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TagSection: Extract Find() methods taking Pos instead of Key
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This allows us to add a perfect hash function to the tag file
without having to reimplement the methods a second time.
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@julian-klode
julian-klode committed Nov 22, 2016
1 parent 3e63306 commit 45ecab4
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Showing 2 changed files with 65 additions and 20 deletions.
74 changes: 54 additions & 20 deletions apt-pkg/tagfile.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -645,13 +645,9 @@ bool pkgTagSection::Find(StringView TagView,unsigned int &Pos) const
return false;
}

bool pkgTagSection::Find(StringView Tag,const char *&Start,
bool pkgTagSection::FindInternal(unsigned int Pos, const char *&Start,
const char *&End) const
{
unsigned int Pos;
if (Find(Tag, Pos) == false)
return false;

Start = Section + d->Tags[Pos].StartValue;
// Strip off the gunk from the end
End = Section + d->Tags[Pos + 1].StartTag;
Expand All @@ -661,6 +657,12 @@ bool pkgTagSection::Find(StringView Tag,const char *&Start,
for (; isspace_ascii(End[-1]) != 0 && End > Start; --End);

return true;
}
bool pkgTagSection::Find(StringView Tag,const char *&Start,
const char *&End) const
{
unsigned int Pos;
return Find(Tag, Pos) && FindInternal(Pos, Start, End);
}
/*}}}*/
// TagSection::FindS - Find a string /*{{{*/
Expand All @@ -674,12 +676,8 @@ StringView pkgTagSection::Find(StringView Tag) const
}
/*}}}*/
// TagSection::FindRawS - Find a string /*{{{*/
StringView pkgTagSection::FindRaw(StringView Tag) const
StringView pkgTagSection::FindRawInternal(unsigned int Pos) const
{
unsigned int Pos;
if (Find(Tag, Pos) == false)
return "";

char const *Start = (char const *) memchr(Section + d->Tags[Pos].EndTag, ':', d->Tags[Pos].StartValue - d->Tags[Pos].EndTag);
++Start;
char const *End = Section + d->Tags[Pos + 1].StartTag;
Expand All @@ -689,16 +687,21 @@ StringView pkgTagSection::FindRaw(StringView Tag) const
for (; isspace_ascii(End[-1]) != 0 && End > Start; --End);

return StringView(Start, End - Start);
}
StringView pkgTagSection::FindRaw(StringView Tag) const
{
unsigned int Pos;
return Find(Tag, Pos) ? FindRawInternal(Pos) : "";
}
/*}}}*/
// TagSection::FindI - Find an integer /*{{{*/
// ---------------------------------------------------------------------
/* */
signed int pkgTagSection::FindI(StringView Tag,signed long Default) const
signed int pkgTagSection::FindIInternal(unsigned int Pos,signed long Default) const
{
const char *Start;
const char *Stop;
if (Find(Tag,Start,Stop) == false)
if (FindInternal(Pos,Start,Stop) == false)
return Default;

// Copy it into a temp buffer so we can use strtol
Expand All @@ -719,16 +722,22 @@ signed int pkgTagSection::FindI(StringView Tag,signed long Default) const
if (S == End)
return Default;
return Result;
}
signed int pkgTagSection::FindI(StringView Tag,signed long Default) const
{
unsigned int Pos;

return Find(Tag, Pos) ? FindIInternal(Pos, Default) : Default;
}
/*}}}*/
// TagSection::FindULL - Find an unsigned long long integer /*{{{*/
// ---------------------------------------------------------------------
/* */
unsigned long long pkgTagSection::FindULL(StringView Tag, unsigned long long const &Default) const
unsigned long long pkgTagSection::FindULLInternal(unsigned int Pos, unsigned long long const &Default) const
{
const char *Start;
const char *Stop;
if (Find(Tag,Start,Stop) == false)
if (FindInternal(Pos,Start,Stop) == false)
return Default;

// Copy it into a temp buffer so we can use strtoull
Expand All @@ -743,31 +752,50 @@ unsigned long long pkgTagSection::FindULL(StringView Tag, unsigned long long con
if (S == End)
return Default;
return Result;
}
unsigned long long pkgTagSection::FindULL(StringView Tag, unsigned long long const &Default) const
{
unsigned int Pos;

return Find(Tag, Pos) ? FindULLInternal(Pos, Default) : Default;
}
/*}}}*/
// TagSection::FindB - Find boolean value /*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgTagSection::FindB(StringView Tag, bool Default) const
bool pkgTagSection::FindBInternal(unsigned int Pos, bool Default) const
{
const char *Start, *Stop;
if (Find(Tag, Start, Stop) == false)
if (FindInternal(Pos, Start, Stop) == false)
return Default;
return StringToBool(string(Start, Stop));
}
bool pkgTagSection::FindB(StringView Tag, bool Default) const
{
unsigned int Pos;
return Find(Tag, Pos) ? FindBInternal(Pos, Default) : Default;
}
/*}}}*/
// TagSection::FindFlag - Locate a yes/no type flag /*{{{*/
// ---------------------------------------------------------------------
/* The bits marked in Flag are masked on/off in Flags */
bool pkgTagSection::FindFlag(StringView Tag, uint8_t &Flags,
bool pkgTagSection::FindFlagInternal(unsigned int Pos, uint8_t &Flags,
uint8_t const Flag) const
{
const char *Start;
const char *Stop;
if (Find(Tag,Start,Stop) == false)
if (FindInternal(Pos,Start,Stop) == false)
return true;
return FindFlag(Flags, Flag, Start, Stop);
}
bool pkgTagSection::FindFlag(StringView Tag, uint8_t &Flags,
uint8_t const Flag) const
{
unsigned int Pos;
if (Find(Tag,Pos) == false)
return true;
return FindFlagInternal(Pos, Flags, Flag);
}
bool pkgTagSection::FindFlag(uint8_t &Flags, uint8_t const Flag,
char const* const Start, char const* const Stop)
{
Expand All @@ -787,15 +815,21 @@ bool pkgTagSection::FindFlag(uint8_t &Flags, uint8_t const Flag,
}
return true;
}
bool pkgTagSection::FindFlag(StringView Tag,unsigned long &Flags,
bool pkgTagSection::FindFlagInternal(unsigned int Pos,unsigned long &Flags,
unsigned long Flag) const
{
const char *Start;
const char *Stop;
if (Find(Tag,Start,Stop) == false)
if (FindInternal(Pos,Start,Stop) == false)
return true;
return FindFlag(Flags, Flag, Start, Stop);
}
bool pkgTagSection::FindFlag(StringView Tag,unsigned long &Flags,
unsigned long Flag) const
{
unsigned int Pos;
return Find(Tag, Pos) ? FindFlagInternal(Pos, Flags, Flag) : true;
}
bool pkgTagSection::FindFlag(unsigned long &Flags, unsigned long Flag,
char const* Start, char const* Stop)
{
Expand Down
11 changes: 11 additions & 0 deletions apt-pkg/tagfile.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,17 @@ class pkgTagSection

pkgTagSectionPrivate * const d;

APT_HIDDEN bool FindInternal(unsigned int Pos,const char *&Start, const char *&End) const;
#if defined(APT_PKG_EXPOSE_STRING_VIEW)
APT_HIDDEN APT::StringView FindInternal(unsigned int Pos) const;
APT_HIDDEN APT::StringView FindRawInternal(unsigned int Pos) const;
#endif
APT_HIDDEN signed int FindIInternal(unsigned int Pos,signed long Default = 0) const;
APT_HIDDEN bool FindBInternal(unsigned int Pos, bool Default = false) const;
APT_HIDDEN unsigned long long FindULLInternal(unsigned int Pos, unsigned long long const &Default = 0) const;
APT_HIDDEN bool FindFlagInternal(unsigned int Pos,uint8_t &Flags, uint8_t const Flag) const;
APT_HIDDEN bool FindFlagInternal(unsigned int Pos,unsigned long &Flags, unsigned long Flag) const;

protected:
const char *Stop;

Expand Down

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