libgo/runtime/go-print.c

   1 /* go-print.c -- support for the go print statement.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include <math.h>
   8 #include <stdint.h>
   9 #include <stdio.h>
  10
  11 #include "array.h"
  12 #include "go-panic.h"
  13 #include "go-string.h"
  14 #include "interface.h"
  15
  16 /* This implements the various little functions which are called by
  17    the predeclared functions print/println/panic/panicln.  */
  18
  19 void
  20 __go_print_space ()
  21 {
  22   putc (' ', stderr);
  23 }
  24
  25 void
  26 __go_print_nl ()
  27 {
  28   putc ('\n', stderr);
  29 }
  30
  31 void
  32 __go_print_string (struct __go_string val)
  33 {
  34   fprintf (stderr, "%.*s", (int) val.__length, (const char *) val.__data);
  35 }
  36
  37 void
  38 __go_print_uint64 (uint64_t val)
  39 {
  40   fprintf (stderr, "%llu", (unsigned long long) val);
  41 }
  42
  43 void
  44 __go_print_int64 (int64_t val)
  45 {
  46   fprintf (stderr, "%lld", (long long) val);
  47 }
  48
  49 void
  50 __go_print_double (double v)
  51 {
  52   char buf[20];
  53   int e, s, i, n;
  54   double h;
  55
  56   if (isnan (v))
  57     {
  58       fputs ("NaN", stderr);
  59       return;
  60     }
  61   if (__builtin_isinf (v))
  62     {
  63       putc (v < 0 ? '-' : '+', stderr);
  64       fputs ("Inf", stderr);
  65       return;
  66     }
  67
  68   /* The number of digits printed.  */
  69   n = 7;
  70   /* The exponent.  */
  71   e = 0;
  72   /* The sign.  */
  73   s = 0;
  74   if (v != 0)
  75     {
  76       if (v < 0)
  77         {
  78           v = -v;
  79           s = 1;
  80         }
  81
  82       /* Normalize.  */
  83       while (v >= 10)
  84         {
  85           ++e;
  86           v /= 10;
  87         }
  88       while (v < 1)
  89         {
  90           --e;
  91           v *= 10;
  92         }
  93
  94       /* Round.  */
  95       h = 5;
  96       for (i = 0; i < n; ++i)
  97         h /= 10;
  98
  99       v += h;
 100       if (v >= 10)
 101         {
 102           ++e;
 103           v /= 10;
 104         }
 105     }
 106
 107   /* The format is +d.dddd+edd.  */
 108   buf[0] = s ? '-' : '+';
 109   for (i = 0; i < n; ++i)
 110     {
 111       int d;
 112
 113       d = v;
 114       buf[i + 2] = d + '0';
 115       v -= d;
 116       v *= 10;
 117     }
 118   buf[1] = buf[2];
 119   buf[2] = '.';
 120
 121   buf[n + 2] = 'e';
 122   buf[n + 3] = e < 0 ? '-' : '+';
 123   if (e < 0)
 124     e = - e;
 125   buf[n + 4] = e / 100 + '0';
 126   buf[n + 5] = (e / 10) % 10 + '0';
 127   buf[n + 6] = e % 10 + '0';
 128   buf[n + 7] = '\0';
 129   fputs (buf, stderr);
 130 }
 131
 132 void
 133 __go_print_complex (__complex double val)
 134 {
 135   putc ('(', stderr);
 136   __go_print_double (__builtin_creal (val));
 137   __go_print_double (__builtin_cimag (val));
 138   fputs ("i)", stderr);
 139 }
 140
 141 void
 142 __go_print_bool (_Bool val)
 143 {
 144   fputs (val ? "true" : "false", stderr);
 145 }
 146
 147 void
 148 __go_print_pointer (void *val)
 149 {
 150   fprintf (stderr, "0x%lx", (unsigned long) (uintptr_t) val);
 151 }
 152
 153 void
 154 __go_print_empty_interface (struct __go_empty_interface e)
 155 {
 156   fprintf (stderr, "(%p,%p)", e.__type_descriptor, e.__object);
 157 }
 158
 159 void
 160 __go_print_interface (struct __go_interface i)
 161 {
 162   fprintf (stderr, "(%p,%p)", i.__methods, i.__object);
 163 }
 164
 165 void
 166 __go_print_slice (struct __go_open_array val)
 167 {
 168   fprintf (stderr, "[%d/%d]", val.__count, val.__capacity);
 169   __go_print_pointer (val.__values);
 170 }