1 | #include <stdint.h>
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2 | #include <stdio.h>
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3 | #include <math.h>
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4 | #include <float.h>
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5 | #include <limits.h>
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6 | #include <errno.h>
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7 | #include <ctype.h>
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8 |
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9 | #include "shgetc.h"
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10 | #include "floatscan.h"
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11 |
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12 | #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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13 |
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14 | #define LD_B1B_DIG 2
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15 | #define LD_B1B_MAX 9007199, 254740991
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16 | #define KMAX 128
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17 |
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18 | #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
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19 |
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20 | #define LD_B1B_DIG 3
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21 | #define LD_B1B_MAX 18, 446744073, 709551615
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22 | #define KMAX 2048
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23 |
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24 | #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
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25 |
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26 | #define LD_B1B_DIG 4
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27 | #define LD_B1B_MAX 10384593, 717069655, 257060992, 658440191
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28 | #define KMAX 2048
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29 |
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30 | #else
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31 | #error Unsupported long double representation
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32 | #endif
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33 |
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34 | #define MASK (KMAX-1)
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35 |
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36 | #define CONCAT2(x,y) x ## y
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37 | #define CONCAT(x,y) CONCAT2(x,y)
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38 |
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39 | static long long scanexp(FILE *f, int pok)
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40 | {
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41 | int c;
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42 | int x;
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43 | long long y;
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44 | int neg = 0;
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45 |
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46 | c = shgetc(f);
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47 | if (c=='+' || c=='-') {
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48 | neg = (c=='-');
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49 | c = shgetc(f);
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50 | if (c-'0'>=10U && pok) shunget(f);
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51 | }
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52 | if (c-'0'>=10U) {
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53 | shunget(f);
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54 | return LLONG_MIN;
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55 | }
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56 | for (x=0; c-'0'<10U && x<INT_MAX/10; c = shgetc(f))
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57 | x = 10*x + c-'0';
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58 | for (y=x; c-'0'<10U && y<LLONG_MAX/100; c = shgetc(f))
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59 | y = 10*y + c-'0';
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60 | for (; c-'0'<10U; c = shgetc(f));
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61 | shunget(f);
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62 | return neg ? -y : y;
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63 | }
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64 |
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65 |
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66 | static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int pok)
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67 | {
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68 | uint32_t x[KMAX];
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69 | static const uint32_t th[] = { LD_B1B_MAX };
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70 | int i, j, k, a, z;
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71 | long long lrp=0, dc=0;
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72 | long long e10=0;
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73 | int lnz = 0;
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74 | int gotdig = 0, gotrad = 0;
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75 | int rp;
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76 | int e2;
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77 | int emax = -emin-bits+3;
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78 | int denormal = 0;
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79 | long double y;
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80 | long double frac=0;
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81 | long double bias=0;
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82 | static const int p10s[] = { 10, 100, 1000, 10000,
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83 | 100000, 1000000, 10000000, 100000000 };
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84 |
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85 | j=0;
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86 | k=0;
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87 |
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88 | /* Don't let leading zeros consume buffer space */
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89 | for (; c=='0'; c = shgetc(f)) gotdig=1;
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90 | if (c=='.') {
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91 | gotrad = 1;
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92 | for (c = shgetc(f); c=='0'; c = shgetc(f)) gotdig=1, lrp--;
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93 | }
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94 |
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95 | x[0] = 0;
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96 | for (; c-'0'<10U || c=='.'; c = shgetc(f)) {
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97 | if (c == '.') {
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98 | if (gotrad) break;
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99 | gotrad = 1;
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100 | lrp = dc;
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101 | } else if (k < KMAX-3) {
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102 | dc++;
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103 | if (c!='0') lnz = dc;
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104 | if (j) x[k] = x[k]*10 + c-'0';
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105 | else x[k] = c-'0';
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106 | if (++j==9) {
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107 | k++;
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108 | j=0;
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109 | }
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110 | gotdig=1;
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111 | } else {
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112 | dc++;
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113 | if (c!='0') {
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114 | lnz = (KMAX-4)*9;
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115 | x[KMAX-4] |= 1;
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116 | }
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117 | }
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118 | }
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119 | if (!gotrad) lrp=dc;
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120 |
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121 | if (gotdig && (c|32)=='e') {
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122 | e10 = scanexp(f, pok);
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123 | if (e10 == LLONG_MIN) {
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124 | if (pok) {
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125 | shunget(f);
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126 | } else {
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127 | shlim(f, 0);
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128 | return 0;
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129 | }
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130 | e10 = 0;
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131 | }
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132 | lrp += e10;
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133 | } else if (c>=0) {
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134 | shunget(f);
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135 | }
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136 | if (!gotdig) {
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137 | errno = EINVAL;
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138 | shlim(f, 0);
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139 | return 0;
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140 | }
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141 |
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142 | /* Handle zero specially to avoid nasty special cases later */
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143 | if (!x[0]) return sign * 0.0;
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144 |
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145 | /* Optimize small integers (w/no exponent) and over/under-flow */
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146 | if (lrp==dc && dc<10 && (bits>30 || x[0]>>bits==0))
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147 | return sign * (long double)x[0];
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148 | if (lrp > -emin/2) {
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149 | errno = ERANGE;
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150 | return sign * LDBL_MAX * LDBL_MAX;
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151 | }
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152 | if (lrp < emin-2*LDBL_MANT_DIG) {
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153 | errno = ERANGE;
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154 | return sign * LDBL_MIN * LDBL_MIN;
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155 | }
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156 |
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157 | /* Align incomplete final B1B digit */
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158 | if (j) {
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159 | for (; j<9; j++) x[k]*=10;
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160 | k++;
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161 | j=0;
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162 | }
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163 |
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164 | a = 0;
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165 | z = k;
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166 | e2 = 0;
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167 | rp = lrp;
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168 |
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169 | /* Optimize small to mid-size integers (even in exp. notation) */
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170 | if (lnz<9 && lnz<=rp && rp < 18) {
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171 | if (rp == 9) return sign * (long double)x[0];
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172 | if (rp < 9) return sign * (long double)x[0] / p10s[8-rp];
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173 | int bitlim = bits-3*(int)(rp-9);
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174 | if (bitlim>30 || x[0]>>bitlim==0)
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175 | return sign * (long double)x[0] * p10s[rp-10];
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176 | }
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177 |
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178 | /* Drop trailing zeros */
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179 | for (; !x[z-1]; z--);
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180 |
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181 | /* Align radix point to B1B digit boundary */
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182 | if (rp % 9) {
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183 | int rpm9 = rp>=0 ? rp%9 : rp%9+9;
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184 | int p10 = p10s[8-rpm9];
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185 | uint32_t carry = 0;
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186 | for (k=a; k!=z; k++) {
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187 | uint32_t tmp = x[k] % p10;
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188 | x[k] = x[k]/p10 + carry;
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189 | carry = 1000000000/p10 * tmp;
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190 | if (k==a && !x[k]) {
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191 | a = (a+1 & MASK);
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192 | rp -= 9;
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193 | }
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194 | }
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195 | if (carry) x[z++] = carry;
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196 | rp += 9-rpm9;
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197 | }
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198 |
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199 | /* Upscale until desired number of bits are left of radix point */
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200 | while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[a]<th[0])) {
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201 | uint32_t carry = 0;
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202 | e2 -= 29;
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203 | for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
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204 | uint64_t tmp = ((uint64_t)x[k] << 29) + carry;
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205 | if (tmp > 1000000000) {
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206 | carry = tmp / 1000000000;
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207 | x[k] = tmp % 1000000000;
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208 | } else {
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209 | carry = 0;
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210 | x[k] = tmp;
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211 | }
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212 | if (k==(z-1 & MASK) && k!=a && !x[k]) z = k;
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213 | if (k==a) break;
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214 | }
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215 | if (carry) {
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216 | rp += 9;
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217 | a = (a-1 & MASK);
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218 | if (a == z) {
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219 | z = (z-1 & MASK);
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220 | x[z-1 & MASK] |= x[z];
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221 | }
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222 | x[a] = carry;
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223 | }
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224 | }
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225 |
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226 | /* Downscale until exactly number of bits are left of radix point */
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227 | for (;;) {
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228 | uint32_t carry = 0;
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229 | int sh = 1;
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230 | for (i=0; i<LD_B1B_DIG; i++) {
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231 | k = (a+i & MASK);
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232 | if (k == z || x[k] < th[i]) {
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233 | i=LD_B1B_DIG;
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234 | break;
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235 | }
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236 | if (x[a+i & MASK] > th[i]) break;
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237 | }
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238 | if (i==LD_B1B_DIG && rp==9*LD_B1B_DIG) break;
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239 | /* FIXME: find a way to compute optimal sh */
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240 | if (rp > 9+9*LD_B1B_DIG) sh = 9;
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241 | e2 += sh;
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242 | for (k=a; k!=z; k=(k+1 & MASK)) {
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243 | uint32_t tmp = x[k] & (1<<sh)-1;
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244 | x[k] = (x[k]>>sh) + carry;
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245 | carry = (1000000000>>sh) * tmp;
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246 | if (k==a && !x[k]) {
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247 | a = (a+1 & MASK);
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248 | i--;
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249 | rp -= 9;
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250 | }
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251 | }
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252 | if (carry) {
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253 | if ((z+1 & MASK) != a) {
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254 | x[z] = carry;
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255 | z = (z+1 & MASK);
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256 | } else x[z-1 & MASK] |= 1;
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257 | }
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258 | }
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259 |
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260 | /* Assemble desired bits into floating point variable */
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261 | for (y=i=0; i<LD_B1B_DIG; i++) {
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262 | if ((a+i & MASK)==z) x[(z=(z+1 & MASK))-1] = 0;
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263 | y = 1000000000.0L * y + x[a+i & MASK];
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264 | }
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265 |
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266 | y *= sign;
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267 |
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268 | /* Limit precision for denormal results */
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269 | if (bits > LDBL_MANT_DIG+e2-emin) {
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270 | bits = LDBL_MANT_DIG+e2-emin;
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271 | if (bits<0) bits=0;
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272 | denormal = 1;
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273 | }
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274 |
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275 | /* Calculate bias term to force rounding, move out lower bits */
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276 | if (bits < LDBL_MANT_DIG) {
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277 | bias = copysignl(scalbn(1, 2*LDBL_MANT_DIG-bits-1), y);
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278 | frac = fmodl(y, scalbn(1, LDBL_MANT_DIG-bits));
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279 | y -= frac;
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280 | y += bias;
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281 | }
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282 |
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283 | /* Process tail of decimal input so it can affect rounding */
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284 | if ((a+i & MASK) != z) {
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285 | uint32_t t = x[a+i & MASK];
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286 | if (t < 500000000 && (t || (a+i+1 & MASK) != z))
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287 | frac += 0.25*sign;
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288 | else if (t > 500000000)
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289 | frac += 0.75*sign;
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290 | else if (t == 500000000) {
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291 | if ((a+i+1 & MASK) == z)
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292 | frac += 0.5*sign;
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293 | else
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294 | frac += 0.75*sign;
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295 | }
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296 | if (LDBL_MANT_DIG-bits >= 2 && !fmodl(frac, 1))
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297 | frac++;
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298 | }
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299 |
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300 | y += frac;
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301 | y -= bias;
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302 |
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303 | if ((e2+LDBL_MANT_DIG & INT_MAX) > emax-5) {
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304 | if (fabs(y) >= CONCAT(0x1p, LDBL_MANT_DIG)) {
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305 | if (denormal && bits==LDBL_MANT_DIG+e2-emin)
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306 | denormal = 0;
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307 | y *= 0.5;
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308 | e2++;
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309 | }
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310 | if (e2+LDBL_MANT_DIG>emax || (denormal && frac))
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311 | errno = ERANGE;
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312 | }
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313 |
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314 | return scalbnl(y, e2);
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315 | }
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316 |
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317 | static long double hexfloat(FILE *f, int bits, int emin, int sign, int pok)
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318 | {
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319 | uint32_t x = 0;
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320 | long double y = 0;
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321 | long double scale = 1;
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322 | long double bias = 0;
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323 | int gottail = 0, gotrad = 0, gotdig = 0;
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324 | long long rp = 0;
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325 | long long dc = 0;
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326 | long long e2 = 0;
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327 | int d;
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328 | int c;
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329 |
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330 | c = shgetc(f);
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331 |
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332 | /* Skip leading zeros */
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333 | for (; c=='0'; c = shgetc(f)) gotdig = 1;
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334 |
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335 | if (c=='.') {
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336 | gotrad = 1;
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337 | c = shgetc(f);
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338 | /* Count zeros after the radix point before significand */
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339 | for (rp=0; c=='0'; c = shgetc(f), rp--) gotdig = 1;
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340 | }
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341 |
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342 | for (; c-'0'<10U || (c|32)-'a'<6U || c=='.'; c = shgetc(f)) {
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343 | if (c=='.') {
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344 | if (gotrad) break;
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345 | rp = dc;
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346 | gotrad = 1;
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347 | } else {
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348 | gotdig = 1;
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349 | if (c > '9') d = (c|32)+10-'a';
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350 | else d = c-'0';
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351 | if (dc<8) {
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352 | x = x*16 + d;
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353 | } else if (dc < LDBL_MANT_DIG/4+1) {
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354 | y += d*(scale/=16);
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355 | } else if (d && !gottail) {
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356 | y += 0.5*scale;
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357 | gottail = 1;
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358 | }
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359 | dc++;
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360 | }
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361 | }
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362 | if (!gotdig) {
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363 | shunget(f);
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364 | if (pok) {
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365 | shunget(f);
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366 | if (gotrad) shunget(f);
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367 | } else {
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368 | shlim(f, 0);
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369 | }
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370 | return sign * 0.0;
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371 | }
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372 | if (!gotrad) rp = dc;
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373 | while (dc<8) x *= 16, dc++;
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374 | if ((c|32)=='p') {
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375 | e2 = scanexp(f, pok);
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376 | if (e2 == LLONG_MIN) {
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377 | if (pok) {
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378 | shunget(f);
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379 | } else {
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380 | shlim(f, 0);
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381 | return 0;
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382 | }
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383 | e2 = 0;
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384 | }
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385 | } else {
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386 | shunget(f);
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387 | }
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388 | e2 += 4*rp - 32;
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389 |
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390 | if (!x) return sign * 0.0;
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391 | if (e2 > -emin) {
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392 | errno = ERANGE;
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393 | return sign * LDBL_MAX * LDBL_MAX;
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394 | }
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395 | if (e2 < emin-2*LDBL_MANT_DIG) {
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396 | errno = ERANGE;
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397 | return sign * LDBL_MIN * LDBL_MIN;
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398 | }
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399 |
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400 | while (x < 0x80000000) {
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401 | if (y>=0.5) {
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402 | x += x + 1;
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403 | y += y - 1;
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404 | } else {
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405 | x += x;
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406 | y += y;
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407 | }
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408 | e2--;
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409 | }
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410 |
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411 | if (bits > 32+e2-emin) {
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412 | bits = 32+e2-emin;
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413 | if (bits<0) bits=0;
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414 | }
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415 |
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416 | if (bits < LDBL_MANT_DIG)
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417 | bias = copysignl(scalbn(1, 32+LDBL_MANT_DIG-bits-1), sign);
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418 |
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419 | if (bits<32 && y && !(x&1)) x++, y=0;
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420 |
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421 | y = bias + sign*(long double)x + sign*y;
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422 | y -= bias;
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423 |
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424 | if (!y) errno = ERANGE;
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425 |
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426 | return scalbnl(y, e2);
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427 | }
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428 |
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429 | long double __floatscan(FILE *f, int prec, int pok)
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430 | {
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431 | int sign = 1;
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432 | size_t i;
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433 | int bits;
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434 | int emin;
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435 | int c;
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436 |
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437 | switch (prec) {
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438 | case 0:
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439 | bits = FLT_MANT_DIG;
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440 | emin = FLT_MIN_EXP-bits;
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441 | break;
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442 | case 1:
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443 | bits = DBL_MANT_DIG;
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444 | emin = DBL_MIN_EXP-bits;
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445 | break;
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446 | case 2:
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447 | bits = LDBL_MANT_DIG;
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448 | emin = LDBL_MIN_EXP-bits;
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449 | break;
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450 | default:
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451 | return 0;
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452 | }
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453 |
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454 | while (isspace((c=shgetc(f))));
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455 |
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456 | if (c=='+' || c=='-') {
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457 | sign -= 2*(c=='-');
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458 | c = shgetc(f);
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459 | }
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460 |
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461 | for (i=0; i<8 && (c|32)=="infinity"[i]; i++)
|
---|
462 | if (i<7) c = shgetc(f);
|
---|
463 | if (i==3 || i==8 || (i>3 && pok)) {
|
---|
464 | if (i!=8) {
|
---|
465 | shunget(f);
|
---|
466 | if (pok) for (; i>3; i--) shunget(f);
|
---|
467 | }
|
---|
468 | return sign * INFINITY;
|
---|
469 | }
|
---|
470 | if (!i) for (i=0; i<3 && (c|32)=="nan"[i]; i++)
|
---|
471 | if (i<2) c = shgetc(f);
|
---|
472 | if (i==3) {
|
---|
473 | if (shgetc(f) != '(') {
|
---|
474 | shunget(f);
|
---|
475 | return NAN;
|
---|
476 | }
|
---|
477 | for (i=1; ; i++) {
|
---|
478 | c = shgetc(f);
|
---|
479 | if (c-'0'<10U || c-'A'<26U || c-'a'<26U || c=='_')
|
---|
480 | continue;
|
---|
481 | if (c==')') return NAN;
|
---|
482 | shunget(f);
|
---|
483 | if (!pok) {
|
---|
484 | errno = EINVAL;
|
---|
485 | shlim(f, 0);
|
---|
486 | return 0;
|
---|
487 | }
|
---|
488 | while (i--) shunget(f);
|
---|
489 | return NAN;
|
---|
490 | }
|
---|
491 | return NAN;
|
---|
492 | }
|
---|
493 |
|
---|
494 | if (i) {
|
---|
495 | shunget(f);
|
---|
496 | errno = EINVAL;
|
---|
497 | shlim(f, 0);
|
---|
498 | return 0;
|
---|
499 | }
|
---|
500 |
|
---|
501 | if (c=='0') {
|
---|
502 | c = shgetc(f);
|
---|
503 | if ((c|32) == 'x')
|
---|
504 | return hexfloat(f, bits, emin, sign, pok);
|
---|
505 | shunget(f);
|
---|
506 | c = '0';
|
---|
507 | }
|
---|
508 |
|
---|
509 | return decfloat(f, c, bits, emin, sign, pok);
|
---|
510 | }
|
---|