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@@ -1,185 +1,182 b'' | |||||
1 | /* |
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1 | /* | |
2 | base85 codec |
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2 | base85 codec | |
3 |
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3 | |||
4 | Copyright 2006 Brendan Cully <brendan@kublai.com> |
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4 | Copyright 2006 Brendan Cully <brendan@kublai.com> | |
5 |
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5 | |||
6 | This software may be used and distributed according to the terms of |
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6 | This software may be used and distributed according to the terms of | |
7 | the GNU General Public License, incorporated herein by reference. |
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7 | the GNU General Public License, incorporated herein by reference. | |
8 |
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8 | |||
9 | Largely based on git's implementation |
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9 | Largely based on git's implementation | |
10 | */ |
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10 | */ | |
11 |
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11 | |||
12 | #define PY_SSIZE_T_CLEAN |
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12 | #define PY_SSIZE_T_CLEAN | |
13 | #include <Python.h> |
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13 | #include <Python.h> | |
14 |
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14 | |||
15 | #include "util.h" |
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15 | #include "util.h" | |
16 |
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16 | |||
17 | static const char b85chars[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" |
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17 | static const char b85chars[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" | |
18 | "abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"; |
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18 | "abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"; | |
19 | static char b85dec[256]; |
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19 | static char b85dec[256]; | |
20 |
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20 | |||
21 | static void |
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21 | static void b85prep(void) | |
22 | b85prep(void) |
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23 | { |
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22 | { | |
24 | unsigned i; |
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23 | unsigned i; | |
25 |
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24 | |||
26 | memset(b85dec, 0, sizeof(b85dec)); |
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25 | memset(b85dec, 0, sizeof(b85dec)); | |
27 | for (i = 0; i < sizeof(b85chars); i++) |
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26 | for (i = 0; i < sizeof(b85chars); i++) | |
28 | b85dec[(int)(b85chars[i])] = i + 1; |
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27 | b85dec[(int)(b85chars[i])] = i + 1; | |
29 | } |
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28 | } | |
30 |
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29 | |||
31 | static PyObject * |
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30 | static PyObject *b85encode(PyObject *self, PyObject *args) | |
32 | b85encode(PyObject *self, PyObject *args) |
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33 | { |
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31 | { | |
34 | const unsigned char *text; |
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32 | const unsigned char *text; | |
35 | PyObject *out; |
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33 | PyObject *out; | |
36 | char *dst; |
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34 | char *dst; | |
37 | Py_ssize_t len, olen, i; |
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35 | Py_ssize_t len, olen, i; | |
38 | unsigned int acc, val, ch; |
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36 | unsigned int acc, val, ch; | |
39 | int pad = 0; |
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37 | int pad = 0; | |
40 |
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38 | |||
41 | if (!PyArg_ParseTuple(args, "s#|i", &text, &len, &pad)) |
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39 | if (!PyArg_ParseTuple(args, "s#|i", &text, &len, &pad)) | |
42 | return NULL; |
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40 | return NULL; | |
43 |
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41 | |||
44 | if (pad) |
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42 | if (pad) | |
45 | olen = ((len + 3) / 4 * 5) - 3; |
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43 | olen = ((len + 3) / 4 * 5) - 3; | |
46 | else { |
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44 | else { | |
47 | olen = len % 4; |
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45 | olen = len % 4; | |
48 | if (olen) |
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46 | if (olen) | |
49 | olen++; |
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47 | olen++; | |
50 | olen += len / 4 * 5; |
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48 | olen += len / 4 * 5; | |
51 | } |
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49 | } | |
52 | if (!(out = PyBytes_FromStringAndSize(NULL, olen + 3))) |
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50 | if (!(out = PyBytes_FromStringAndSize(NULL, olen + 3))) | |
53 | return NULL; |
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51 | return NULL; | |
54 |
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52 | |||
55 | dst = PyBytes_AsString(out); |
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53 | dst = PyBytes_AsString(out); | |
56 |
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54 | |||
57 | while (len) { |
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55 | while (len) { | |
58 | acc = 0; |
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56 | acc = 0; | |
59 | for (i = 24; i >= 0; i -= 8) { |
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57 | for (i = 24; i >= 0; i -= 8) { | |
60 | ch = *text++; |
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58 | ch = *text++; | |
61 | acc |= ch << i; |
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59 | acc |= ch << i; | |
62 | if (--len == 0) |
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60 | if (--len == 0) | |
63 | break; |
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61 | break; | |
64 | } |
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62 | } | |
65 | for (i = 4; i >= 0; i--) { |
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63 | for (i = 4; i >= 0; i--) { | |
66 | val = acc % 85; |
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64 | val = acc % 85; | |
67 | acc /= 85; |
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65 | acc /= 85; | |
68 | dst[i] = b85chars[val]; |
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66 | dst[i] = b85chars[val]; | |
69 | } |
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67 | } | |
70 | dst += 5; |
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68 | dst += 5; | |
71 | } |
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69 | } | |
72 |
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70 | |||
73 | if (!pad) |
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71 | if (!pad) | |
74 | _PyBytes_Resize(&out, olen); |
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72 | _PyBytes_Resize(&out, olen); | |
75 |
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73 | |||
76 | return out; |
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74 | return out; | |
77 | } |
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75 | } | |
78 |
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76 | |||
79 | static PyObject * |
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77 | static PyObject *b85decode(PyObject *self, PyObject *args) | |
80 | b85decode(PyObject *self, PyObject *args) |
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81 | { |
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78 | { | |
82 | PyObject *out; |
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79 | PyObject *out; | |
83 | const char *text; |
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80 | const char *text; | |
84 | char *dst; |
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81 | char *dst; | |
85 | Py_ssize_t len, i, j, olen, cap; |
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82 | Py_ssize_t len, i, j, olen, cap; | |
86 | int c; |
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83 | int c; | |
87 | unsigned int acc; |
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84 | unsigned int acc; | |
88 |
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85 | |||
89 | if (!PyArg_ParseTuple(args, "s#", &text, &len)) |
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86 | if (!PyArg_ParseTuple(args, "s#", &text, &len)) | |
90 | return NULL; |
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87 | return NULL; | |
91 |
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88 | |||
92 | olen = len / 5 * 4; |
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89 | olen = len / 5 * 4; | |
93 | i = len % 5; |
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90 | i = len % 5; | |
94 | if (i) |
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91 | if (i) | |
95 | olen += i - 1; |
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92 | olen += i - 1; | |
96 | if (!(out = PyBytes_FromStringAndSize(NULL, olen))) |
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93 | if (!(out = PyBytes_FromStringAndSize(NULL, olen))) | |
97 | return NULL; |
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94 | return NULL; | |
98 |
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95 | |||
99 | dst = PyBytes_AsString(out); |
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96 | dst = PyBytes_AsString(out); | |
100 |
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97 | |||
101 | i = 0; |
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98 | i = 0; | |
102 | while (i < len) |
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99 | while (i < len) | |
103 | { |
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100 | { | |
104 | acc = 0; |
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101 | acc = 0; | |
105 | cap = len - i - 1; |
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102 | cap = len - i - 1; | |
106 | if (cap > 4) |
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103 | if (cap > 4) | |
107 | cap = 4; |
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104 | cap = 4; | |
108 | for (j = 0; j < cap; i++, j++) |
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105 | for (j = 0; j < cap; i++, j++) | |
109 | { |
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106 | { | |
110 | c = b85dec[(int)*text++] - 1; |
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107 | c = b85dec[(int)*text++] - 1; | |
111 | if (c < 0) |
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108 | if (c < 0) | |
112 | return PyErr_Format( |
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109 | return PyErr_Format( | |
113 | PyExc_ValueError, |
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110 | PyExc_ValueError, | |
114 | "bad base85 character at position %d", |
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111 | "bad base85 character at position %d", | |
115 | (int)i); |
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112 | (int)i); | |
116 | acc = acc * 85 + c; |
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113 | acc = acc * 85 + c; | |
117 | } |
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114 | } | |
118 | if (i++ < len) |
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115 | if (i++ < len) | |
119 | { |
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116 | { | |
120 | c = b85dec[(int)*text++] - 1; |
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117 | c = b85dec[(int)*text++] - 1; | |
121 | if (c < 0) |
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118 | if (c < 0) | |
122 | return PyErr_Format( |
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119 | return PyErr_Format( | |
123 | PyExc_ValueError, |
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120 | PyExc_ValueError, | |
124 | "bad base85 character at position %d", |
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121 | "bad base85 character at position %d", | |
125 | (int)i); |
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122 | (int)i); | |
126 | /* overflow detection: 0xffffffff == "|NsC0", |
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123 | /* overflow detection: 0xffffffff == "|NsC0", | |
127 | * "|NsC" == 0x03030303 */ |
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124 | * "|NsC" == 0x03030303 */ | |
128 | if (acc > 0x03030303 || (acc *= 85) > 0xffffffff - c) |
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125 | if (acc > 0x03030303 || (acc *= 85) > 0xffffffff - c) | |
129 | return PyErr_Format( |
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126 | return PyErr_Format( | |
130 | PyExc_ValueError, |
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127 | PyExc_ValueError, | |
131 | "bad base85 sequence at position %d", |
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128 | "bad base85 sequence at position %d", | |
132 | (int)i); |
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129 | (int)i); | |
133 | acc += c; |
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130 | acc += c; | |
134 | } |
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131 | } | |
135 |
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132 | |||
136 | cap = olen < 4 ? olen : 4; |
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133 | cap = olen < 4 ? olen : 4; | |
137 | olen -= cap; |
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134 | olen -= cap; | |
138 | for (j = 0; j < 4 - cap; j++) |
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135 | for (j = 0; j < 4 - cap; j++) | |
139 | acc *= 85; |
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136 | acc *= 85; | |
140 | if (cap && cap < 4) |
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137 | if (cap && cap < 4) | |
141 | acc += 0xffffff >> (cap - 1) * 8; |
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138 | acc += 0xffffff >> (cap - 1) * 8; | |
142 | for (j = 0; j < cap; j++) |
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139 | for (j = 0; j < cap; j++) | |
143 | { |
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140 | { | |
144 | acc = (acc << 8) | (acc >> 24); |
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141 | acc = (acc << 8) | (acc >> 24); | |
145 | *dst++ = acc; |
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142 | *dst++ = acc; | |
146 | } |
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143 | } | |
147 | } |
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144 | } | |
148 |
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145 | |||
149 | return out; |
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146 | return out; | |
150 | } |
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147 | } | |
151 |
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148 | |||
152 | static char base85_doc[] = "Base85 Data Encoding"; |
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149 | static char base85_doc[] = "Base85 Data Encoding"; | |
153 |
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150 | |||
154 | static PyMethodDef methods[] = { |
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151 | static PyMethodDef methods[] = { | |
155 | {"b85encode", b85encode, METH_VARARGS, |
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152 | {"b85encode", b85encode, METH_VARARGS, | |
156 | "Encode text in base85.\n\n" |
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153 | "Encode text in base85.\n\n" | |
157 | "If the second parameter is true, pad the result to a multiple of " |
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154 | "If the second parameter is true, pad the result to a multiple of " | |
158 | "five characters.\n"}, |
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155 | "five characters.\n"}, | |
159 | {"b85decode", b85decode, METH_VARARGS, "Decode base85 text.\n"}, |
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156 | {"b85decode", b85decode, METH_VARARGS, "Decode base85 text.\n"}, | |
160 | {NULL, NULL} |
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157 | {NULL, NULL} | |
161 | }; |
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158 | }; | |
162 |
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159 | |||
163 | #ifdef IS_PY3K |
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160 | #ifdef IS_PY3K | |
164 | static struct PyModuleDef base85_module = { |
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161 | static struct PyModuleDef base85_module = { | |
165 | PyModuleDef_HEAD_INIT, |
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162 | PyModuleDef_HEAD_INIT, | |
166 | "base85", |
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163 | "base85", | |
167 | base85_doc, |
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164 | base85_doc, | |
168 | -1, |
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165 | -1, | |
169 | methods |
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166 | methods | |
170 | }; |
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167 | }; | |
171 |
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168 | |||
172 | PyMODINIT_FUNC PyInit_base85(void) |
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169 | PyMODINIT_FUNC PyInit_base85(void) | |
173 | { |
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170 | { | |
174 | b85prep(); |
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171 | b85prep(); | |
175 |
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172 | |||
176 | return PyModule_Create(&base85_module); |
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173 | return PyModule_Create(&base85_module); | |
177 | } |
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174 | } | |
178 | #else |
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175 | #else | |
179 | PyMODINIT_FUNC initbase85(void) |
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176 | PyMODINIT_FUNC initbase85(void) | |
180 | { |
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177 | { | |
181 | Py_InitModule3("base85", methods, base85_doc); |
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178 | Py_InitModule3("base85", methods, base85_doc); | |
182 |
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179 | |||
183 | b85prep(); |
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180 | b85prep(); | |
184 | } |
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181 | } | |
185 | #endif |
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182 | #endif |
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