diff options
Diffstat (limited to 'vendor/github.com/bits-and-blooms/bitset/bitset.go')
| -rw-r--r-- | vendor/github.com/bits-and-blooms/bitset/bitset.go | 952 |
1 files changed, 0 insertions, 952 deletions
diff --git a/vendor/github.com/bits-and-blooms/bitset/bitset.go b/vendor/github.com/bits-and-blooms/bitset/bitset.go deleted file mode 100644 index d688806a5..000000000 --- a/vendor/github.com/bits-and-blooms/bitset/bitset.go +++ /dev/null @@ -1,952 +0,0 @@ -/* -Package bitset implements bitsets, a mapping -between non-negative integers and boolean values. It should be more -efficient than map[uint] bool. - -It provides methods for setting, clearing, flipping, and testing -individual integers. - -But it also provides set intersection, union, difference, -complement, and symmetric operations, as well as tests to -check whether any, all, or no bits are set, and querying a -bitset's current length and number of positive bits. - -BitSets are expanded to the size of the largest set bit; the -memory allocation is approximately Max bits, where Max is -the largest set bit. BitSets are never shrunk. On creation, -a hint can be given for the number of bits that will be used. - -Many of the methods, including Set,Clear, and Flip, return -a BitSet pointer, which allows for chaining. - -Example use: - - import "bitset" - var b BitSet - b.Set(10).Set(11) - if b.Test(1000) { - b.Clear(1000) - } - if B.Intersection(bitset.New(100).Set(10)).Count() > 1 { - fmt.Println("Intersection works.") - } - -As an alternative to BitSets, one should check out the 'big' package, -which provides a (less set-theoretical) view of bitsets. - -*/ -package bitset - -import ( - "bufio" - "bytes" - "encoding/base64" - "encoding/binary" - "encoding/json" - "errors" - "fmt" - "io" - "strconv" -) - -// the wordSize of a bit set -const wordSize = uint(64) - -// log2WordSize is lg(wordSize) -const log2WordSize = uint(6) - -// allBits has every bit set -const allBits uint64 = 0xffffffffffffffff - -// default binary BigEndian -var binaryOrder binary.ByteOrder = binary.BigEndian - -// default json encoding base64.URLEncoding -var base64Encoding = base64.URLEncoding - -// Base64StdEncoding Marshal/Unmarshal BitSet with base64.StdEncoding(Default: base64.URLEncoding) -func Base64StdEncoding() { base64Encoding = base64.StdEncoding } - -// LittleEndian Marshal/Unmarshal Binary as Little Endian(Default: binary.BigEndian) -func LittleEndian() { binaryOrder = binary.LittleEndian } - -// A BitSet is a set of bits. The zero value of a BitSet is an empty set of length 0. -type BitSet struct { - length uint - set []uint64 -} - -// Error is used to distinguish errors (panics) generated in this package. -type Error string - -// safeSet will fixup b.set to be non-nil and return the field value -func (b *BitSet) safeSet() []uint64 { - if b.set == nil { - b.set = make([]uint64, wordsNeeded(0)) - } - return b.set -} - -// From is a constructor used to create a BitSet from an array of integers -func From(buf []uint64) *BitSet { - return &BitSet{uint(len(buf)) * 64, buf} -} - -// Bytes returns the bitset as array of integers -func (b *BitSet) Bytes() []uint64 { - return b.set -} - -// wordsNeeded calculates the number of words needed for i bits -func wordsNeeded(i uint) int { - if i > (Cap() - wordSize + 1) { - return int(Cap() >> log2WordSize) - } - return int((i + (wordSize - 1)) >> log2WordSize) -} - -// New creates a new BitSet with a hint that length bits will be required -func New(length uint) (bset *BitSet) { - defer func() { - if r := recover(); r != nil { - bset = &BitSet{ - 0, - make([]uint64, 0), - } - } - }() - - bset = &BitSet{ - length, - make([]uint64, wordsNeeded(length)), - } - - return bset -} - -// Cap returns the total possible capacity, or number of bits -func Cap() uint { - return ^uint(0) -} - -// Len returns the number of bits in the BitSet. -// Note the difference to method Count, see example. -func (b *BitSet) Len() uint { - return b.length -} - -// extendSetMaybe adds additional words to incorporate new bits if needed -func (b *BitSet) extendSetMaybe(i uint) { - if i >= b.length { // if we need more bits, make 'em - if i >= Cap() { - panic("You are exceeding the capacity") - } - nsize := wordsNeeded(i + 1) - if b.set == nil { - b.set = make([]uint64, nsize) - } else if cap(b.set) >= nsize { - b.set = b.set[:nsize] // fast resize - } else if len(b.set) < nsize { - newset := make([]uint64, nsize, 2*nsize) // increase capacity 2x - copy(newset, b.set) - b.set = newset - } - b.length = i + 1 - } -} - -// Test whether bit i is set. -func (b *BitSet) Test(i uint) bool { - if i >= b.length { - return false - } - return b.set[i>>log2WordSize]&(1<<(i&(wordSize-1))) != 0 -} - -// Set bit i to 1, the capacity of the bitset is automatically -// increased accordingly. -// If i>= Cap(), this function will panic. -// Warning: using a very large value for 'i' -// may lead to a memory shortage and a panic: the caller is responsible -// for providing sensible parameters in line with their memory capacity. -func (b *BitSet) Set(i uint) *BitSet { - b.extendSetMaybe(i) - b.set[i>>log2WordSize] |= 1 << (i & (wordSize - 1)) - return b -} - -// Clear bit i to 0 -func (b *BitSet) Clear(i uint) *BitSet { - if i >= b.length { - return b - } - b.set[i>>log2WordSize] &^= 1 << (i & (wordSize - 1)) - return b -} - -// SetTo sets bit i to value. -// If i>= Cap(), this function will panic. -// Warning: using a very large value for 'i' -// may lead to a memory shortage and a panic: the caller is responsible -// for providing sensible parameters in line with their memory capacity. -func (b *BitSet) SetTo(i uint, value bool) *BitSet { - if value { - return b.Set(i) - } - return b.Clear(i) -} - -// Flip bit at i. -// If i>= Cap(), this function will panic. -// Warning: using a very large value for 'i' -// may lead to a memory shortage and a panic: the caller is responsible -// for providing sensible parameters in line with their memory capacity. -func (b *BitSet) Flip(i uint) *BitSet { - if i >= b.length { - return b.Set(i) - } - b.set[i>>log2WordSize] ^= 1 << (i & (wordSize - 1)) - return b -} - -// FlipRange bit in [start, end). -// If end>= Cap(), this function will panic. -// Warning: using a very large value for 'end' -// may lead to a memory shortage and a panic: the caller is responsible -// for providing sensible parameters in line with their memory capacity. -func (b *BitSet) FlipRange(start, end uint) *BitSet { - if start >= end { - return b - } - - b.extendSetMaybe(end - 1) - var startWord uint = start >> log2WordSize - var endWord uint = end >> log2WordSize - b.set[startWord] ^= ^(^uint64(0) << (start & (wordSize - 1))) - for i := startWord; i < endWord; i++ { - b.set[i] = ^b.set[i] - } - b.set[endWord] ^= ^uint64(0) >> (-end & (wordSize - 1)) - return b -} - -// Shrink shrinks BitSet so that the provided value is the last possible -// set value. It clears all bits > the provided index and reduces the size -// and length of the set. -// -// Note that the parameter value is not the new length in bits: it is the -// maximal value that can be stored in the bitset after the function call. -// The new length in bits is the parameter value + 1. Thus it is not possible -// to use this function to set the length to 0, the minimal value of the length -// after this function call is 1. -// -// A new slice is allocated to store the new bits, so you may see an increase in -// memory usage until the GC runs. Normally this should not be a problem, but if you -// have an extremely large BitSet its important to understand that the old BitSet will -// remain in memory until the GC frees it. -func (b *BitSet) Shrink(lastbitindex uint) *BitSet { - length := lastbitindex + 1 - idx := wordsNeeded(length) - if idx > len(b.set) { - return b - } - shrunk := make([]uint64, idx) - copy(shrunk, b.set[:idx]) - b.set = shrunk - b.length = length - b.set[idx-1] &= (allBits >> (uint64(64) - uint64(length&(wordSize-1)))) - return b -} - -// Compact shrinks BitSet to so that we preserve all set bits, while minimizing -// memory usage. Compact calls Shrink. -func (b *BitSet) Compact() *BitSet { - idx := len(b.set) - 1 - for ; idx >= 0 && b.set[idx] == 0; idx-- { - } - newlength := uint((idx + 1) << log2WordSize) - if newlength >= b.length { - return b // nothing to do - } - if newlength > 0 { - return b.Shrink(newlength - 1) - } - // We preserve one word - return b.Shrink(63) -} - -// InsertAt takes an index which indicates where a bit should be -// inserted. Then it shifts all the bits in the set to the left by 1, starting -// from the given index position, and sets the index position to 0. -// -// Depending on the size of your BitSet, and where you are inserting the new entry, -// this method could be extremely slow and in some cases might cause the entire BitSet -// to be recopied. -func (b *BitSet) InsertAt(idx uint) *BitSet { - insertAtElement := (idx >> log2WordSize) - - // if length of set is a multiple of wordSize we need to allocate more space first - if b.isLenExactMultiple() { - b.set = append(b.set, uint64(0)) - } - - var i uint - for i = uint(len(b.set) - 1); i > insertAtElement; i-- { - // all elements above the position where we want to insert can simply by shifted - b.set[i] <<= 1 - - // we take the most significant bit of the previous element and set it as - // the least significant bit of the current element - b.set[i] |= (b.set[i-1] & 0x8000000000000000) >> 63 - } - - // generate a mask to extract the data that we need to shift left - // within the element where we insert a bit - dataMask := ^(uint64(1)<<uint64(idx&(wordSize-1)) - 1) - - // extract that data that we'll shift - data := b.set[i] & dataMask - - // set the positions of the data mask to 0 in the element where we insert - b.set[i] &= ^dataMask - - // shift data mask to the left and insert its data to the slice element - b.set[i] |= data << 1 - - // add 1 to length of BitSet - b.length++ - - return b -} - -// String creates a string representation of the Bitmap -func (b *BitSet) String() string { - // follows code from https://github.com/RoaringBitmap/roaring - var buffer bytes.Buffer - start := []byte("{") - buffer.Write(start) - counter := 0 - i, e := b.NextSet(0) - for e { - counter = counter + 1 - // to avoid exhausting the memory - if counter > 0x40000 { - buffer.WriteString("...") - break - } - buffer.WriteString(strconv.FormatInt(int64(i), 10)) - i, e = b.NextSet(i + 1) - if e { - buffer.WriteString(",") - } - } - buffer.WriteString("}") - return buffer.String() -} - -// DeleteAt deletes the bit at the given index position from -// within the bitset -// All the bits residing on the left of the deleted bit get -// shifted right by 1 -// The running time of this operation may potentially be -// relatively slow, O(length) -func (b *BitSet) DeleteAt(i uint) *BitSet { - // the index of the slice element where we'll delete a bit - deleteAtElement := i >> log2WordSize - - // generate a mask for the data that needs to be shifted right - // within that slice element that gets modified - dataMask := ^((uint64(1) << (i & (wordSize - 1))) - 1) - - // extract the data that we'll shift right from the slice element - data := b.set[deleteAtElement] & dataMask - - // set the masked area to 0 while leaving the rest as it is - b.set[deleteAtElement] &= ^dataMask - - // shift the previously extracted data to the right and then - // set it in the previously masked area - b.set[deleteAtElement] |= (data >> 1) & dataMask - - // loop over all the consecutive slice elements to copy each - // lowest bit into the highest position of the previous element, - // then shift the entire content to the right by 1 - for i := int(deleteAtElement) + 1; i < len(b.set); i++ { - b.set[i-1] |= (b.set[i] & 1) << 63 - b.set[i] >>= 1 - } - - b.length = b.length - 1 - - return b -} - -// NextSet returns the next bit set from the specified index, -// including possibly the current index -// along with an error code (true = valid, false = no set bit found) -// for i,e := v.NextSet(0); e; i,e = v.NextSet(i + 1) {...} -// -// Users concerned with performance may want to use NextSetMany to -// retrieve several values at once. -func (b *BitSet) NextSet(i uint) (uint, bool) { - x := int(i >> log2WordSize) - if x >= len(b.set) { - return 0, false - } - w := b.set[x] - w = w >> (i & (wordSize - 1)) - if w != 0 { - return i + trailingZeroes64(w), true - } - x = x + 1 - for x < len(b.set) { - if b.set[x] != 0 { - return uint(x)*wordSize + trailingZeroes64(b.set[x]), true - } - x = x + 1 - - } - return 0, false -} - -// NextSetMany returns many next bit sets from the specified index, -// including possibly the current index and up to cap(buffer). -// If the returned slice has len zero, then no more set bits were found -// -// buffer := make([]uint, 256) // this should be reused -// j := uint(0) -// j, buffer = bitmap.NextSetMany(j, buffer) -// for ; len(buffer) > 0; j, buffer = bitmap.NextSetMany(j,buffer) { -// for k := range buffer { -// do something with buffer[k] -// } -// j += 1 -// } -// -// -// It is possible to retrieve all set bits as follow: -// -// indices := make([]uint, bitmap.Count()) -// bitmap.NextSetMany(0, indices) -// -// However if bitmap.Count() is large, it might be preferable to -// use several calls to NextSetMany, for performance reasons. -func (b *BitSet) NextSetMany(i uint, buffer []uint) (uint, []uint) { - myanswer := buffer - capacity := cap(buffer) - x := int(i >> log2WordSize) - if x >= len(b.set) || capacity == 0 { - return 0, myanswer[:0] - } - skip := i & (wordSize - 1) - word := b.set[x] >> skip - myanswer = myanswer[:capacity] - size := int(0) - for word != 0 { - r := trailingZeroes64(word) - t := word & ((^word) + 1) - myanswer[size] = r + i - size++ - if size == capacity { - goto End - } - word = word ^ t - } - x++ - for idx, word := range b.set[x:] { - for word != 0 { - r := trailingZeroes64(word) - t := word & ((^word) + 1) - myanswer[size] = r + (uint(x+idx) << 6) - size++ - if size == capacity { - goto End - } - word = word ^ t - } - } -End: - if size > 0 { - return myanswer[size-1], myanswer[:size] - } - return 0, myanswer[:0] -} - -// NextClear returns the next clear bit from the specified index, -// including possibly the current index -// along with an error code (true = valid, false = no bit found i.e. all bits are set) -func (b *BitSet) NextClear(i uint) (uint, bool) { - x := int(i >> log2WordSize) - if x >= len(b.set) { - return 0, false - } - w := b.set[x] - w = w >> (i & (wordSize - 1)) - wA := allBits >> (i & (wordSize - 1)) - index := i + trailingZeroes64(^w) - if w != wA && index < b.length { - return index, true - } - x++ - for x < len(b.set) { - index = uint(x)*wordSize + trailingZeroes64(^b.set[x]) - if b.set[x] != allBits && index < b.length { - return index, true - } - x++ - } - return 0, false -} - -// ClearAll clears the entire BitSet -func (b *BitSet) ClearAll() *BitSet { - if b != nil && b.set != nil { - for i := range b.set { - b.set[i] = 0 - } - } - return b -} - -// wordCount returns the number of words used in a bit set -func (b *BitSet) wordCount() int { - return len(b.set) -} - -// Clone this BitSet -func (b *BitSet) Clone() *BitSet { - c := New(b.length) - if b.set != nil { // Clone should not modify current object - copy(c.set, b.set) - } - return c -} - -// Copy into a destination BitSet -// Returning the size of the destination BitSet -// like array copy -func (b *BitSet) Copy(c *BitSet) (count uint) { - if c == nil { - return - } - if b.set != nil { // Copy should not modify current object - copy(c.set, b.set) - } - count = c.length - if b.length < c.length { - count = b.length - } - return -} - -// Count (number of set bits). -// Also known as "popcount" or "population count". -func (b *BitSet) Count() uint { - if b != nil && b.set != nil { - return uint(popcntSlice(b.set)) - } - return 0 -} - -// Equal tests the equivalence of two BitSets. -// False if they are of different sizes, otherwise true -// only if all the same bits are set -func (b *BitSet) Equal(c *BitSet) bool { - if c == nil || b == nil { - return c == b - } - if b.length != c.length { - return false - } - if b.length == 0 { // if they have both length == 0, then could have nil set - return true - } - // testing for equality shoud not transform the bitset (no call to safeSet) - - for p, v := range b.set { - if c.set[p] != v { - return false - } - } - return true -} - -func panicIfNull(b *BitSet) { - if b == nil { - panic(Error("BitSet must not be null")) - } -} - -// Difference of base set and other set -// This is the BitSet equivalent of &^ (and not) -func (b *BitSet) Difference(compare *BitSet) (result *BitSet) { - panicIfNull(b) - panicIfNull(compare) - result = b.Clone() // clone b (in case b is bigger than compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - for i := 0; i < l; i++ { - result.set[i] = b.set[i] &^ compare.set[i] - } - return -} - -// DifferenceCardinality computes the cardinality of the differnce -func (b *BitSet) DifferenceCardinality(compare *BitSet) uint { - panicIfNull(b) - panicIfNull(compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - cnt := uint64(0) - cnt += popcntMaskSlice(b.set[:l], compare.set[:l]) - cnt += popcntSlice(b.set[l:]) - return uint(cnt) -} - -// InPlaceDifference computes the difference of base set and other set -// This is the BitSet equivalent of &^ (and not) -func (b *BitSet) InPlaceDifference(compare *BitSet) { - panicIfNull(b) - panicIfNull(compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - for i := 0; i < l; i++ { - b.set[i] &^= compare.set[i] - } -} - -// Convenience function: return two bitsets ordered by -// increasing length. Note: neither can be nil -func sortByLength(a *BitSet, b *BitSet) (ap *BitSet, bp *BitSet) { - if a.length <= b.length { - ap, bp = a, b - } else { - ap, bp = b, a - } - return -} - -// Intersection of base set and other set -// This is the BitSet equivalent of & (and) -func (b *BitSet) Intersection(compare *BitSet) (result *BitSet) { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - result = New(b.length) - for i, word := range b.set { - result.set[i] = word & compare.set[i] - } - return -} - -// IntersectionCardinality computes the cardinality of the union -func (b *BitSet) IntersectionCardinality(compare *BitSet) uint { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - cnt := popcntAndSlice(b.set, compare.set) - return uint(cnt) -} - -// InPlaceIntersection destructively computes the intersection of -// base set and the compare set. -// This is the BitSet equivalent of & (and) -func (b *BitSet) InPlaceIntersection(compare *BitSet) { - panicIfNull(b) - panicIfNull(compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - for i := 0; i < l; i++ { - b.set[i] &= compare.set[i] - } - for i := l; i < len(b.set); i++ { - b.set[i] = 0 - } - if compare.length > 0 { - b.extendSetMaybe(compare.length - 1) - } -} - -// Union of base set and other set -// This is the BitSet equivalent of | (or) -func (b *BitSet) Union(compare *BitSet) (result *BitSet) { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - result = compare.Clone() - for i, word := range b.set { - result.set[i] = word | compare.set[i] - } - return -} - -// UnionCardinality computes the cardinality of the uniton of the base set -// and the compare set. -func (b *BitSet) UnionCardinality(compare *BitSet) uint { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - cnt := popcntOrSlice(b.set, compare.set) - if len(compare.set) > len(b.set) { - cnt += popcntSlice(compare.set[len(b.set):]) - } - return uint(cnt) -} - -// InPlaceUnion creates the destructive union of base set and compare set. -// This is the BitSet equivalent of | (or). -func (b *BitSet) InPlaceUnion(compare *BitSet) { - panicIfNull(b) - panicIfNull(compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - if compare.length > 0 { - b.extendSetMaybe(compare.length - 1) - } - for i := 0; i < l; i++ { - b.set[i] |= compare.set[i] - } - if len(compare.set) > l { - for i := l; i < len(compare.set); i++ { - b.set[i] = compare.set[i] - } - } -} - -// SymmetricDifference of base set and other set -// This is the BitSet equivalent of ^ (xor) -func (b *BitSet) SymmetricDifference(compare *BitSet) (result *BitSet) { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - // compare is bigger, so clone it - result = compare.Clone() - for i, word := range b.set { - result.set[i] = word ^ compare.set[i] - } - return -} - -// SymmetricDifferenceCardinality computes the cardinality of the symmetric difference -func (b *BitSet) SymmetricDifferenceCardinality(compare *BitSet) uint { - panicIfNull(b) - panicIfNull(compare) - b, compare = sortByLength(b, compare) - cnt := popcntXorSlice(b.set, compare.set) - if len(compare.set) > len(b.set) { - cnt += popcntSlice(compare.set[len(b.set):]) - } - return uint(cnt) -} - -// InPlaceSymmetricDifference creates the destructive SymmetricDifference of base set and other set -// This is the BitSet equivalent of ^ (xor) -func (b *BitSet) InPlaceSymmetricDifference(compare *BitSet) { - panicIfNull(b) - panicIfNull(compare) - l := int(compare.wordCount()) - if l > int(b.wordCount()) { - l = int(b.wordCount()) - } - if compare.length > 0 { - b.extendSetMaybe(compare.length - 1) - } - for i := 0; i < l; i++ { - b.set[i] ^= compare.set[i] - } - if len(compare.set) > l { - for i := l; i < len(compare.set); i++ { - b.set[i] = compare.set[i] - } - } -} - -// Is the length an exact multiple of word sizes? -func (b *BitSet) isLenExactMultiple() bool { - return b.length%wordSize == 0 -} - -// Clean last word by setting unused bits to 0 -func (b *BitSet) cleanLastWord() { - if !b.isLenExactMultiple() { - b.set[len(b.set)-1] &= allBits >> (wordSize - b.length%wordSize) - } -} - -// Complement computes the (local) complement of a biset (up to length bits) -func (b *BitSet) Complement() (result *BitSet) { - panicIfNull(b) - result = New(b.length) - for i, word := range b.set { - result.set[i] = ^word - } - result.cleanLastWord() - return -} - -// All returns true if all bits are set, false otherwise. Returns true for -// empty sets. -func (b *BitSet) All() bool { - panicIfNull(b) - return b.Count() == b.length -} - -// None returns true if no bit is set, false otherwise. Returns true for -// empty sets. -func (b *BitSet) None() bool { - panicIfNull(b) - if b != nil && b.set != nil { - for _, word := range b.set { - if word > 0 { - return false - } - } - return true - } - return true -} - -// Any returns true if any bit is set, false otherwise -func (b *BitSet) Any() bool { - panicIfNull(b) - return !b.None() -} - -// IsSuperSet returns true if this is a superset of the other set -func (b *BitSet) IsSuperSet(other *BitSet) bool { - for i, e := other.NextSet(0); e; i, e = other.NextSet(i + 1) { - if !b.Test(i) { - return false - } - } - return true -} - -// IsStrictSuperSet returns true if this is a strict superset of the other set -func (b *BitSet) IsStrictSuperSet(other *BitSet) bool { - return b.Count() > other.Count() && b.IsSuperSet(other) -} - -// DumpAsBits dumps a bit set as a string of bits -func (b *BitSet) DumpAsBits() string { - if b.set == nil { - return "." - } - buffer := bytes.NewBufferString("") - i := len(b.set) - 1 - for ; i >= 0; i-- { - fmt.Fprintf(buffer, "%064b.", b.set[i]) - } - return buffer.String() -} - -// BinaryStorageSize returns the binary storage requirements -func (b *BitSet) BinaryStorageSize() int { - return binary.Size(uint64(0)) + binary.Size(b.set) -} - -// WriteTo writes a BitSet to a stream -func (b *BitSet) WriteTo(stream io.Writer) (int64, error) { - length := uint64(b.length) - - // Write length - err := binary.Write(stream, binaryOrder, length) - if err != nil { - return 0, err - } - - // Write set - err = binary.Write(stream, binaryOrder, b.set) - return int64(b.BinaryStorageSize()), err -} - -// ReadFrom reads a BitSet from a stream written using WriteTo -func (b *BitSet) ReadFrom(stream io.Reader) (int64, error) { - var length uint64 - - // Read length first - err := binary.Read(stream, binaryOrder, &length) - if err != nil { - return 0, err - } - newset := New(uint(length)) - - if uint64(newset.length) != length { - return 0, errors.New("unmarshalling error: type mismatch") - } - - // Read remaining bytes as set - err = binary.Read(stream, binaryOrder, newset.set) - if err != nil { - return 0, err - } - - *b = *newset - return int64(b.BinaryStorageSize()), nil -} - -// MarshalBinary encodes a BitSet into a binary form and returns the result. -func (b *BitSet) MarshalBinary() ([]byte, error) { - var buf bytes.Buffer - writer := bufio.NewWriter(&buf) - - _, err := b.WriteTo(writer) - if err != nil { - return []byte{}, err - } - - err = writer.Flush() - - return buf.Bytes(), err -} - -// UnmarshalBinary decodes the binary form generated by MarshalBinary. -func (b *BitSet) UnmarshalBinary(data []byte) error { - buf := bytes.NewReader(data) - reader := bufio.NewReader(buf) - - _, err := b.ReadFrom(reader) - - return err -} - -// MarshalJSON marshals a BitSet as a JSON structure -func (b *BitSet) MarshalJSON() ([]byte, error) { - buffer := bytes.NewBuffer(make([]byte, 0, b.BinaryStorageSize())) - _, err := b.WriteTo(buffer) - if err != nil { - return nil, err - } - - // URLEncode all bytes - return json.Marshal(base64Encoding.EncodeToString(buffer.Bytes())) -} - -// UnmarshalJSON unmarshals a BitSet from JSON created using MarshalJSON -func (b *BitSet) UnmarshalJSON(data []byte) error { - // Unmarshal as string - var s string - err := json.Unmarshal(data, &s) - if err != nil { - return err - } - - // URLDecode string - buf, err := base64Encoding.DecodeString(s) - if err != nil { - return err - } - - _, err = b.ReadFrom(bytes.NewReader(buf)) - return err -} |