4 Commits

Author SHA1 Message Date
brent saner
688abd0874 v1.9.5
FIXED:
* HasFlag would inappropriately report true for m = A, flag = A | B.
  This has been rectified, and this behavior is now explicitly
  exposed via IsOneOf.
2025-08-26 20:39:29 -04:00
brent saner
a1f87d6b51 stubbing encoding/bit 2025-08-23 19:32:48 -04:00
brent saner
07951f1f03 v1.9.4
FIXED:
* remap.ReMap.MapString() was not properly correllating groups. It is
  now.
2025-08-17 00:45:24 -04:00
brent saner
bae0abe960 v1.9.3
IMPROVED:
* Better documentation for remap
2025-08-12 00:06:51 -04:00
7 changed files with 352 additions and 47 deletions

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@@ -0,0 +1,19 @@
/*
Package bit aims to provide feature parity with stdlib's [encoding/hex].
It's a ludicrous tragedy that hex/base16, base32, base64 all have libraries for converting
to/from string representations... but there's nothing for binary ('01010001' etc.) whatsoever.
This package also provides some extra convenience functions and types in an attempt to provide
an abstracted bit-level fidelity in Go. A [Bit] is a bool type, in which that underlying bool
being false represents a 0 and that underlying bool being true represents a 1.
Note that a [Bit] or arbitrary-length or non-octal-aligned [][Bit] may take up more bytes in memory
than expected; a [Bit] will actually always occupy a single byte -- thus representing
`00000000 00000000` as a [][Bit] or [16][Bit] will actually occupy *sixteen bytes* in memory,
NOT 2 bytes (nor, obviously, [2][Byte])!
It is recommended instead to use a [Bits] instead of a [Bit] slice or array, as it will try to properly align to the
smallest memory allocation possible (at the cost of a few extra CPU cycles on adding/removing one or more [Bit]).
It will properly retain any appended, prepended, leading, or trailing bits that do not currently align to a byte.
*/
package bit

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@@ -0,0 +1,14 @@
package bit
// TODO: Provide analogues of encoding/hex, encoding/base64, etc. functions etc.
/*
TODO: Also provide interfaces for the following:
* https://pkg.go.dev/encoding#BinaryAppender
* https://pkg.go.dev/encoding#BinaryMarshaler
* https://pkg.go.dev/encoding#BinaryUnmarshaler
* https://pkg.go.dev/encoding#TextAppender
* https://pkg.go.dev/encoding#TextMarshaler
* https://pkg.go.dev/encoding#TextUnmarshaler
*/

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@@ -0,0 +1,34 @@
package bit
type (
// Bit aims to provide a native-like type for a single bit (Golang operates on the smallest fidelity level of *byte*/uint8).
Bit bool
// Bits is an arbitrary length of bits.
Bits struct {
/*
leading is a series of Bit that do not cleanly align to the beginning of Bits.b.
They will always be the bits at the *beginning* of the sequence.
len(Bits.leading) will *never* be more than 7;
it's converted into a byte, prepended to Bits.b, and cleared if it reaches that point.
*/
leading []Bit
// b is the condensed/memory-aligned alternative to an [][8]Bit (or []Bit, or [][]Bit, etc.).
b []byte
/*
remaining is a series of Bit that do not cleanly align to the end of Bits.b.
They will always be the bits at the *end* of the sequence.
len(Bits.remaining) will *never* be more than 7;
it's converted into a byte, appended to Bits.b, and cleared if it reaches that point.
*/
remaining []Bit
// fixedLen, if 0, represents a "slice". If >= 1, it represents an "array".
fixedLen uint
}
// Byte is this package's representation of a byte. It's primarily for convenience.
Byte byte
// Bytes is defined as a type for convenience single-call functions.
Bytes []Byte
)

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@@ -34,11 +34,47 @@ func NewMaskBitExplicit(value uint) (m *MaskBit) {
return
}
// HasFlag is true if m has MaskBit flag set/enabled.
/*
HasFlag is true if m has MaskBit flag set/enabled.
THIS WILL RETURN FALSE FOR OR'd FLAGS.
For example:
flagA MaskBit = 0x01
flagB MaskBit = 0x02
flagComposite = flagA | flagB
m *MaskBit = NewMaskBitExplicit(uint(flagA))
m.HasFlag(flagComposite) will return false even though flagComposite is an OR
that contains flagA.
Use [MaskBit.IsOneOf] instead if you do not desire this behavior,
and instead want to test composite flag *membership*.
(MaskBit.IsOneOf will also return true for non-composite equality.)
*/
func (m *MaskBit) HasFlag(flag MaskBit) (r bool) {
var b MaskBit = *m
if b&flag == flag {
r = true
}
return
}
/*
IsOneOf is like a "looser" form of [MaskBit.HasFlag]
in that it allows for testing composite membership.
See [MaskBit.HasFlag] for more information.
If composite is *not* an OR'd MaskBit (i.e.
it falls directly on a boundary -- 0, 1, 2, 4, 8, 16, etc.),
then IsOneOf will behave exactly like HasFlag.
*/
func (m *MaskBit) IsOneOf(composite MaskBit) (r bool) {
var b MaskBit = *m
if b&flag != 0 {
r = true
}

View File

@@ -1,4 +1,4 @@
/*
Package remap provides convenience functions around regular expressions.
Package remap provides convenience functions around regular expressions, primarily offering maps for named capture groups.
*/
package remap

View File

@@ -1,11 +1,67 @@
package remap
/*
Map returns a map[string]<match bytes> for regexes with named capture groups matched in bytes b.
Note that this supports non-unique group names; regexp.Regexp allows for patterns with multiple groups
using the same group name. Each match for each group is in a slice keyed under that group name, with
that slice ordered by the indexing done by the regex match itself.
matches and/or its values may be nil or empty under the following condition tree:
Map returns a map[string][]<match bytes> for regexes with named capture groups matched in bytes b.
Note that this supports non-unique group names; [regexp.Regexp] allows for patterns with multiple groups
using the same group name (though your IDE might complain; I know GoLand does).
Each match for each group is in a slice keyed under that group name, with that slice
ordered by the indexing done by the regex match itself.
In summary, the parameters are as follows:
# inclNoMatch
If true, then attempt to return a non-nil matches (as long as b isn't nil).
Group keys will be populated and explicitly defined as nil.
For example, if a pattern
^(?P<g1>foo)(?P<g1>bar)(?P<g2>baz)$
is provided but b does not match then matches will be:
map[string][][]byte{
"g1": nil,
"g2": nil,
}
# inclNoMatchStrict
If true (and inclNoMatch is true), instead of a single nil the group's values will be
a slice of nil values explicitly matching the number of times the group name is specified
in the pattern.
For example, if a pattern:
^(?P<g1>foo)(?P<g1>bar)(?P<g2>baz)$
is provided but b does not match then matches will be:
map[string][][]byte{
"g1": [][]byte{
nil,
nil,
},
"g2": [][]byte{
nil,
},
}
# mustMatch
If true, matches will be nil if the entirety of b does not match the pattern (and thus
no capture groups matched) (overrides inclNoMatch) -- explicitly:
matches == nil
Otherwise if false (and assuming inclNoMatch is false), matches will be:
map[string][][]byte{}{}
# Condition Tree
In detail, matches and/or its values may be nil or empty under the following condition tree:
IF b is nil:
THEN matches will always be nil
@@ -79,7 +135,7 @@ func (r *ReMap) Map(b []byte, inclNoMatch, inclNoMatchStrict, mustMatch bool) (m
if len(matchBytes) == 0 || len(matchBytes) == 1 {
/*
no submatches whatsoever.
*technically* I don't think this condition can actually be reached.
*Technically* I don't think this condition can actually be reached.
This is more of a safe-return before we re-slice.
*/
matches = make(map[string][][]byte)
@@ -148,9 +204,100 @@ func (r *ReMap) Map(b []byte, inclNoMatch, inclNoMatchStrict, mustMatch bool) (m
}
/*
MapString is exactly like ReMap.Map(), but operates on (and returns) strings instead. (matches will always be nil if s == ``.)
MapString is exactly like ReMap.Map(), but operates on (and returns) strings instead.
(matches will always be nil if s == “.)
A small deviation, though; empty strings instead of nils (because duh) will occupy placeholders (if inclNoMatchStrict is specified).
A small deviation, though; empty strings instead of nils (because duh) will occupy slice placeholders (if `inclNoMatchStrict` is specified).
This unfortunately *does not provide any indication* if an empty string positively matched the pattern (a "hit") or if it was simply
not matched at all (a "miss"). If you need definitive determination between the two conditions, it is instead recommended to either
*not* use inclNoMatchStrict or to use ReMap.Map() instead and convert any non-nil values to strings after.
Particularly:
# inclNoMatch
If true, then attempt to return a non-nil matches (as long as s isn't empty).
Group keys will be populated and explicitly defined as nil.
For example, if a pattern
^(?P<g1>foo)(?P<g1>bar)(?P<g2>baz)$
is provided but s does not match then matches will be:
map[string][]string{
"g1": nil,
"g2": nil,
}
# inclNoMatchStrict
If true (and inclNoMatch is true), instead of a single nil the group's values will be
a slice of eempty string values explicitly matching the number of times the group name is specified
in the pattern.
For example, if a pattern:
^(?P<g1>foo)(?P<g1>bar)(?P<g2>baz)$
is provided but s does not match then matches will be:
map[string][]string{
"g1": []string{
"",
"",
},
"g2": []string{
"",
},
}
# mustMatch
If true, matches will be nil if the entirety of s does not match the pattern (and thus
no capture groups matched) (overrides inclNoMatch) -- explicitly:
matches == nil
Otherwise if false (and assuming inclNoMatch is false), matches will be:
map[string][]string{}{}
# Condition Tree
In detail, matches and/or its values may be nil or empty under the following condition tree:
IF s is empty:
THEN matches will always be nil
ELSE:
IF all of s does not match pattern
IF mustMuch is true
THEN matches == nil
ELSE
THEN matches == map[string][]string{} (non-nil but empty)
ELSE IF pattern has no named capture groups
IF inclNoMatch is true
THEN matches == map[string][]string{} (non-nil but empty)
ELSE
THEN matches == nil
ELSE
IF there are no named group matches
IF inclNoMatch is true
THEN matches is non-nil; matches[<group name>, ...] is/are defined but nil (_, ok = matches[<group name>]; ok == true)
ELSE
THEN matches == nil
ELSE
IF <group name> does not have a match
IF inclNoMatch is true
IF inclNoMatchStrict is true
THEN matches[<group name>] is defined and non-nil, but populated with placeholder nils
(matches[<group name>] == []string{""[, ""...]})
ELSE
THEN matches[<group name>] is guaranteed defined but may be nil (_, ok = matches[<group name>]; ok == true)
ELSE
THEN matches[<group name>] is not defined (_, ok = matches[<group name>]; ok == false)
ELSE
matches[<group name>] == []{<match>[, <match>...]}
*/
func (r *ReMap) MapString(s string, inclNoMatch, inclNoMatchStrict, mustMatch bool) (matches map[string][]string) {
@@ -161,6 +308,13 @@ func (r *ReMap) MapString(s string, inclNoMatch, inclNoMatchStrict, mustMatch bo
var grpNm string
var names []string
var matchStr string
/*
A slice of indices or index pairs.
For each element `e` in idxChunks,
* if `e` is nil, no group match.
* if len(e) == 1, only a single character was matched.
* otherwise len(e) == 2, the start and end of the match.
*/
var idxChunks [][]int
var matchIndices []int
var chunkIndices []int // always 2 elements; start pos and end pos
@@ -170,7 +324,7 @@ func (r *ReMap) MapString(s string, inclNoMatch, inclNoMatchStrict, mustMatch bo
OK so this is a bit of a deviation.
It's not as straightforward as above, because there isn't an explicit way
like above to determine if a patterb was *matched as an empty string* vs.
like above to determine if a pattern was *matched as an empty string* vs.
*not matched*.
So instead do roundabout index-y things.
@@ -179,73 +333,111 @@ func (r *ReMap) MapString(s string, inclNoMatch, inclNoMatchStrict, mustMatch bo
if s == "" {
return
}
names = r.Regexp.SubexpNames()
/*
I'm not entirely sure how serious they are about "the slice should not be modified"...
DO NOT sort or dedupe `names`! If the same name for groups is duplicated,
it will be duplicated here in proper order and the ordering is tied to
the ordering of matchIndices.
*/
names = r.Regexp.SubexpNames()[:]
matchIndices = r.Regexp.FindStringSubmatchIndex(s)
if matchIndices == nil {
// s does not match pattern
// s does not match pattern at all.
if !mustMatch {
matches = make(map[string][]string)
}
return
}
if names == nil || len(names) == 0 || len(names) == 1 {
if names == nil || len(names) <= 1 {
/*
no named capture groups;
technically only the last condition would be the case.
No named capture groups;
technically only the last condition would be the case,
as (regexp.Regexp).SubexpNames() will ALWAYS at the LEAST
return a `[]string{""}`.
*/
if inclNoMatch {
matches = make(map[string][]string)
}
return
}
names = names[1:]
if len(matchIndices) == 0 || len(matchIndices) == 1 {
/*
no submatches whatsoever.
*technically* I don't think this condition can actually be reached.
No (sub)matches whatsoever.
*technically* I don't think this condition can actually be reached;
matchIndices should ALWAYS either be `nil` or len will be at LEAST 2,
and modulo 2 thereafter since they're PAIRS of indices...
Why they didn't just return a [][]int or [][2]int or something
instead of an []int, who knows.
But we're correcting that poor design.
This is more of a safe-return before we chunk the indices.
*/
matches = make(map[string][]string)
if inclNoMatch {
if len(names) >= 1 {
for _, grpNm = range names {
if grpNm != "" {
matches[grpNm] = nil
}
}
}
return
}
/*
The reslice starts at 2 because they're in pairs: []int{<start>, <end>, <start>, <end>, ...}
and the first *pair* is the entire pattern match.
Thus the len(matchIndices) == 2*len(names).
Keep in mind that since the first element of names is removed,
the first pair here is also removed.
*/
matchIndices = matchIndices[2:]
/*
A reslice of `matchIndices` could technically start at 2 (as long as `names` is sliced [1:])
because they're in pairs: []int{<start>, <end>, <start>, <end>, ...}
and the first pair is the entire pattern match (un-resliced names[0]).
Thus the len(matchIndices) == 2*len(names), *even* if you
Keep in mind that since the first element of names is removed,
the first pair here is skipped.
This provides a bit more consistent readability, though.
*/
idxChunks = make([][]int, len(names))
for startIdx = 0; startIdx < len(idxChunks); startIdx += 2 {
chunkIdx = 0
endIdx = 0
for startIdx = 0; endIdx < len(matchIndices); startIdx += 2 {
endIdx = startIdx + 2
// This technically should never happen.
if endIdx > len(matchIndices) {
endIdx = len(matchIndices)
}
chunkIndices = matchIndices[startIdx:endIdx]
if chunkIndices[0] == -1 || chunkIndices[1] == -1 {
// group did not match
chunkIndices = nil
} else {
if chunkIndices[0] == chunkIndices[1] {
chunkIndices = []int{chunkIndices[0]}
} else {
chunkIndices = matchIndices[startIdx:endIdx]
}
}
idxChunks[chunkIdx] = chunkIndices
chunkIdx++
}
// Now associate with names and pull the string sequence.
for chunkIdx, chunkIndices = range idxChunks {
grpNm = names[chunkIdx]
/*
Thankfully, it's actually a build error if a pattern specifies a named
capture group with an empty name.
So we don't need to worry about accounting for that,
and can just skip over grpNm == "" (which is an *unnamed* capture group).
and can just skip over grpNm == ""
(which is either an *unnamed* capture group
OR the first element in `names`, which is always
the entire match).
*/
if grpNm == "" {
continue
}
// This technically should never happen.
if endIdx > len(matchIndices) {
endIdx = len(matchIndices)
}
chunkIndices = matchIndices[startIdx:endIdx]
if chunkIndices[0] == -1 || chunkIndices[1] == -1 {
if chunkIndices == nil || len(chunkIndices) == 0 {
// group did not match
if !inclNoMatch {
continue
@@ -264,13 +456,19 @@ func (r *ReMap) MapString(s string, inclNoMatch, inclNoMatchStrict, mustMatch bo
continue
}
switch len(chunkIndices) {
case 1:
// Single character
matchStr = string(s[chunkIndices[0]])
case 2:
// Multiple characters
matchStr = s[chunkIndices[0]:chunkIndices[1]]
}
if _, ok = tmpMap[grpNm]; !ok {
tmpMap[grpNm] = make([]string, 0)
}
tmpMap[grpNm] = append(tmpMap[grpNm], matchStr)
chunkIdx++
}
// This *technically* should be completely handled above.

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@@ -1,7 +1,7 @@
package remap
import (
`regexp`
"regexp"
)
type (
@@ -10,14 +10,18 @@ type (
*regexp.Regexp
}
// TODO?
/*
ExplicitStringMatch is used with ReMap.MapStringExplicit to indicate if a
capture group result is a hit (a group matched, but e.g. the match value is empty string)
or not (a group did not match)
or not (a group did not match).
*/
/*
ExplicitStringMatch struct {
Group string
IsMatch bool
Value string
}
*/
)