1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code by Matt McCutchen, see the LICENSE file.
#include "BigUnsignedInABase.hh"
BigUnsignedInABase::BigUnsignedInABase(const Digit *d, Index l, Base base)
: NumberlikeArray<Digit>(d, l), base(base) {
// Check the base
if (base < 2)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase::BigUnsignedInABase(const Digit *, Index, Base): The base must be at least 2";
#endif
// Validate the digits.
for (Index i = 0; i < l; i++)
if (blk[i] >= base)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase::BigUnsignedInABase(const Digit *, Index, Base): A digit is too large for the specified base";
#endif
// Eliminate any leading zeros we may have been passed.
zapLeadingZeros();
}
namespace {
unsigned int bitLen(unsigned int x) {
unsigned int len = 0;
while (x > 0) {
x >>= 1;
len++;
}
return len;
}
unsigned int ceilingDiv(unsigned int a, unsigned int b) {
return (a + b - 1) / b;
}
}
BigUnsignedInABase::BigUnsignedInABase(const BigUnsigned &x, Base base) {
// Check the base
if (base < 2)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase(BigUnsigned, Base): The base must be at least 2";
#endif
this->base = base;
// Get an upper bound on how much space we need
int maxBitLenOfX = x.getLength() * BigUnsigned::N;
int minBitsPerDigit = bitLen(base) - 1;
int maxDigitLenOfX = ceilingDiv(maxBitLenOfX, minBitsPerDigit);
len = maxDigitLenOfX; // Another change to comply with `staying in bounds'.
allocate(len); // Get the space
BigUnsigned x2(x), buBase(base);
Index digitNum = 0;
while (!x2.isZero()) {
// Get last digit. This is like `lastDigit = x2 % buBase, x2 /= buBase'.
BigUnsigned lastDigit(x2);
lastDigit.divideWithRemainder(buBase, x2);
// Save the digit.
blk[digitNum] = lastDigit.toUnsignedShort();
// Move on. We can't run out of room: we figured it out above.
digitNum++;
}
// Save the actual length.
len = digitNum;
}
BigUnsignedInABase::operator BigUnsigned() const {
BigUnsigned ans(0), buBase(base), temp;
Index digitNum = len;
while (digitNum > 0) {
digitNum--;
temp.multiply(ans, buBase);
ans.add(temp, BigUnsigned(blk[digitNum]));
}
return ans;
}
BigUnsignedInABase::BigUnsignedInABase(const std::string &s, Base base) {
// Check the base.
if (base > 36)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase(std::string, Base): The default string conversion routines use the symbol set 0-9, A-Z and therefore support only up to base 36. You tried a conversion with a base over 36; write your own string conversion routine.";
#endif
// Save the base.
// This pattern is seldom seen in C++, but the analogous ``this.'' is common in Java.
this->base = base;
// `s.length()' is a `size_t', while `len' is a `NumberlikeArray::Index',
// also known as an `unsigned int'. Some compilers warn without this cast.
len = Index(s.length());
allocate(len);
Index digitNum, symbolNumInString;
for (digitNum = 0; digitNum < len; digitNum++) {
symbolNumInString = len - 1 - digitNum;
char theSymbol = s[symbolNumInString];
if (theSymbol >= '0' && theSymbol <= '9')
blk[digitNum] = theSymbol - '0';
else if (theSymbol >= 'A' && theSymbol <= 'Z')
blk[digitNum] = theSymbol - 'A' + 10;
else if (theSymbol >= 'a' && theSymbol <= 'z')
blk[digitNum] = theSymbol - 'a' + 10;
else
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase(std::string, Base): Bad symbol in input. Only 0-9, A-Z, a-z are accepted.";
#endif
if (blk[digitNum] >= base)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase::BigUnsignedInABase(const Digit *, Index, Base): A digit is too large for the specified base";
#endif
}
zapLeadingZeros();
}
BigUnsignedInABase::operator std::string() const {
if (base > 36)
#ifdef FOXIT_CHROME_BUILD
abort();
#else
throw "BigUnsignedInABase ==> std::string: The default string conversion routines use the symbol set 0-9, A-Z and therefore support only up to base 36. You tried a conversion with a base over 36; write your own string conversion routine.";
#endif
if (len == 0)
return std::string("0");
// Some compilers don't have push_back, so use a char * buffer instead.
char *s = new char[len + 1];
s[len] = '\0';
Index digitNum, symbolNumInString;
for (symbolNumInString = 0; symbolNumInString < len; symbolNumInString++) {
digitNum = len - 1 - symbolNumInString;
Digit theDigit = blk[digitNum];
if (theDigit < 10)
s[symbolNumInString] = char('0' + theDigit);
else
s[symbolNumInString] = char('A' + theDigit - 10);
}
std::string s2(s);
delete [] s;
return s2;
}
|
