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1 |
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2 /* Buffer object implementation */ |
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3 |
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4 #include "Python.h" |
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5 |
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6 |
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7 typedef struct { |
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8 PyObject_HEAD |
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9 PyObject *b_base; |
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10 void *b_ptr; |
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11 Py_ssize_t b_size; |
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12 Py_ssize_t b_offset; |
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13 int b_readonly; |
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14 long b_hash; |
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15 } PyBufferObject; |
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16 |
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17 |
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18 enum buffer_t { |
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19 READ_BUFFER, |
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20 WRITE_BUFFER, |
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21 CHAR_BUFFER, |
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22 ANY_BUFFER |
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23 }; |
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24 |
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25 static int |
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26 get_buf(PyBufferObject *self, void **ptr, Py_ssize_t *size, |
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27 enum buffer_t buffer_type) |
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28 { |
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29 if (self->b_base == NULL) { |
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30 assert (ptr != NULL); |
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31 *ptr = self->b_ptr; |
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32 *size = self->b_size; |
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33 } |
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34 else { |
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35 Py_ssize_t count, offset; |
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36 readbufferproc proc = 0; |
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37 PyBufferProcs *bp = self->b_base->ob_type->tp_as_buffer; |
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38 if ((*bp->bf_getsegcount)(self->b_base, NULL) != 1) { |
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39 PyErr_SetString(PyExc_TypeError, |
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40 "single-segment buffer object expected"); |
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41 return 0; |
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42 } |
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43 if ((buffer_type == READ_BUFFER) || |
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44 ((buffer_type == ANY_BUFFER) && self->b_readonly)) |
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45 proc = bp->bf_getreadbuffer; |
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46 else if ((buffer_type == WRITE_BUFFER) || |
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47 (buffer_type == ANY_BUFFER)) |
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48 proc = (readbufferproc)bp->bf_getwritebuffer; |
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49 else if (buffer_type == CHAR_BUFFER) { |
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50 if (!PyType_HasFeature(self->ob_type, |
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51 Py_TPFLAGS_HAVE_GETCHARBUFFER)) { |
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52 PyErr_SetString(PyExc_TypeError, |
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53 "Py_TPFLAGS_HAVE_GETCHARBUFFER needed"); |
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54 return 0; |
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55 } |
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56 proc = (readbufferproc)bp->bf_getcharbuffer; |
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57 } |
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58 if (!proc) { |
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59 char *buffer_type_name; |
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60 switch (buffer_type) { |
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61 case READ_BUFFER: |
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62 buffer_type_name = "read"; |
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63 break; |
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64 case WRITE_BUFFER: |
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65 buffer_type_name = "write"; |
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66 break; |
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67 case CHAR_BUFFER: |
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68 buffer_type_name = "char"; |
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69 break; |
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70 default: |
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71 buffer_type_name = "no"; |
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72 break; |
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73 } |
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74 PyErr_Format(PyExc_TypeError, |
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75 "%s buffer type not available", |
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76 buffer_type_name); |
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77 return 0; |
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78 } |
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79 if ((count = (*proc)(self->b_base, 0, ptr)) < 0) |
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80 return 0; |
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81 /* apply constraints to the start/end */ |
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82 if (self->b_offset > count) |
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83 offset = count; |
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84 else |
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85 offset = self->b_offset; |
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86 *(char **)ptr = *(char **)ptr + offset; |
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87 if (self->b_size == Py_END_OF_BUFFER) |
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88 *size = count; |
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89 else |
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90 *size = self->b_size; |
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91 if (offset + *size > count) |
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92 *size = count - offset; |
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93 } |
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94 return 1; |
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95 } |
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96 |
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97 |
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98 static PyObject * |
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99 buffer_from_memory(PyObject *base, Py_ssize_t size, Py_ssize_t offset, void *ptr, |
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100 int readonly) |
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101 { |
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102 PyBufferObject * b; |
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103 |
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104 if (size < 0 && size != Py_END_OF_BUFFER) { |
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105 PyErr_SetString(PyExc_ValueError, |
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106 "size must be zero or positive"); |
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107 return NULL; |
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108 } |
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109 if (offset < 0) { |
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110 PyErr_SetString(PyExc_ValueError, |
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111 "offset must be zero or positive"); |
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112 return NULL; |
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113 } |
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114 |
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115 b = PyObject_NEW(PyBufferObject, &PyBuffer_Type); |
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116 if ( b == NULL ) |
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117 return NULL; |
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118 |
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119 Py_XINCREF(base); |
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120 b->b_base = base; |
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121 b->b_ptr = ptr; |
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122 b->b_size = size; |
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123 b->b_offset = offset; |
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124 b->b_readonly = readonly; |
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125 b->b_hash = -1; |
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126 |
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127 return (PyObject *) b; |
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128 } |
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129 |
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130 static PyObject * |
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131 buffer_from_object(PyObject *base, Py_ssize_t size, Py_ssize_t offset, int readonly) |
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132 { |
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133 if (offset < 0) { |
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134 PyErr_SetString(PyExc_ValueError, |
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135 "offset must be zero or positive"); |
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136 return NULL; |
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137 } |
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138 if ( PyBuffer_Check(base) && (((PyBufferObject *)base)->b_base) ) { |
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139 /* another buffer, refer to the base object */ |
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140 PyBufferObject *b = (PyBufferObject *)base; |
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141 if (b->b_size != Py_END_OF_BUFFER) { |
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142 Py_ssize_t base_size = b->b_size - offset; |
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143 if (base_size < 0) |
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144 base_size = 0; |
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145 if (size == Py_END_OF_BUFFER || size > base_size) |
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146 size = base_size; |
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147 } |
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148 offset += b->b_offset; |
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149 base = b->b_base; |
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150 } |
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151 return buffer_from_memory(base, size, offset, NULL, readonly); |
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152 } |
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153 |
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154 |
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155 PyObject * |
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156 PyBuffer_FromObject(PyObject *base, Py_ssize_t offset, Py_ssize_t size) |
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157 { |
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158 PyBufferProcs *pb = base->ob_type->tp_as_buffer; |
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159 |
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160 if ( pb == NULL || |
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161 pb->bf_getreadbuffer == NULL || |
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162 pb->bf_getsegcount == NULL ) |
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163 { |
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164 PyErr_SetString(PyExc_TypeError, "buffer object expected"); |
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165 return NULL; |
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166 } |
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167 |
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168 return buffer_from_object(base, size, offset, 1); |
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169 } |
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170 |
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171 PyObject * |
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172 PyBuffer_FromReadWriteObject(PyObject *base, Py_ssize_t offset, Py_ssize_t size) |
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173 { |
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174 PyBufferProcs *pb = base->ob_type->tp_as_buffer; |
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175 |
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176 if ( pb == NULL || |
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177 pb->bf_getwritebuffer == NULL || |
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178 pb->bf_getsegcount == NULL ) |
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179 { |
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180 PyErr_SetString(PyExc_TypeError, "buffer object expected"); |
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181 return NULL; |
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182 } |
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183 |
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184 return buffer_from_object(base, size, offset, 0); |
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185 } |
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186 |
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187 PyObject * |
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188 PyBuffer_FromMemory(void *ptr, Py_ssize_t size) |
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189 { |
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190 return buffer_from_memory(NULL, size, 0, ptr, 1); |
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191 } |
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192 |
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193 PyObject * |
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194 PyBuffer_FromReadWriteMemory(void *ptr, Py_ssize_t size) |
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195 { |
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196 return buffer_from_memory(NULL, size, 0, ptr, 0); |
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197 } |
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198 |
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199 PyObject * |
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200 PyBuffer_New(Py_ssize_t size) |
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201 { |
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202 PyObject *o; |
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203 PyBufferObject * b; |
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204 |
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205 if (size < 0) { |
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206 PyErr_SetString(PyExc_ValueError, |
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207 "size must be zero or positive"); |
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208 return NULL; |
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209 } |
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210 if (sizeof(*b) > PY_SSIZE_T_MAX - size) { |
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211 /* unlikely */ |
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212 return PyErr_NoMemory(); |
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213 } |
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214 /* Inline PyObject_New */ |
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215 o = (PyObject *)PyObject_MALLOC(sizeof(*b) + size); |
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216 if ( o == NULL ) |
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217 return PyErr_NoMemory(); |
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218 b = (PyBufferObject *) PyObject_INIT(o, &PyBuffer_Type); |
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219 |
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220 b->b_base = NULL; |
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221 b->b_ptr = (void *)(b + 1); |
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222 b->b_size = size; |
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223 b->b_offset = 0; |
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224 b->b_readonly = 0; |
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225 b->b_hash = -1; |
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226 |
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227 return o; |
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228 } |
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229 |
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230 /* Methods */ |
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231 |
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232 static PyObject * |
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233 buffer_new(PyTypeObject *type, PyObject *args, PyObject *kw) |
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234 { |
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235 PyObject *ob; |
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236 Py_ssize_t offset = 0; |
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237 Py_ssize_t size = Py_END_OF_BUFFER; |
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238 |
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239 if (PyErr_WarnPy3k("buffer() not supported in 3.x", 1) < 0) |
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240 return NULL; |
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241 |
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242 if (!_PyArg_NoKeywords("buffer()", kw)) |
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243 return NULL; |
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244 |
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245 if (!PyArg_ParseTuple(args, "O|nn:buffer", &ob, &offset, &size)) |
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246 return NULL; |
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247 return PyBuffer_FromObject(ob, offset, size); |
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248 } |
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249 |
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250 PyDoc_STRVAR(buffer_doc, |
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251 "buffer(object [, offset[, size]])\n\ |
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252 \n\ |
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253 Create a new buffer object which references the given object.\n\ |
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254 The buffer will reference a slice of the target object from the\n\ |
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255 start of the object (or at the specified offset). The slice will\n\ |
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256 extend to the end of the target object (or with the specified size)."); |
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257 |
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258 |
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259 static void |
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260 buffer_dealloc(PyBufferObject *self) |
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261 { |
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262 Py_XDECREF(self->b_base); |
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263 PyObject_DEL(self); |
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264 } |
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265 |
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266 static int |
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267 buffer_compare(PyBufferObject *self, PyBufferObject *other) |
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268 { |
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269 void *p1, *p2; |
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270 Py_ssize_t len_self, len_other, min_len; |
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271 int cmp; |
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272 |
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273 if (!get_buf(self, &p1, &len_self, ANY_BUFFER)) |
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274 return -1; |
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275 if (!get_buf(other, &p2, &len_other, ANY_BUFFER)) |
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276 return -1; |
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277 min_len = (len_self < len_other) ? len_self : len_other; |
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278 if (min_len > 0) { |
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279 cmp = memcmp(p1, p2, min_len); |
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280 if (cmp != 0) |
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281 return cmp < 0 ? -1 : 1; |
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282 } |
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283 return (len_self < len_other) ? -1 : (len_self > len_other) ? 1 : 0; |
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284 } |
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285 |
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286 static PyObject * |
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287 buffer_repr(PyBufferObject *self) |
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288 { |
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289 const char *status = self->b_readonly ? "read-only" : "read-write"; |
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290 |
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291 if ( self->b_base == NULL ) |
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292 return PyString_FromFormat("<%s buffer ptr %p, size %zd at %p>", |
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293 status, |
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294 self->b_ptr, |
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295 self->b_size, |
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296 self); |
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297 else |
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298 return PyString_FromFormat( |
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299 "<%s buffer for %p, size %zd, offset %zd at %p>", |
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300 status, |
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301 self->b_base, |
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302 self->b_size, |
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303 self->b_offset, |
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304 self); |
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305 } |
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306 |
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307 static long |
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308 buffer_hash(PyBufferObject *self) |
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309 { |
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310 void *ptr; |
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311 Py_ssize_t size; |
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312 register Py_ssize_t len; |
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313 register unsigned char *p; |
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314 register long x; |
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315 |
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316 if ( self->b_hash != -1 ) |
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317 return self->b_hash; |
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318 |
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319 /* XXX potential bugs here, a readonly buffer does not imply that the |
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320 * underlying memory is immutable. b_readonly is a necessary but not |
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321 * sufficient condition for a buffer to be hashable. Perhaps it would |
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322 * be better to only allow hashing if the underlying object is known to |
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323 * be immutable (e.g. PyString_Check() is true). Another idea would |
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324 * be to call tp_hash on the underlying object and see if it raises |
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325 * an error. */ |
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326 if ( !self->b_readonly ) |
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327 { |
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328 PyErr_SetString(PyExc_TypeError, |
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329 "writable buffers are not hashable"); |
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330 return -1; |
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331 } |
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332 |
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333 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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334 return -1; |
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335 p = (unsigned char *) ptr; |
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336 len = size; |
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337 x = *p << 7; |
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338 while (--len >= 0) |
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339 x = (1000003*x) ^ *p++; |
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340 x ^= size; |
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341 if (x == -1) |
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342 x = -2; |
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343 self->b_hash = x; |
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344 return x; |
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345 } |
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346 |
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347 static PyObject * |
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348 buffer_str(PyBufferObject *self) |
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349 { |
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350 void *ptr; |
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351 Py_ssize_t size; |
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352 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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353 return NULL; |
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354 return PyString_FromStringAndSize((const char *)ptr, size); |
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355 } |
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356 |
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357 /* Sequence methods */ |
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358 |
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359 static Py_ssize_t |
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360 buffer_length(PyBufferObject *self) |
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361 { |
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362 void *ptr; |
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363 Py_ssize_t size; |
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364 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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365 return -1; |
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366 return size; |
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367 } |
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368 |
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369 static PyObject * |
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370 buffer_concat(PyBufferObject *self, PyObject *other) |
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371 { |
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372 PyBufferProcs *pb = other->ob_type->tp_as_buffer; |
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373 void *ptr1, *ptr2; |
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374 char *p; |
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375 PyObject *ob; |
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376 Py_ssize_t size, count; |
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377 |
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378 if ( pb == NULL || |
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379 pb->bf_getreadbuffer == NULL || |
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380 pb->bf_getsegcount == NULL ) |
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381 { |
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382 PyErr_BadArgument(); |
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383 return NULL; |
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384 } |
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385 if ( (*pb->bf_getsegcount)(other, NULL) != 1 ) |
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386 { |
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387 /* ### use a different exception type/message? */ |
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388 PyErr_SetString(PyExc_TypeError, |
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389 "single-segment buffer object expected"); |
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390 return NULL; |
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391 } |
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392 |
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393 if (!get_buf(self, &ptr1, &size, ANY_BUFFER)) |
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394 return NULL; |
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395 |
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396 /* optimize special case */ |
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397 if ( size == 0 ) |
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398 { |
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399 Py_INCREF(other); |
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400 return other; |
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401 } |
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402 |
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403 if ( (count = (*pb->bf_getreadbuffer)(other, 0, &ptr2)) < 0 ) |
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404 return NULL; |
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405 |
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406 assert(count <= PY_SIZE_MAX - size); |
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407 |
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408 ob = PyString_FromStringAndSize(NULL, size + count); |
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409 if ( ob == NULL ) |
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410 return NULL; |
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411 p = PyString_AS_STRING(ob); |
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412 memcpy(p, ptr1, size); |
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413 memcpy(p + size, ptr2, count); |
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414 |
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415 /* there is an extra byte in the string object, so this is safe */ |
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416 p[size + count] = '\0'; |
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417 |
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418 return ob; |
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419 } |
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420 |
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421 static PyObject * |
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422 buffer_repeat(PyBufferObject *self, Py_ssize_t count) |
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423 { |
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424 PyObject *ob; |
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425 register char *p; |
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426 void *ptr; |
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427 Py_ssize_t size; |
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428 |
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429 if ( count < 0 ) |
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430 count = 0; |
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431 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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432 return NULL; |
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433 if (count > PY_SSIZE_T_MAX / size) { |
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434 PyErr_SetString(PyExc_MemoryError, "result too large"); |
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435 return NULL; |
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436 } |
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437 ob = PyString_FromStringAndSize(NULL, size * count); |
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438 if ( ob == NULL ) |
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439 return NULL; |
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440 |
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441 p = PyString_AS_STRING(ob); |
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442 while ( count-- ) |
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443 { |
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444 memcpy(p, ptr, size); |
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445 p += size; |
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446 } |
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447 |
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448 /* there is an extra byte in the string object, so this is safe */ |
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449 *p = '\0'; |
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450 |
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451 return ob; |
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452 } |
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453 |
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454 static PyObject * |
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455 buffer_item(PyBufferObject *self, Py_ssize_t idx) |
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456 { |
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457 void *ptr; |
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458 Py_ssize_t size; |
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459 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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460 return NULL; |
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461 if ( idx < 0 || idx >= size ) { |
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462 PyErr_SetString(PyExc_IndexError, "buffer index out of range"); |
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463 return NULL; |
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464 } |
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465 return PyString_FromStringAndSize((char *)ptr + idx, 1); |
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466 } |
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467 |
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468 static PyObject * |
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469 buffer_slice(PyBufferObject *self, Py_ssize_t left, Py_ssize_t right) |
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470 { |
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471 void *ptr; |
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472 Py_ssize_t size; |
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473 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
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474 return NULL; |
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475 if ( left < 0 ) |
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476 left = 0; |
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477 if ( right < 0 ) |
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478 right = 0; |
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479 if ( right > size ) |
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480 right = size; |
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481 if ( right < left ) |
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482 right = left; |
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483 return PyString_FromStringAndSize((char *)ptr + left, |
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484 right - left); |
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485 } |
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486 |
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487 static PyObject * |
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488 buffer_subscript(PyBufferObject *self, PyObject *item) |
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489 { |
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490 void *p; |
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491 Py_ssize_t size; |
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492 |
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493 if (!get_buf(self, &p, &size, ANY_BUFFER)) |
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494 return NULL; |
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495 if (PyIndex_Check(item)) { |
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496 Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError); |
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497 if (i == -1 && PyErr_Occurred()) |
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498 return NULL; |
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499 if (i < 0) |
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500 i += size; |
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501 return buffer_item(self, i); |
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502 } |
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503 else if (PySlice_Check(item)) { |
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504 Py_ssize_t start, stop, step, slicelength, cur, i; |
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505 |
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506 if (PySlice_GetIndicesEx((PySliceObject*)item, size, |
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507 &start, &stop, &step, &slicelength) < 0) { |
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508 return NULL; |
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509 } |
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510 |
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511 if (slicelength <= 0) |
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512 return PyString_FromStringAndSize("", 0); |
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513 else if (step == 1) |
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514 return PyString_FromStringAndSize((char *)p + start, |
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515 stop - start); |
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516 else { |
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517 PyObject *result; |
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518 char *source_buf = (char *)p; |
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519 char *result_buf = (char *)PyMem_Malloc(slicelength); |
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520 |
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521 if (result_buf == NULL) |
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522 return PyErr_NoMemory(); |
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523 |
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524 for (cur = start, i = 0; i < slicelength; |
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525 cur += step, i++) { |
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526 result_buf[i] = source_buf[cur]; |
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527 } |
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528 |
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529 result = PyString_FromStringAndSize(result_buf, |
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530 slicelength); |
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531 PyMem_Free(result_buf); |
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532 return result; |
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533 } |
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534 } |
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535 else { |
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536 PyErr_SetString(PyExc_TypeError, |
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537 "sequence index must be integer"); |
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538 return NULL; |
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539 } |
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540 } |
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541 |
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542 static int |
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543 buffer_ass_item(PyBufferObject *self, Py_ssize_t idx, PyObject *other) |
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544 { |
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545 PyBufferProcs *pb; |
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546 void *ptr1, *ptr2; |
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547 Py_ssize_t size; |
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548 Py_ssize_t count; |
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549 |
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550 if ( self->b_readonly ) { |
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551 PyErr_SetString(PyExc_TypeError, |
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552 "buffer is read-only"); |
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553 return -1; |
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554 } |
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555 |
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556 if (!get_buf(self, &ptr1, &size, ANY_BUFFER)) |
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557 return -1; |
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558 |
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559 if (idx < 0 || idx >= size) { |
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560 PyErr_SetString(PyExc_IndexError, |
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561 "buffer assignment index out of range"); |
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562 return -1; |
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563 } |
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564 |
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565 pb = other ? other->ob_type->tp_as_buffer : NULL; |
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566 if ( pb == NULL || |
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567 pb->bf_getreadbuffer == NULL || |
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568 pb->bf_getsegcount == NULL ) |
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569 { |
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570 PyErr_BadArgument(); |
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571 return -1; |
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572 } |
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573 if ( (*pb->bf_getsegcount)(other, NULL) != 1 ) |
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574 { |
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575 /* ### use a different exception type/message? */ |
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576 PyErr_SetString(PyExc_TypeError, |
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577 "single-segment buffer object expected"); |
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578 return -1; |
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579 } |
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580 |
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581 if ( (count = (*pb->bf_getreadbuffer)(other, 0, &ptr2)) < 0 ) |
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582 return -1; |
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583 if ( count != 1 ) { |
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584 PyErr_SetString(PyExc_TypeError, |
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585 "right operand must be a single byte"); |
|
586 return -1; |
|
587 } |
|
588 |
|
589 ((char *)ptr1)[idx] = *(char *)ptr2; |
|
590 return 0; |
|
591 } |
|
592 |
|
593 static int |
|
594 buffer_ass_slice(PyBufferObject *self, Py_ssize_t left, Py_ssize_t right, PyObject *other) |
|
595 { |
|
596 PyBufferProcs *pb; |
|
597 void *ptr1, *ptr2; |
|
598 Py_ssize_t size; |
|
599 Py_ssize_t slice_len; |
|
600 Py_ssize_t count; |
|
601 |
|
602 if ( self->b_readonly ) { |
|
603 PyErr_SetString(PyExc_TypeError, |
|
604 "buffer is read-only"); |
|
605 return -1; |
|
606 } |
|
607 |
|
608 pb = other ? other->ob_type->tp_as_buffer : NULL; |
|
609 if ( pb == NULL || |
|
610 pb->bf_getreadbuffer == NULL || |
|
611 pb->bf_getsegcount == NULL ) |
|
612 { |
|
613 PyErr_BadArgument(); |
|
614 return -1; |
|
615 } |
|
616 if ( (*pb->bf_getsegcount)(other, NULL) != 1 ) |
|
617 { |
|
618 /* ### use a different exception type/message? */ |
|
619 PyErr_SetString(PyExc_TypeError, |
|
620 "single-segment buffer object expected"); |
|
621 return -1; |
|
622 } |
|
623 if (!get_buf(self, &ptr1, &size, ANY_BUFFER)) |
|
624 return -1; |
|
625 if ( (count = (*pb->bf_getreadbuffer)(other, 0, &ptr2)) < 0 ) |
|
626 return -1; |
|
627 |
|
628 if ( left < 0 ) |
|
629 left = 0; |
|
630 else if ( left > size ) |
|
631 left = size; |
|
632 if ( right < left ) |
|
633 right = left; |
|
634 else if ( right > size ) |
|
635 right = size; |
|
636 slice_len = right - left; |
|
637 |
|
638 if ( count != slice_len ) { |
|
639 PyErr_SetString( |
|
640 PyExc_TypeError, |
|
641 "right operand length must match slice length"); |
|
642 return -1; |
|
643 } |
|
644 |
|
645 if ( slice_len ) |
|
646 memcpy((char *)ptr1 + left, ptr2, slice_len); |
|
647 |
|
648 return 0; |
|
649 } |
|
650 |
|
651 static int |
|
652 buffer_ass_subscript(PyBufferObject *self, PyObject *item, PyObject *value) |
|
653 { |
|
654 PyBufferProcs *pb; |
|
655 void *ptr1, *ptr2; |
|
656 Py_ssize_t selfsize; |
|
657 Py_ssize_t othersize; |
|
658 |
|
659 if ( self->b_readonly ) { |
|
660 PyErr_SetString(PyExc_TypeError, |
|
661 "buffer is read-only"); |
|
662 return -1; |
|
663 } |
|
664 |
|
665 pb = value ? value->ob_type->tp_as_buffer : NULL; |
|
666 if ( pb == NULL || |
|
667 pb->bf_getreadbuffer == NULL || |
|
668 pb->bf_getsegcount == NULL ) |
|
669 { |
|
670 PyErr_BadArgument(); |
|
671 return -1; |
|
672 } |
|
673 if ( (*pb->bf_getsegcount)(value, NULL) != 1 ) |
|
674 { |
|
675 /* ### use a different exception type/message? */ |
|
676 PyErr_SetString(PyExc_TypeError, |
|
677 "single-segment buffer object expected"); |
|
678 return -1; |
|
679 } |
|
680 if (!get_buf(self, &ptr1, &selfsize, ANY_BUFFER)) |
|
681 return -1; |
|
682 if (PyIndex_Check(item)) { |
|
683 Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError); |
|
684 if (i == -1 && PyErr_Occurred()) |
|
685 return -1; |
|
686 if (i < 0) |
|
687 i += selfsize; |
|
688 return buffer_ass_item(self, i, value); |
|
689 } |
|
690 else if (PySlice_Check(item)) { |
|
691 Py_ssize_t start, stop, step, slicelength; |
|
692 |
|
693 if (PySlice_GetIndicesEx((PySliceObject *)item, selfsize, |
|
694 &start, &stop, &step, &slicelength) < 0) |
|
695 return -1; |
|
696 |
|
697 if ((othersize = (*pb->bf_getreadbuffer)(value, 0, &ptr2)) < 0) |
|
698 return -1; |
|
699 |
|
700 if (othersize != slicelength) { |
|
701 PyErr_SetString( |
|
702 PyExc_TypeError, |
|
703 "right operand length must match slice length"); |
|
704 return -1; |
|
705 } |
|
706 |
|
707 if (slicelength == 0) |
|
708 return 0; |
|
709 else if (step == 1) { |
|
710 memcpy((char *)ptr1 + start, ptr2, slicelength); |
|
711 return 0; |
|
712 } |
|
713 else { |
|
714 Py_ssize_t cur, i; |
|
715 |
|
716 for (cur = start, i = 0; i < slicelength; |
|
717 cur += step, i++) { |
|
718 ((char *)ptr1)[cur] = ((char *)ptr2)[i]; |
|
719 } |
|
720 |
|
721 return 0; |
|
722 } |
|
723 } else { |
|
724 PyErr_SetString(PyExc_TypeError, |
|
725 "buffer indices must be integers"); |
|
726 return -1; |
|
727 } |
|
728 } |
|
729 |
|
730 /* Buffer methods */ |
|
731 |
|
732 static Py_ssize_t |
|
733 buffer_getreadbuf(PyBufferObject *self, Py_ssize_t idx, void **pp) |
|
734 { |
|
735 Py_ssize_t size; |
|
736 if ( idx != 0 ) { |
|
737 PyErr_SetString(PyExc_SystemError, |
|
738 "accessing non-existent buffer segment"); |
|
739 return -1; |
|
740 } |
|
741 if (!get_buf(self, pp, &size, READ_BUFFER)) |
|
742 return -1; |
|
743 return size; |
|
744 } |
|
745 |
|
746 static Py_ssize_t |
|
747 buffer_getwritebuf(PyBufferObject *self, Py_ssize_t idx, void **pp) |
|
748 { |
|
749 Py_ssize_t size; |
|
750 |
|
751 if ( self->b_readonly ) |
|
752 { |
|
753 PyErr_SetString(PyExc_TypeError, "buffer is read-only"); |
|
754 return -1; |
|
755 } |
|
756 |
|
757 if ( idx != 0 ) { |
|
758 PyErr_SetString(PyExc_SystemError, |
|
759 "accessing non-existent buffer segment"); |
|
760 return -1; |
|
761 } |
|
762 if (!get_buf(self, pp, &size, WRITE_BUFFER)) |
|
763 return -1; |
|
764 return size; |
|
765 } |
|
766 |
|
767 static Py_ssize_t |
|
768 buffer_getsegcount(PyBufferObject *self, Py_ssize_t *lenp) |
|
769 { |
|
770 void *ptr; |
|
771 Py_ssize_t size; |
|
772 if (!get_buf(self, &ptr, &size, ANY_BUFFER)) |
|
773 return -1; |
|
774 if (lenp) |
|
775 *lenp = size; |
|
776 return 1; |
|
777 } |
|
778 |
|
779 static Py_ssize_t |
|
780 buffer_getcharbuf(PyBufferObject *self, Py_ssize_t idx, const char **pp) |
|
781 { |
|
782 void *ptr; |
|
783 Py_ssize_t size; |
|
784 if ( idx != 0 ) { |
|
785 PyErr_SetString(PyExc_SystemError, |
|
786 "accessing non-existent buffer segment"); |
|
787 return -1; |
|
788 } |
|
789 if (!get_buf(self, &ptr, &size, CHAR_BUFFER)) |
|
790 return -1; |
|
791 *pp = (const char *)ptr; |
|
792 return size; |
|
793 } |
|
794 |
|
795 static PySequenceMethods buffer_as_sequence = { |
|
796 (lenfunc)buffer_length, /*sq_length*/ |
|
797 (binaryfunc)buffer_concat, /*sq_concat*/ |
|
798 (ssizeargfunc)buffer_repeat, /*sq_repeat*/ |
|
799 (ssizeargfunc)buffer_item, /*sq_item*/ |
|
800 (ssizessizeargfunc)buffer_slice, /*sq_slice*/ |
|
801 (ssizeobjargproc)buffer_ass_item, /*sq_ass_item*/ |
|
802 (ssizessizeobjargproc)buffer_ass_slice, /*sq_ass_slice*/ |
|
803 }; |
|
804 |
|
805 static PyMappingMethods buffer_as_mapping = { |
|
806 (lenfunc)buffer_length, |
|
807 (binaryfunc)buffer_subscript, |
|
808 (objobjargproc)buffer_ass_subscript, |
|
809 }; |
|
810 |
|
811 static PyBufferProcs buffer_as_buffer = { |
|
812 (readbufferproc)buffer_getreadbuf, |
|
813 (writebufferproc)buffer_getwritebuf, |
|
814 (segcountproc)buffer_getsegcount, |
|
815 (charbufferproc)buffer_getcharbuf, |
|
816 }; |
|
817 |
|
818 PyTypeObject PyBuffer_Type = { |
|
819 PyVarObject_HEAD_INIT(&PyType_Type, 0) |
|
820 "buffer", |
|
821 sizeof(PyBufferObject), |
|
822 0, |
|
823 (destructor)buffer_dealloc, /* tp_dealloc */ |
|
824 0, /* tp_print */ |
|
825 0, /* tp_getattr */ |
|
826 0, /* tp_setattr */ |
|
827 (cmpfunc)buffer_compare, /* tp_compare */ |
|
828 (reprfunc)buffer_repr, /* tp_repr */ |
|
829 0, /* tp_as_number */ |
|
830 &buffer_as_sequence, /* tp_as_sequence */ |
|
831 &buffer_as_mapping, /* tp_as_mapping */ |
|
832 (hashfunc)buffer_hash, /* tp_hash */ |
|
833 0, /* tp_call */ |
|
834 (reprfunc)buffer_str, /* tp_str */ |
|
835 PyObject_GenericGetAttr, /* tp_getattro */ |
|
836 0, /* tp_setattro */ |
|
837 &buffer_as_buffer, /* tp_as_buffer */ |
|
838 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GETCHARBUFFER, /* tp_flags */ |
|
839 buffer_doc, /* tp_doc */ |
|
840 0, /* tp_traverse */ |
|
841 0, /* tp_clear */ |
|
842 0, /* tp_richcompare */ |
|
843 0, /* tp_weaklistoffset */ |
|
844 0, /* tp_iter */ |
|
845 0, /* tp_iternext */ |
|
846 0, /* tp_methods */ |
|
847 0, /* tp_members */ |
|
848 0, /* tp_getset */ |
|
849 0, /* tp_base */ |
|
850 0, /* tp_dict */ |
|
851 0, /* tp_descr_get */ |
|
852 0, /* tp_descr_set */ |
|
853 0, /* tp_dictoffset */ |
|
854 0, /* tp_init */ |
|
855 0, /* tp_alloc */ |
|
856 buffer_new, /* tp_new */ |
|
857 }; |