scoutos / prex-0.9.0 / sys / lib / vsprintf.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 2005, Kohsuke Ohtani
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | /*
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31 | * vsprintf.c - Format and output data to buffer
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32 | */
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33 | |||
34 | #include <kernel.h> |
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35 | |||
36 | #define isdigit(c) ((u_int)((c) - '0') < 10) |
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37 | |||
38 | static u_long
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39 | divide(long *n, int base) |
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40 | { |
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41 | u_long res; |
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42 | |||
43 | res = ((u_long)*n) % base; |
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44 | *n = (long)(((u_long)*n) / base);
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45 | return res;
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46 | } |
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47 | |||
48 | static int |
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49 | atoi(const char **s) |
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50 | { |
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51 | int i = 0; |
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52 | while (isdigit((int)**s)) |
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53 | i = i * 10 + *((*s)++) - '0'; |
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54 | return i;
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55 | } |
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56 | |||
57 | /*
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58 | * Print formatted output - scaled down version
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59 | *
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60 | * Identifiers:
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61 | * %d - Decimal signed int
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62 | * %x - Hex integer
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63 | * %u - Unsigned integer
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64 | * %c - Character
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65 | * %s - String
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66 | *
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67 | * Flags:
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68 | * 0 - Zero pad
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69 | */
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70 | int
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71 | vsprintf(char *buf, const char *fmt, va_list args) |
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72 | { |
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73 | char *p, *str;
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74 | const char *digits = "0123456789abcdef"; |
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75 | char pad, tmp[16]; |
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76 | int width, base, sign, i;
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77 | long num;
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78 | |||
79 | for (p = buf; *fmt; fmt++) {
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80 | if (*fmt != '%') { |
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81 | *p++ = *fmt; |
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82 | continue;
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83 | } |
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84 | /* get flags */
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85 | ++fmt; |
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86 | pad = ' ';
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87 | if (*fmt == '0') { |
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88 | pad = '0';
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89 | fmt++; |
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90 | } |
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91 | /* get width */
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92 | width = -1;
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93 | if (isdigit(*fmt)) {
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94 | width = atoi(&fmt); |
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95 | } |
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96 | /* ignore long */
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97 | if (*fmt == 'l') |
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98 | fmt++; |
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99 | base = 10;
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100 | sign = 0;
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101 | switch (*fmt) {
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102 | case 'c': |
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103 | *p++ = (char)va_arg(args, int); |
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104 | continue;
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105 | case 's': |
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106 | str = va_arg(args, char *);
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107 | if (str == NULL) |
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108 | str = "<NULL>";
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109 | for (; *str && width != 0; str++, width--) { |
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110 | *p++ = *str; |
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111 | } |
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112 | while (width-- > 0) |
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113 | *p++ = pad; |
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114 | continue;
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115 | case 'X': |
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116 | case 'x': |
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117 | base = 16;
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118 | break;
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119 | case 'd': |
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120 | sign = 1;
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121 | break;
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122 | case 'u': |
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123 | break;
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124 | default:
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125 | continue;
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126 | } |
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127 | num = va_arg(args, long);
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128 | if (sign && num < 0) { |
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129 | num = -num; |
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130 | *p++ = '-';
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131 | width--; |
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132 | } |
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133 | i = 0;
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134 | if (num == 0) |
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135 | tmp[i++] = '0';
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136 | else
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137 | while (num != 0) |
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138 | tmp[i++] = digits[divide(&num, base)]; |
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139 | width -= i; |
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140 | while (width-- > 0) |
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141 | *p++ = pad; |
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142 | while (i-- > 0) |
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143 | *p++ = tmp[i]; |
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144 | } |
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145 | *p = '\0';
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146 | return 0; |
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147 | } |