improve readability of Pool.UnmarshalBinary
Change-Id: If0a0ac668f910a8dd5a05b87e841403b8d390de1
Reviewed-on: https://go-review.googlesource.com/18121
Reviewed-by: David Crawshaw <crawshaw@golang.org>
diff --git a/internal/binres/pool.go b/internal/binres/pool.go
index 2e2d113..b8e05cd 100644
--- a/internal/binres/pool.go
+++ b/internal/binres/pool.go
@@ -53,101 +53,78 @@
return fmt.Errorf("have type %s, want %s", pl.typ, ResStringPool)
}
- nstrings := btou32(bin[8:])
- pl.strings = make([]string, nstrings)
-
- nstyles := btou32(bin[12:])
- pl.styles = make([]*Span, nstyles)
-
+ pl.strings = make([]string, btou32(bin[8:]))
+ pl.styles = make([]*Span, btou32(bin[12:]))
pl.flags = btou32(bin[16:])
offstrings := btou32(bin[20:])
offstyle := btou32(bin[24:])
+ hdrlen := 28
- hdrlen := 28 // header size is always 28
if pl.IsUTF8() {
for i := range pl.strings {
- ii := btou32(bin[hdrlen+i*4:]) // index of string index
- r := int(offstrings + ii) // read index of string
+ offset := int(offstrings + btou32(bin[hdrlen+i*4:]))
- // for char and byte sizes below, if leading bit set,
- // treat first as 7-bit high word and the next byte as low word.
-
- // get char size of string
- cn := uint8(bin[r])
- rcn := int(cn)
- r++
- if cn&(1<<7) != 0 {
- cn0 := int(cn ^ (1 << 7)) // high word
- cn1 := int(bin[r]) // low word
- rcn = cn0*256 + cn1
- r++
+ // if leading bit set for nchars and nbytes,
+ // treat first byte as 7-bit high word and next as low word.
+ nchars := int(bin[offset])
+ offset++
+ if nchars&(1<<7) != 0 {
+ n0 := nchars ^ (1 << 7) // high word
+ n1 := int(bin[offset]) // low word
+ nchars = n0*(1<<8) + n1
+ offset++
}
- // get byte size of string
- // TODO(d) i've seen at least one case in android.jar resource table that has only
- // highbit set, effectively making 7-bit highword zero. The reason for this is currently
- // unknown but would make tests that unmarshal-marshal to match bytes impossible to pass.
+ // TODO(d) At least one case in android.jar (api-10) resource table has only
+ // highbit set, making 7-bit highword zero. The reason for this is currently
+ // unknown but would make tests that unmarshal-marshal to match bytes impossible.
// The values noted were high-word: 0 (after highbit unset), low-word: 141
- // I don't recall character count but was around ?78?
- // The case here may very well be that the size is treated like int8 triggering the use of
- // two bytes to store size even though the implementation uses uint8.
- n := uint8(bin[r])
- r++
- rn := int(n)
- if n&(1<<7) != 0 {
- n0 := int(n ^ (1 << 7)) // high word
- n1 := int(bin[r]) // low word
- rn = n0*(1<<8) + n1
- r++
+ // The size may be treated as an int8 triggering the use of two bytes to store size
+ // even though the implementation uses uint8.
+ nbytes := int(bin[offset])
+ offset++
+ if nbytes&(1<<7) != 0 {
+ n0 := nbytes ^ (1 << 7) // high word
+ n1 := int(bin[offset]) // low word
+ nbytes = n0*(1<<8) + n1
+ offset++
}
- //
- data := bin[r : r+rn]
- if x := uint8(bin[r+rn]); x != 0 {
- return fmt.Errorf("expected zero terminator, got %v for byte size %v char len %v", x, rn, rcn)
+ data := bin[offset : offset+nbytes]
+ if x := uint8(bin[offset+nbytes]); x != 0 {
+ return fmt.Errorf("expected zero terminator, got 0x%02X for nchars=%v nbytes=%v data=%q", x, nchars, nbytes, data)
}
pl.strings[i] = string(data)
}
} else {
for i := range pl.strings {
- ii := btou32(bin[hdrlen+i*4:]) // index of string index
- r := int(offstrings + ii) // read index of string
- n := btou16(bin[r:]) // string length
- rn := int(n)
- r += 2
+ offset := int(offstrings + btou32(bin[hdrlen+i*4:])) // read index of string
- if n&(1<<15) != 0 { // TODO this is untested
- n0 := int(n ^ (1 << 15)) // high word
- n1 := int(btou16(bin[r:]))
- rn = n0*(1<<16) + n1
- r += 2
+ // if leading bit set for nchars, treat first byte as 7-bit high word and next as low word.
+ nchars := int(btou16(bin[offset:]))
+ offset += 2
+ if nchars&(1<<15) != 0 { // TODO(d) this is untested
+ n0 := nchars ^ (1 << 15) // high word
+ n1 := int(btou16(bin[offset:])) // low word
+ nchars = n0*(1<<16) + n1
+ offset += 2
}
- data := make([]uint16, int(rn))
+ data := make([]uint16, nchars)
for i := range data {
- data[i] = btou16(bin[r+(2*i):])
+ data[i] = btou16(bin[offset+2*i:])
}
- r += int(n * 2)
- if x := btou16(bin[r:]); x != 0 {
- return fmt.Errorf("expected zero terminator, got 0x%04X\n%s", x)
+ if x := btou16(bin[offset+nchars*2:]); x != 0 {
+ return fmt.Errorf("expected zero terminator, got 0x%04X for nchars=%v data=%q", x, nchars, data)
}
-
pl.strings[i] = string(utf16.Decode(data))
}
}
- // TODO
+ // TODO decode styles
_ = offstyle
- // styii := hdrlen + int(nstrings*4)
- // for i := range pl.styles {
- // ii := btou32(bin[styii+i*4:])
- // r := int(offstyle + ii)
- // spn := new(binSpan)
- // spn.UnmarshalBinary(bin[r:])
- // pl.styles[i] = spn
- // }
return nil
}
