i = 0; i < cnt; ++i) {
+                dragonbox_dtoa(d, buf);
+            }
+            ms2 = _system_ms_get();
+            ms3 = ms2 - ms1;
+            printf("dragonbox : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
         }
-        ms2 = _system_ms_get();
-        ms3 = ms2 - ms1;
-        printf("dragonbox : %s\t%ums\t%.0lf%%\n", buf, ms3, ms3 ? 100.0 * ms / ms3 : 0);
+        break;
     }
 
     return 0;
diff --git a/json.c b/json.c
@@ -2060,10 +2060,10 @@ static json_type_t _parse_hex(const char **sstr, json_number_t *value)
             c -= '0';
             break;
         case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
-            c -= 'a';
+            c -= 'a' - 10;
             break;
         case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
-            c -= 'A';
+            c -= 'A' - 10;
             break;
         default:
             goto end;
@@ -2107,26 +2107,22 @@ static json_type_t _parse_num(const char **sstr, json_number_t *value)
     while (*s == '0')
         ++s;
 
-    while (1) {
-        switch (*s) {
-        case '0': case '1': case '2': case '3': case '4':
-        case '5': case '6': case '7': case '8': case '9':
-            break;
-        case 'e': case 'E':
-            goto end;
-        case '.':
-            goto next2;
-        default:
-            goto next1;
-        }
+    while (*s >= '0' && *s <= '9') {
         m = (m << 3) + (m << 1) + (*s++ - '0');
         ++k;
     }
-
-next1:
     if (unlikely(k >= 20))
         goto end;
 
+    switch (*s) {
+    case 'e': case 'E':
+        goto end;
+    case '.':
+        goto next;
+    default:
+        break;
+    }
+
     if (m <= 2147483647U /*INT_MAX*/) {
         type = JSON_INT;
         value->vint = sign == 1 ? (int32_t)m : -((int32_t)m);
@@ -2138,34 +2134,30 @@ static json_type_t _parse_num(const char **sstr, json_number_t *value)
             type = JSON_LINT;
             value->vlint = -m;
         } else {
-            goto end;
+            type = JSON_DOUBLE;
+            value->vdbl = sign == 1 ? (double)m : -((double)m);
         }
     }
     *sstr = s;
     return type;
 
-next2:
-    if (unlikely(k >= 20))
-        goto end;
-
+next:
     ++s;
     k = 0;
-    while (1) {
-        switch (*s) {
-        case '0': case '1': case '2': case '3': case '4':
-        case '5': case '6': case '7': case '8': case '9':
-            break;
-        default:
-            goto next3;
-        }
+    while (*s >= '0' && *s <= '9') {
         n = (n << 3) + (n << 1) + (*s++ - '0');
         ++k;
     }
-
-next3:
     if (unlikely(k >= 20))
         goto end;
 
+    switch (*s) {
+    case 'e': case 'E':
+        goto end;
+    default:
+        break;
+    }
+
     d = m + n * div10_lut[k];
     type = JSON_DOUBLE;
     value->vdbl = sign == 1 ? d : -d;
