Elia Battiston | 4750d3c | 2022-07-14 13:24:56 +0000 | [diff] [blame] | 1 | package ndr |
| 2 | |
| 3 | import ( |
| 4 | "errors" |
| 5 | "fmt" |
| 6 | "reflect" |
| 7 | "strconv" |
| 8 | ) |
| 9 | |
| 10 | // intFromTag returns an int that is a value in a struct tag key/value pair |
| 11 | func intFromTag(tag reflect.StructTag, key string) (int, error) { |
| 12 | ndrTag := parseTags(tag) |
| 13 | d := 1 |
| 14 | if n, ok := ndrTag.Map[key]; ok { |
| 15 | i, err := strconv.Atoi(n) |
| 16 | if err != nil { |
| 17 | return d, fmt.Errorf("invalid dimensions tag [%s]: %v", n, err) |
| 18 | } |
| 19 | d = i |
| 20 | } |
| 21 | return d, nil |
| 22 | } |
| 23 | |
| 24 | // parseDimensions returns the a slice of the size of each dimension and type of the member at the deepest level. |
| 25 | func parseDimensions(v reflect.Value) (l []int, tb reflect.Type) { |
| 26 | if v.Kind() == reflect.Ptr { |
| 27 | v = v.Elem() |
| 28 | } |
| 29 | t := v.Type() |
| 30 | if t.Kind() == reflect.Ptr { |
| 31 | t = t.Elem() |
| 32 | } |
| 33 | if t.Kind() != reflect.Array && t.Kind() != reflect.Slice { |
| 34 | return |
| 35 | } |
| 36 | l = append(l, v.Len()) |
| 37 | if t.Elem().Kind() == reflect.Array || t.Elem().Kind() == reflect.Slice { |
| 38 | // contains array or slice |
| 39 | var m []int |
| 40 | m, tb = parseDimensions(v.Index(0)) |
| 41 | l = append(l, m...) |
| 42 | } else { |
| 43 | tb = t.Elem() |
| 44 | } |
| 45 | return |
| 46 | } |
| 47 | |
| 48 | // sliceDimensions returns the count of dimensions a slice has. |
| 49 | func sliceDimensions(t reflect.Type) (d int, tb reflect.Type) { |
| 50 | if t.Kind() == reflect.Ptr { |
| 51 | t = t.Elem() |
| 52 | } |
| 53 | if t.Kind() == reflect.Slice { |
| 54 | d++ |
| 55 | var n int |
| 56 | n, tb = sliceDimensions(t.Elem()) |
| 57 | d += n |
| 58 | } else { |
| 59 | tb = t |
| 60 | } |
| 61 | return |
| 62 | } |
| 63 | |
| 64 | // makeSubSlices is a deep recursive creation/initialisation of multi-dimensional slices. |
| 65 | // Takes the reflect.Value of the 1st dimension and a slice of the lengths of the sub dimensions |
| 66 | func makeSubSlices(v reflect.Value, l []int) { |
| 67 | ty := v.Type().Elem() |
| 68 | if ty.Kind() != reflect.Slice { |
| 69 | return |
| 70 | } |
| 71 | for i := 0; i < v.Len(); i++ { |
| 72 | s := reflect.MakeSlice(ty, l[0], l[0]) |
| 73 | v.Index(i).Set(s) |
| 74 | // Are there more sub dimensions? |
| 75 | if len(l) > 1 { |
| 76 | makeSubSlices(v.Index(i), l[1:]) |
| 77 | } |
| 78 | } |
| 79 | return |
| 80 | } |
| 81 | |
| 82 | // multiDimensionalIndexPermutations returns all the permutations of the indexes of a multi-dimensional slice. |
| 83 | // The input is a slice of integers that indicates the max size/length of each dimension |
| 84 | func multiDimensionalIndexPermutations(l []int) (ps [][]int) { |
| 85 | z := make([]int, len(l), len(l)) // The zeros permutation |
| 86 | ps = append(ps, z) |
| 87 | // for each dimension, in reverse |
| 88 | for i := len(l) - 1; i >= 0; i-- { |
| 89 | ws := make([][]int, len(ps)) |
| 90 | copy(ws, ps) |
| 91 | //create a permutation for each of the iterations of the current dimension |
| 92 | for j := 1; j <= l[i]-1; j++ { |
| 93 | // For each existing permutation |
| 94 | for _, p := range ws { |
| 95 | np := make([]int, len(p), len(p)) |
| 96 | copy(np, p) |
| 97 | np[i] = j |
| 98 | ps = append(ps, np) |
| 99 | } |
| 100 | } |
| 101 | } |
| 102 | return |
| 103 | } |
| 104 | |
| 105 | // precedingMax reads off the next conformant max value |
| 106 | func (dec *Decoder) precedingMax() uint32 { |
| 107 | m := dec.conformantMax[0] |
| 108 | dec.conformantMax = dec.conformantMax[1:] |
| 109 | return m |
| 110 | } |
| 111 | |
| 112 | // fillFixedArray establishes if the fixed array is uni or multi dimensional and then fills it. |
| 113 | func (dec *Decoder) fillFixedArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 114 | l, t := parseDimensions(v) |
| 115 | if t.Kind() == reflect.String { |
| 116 | tag = reflect.StructTag(subStringArrayTag) |
| 117 | } |
| 118 | if len(l) < 1 { |
| 119 | return errors.New("could not establish dimensions of fixed array") |
| 120 | } |
| 121 | if len(l) == 1 { |
| 122 | err := dec.fillUniDimensionalFixedArray(v, tag, def) |
| 123 | if err != nil { |
| 124 | return fmt.Errorf("could not fill uni-dimensional fixed array: %v", err) |
| 125 | } |
| 126 | return nil |
| 127 | } |
| 128 | // Fixed array is multidimensional |
| 129 | ps := multiDimensionalIndexPermutations(l[:len(l)-1]) |
| 130 | for _, p := range ps { |
| 131 | // Get current multi-dimensional index to fill |
| 132 | a := v |
| 133 | for _, i := range p { |
| 134 | a = a.Index(i) |
| 135 | } |
| 136 | // fill with the last dimension array |
| 137 | err := dec.fillUniDimensionalFixedArray(a, tag, def) |
| 138 | if err != nil { |
| 139 | return fmt.Errorf("could not fill dimension %v of multi-dimensional fixed array: %v", p, err) |
| 140 | } |
| 141 | } |
| 142 | return nil |
| 143 | } |
| 144 | |
| 145 | // readUniDimensionalFixedArray reads an array (not slice) from the byte stream. |
| 146 | func (dec *Decoder) fillUniDimensionalFixedArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 147 | for i := 0; i < v.Len(); i++ { |
| 148 | err := dec.fill(v.Index(i), tag, def) |
| 149 | if err != nil { |
| 150 | return fmt.Errorf("could not fill index %d of fixed array: %v", i, err) |
| 151 | } |
| 152 | } |
| 153 | return nil |
| 154 | } |
| 155 | |
| 156 | // fillConformantArray establishes if the conformant array is uni or multi dimensional and then fills the slice. |
| 157 | func (dec *Decoder) fillConformantArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 158 | d, _ := sliceDimensions(v.Type()) |
| 159 | if d > 1 { |
| 160 | err := dec.fillMultiDimensionalConformantArray(v, d, tag, def) |
| 161 | if err != nil { |
| 162 | return err |
| 163 | } |
| 164 | } else { |
| 165 | err := dec.fillUniDimensionalConformantArray(v, tag, def) |
| 166 | if err != nil { |
| 167 | return err |
| 168 | } |
| 169 | } |
| 170 | return nil |
| 171 | } |
| 172 | |
| 173 | // fillUniDimensionalConformantArray fills the uni-dimensional slice value. |
| 174 | func (dec *Decoder) fillUniDimensionalConformantArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 175 | m := dec.precedingMax() |
| 176 | n := int(m) |
| 177 | a := reflect.MakeSlice(v.Type(), n, n) |
| 178 | for i := 0; i < n; i++ { |
| 179 | err := dec.fill(a.Index(i), tag, def) |
| 180 | if err != nil { |
| 181 | return fmt.Errorf("could not fill index %d of uni-dimensional conformant array: %v", i, err) |
| 182 | } |
| 183 | } |
| 184 | v.Set(a) |
| 185 | return nil |
| 186 | } |
| 187 | |
| 188 | // fillMultiDimensionalConformantArray fills the multi-dimensional slice value provided from conformant array data. |
| 189 | // The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this |
| 190 | // method not to panic. |
| 191 | func (dec *Decoder) fillMultiDimensionalConformantArray(v reflect.Value, d int, tag reflect.StructTag, def *[]deferedPtr) error { |
| 192 | // Read the max size of each dimensions from the ndr stream |
| 193 | l := make([]int, d, d) |
| 194 | for i := range l { |
| 195 | l[i] = int(dec.precedingMax()) |
| 196 | } |
| 197 | // Initialise size of slices |
| 198 | // Initialise the size of the 1st dimension |
| 199 | ty := v.Type() |
| 200 | v.Set(reflect.MakeSlice(ty, l[0], l[0])) |
| 201 | // Initialise the size of the other dimensions recursively |
| 202 | makeSubSlices(v, l[1:]) |
| 203 | |
| 204 | // Get all permutations of the indexes and go through each and fill |
| 205 | ps := multiDimensionalIndexPermutations(l) |
| 206 | for _, p := range ps { |
| 207 | // Get current multi-dimensional index to fill |
| 208 | a := v |
| 209 | for _, i := range p { |
| 210 | a = a.Index(i) |
| 211 | } |
| 212 | err := dec.fill(a, tag, def) |
| 213 | if err != nil { |
| 214 | return fmt.Errorf("could not fill index %v of slice: %v", p, err) |
| 215 | } |
| 216 | } |
| 217 | return nil |
| 218 | } |
| 219 | |
| 220 | // fillVaryingArray establishes if the varying array is uni or multi dimensional and then fills the slice. |
| 221 | func (dec *Decoder) fillVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 222 | d, t := sliceDimensions(v.Type()) |
| 223 | if d > 1 { |
| 224 | err := dec.fillMultiDimensionalVaryingArray(v, t, d, tag, def) |
| 225 | if err != nil { |
| 226 | return err |
| 227 | } |
| 228 | } else { |
| 229 | err := dec.fillUniDimensionalVaryingArray(v, tag, def) |
| 230 | if err != nil { |
| 231 | return err |
| 232 | } |
| 233 | } |
| 234 | return nil |
| 235 | } |
| 236 | |
| 237 | // fillUniDimensionalVaryingArray fills the uni-dimensional slice value. |
| 238 | func (dec *Decoder) fillUniDimensionalVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 239 | o, err := dec.readUint32() |
| 240 | if err != nil { |
| 241 | return fmt.Errorf("could not read offset of uni-dimensional varying array: %v", err) |
| 242 | } |
| 243 | s, err := dec.readUint32() |
| 244 | if err != nil { |
| 245 | return fmt.Errorf("could not establish actual count of uni-dimensional varying array: %v", err) |
| 246 | } |
| 247 | t := v.Type() |
| 248 | // Total size of the array is the offset in the index being passed plus the actual count of elements being passed. |
| 249 | n := int(s + o) |
| 250 | a := reflect.MakeSlice(t, n, n) |
| 251 | // Populate the array starting at the offset specified |
| 252 | for i := int(o); i < n; i++ { |
| 253 | err := dec.fill(a.Index(i), tag, def) |
| 254 | if err != nil { |
| 255 | return fmt.Errorf("could not fill index %d of uni-dimensional varying array: %v", i, err) |
| 256 | } |
| 257 | } |
| 258 | v.Set(a) |
| 259 | return nil |
| 260 | } |
| 261 | |
| 262 | // fillMultiDimensionalVaryingArray fills the multi-dimensional slice value provided from varying array data. |
| 263 | // The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this |
| 264 | // method not to panic. |
| 265 | func (dec *Decoder) fillMultiDimensionalVaryingArray(v reflect.Value, t reflect.Type, d int, tag reflect.StructTag, def *[]deferedPtr) error { |
| 266 | // Read the offset and actual count of each dimensions from the ndr stream |
| 267 | o := make([]int, d, d) |
| 268 | l := make([]int, d, d) |
| 269 | for i := range l { |
| 270 | off, err := dec.readUint32() |
| 271 | if err != nil { |
| 272 | return fmt.Errorf("could not read offset of dimension %d: %v", i+1, err) |
| 273 | } |
| 274 | o[i] = int(off) |
| 275 | s, err := dec.readUint32() |
| 276 | if err != nil { |
| 277 | return fmt.Errorf("could not read size of dimension %d: %v", i+1, err) |
| 278 | } |
| 279 | l[i] = int(s) + int(off) |
| 280 | } |
| 281 | // Initialise size of slices |
| 282 | // Initialise the size of the 1st dimension |
| 283 | ty := v.Type() |
| 284 | v.Set(reflect.MakeSlice(ty, l[0], l[0])) |
| 285 | // Initialise the size of the other dimensions recursively |
| 286 | makeSubSlices(v, l[1:]) |
| 287 | |
| 288 | // Get all permutations of the indexes and go through each and fill |
| 289 | ps := multiDimensionalIndexPermutations(l) |
| 290 | for _, p := range ps { |
| 291 | // Get current multi-dimensional index to fill |
| 292 | a := v |
| 293 | var os bool // should this permutation be skipped due to the offset of any of the dimensions? |
| 294 | for i, j := range p { |
| 295 | if j < o[i] { |
| 296 | os = true |
| 297 | break |
| 298 | } |
| 299 | a = a.Index(j) |
| 300 | } |
| 301 | if os { |
| 302 | // This permutation should be skipped as it is less than the offset for one of the dimensions. |
| 303 | continue |
| 304 | } |
| 305 | err := dec.fill(a, tag, def) |
| 306 | if err != nil { |
| 307 | return fmt.Errorf("could not fill index %v of slice: %v", p, err) |
| 308 | } |
| 309 | } |
| 310 | return nil |
| 311 | } |
| 312 | |
| 313 | // fillConformantVaryingArray establishes if the varying array is uni or multi dimensional and then fills the slice. |
| 314 | func (dec *Decoder) fillConformantVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 315 | d, t := sliceDimensions(v.Type()) |
| 316 | if d > 1 { |
| 317 | err := dec.fillMultiDimensionalConformantVaryingArray(v, t, d, tag, def) |
| 318 | if err != nil { |
| 319 | return err |
| 320 | } |
| 321 | } else { |
| 322 | err := dec.fillUniDimensionalConformantVaryingArray(v, tag, def) |
| 323 | if err != nil { |
| 324 | return err |
| 325 | } |
| 326 | } |
| 327 | return nil |
| 328 | } |
| 329 | |
| 330 | // fillUniDimensionalConformantVaryingArray fills the uni-dimensional slice value. |
| 331 | func (dec *Decoder) fillUniDimensionalConformantVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error { |
| 332 | m := dec.precedingMax() |
| 333 | o, err := dec.readUint32() |
| 334 | if err != nil { |
| 335 | return fmt.Errorf("could not read offset of uni-dimensional conformant varying array: %v", err) |
| 336 | } |
| 337 | s, err := dec.readUint32() |
| 338 | if err != nil { |
| 339 | return fmt.Errorf("could not establish actual count of uni-dimensional conformant varying array: %v", err) |
| 340 | } |
| 341 | if m < o+s { |
| 342 | return errors.New("max count is less than the offset plus actual count") |
| 343 | } |
| 344 | t := v.Type() |
| 345 | n := int(s) |
| 346 | a := reflect.MakeSlice(t, n, n) |
| 347 | for i := int(o); i < n; i++ { |
| 348 | err := dec.fill(a.Index(i), tag, def) |
| 349 | if err != nil { |
| 350 | return fmt.Errorf("could not fill index %d of uni-dimensional conformant varying array: %v", i, err) |
| 351 | } |
| 352 | } |
| 353 | v.Set(a) |
| 354 | return nil |
| 355 | } |
| 356 | |
| 357 | // fillMultiDimensionalConformantVaryingArray fills the multi-dimensional slice value provided from conformant varying array data. |
| 358 | // The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this |
| 359 | // method not to panic. |
| 360 | func (dec *Decoder) fillMultiDimensionalConformantVaryingArray(v reflect.Value, t reflect.Type, d int, tag reflect.StructTag, def *[]deferedPtr) error { |
| 361 | // Read the offset and actual count of each dimensions from the ndr stream |
| 362 | m := make([]int, d, d) |
| 363 | for i := range m { |
| 364 | m[i] = int(dec.precedingMax()) |
| 365 | } |
| 366 | o := make([]int, d, d) |
| 367 | l := make([]int, d, d) |
| 368 | for i := range l { |
| 369 | off, err := dec.readUint32() |
| 370 | if err != nil { |
| 371 | return fmt.Errorf("could not read offset of dimension %d: %v", i+1, err) |
| 372 | } |
| 373 | o[i] = int(off) |
| 374 | s, err := dec.readUint32() |
| 375 | if err != nil { |
| 376 | return fmt.Errorf("could not read actual count of dimension %d: %v", i+1, err) |
| 377 | } |
| 378 | if m[i] < int(s)+int(off) { |
| 379 | m[i] = int(s) + int(off) |
| 380 | } |
| 381 | l[i] = int(s) |
| 382 | } |
| 383 | // Initialise size of slices |
| 384 | // Initialise the size of the 1st dimension |
| 385 | ty := v.Type() |
| 386 | v.Set(reflect.MakeSlice(ty, m[0], m[0])) |
| 387 | // Initialise the size of the other dimensions recursively |
| 388 | makeSubSlices(v, m[1:]) |
| 389 | |
| 390 | // Get all permutations of the indexes and go through each and fill |
| 391 | ps := multiDimensionalIndexPermutations(m) |
| 392 | for _, p := range ps { |
| 393 | // Get current multi-dimensional index to fill |
| 394 | a := v |
| 395 | var os bool // should this permutation be skipped due to the offset of any of the dimensions or max is higher than the actual count being passed |
| 396 | for i, j := range p { |
| 397 | if j < o[i] || j >= l[i] { |
| 398 | os = true |
| 399 | break |
| 400 | } |
| 401 | a = a.Index(j) |
| 402 | } |
| 403 | if os { |
| 404 | // This permutation should be skipped as it is less than the offset for one of the dimensions. |
| 405 | continue |
| 406 | } |
| 407 | err := dec.fill(a, tag, def) |
| 408 | if err != nil { |
| 409 | return fmt.Errorf("could not fill index %v of slice: %v", p, err) |
| 410 | } |
| 411 | } |
| 412 | return nil |
| 413 | } |