Add more real formatting tests

See #61

libc/fmt/fmt.c

@@ -23,12 +23,23 @@
 #include "libc/fmt/fmt.h"
 #include "libc/fmt/fmts.h"
 #include "libc/fmt/internal.h"
+#include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
+#include "libc/nexgen32e/bsr.h"
 #include "libc/runtime/internal.h"
 #include "libc/str/str.h"
 #include "libc/sysv/errfuns.h"
 #include "third_party/gdtoa/gdtoa.h"
 
+#define PUT(C)               \
+  do {                       \
+    if (out(C, arg) == -1) { \
+      return -1;             \
+    }                        \
+  } while (0)
+
+static const char kSpecialFloats[2][2][4] = {{"INF", "inf"}, {"NAN", "nan"}};
+
 static int __fmt_atoi(const char **str) {
   int i;
   for (i = 0; '0' <= **str && **str <= '9'; ++*str) {
@@ -107,11 +118,10 @@ static int __fmt_atoi(const char **str) {
 hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
   union {
     double d;
-    unsigned int u[2];
+    uint32_t u[2];
+    uint64_t q;
   } pun;
   void *p;
-  char qchar;
-  char *s, *se;
   bool longdouble;
   long double ldbl;
   wchar_t charbuf[1];
@@ -119,6 +129,7 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
   int (*out)(long, void *);
   unsigned char signbit, log2base;
   int c, d, k, w, i1, ui, bw, bex;
+  char *s, *q, *se, qchar, special[8];
   int sgn, alt, sign, prec, prec1, flags, width, decpt, lasterr;
 
   lasterr = errno;
@@ -128,7 +139,7 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
     /* %[flags][width][.prec][length] */
     if (*format != '%') {
       /* no */
-      if (out(*format, arg) == -1) return -1;
+      PUT(*format);
       format++;
       continue;
     } else {
@@ -308,6 +319,7 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
         break;
 
+      case 'F':
       case 'f':
         if (!(flags & FLAGS_PRECISION)) prec = 6;
         if (longdouble) {
@@ -317,19 +329,25 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
       FormatDtoa:
         if (!weaken(__fmt_dtoa)) {
-          p = "nan";
+          p = "?";
-          goto FormatString;
+          goto FormatThatThing;
         }
         s = weaken(__fmt_dtoa)(pun.d, 3, prec, &decpt, &sgn, &se);
         if (decpt == 9999) {
         Format9999:
-          prec = alt = 0;
+          p = q = memset(special, 0, sizeof(special));
-          flags &= ~FLAGS_PRECISION;
+          if (sgn) {
-          if (*s == 'N') {
+            *q++ = '-';
-            p = s;
+          } else if (flags & FLAGS_PLUS) {
-            goto FormatString;
+            *q++ = '+';
+          } else if (flags & FLAGS_SPACE) {
+            *q++ = ' ';
           }
-          decpt = strlen(s);
+          memcpy(q, kSpecialFloats[*s == 'N'][d >= 'a'], 4);
+        FormatThatThing:
+          prec = alt = 0;
+          flags &= ~(FLAGS_PRECISION | FLAGS_PLUS | FLAGS_SPACE);
+          goto FormatString;
         }
       FormatReal:
         if (sgn) sign = '-';
@@ -347,20 +365,21 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
         if (width > 0 && !(flags & FLAGS_LEFT)) {
           if (flags & FLAGS_ZEROPAD) {
-            if (sign) out(sign, arg);
+            if (sign) PUT(sign);
             sign = 0;
-            do out('0', arg);
+            do PUT('0');
             while (--width > 0);
-          } else
+          } else {
-            do out(' ', arg);
+            do PUT(' ');
             while (--width > 0);
+          }
         }
-        if (sign) out(sign, arg);
+        if (sign) PUT(sign);
         if (decpt <= 0) {
-          out('0', arg);
+          PUT('0');
-          if (prec > 0 || alt) out('.', arg);
+          if (prec > 0 || alt) PUT('.');
           while (decpt < 0) {
-            out('0', arg);
+            PUT('0');
             prec--;
             decpt++;
           }
@@ -371,9 +390,9 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
             } else {
               c = '0';
             }
-            out(c, arg);
+            PUT(c);
           } while (--decpt > 0);
-          if (prec > 0 || alt) out('.', arg);
+          if (prec > 0 || alt) PUT('.');
         }
         while (--prec >= 0) {
           if ((c = *s)) {
@@ -381,10 +400,10 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
           } else {
             c = '0';
           }
-          out(c, arg);
+          PUT(c);
         }
         while (--width >= 0) {
-          out(' ', arg);
+          PUT(' ');
         }
         continue;
 
@@ -398,8 +417,8 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
         if (prec < 0) prec = 0;
         if (!weaken(__fmt_dtoa)) {
-          p = "nan";
+          p = "?";
-          goto FormatString;
+          goto FormatThatThing;
         }
         s = weaken(__fmt_dtoa)(pun.d, prec ? 2 : 0, prec, &decpt, &sgn, &se);
         if (decpt == 9999) goto Format9999;
@@ -408,7 +427,6 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         if (!prec) {
           prec = c;
           prec1 = c + (s[1] || alt ? 5 : 4);
-          /* %.0g gives 10 rather than 1e1 */
         }
         if (decpt > -4 && decpt <= prec1) {
           if (alt) {
@@ -434,8 +452,8 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
         if (prec < 0) prec = 0;
         if (!weaken(__fmt_dtoa)) {
-          p = "nan";
+          p = "?";
-          goto FormatString;
+          goto FormatThatThing;
         }
         s = weaken(__fmt_dtoa)(pun.d, 2, prec + 1, &decpt, &sgn, &se);
         if (decpt == 9999) goto Format9999;
@@ -452,44 +470,44 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         }
         if (width > 0 && !(flags & FLAGS_LEFT)) {
           if (flags & FLAGS_ZEROPAD) {
-            if (sign) out(sign, arg);
+            if (sign) PUT(sign);
             sign = 0;
-            do out('0', arg);
+            do PUT('0');
             while (--width > 0);
           } else {
-            do out(' ', arg);
+            do PUT(' ');
             while (--width > 0);
           }
         }
-        if (sign) out(sign, arg);
+        if (sign) PUT(sign);
-        out(*s++, arg);
+        PUT(*s++);
-        if (prec || alt) out('.', arg);
+        if (prec || alt) PUT('.');
         while (--prec >= 0) {
           if ((c = *s)) {
             s++;
           } else {
             c = '0';
           }
-          out(c, arg);
+          PUT(c);
         }
-        out(d, arg);
+        PUT(d);
         if (decpt < 0) {
-          out('-', arg);
+          PUT('-');
           decpt = -decpt;
         } else {
-          out('+', arg);
+          PUT('+');
         }
         for (c = 2, k = 10; 10 * k <= decpt; c++, k *= 10) {
         }
         for (;;) {
           i1 = decpt / k;
-          out(i1 + '0', arg);
+          PUT(i1 + '0');
           if (--c <= 0) break;
           decpt -= i1 * k;
           decpt *= 10;
         }
         while (--width >= 0) {
-          out(' ', arg);
+          PUT(' ');
         }
         continue;
 
@@ -507,12 +525,12 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         if ((pun.u[1] & 0x7ff00000) == 0x7ff00000) {
           goto FormatDtoa;
         }
+        if (pun.u[1] & 0x80000000) {
+          sign = '-';
+          pun.u[1] &= 0x7fffffff;
+        }
         if (pun.d) {
           c = '1';
-          if (pun.u[1] & 0x80000000) {
-            sign = '-';
-            pun.u[1] &= 0x7fffffff;
-          }
           bex = (pun.u[1] >> 20) - 1023;
           pun.u[1] &= 0xfffff;
           if (bex == -1023) {
@@ -595,49 +613,52 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
           if (sign) --width;
           if (prec || alt) --width;
         }
+        if (pun.q && prec > 0) {
+          width -= ROUNDUP(bsrl(pun.q) + 1, 4) >> 2;
+        }
         if (width > 0 && !(flags & FLAGS_LEFT)) {
           if (flags & FLAGS_ZEROPAD) {
             if (sign) {
-              out(sign, arg);
+              PUT(sign);
               sign = 0;
             }
-            do out('0', arg);
+            do PUT('0');
             while (--width > 0);
           } else {
-            do out(' ', arg);
+            do PUT(' ');
             while (--width > 0);
           }
         }
-        if (sign) out(sign, arg);
+        if (sign) PUT(sign);
-        out('0', arg);
+        PUT('0');
-        out(alphabet[17], arg);
+        PUT(alphabet[17]);
-        out(c, arg);
+        PUT(c);
-        if (prec > 0 || alt) out('.', arg);
+        if (prec > 0 || alt) PUT('.');
         if (prec > 0) {
           if ((i1 = prec) > 5) i1 = 5;
           prec -= i1;
           do {
-            out(alphabet[(pun.u[1] >> 16) & 0xf], arg);
+            PUT(alphabet[(pun.u[1] >> 16) & 0xf]);
             pun.u[1] <<= 4;
           } while (--i1 > 0);
           while (prec > 0) {
             --prec;
-            out(alphabet[(pun.u[0] >> 28) & 0xf], arg);
+            PUT(alphabet[(pun.u[0] >> 28) & 0xf]);
             pun.u[0] <<= 4;
           }
         }
-        out(alphabet[16], arg);
+        PUT(alphabet[16]);
         if (bex < 0) {
-          out('-', arg);
+          PUT('-');
           bex = -bex;
         } else {
-          out('+', arg);
+          PUT('+');
         }
         for (c = 1; 10 * c <= bex; c *= 10) {
         }
         for (;;) {
           i1 = bex / c;
-          out('0' + i1, arg);
+          PUT('0' + i1);
           if (!--bw) break;
           bex -= i1 * c;
           bex *= 10;
@@ -645,11 +666,11 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
         continue;
 
       case '%':
-        if (out('%', arg) == -1) return -1;
+        PUT('%');
         break;
 
       default:
-        if (out(format[-1], arg) == -1) return -1;
+        PUT(format[-1]);
         break;
     }
   }

libc/stdio/stdio.h

@@ -8,9 +8,6 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-int Printf(const char *, ...);
-int Sprintf(char *, const char *, ...);
-
 /*───────────────────────────────────────────────────────────────────────────│─╗
 │ cosmopolitan § standard i/o                                              ─╬─│┼
 ╚────────────────────────────────────────────────────────────────────────────│*/

test/libc/fmt/fmt_test.c

@@ -0,0 +1,199 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/fmt.h"
+#include "libc/math.h"
+#include "libc/runtime/gc.h"
+#include "libc/str/str.h"
+#include "libc/testlib/testlib.h"
+#include "libc/x/x.h"
+
+TEST(RealFormatting, g) {
+  EXPECT_STREQ("1", gc(xasprintf("%g", 1.)));
+  EXPECT_STREQ("-1", gc(xasprintf("%g", -1.)));
+  EXPECT_STREQ("10", gc(xasprintf("%g", 10.)));
+  EXPECT_STREQ("10", gc(xasprintf("%.0g", 10.)));
+  EXPECT_STREQ("-10", gc(xasprintf("%g", -10.)));
+  EXPECT_STREQ("-10", gc(xasprintf("%.0g", -10.)));
+  EXPECT_STREQ("1e+100", gc(xasprintf("%g", 1e100)));
+  EXPECT_STREQ("1e-100", gc(xasprintf("%g", 1e-100)));
+  EXPECT_STREQ("-1e-100", gc(xasprintf("%g", -1e-100)));
+  EXPECT_STREQ("3.14159", gc(xasprintf("%g", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("0", gc(xasprintf("%g", 0.)));
+  EXPECT_STREQ("-0", gc(xasprintf("%g", -0.)));
+  EXPECT_STREQ("nan", gc(xasprintf("%g", NAN)));
+  EXPECT_STREQ("-nan", gc(xasprintf("%g", -NAN)));
+  EXPECT_STREQ("inf", gc(xasprintf("%g", INFINITY)));
+  EXPECT_STREQ("-inf", gc(xasprintf("%g", -INFINITY)));
+  EXPECT_STREQ("2.22507e-308", gc(xasprintf("%g", __DBL_MIN__)));
+  EXPECT_STREQ("1.79769e+308", gc(xasprintf("%g", __DBL_MAX__)));
+  EXPECT_STREQ("0", gc(xasprintf("%G", 0.)));
+  EXPECT_STREQ("-0", gc(xasprintf("%G", -0.)));
+  EXPECT_STREQ("NAN", gc(xasprintf("%G", NAN)));
+  EXPECT_STREQ("-NAN", gc(xasprintf("%G", -NAN)));
+  EXPECT_STREQ("INF", gc(xasprintf("%G", INFINITY)));
+  EXPECT_STREQ("-INF", gc(xasprintf("%G", -INFINITY)));
+  EXPECT_STREQ("2.22507E-308", gc(xasprintf("%G", __DBL_MIN__)));
+  EXPECT_STREQ("1.79769E+308", gc(xasprintf("%G", __DBL_MAX__)));
+  EXPECT_STREQ("            0", gc(xasprintf("%13g", 0.)));
+  EXPECT_STREQ("           -0", gc(xasprintf("%13g", -0.)));
+  EXPECT_STREQ("          nan", gc(xasprintf("%13g", NAN)));
+  EXPECT_STREQ("         -nan", gc(xasprintf("%13g", -NAN)));
+  EXPECT_STREQ("          inf", gc(xasprintf("%13g", INFINITY)));
+  EXPECT_STREQ("         -inf", gc(xasprintf("%13g", -INFINITY)));
+  EXPECT_STREQ(" 2.22507e-308", gc(xasprintf("%13g", __DBL_MIN__)));
+  EXPECT_STREQ(" 1.79769e+308", gc(xasprintf("%13g", __DBL_MAX__)));
+  EXPECT_STREQ("            0", gc(xasprintf("%13G", 0.)));
+  EXPECT_STREQ("           -0", gc(xasprintf("%13G", -0.)));
+  EXPECT_STREQ("          NAN", gc(xasprintf("%13G", NAN)));
+  EXPECT_STREQ("         -NAN", gc(xasprintf("%13G", -NAN)));
+  EXPECT_STREQ("          INF", gc(xasprintf("%13G", INFINITY)));
+  EXPECT_STREQ("         -INF", gc(xasprintf("%13G", -INFINITY)));
+  EXPECT_STREQ(" 2.22507E-308", gc(xasprintf("%13G", __DBL_MIN__)));
+  EXPECT_STREQ(" 1.79769E+308", gc(xasprintf("%13G", __DBL_MAX__)));
+}
+
+TEST(RealFormatting, f) {
+  EXPECT_STREQ("3.141593", gc(xasprintf("%f", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("3.1415926535897931",
+               gc(xasprintf("%.16f", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("100000000000000001590289110975991804683608085639452813"
+               "89781327557747838772170381060813469985856815104.000000",
+               gc(xasprintf("%f", 1e100)));
+  EXPECT_STREQ("0.000000", gc(xasprintf("%f", 0.)));
+  EXPECT_STREQ("-0.000000", gc(xasprintf("%f", -0.)));
+  EXPECT_STREQ("nan", gc(xasprintf("%f", NAN)));
+  EXPECT_STREQ("-nan", gc(xasprintf("%f", -NAN)));
+  EXPECT_STREQ("inf", gc(xasprintf("%f", INFINITY)));
+  EXPECT_STREQ("-inf", gc(xasprintf("%f", -INFINITY)));
+  EXPECT_STREQ("0.000000", gc(xasprintf("%f", __DBL_MIN__)));
+  EXPECT_STREQ(
+      "179769313486231570814527423731704356798070567525844996598917476803157260"
+      "780028538760589558632766878171540458953514382464234321326889464182768467"
+      "546703537516986049910576551282076245490090389328944075868508455133942304"
+      "583236903222948165808559332123348274797826204144723168738177180919299881"
+      "250404026184124858368.000000",
+      gc(xasprintf("%f", __DBL_MAX__)));
+  EXPECT_STREQ("0.000000", gc(xasprintf("%F", 0.)));
+  EXPECT_STREQ("-0.000000", gc(xasprintf("%F", -0.)));
+  EXPECT_STREQ("NAN", gc(xasprintf("%F", NAN)));
+  EXPECT_STREQ("-NAN", gc(xasprintf("%F", -NAN)));
+  EXPECT_STREQ("INF", gc(xasprintf("%F", INFINITY)));
+  EXPECT_STREQ("-INF", gc(xasprintf("%F", -INFINITY)));
+  EXPECT_STREQ("0.000000", gc(xasprintf("%F", __DBL_MIN__)));
+  EXPECT_STREQ(
+      "179769313486231570814527423731704356798070567525844996598917476803157260"
+      "780028538760589558632766878171540458953514382464234321326889464182768467"
+      "546703537516986049910576551282076245490090389328944075868508455133942304"
+      "583236903222948165808559332123348274797826204144723168738177180919299881"
+      "250404026184124858368.000000",
+      gc(xasprintf("%F", __DBL_MAX__)));
+  EXPECT_STREQ("  0.000000", gc(xasprintf("%10f", 0.)));
+  EXPECT_STREQ(" -0.000000", gc(xasprintf("%10f", -0.)));
+  EXPECT_STREQ("       nan", gc(xasprintf("%10f", NAN)));
+  EXPECT_STREQ("      -nan", gc(xasprintf("%10f", -NAN)));
+  EXPECT_STREQ("       inf", gc(xasprintf("%10f", INFINITY)));
+  EXPECT_STREQ("      -inf", gc(xasprintf("%10f", -INFINITY)));
+  EXPECT_STREQ("  0.000000", gc(xasprintf("%10f", __DBL_MIN__)));
+  EXPECT_STREQ(
+      "179769313486231570814527423731704356798070567525844996598917476803157260"
+      "780028538760589558632766878171540458953514382464234321326889464182768467"
+      "546703537516986049910576551282076245490090389328944075868508455133942304"
+      "583236903222948165808559332123348274797826204144723168738177180919299881"
+      "250404026184124858368.000000",
+      gc(xasprintf("%10f", __DBL_MAX__)));
+  EXPECT_STREQ("  0.000000", gc(xasprintf("%10F", 0.)));
+  EXPECT_STREQ(" -0.000000", gc(xasprintf("%10F", -0.)));
+  EXPECT_STREQ("       NAN", gc(xasprintf("%10F", NAN)));
+  EXPECT_STREQ("      -NAN", gc(xasprintf("%10F", -NAN)));
+  EXPECT_STREQ("       INF", gc(xasprintf("%10F", INFINITY)));
+  EXPECT_STREQ("      -INF", gc(xasprintf("%10F", -INFINITY)));
+  EXPECT_STREQ("  0.000000", gc(xasprintf("%10F", __DBL_MIN__)));
+  EXPECT_STREQ(
+      "179769313486231570814527423731704356798070567525844996598917476803157260"
+      "780028538760589558632766878171540458953514382464234321326889464182768467"
+      "546703537516986049910576551282076245490090389328944075868508455133942304"
+      "583236903222948165808559332123348274797826204144723168738177180919299881"
+      "250404026184124858368.000000",
+      gc(xasprintf("%10F", __DBL_MAX__)));
+}
+
+TEST(RealFormatting, e) {
+  EXPECT_STREQ("3.14159", gc(xasprintf("%g", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("3.141592653589793",
+               gc(xasprintf("%.16g", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("1.000000e+100", gc(xasprintf("%e", 1e100)));
+  EXPECT_STREQ("1.000000E+100", gc(xasprintf("%E", 1e100)));
+  EXPECT_STREQ("            0.000000e+00", gc(xasprintf("%24e", 0.)));
+  EXPECT_STREQ("           -0.000000e+00", gc(xasprintf("%24e", -0.)));
+  EXPECT_STREQ("                     nan", gc(xasprintf("%24e", NAN)));
+  EXPECT_STREQ("                    -nan", gc(xasprintf("%24e", -NAN)));
+  EXPECT_STREQ("                     inf", gc(xasprintf("%24e", INFINITY)));
+  EXPECT_STREQ("                    -inf", gc(xasprintf("%24e", -INFINITY)));
+  EXPECT_STREQ("           2.225074e-308", gc(xasprintf("%24e", __DBL_MIN__)));
+  EXPECT_STREQ("           1.797693e+308", gc(xasprintf("%24e", __DBL_MAX__)));
+  EXPECT_STREQ("            0.000000E+00", gc(xasprintf("%24E", 0.)));
+  EXPECT_STREQ("           -0.000000E+00", gc(xasprintf("%24E", -0.)));
+  EXPECT_STREQ("                     NAN", gc(xasprintf("%24E", NAN)));
+  EXPECT_STREQ("                    -NAN", gc(xasprintf("%24E", -NAN)));
+  EXPECT_STREQ("                     INF", gc(xasprintf("%24E", INFINITY)));
+  EXPECT_STREQ("                    -INF", gc(xasprintf("%24E", -INFINITY)));
+  EXPECT_STREQ("           2.225074E-308", gc(xasprintf("%24E", __DBL_MIN__)));
+  EXPECT_STREQ("           1.797693E+308", gc(xasprintf("%24E", __DBL_MAX__)));
+  EXPECT_STREQ("           +0.000000e+00", gc(xasprintf("%+24e", 0.)));
+  EXPECT_STREQ("           -0.000000e+00", gc(xasprintf("%+24e", -0.)));
+  EXPECT_STREQ("                    +nan", gc(xasprintf("%+24e", NAN)));
+  EXPECT_STREQ("                    -nan", gc(xasprintf("%+24e", -NAN)));
+  EXPECT_STREQ("                    +inf", gc(xasprintf("%+24e", INFINITY)));
+  EXPECT_STREQ("                    -inf", gc(xasprintf("%+24e", -INFINITY)));
+  EXPECT_STREQ("          +2.225074e-308", gc(xasprintf("%+24e", __DBL_MIN__)));
+  EXPECT_STREQ("          +1.797693e+308", gc(xasprintf("%+24e", __DBL_MAX__)));
+  EXPECT_STREQ("           +0.000000E+00", gc(xasprintf("%+24E", 0.)));
+  EXPECT_STREQ("           -0.000000E+00", gc(xasprintf("%+24E", -0.)));
+  EXPECT_STREQ("                    +NAN", gc(xasprintf("%+24E", NAN)));
+  EXPECT_STREQ("                    -NAN", gc(xasprintf("%+24E", -NAN)));
+  EXPECT_STREQ("                    +INF", gc(xasprintf("%+24E", INFINITY)));
+  EXPECT_STREQ("                    -INF", gc(xasprintf("%+24E", -INFINITY)));
+  EXPECT_STREQ("          +2.225074E-308", gc(xasprintf("%+24E", __DBL_MIN__)));
+  EXPECT_STREQ("          +1.797693E+308", gc(xasprintf("%+24E", __DBL_MAX__)));
+}
+
+TEST(RealFormatting, a) {
+  EXPECT_STREQ("0x1.921fb54442d18p+1",
+               gc(xasprintf("%a", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("0X1.921FB54442D18P+1",
+               gc(xasprintf("%A", 0x1.921fb54442d1846ap+1)));
+  EXPECT_STREQ("                  0x0p+0", gc(xasprintf("%24a", 0.)));
+  EXPECT_STREQ("                 -0x0p+0", gc(xasprintf("%24a", -0.)));
+  EXPECT_STREQ("                     nan", gc(xasprintf("%24a", NAN)));
+  EXPECT_STREQ("                    -nan", gc(xasprintf("%24a", -NAN)));
+  EXPECT_STREQ("                     inf", gc(xasprintf("%24a", INFINITY)));
+  EXPECT_STREQ("                    -inf", gc(xasprintf("%24a", -INFINITY)));
+  EXPECT_STREQ("               0x1p-1022", gc(xasprintf("%24a", __DBL_MIN__)));
+  EXPECT_STREQ(" 0x1.fffffffffffffp+1023", gc(xasprintf("%24a", __DBL_MAX__)));
+  EXPECT_STREQ("                  0X0P+0", gc(xasprintf("%24A", 0.)));
+  EXPECT_STREQ("                 -0X0P+0", gc(xasprintf("%24A", -0.)));
+  EXPECT_STREQ("                     NAN", gc(xasprintf("%24A", NAN)));
+  EXPECT_STREQ("                    -NAN", gc(xasprintf("%24A", -NAN)));
+  EXPECT_STREQ("                     INF", gc(xasprintf("%24A", INFINITY)));
+  EXPECT_STREQ("                    -INF", gc(xasprintf("%24A", -INFINITY)));
+  EXPECT_STREQ("               0X1P-1022", gc(xasprintf("%24A", __DBL_MIN__)));
+  EXPECT_STREQ(" 0X1.FFFFFFFFFFFFFP+1023", gc(xasprintf("%24A", __DBL_MAX__)));
+  EXPECT_STREQ("   0X1.E9A488E8A71DEP+14", gc(xasprintf("%24A", 31337.1337)));
+  EXPECT_STREQ("  -0X1.E9A488E8A71DEP+14", gc(xasprintf("%24A", -31337.1337)));
+}

test/libc/fmt/realfmt_test.c

@@ -1,68 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/fmt/fmt.h"
-#include "libc/math.h"
-#include "libc/runtime/gc.h"
-#include "libc/testlib/testlib.h"
-#include "libc/x/x.h"
-
-TEST(RealFormatting, g) {
-  EXPECT_STREQ("nan", gc(xasprintf("%g", NAN)));
-  EXPECT_STREQ("-nan", gc(xasprintf("%g", -NAN)));
-  EXPECT_STREQ("inf", gc(xasprintf("%g", INFINITY)));
-  EXPECT_STREQ("-inf", gc(xasprintf("%g", -INFINITY)));
-  EXPECT_STREQ("0", gc(xasprintf("%g", 0.)));
-  EXPECT_STREQ("-0", gc(xasprintf("%g", -0.)));
-  EXPECT_STREQ("1", gc(xasprintf("%g", 1.)));
-  EXPECT_STREQ("-1", gc(xasprintf("%g", -1.)));
-  EXPECT_STREQ("10", gc(xasprintf("%g", 10.)));
-  EXPECT_STREQ("10", gc(xasprintf("%.0g", 10.)));
-  EXPECT_STREQ("-10", gc(xasprintf("%g", -10.)));
-  EXPECT_STREQ("-10", gc(xasprintf("%.0g", -10.)));
-  EXPECT_STREQ("       -10", gc(xasprintf("%10g", -10.)));
-  EXPECT_STREQ("       -10", gc(xasprintf("%*g", 10, -10.)));
-  EXPECT_STREQ("1e+100", gc(xasprintf("%g", 1e100)));
-  EXPECT_STREQ("1e-100", gc(xasprintf("%g", 1e-100)));
-  EXPECT_STREQ("-1e-100", gc(xasprintf("%g", -1e-100)));
-  EXPECT_STREQ("3.14159", gc(xasprintf("%g", 0x1.921fb54442d1846ap+1)));
-}
-
-TEST(RealFormatting, f) {
-  EXPECT_STREQ("3.141593", gc(xasprintf("%f", 0x1.921fb54442d1846ap+1)));
-  EXPECT_STREQ("3.1415926535897931",
-               gc(xasprintf("%.16f", 0x1.921fb54442d1846ap+1)));
-  EXPECT_STREQ("100000000000000001590289110975991804683608085639452813"
-               "89781327557747838772170381060813469985856815104.000000",
-               gc(xasprintf("%f", 1e100)));
-}
-
-TEST(RealFormatting, e) {
-  EXPECT_STREQ("3.14159", gc(xasprintf("%g", 0x1.921fb54442d1846ap+1)));
-  EXPECT_STREQ("3.141592653589793",
-               gc(xasprintf("%.16g", 0x1.921fb54442d1846ap+1)));
-  EXPECT_STREQ("1.000000e+100", gc(xasprintf("%e", 1e100)));
-  EXPECT_STREQ("1.000000E+100", gc(xasprintf("%E", 1e100)));
-}
-
-TEST(RealFormatting, a) {
-  EXPECT_STREQ("0x1.921fb54442d18p+1",
-               gc(xasprintf("%a", 0x1.921fb54442d1846ap+1)));
-  EXPECT_STREQ("0X1.921FB54442D18P+1",
-               gc(xasprintf("%A", 0x1.921fb54442d1846ap+1)));
-}

third_party/gdtoa/dtoa.c

@@ -168,9 +168,9 @@ dtoa(double d0, int mode, int ndigits, int *decpt, int *sign, char **rve)
 		*decpt = 9999;
 #ifdef IEEE_Arith
 		if (!word1(&d) && !(word0(&d) & 0xfffff))
-			return nrv_alloc("inf", rve, 8 MTb);
+			return nrv_alloc("Infinity", rve, 8 MTb);
 #endif
-		return nrv_alloc("nan", rve, 3 MTb);
+		return nrv_alloc("NaN", rve, 3 MTb);
 		}
 #endif
 #ifdef IBM