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Diffstat (limited to 'kaldi_io/src/tools/openfst/include/fst/fst.h')
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1 files changed, 949 insertions, 0 deletions
diff --git a/kaldi_io/src/tools/openfst/include/fst/fst.h b/kaldi_io/src/tools/openfst/include/fst/fst.h new file mode 100644 index 0000000..150fc4e --- /dev/null +++ b/kaldi_io/src/tools/openfst/include/fst/fst.h @@ -0,0 +1,949 @@ +// fst.h + +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// Copyright 2005-2010 Google, Inc. +// Author: riley@google.com (Michael Riley) +// +// \file +// Finite-State Transducer (FST) - abstract base class definition, +// state and arc iterator interface, and suggested base implementation. +// + +#ifndef FST_LIB_FST_H__ +#define FST_LIB_FST_H__ + +#include <stddef.h> +#include <sys/types.h> +#include <cmath> +#include <string> + +#include <fst/compat.h> +#include <fst/types.h> + +#include <fst/arc.h> +#include <fst/properties.h> +#include <fst/register.h> +#include <iostream> +#include <fstream> +#include <sstream> +#include <fst/symbol-table.h> +#include <fst/util.h> + + +DECLARE_bool(fst_align); + +namespace fst { + +bool IsFstHeader(istream &, const string &); + +class FstHeader; +template <class A> class StateIteratorData; +template <class A> class ArcIteratorData; +template <class A> class MatcherBase; + +struct FstReadOptions { + // FileReadMode(s) are advisory, there are many conditions than prevent a + // file from being mapped, READ mode will be selected in these cases with + // a warning indicating why it was chosen. + enum FileReadMode { READ, MAP }; + + string source; // Where you're reading from + const FstHeader *header; // Pointer to Fst header. If non-zero, use + // this info (don't read a stream header) + const SymbolTable* isymbols; // Pointer to input symbols. If non-zero, use + // this info (read and skip stream isymbols) + const SymbolTable* osymbols; // Pointer to output symbols. If non-zero, use + // this info (read and skip stream osymbols) + FileReadMode mode; // Read or map files (advisory, if possible) + + explicit FstReadOptions(const string& src = "<unspecified>", + const FstHeader *hdr = 0, + const SymbolTable* isym = 0, + const SymbolTable* osym = 0); + + explicit FstReadOptions(const string& src, + const SymbolTable* isym, + const SymbolTable* osym = 0); + + // Helper function to convert strings FileReadModes into their enum value. + static FileReadMode ReadMode(const string &mode); +}; + +struct FstWriteOptions { + string source; // Where you're writing to + bool write_header; // Write the header? + bool write_isymbols; // Write input symbols? + bool write_osymbols; // Write output symbols? + bool align; // Write data aligned where appropriate; + // this may fail on pipes + + explicit FstWriteOptions(const string& src = "<unspecifed>", + bool hdr = true, bool isym = true, + bool osym = true, bool alig = FLAGS_fst_align) + : source(src), write_header(hdr), + write_isymbols(isym), write_osymbols(osym), align(alig) {} +}; + +// +// Fst HEADER CLASS +// +// This is the recommended Fst file header representation. +// +class FstHeader { + public: + enum { + HAS_ISYMBOLS = 0x1, // Has input symbol table + HAS_OSYMBOLS = 0x2, // Has output symbol table + IS_ALIGNED = 0x4, // Memory-aligned (where appropriate) + } Flags; + + FstHeader() : version_(0), flags_(0), properties_(0), start_(-1), + numstates_(0), numarcs_(0) {} + const string &FstType() const { return fsttype_; } + const string &ArcType() const { return arctype_; } + int32 Version() const { return version_; } + int32 GetFlags() const { return flags_; } + uint64 Properties() const { return properties_; } + int64 Start() const { return start_; } + int64 NumStates() const { return numstates_; } + int64 NumArcs() const { return numarcs_; } + + void SetFstType(const string& type) { fsttype_ = type; } + void SetArcType(const string& type) { arctype_ = type; } + void SetVersion(int32 version) { version_ = version; } + void SetFlags(int32 flags) { flags_ = flags; } + void SetProperties(uint64 properties) { properties_ = properties; } + void SetStart(int64 start) { start_ = start; } + void SetNumStates(int64 numstates) { numstates_ = numstates; } + void SetNumArcs(int64 numarcs) { numarcs_ = numarcs; } + + bool Read(istream &strm, const string &source, bool rewind = false); + bool Write(ostream &strm, const string &source) const; + + private: + + string fsttype_; // E.g. "vector" + string arctype_; // E.g. "standard" + int32 version_; // Type version # + int32 flags_; // File format bits + uint64 properties_; // FST property bits + int64 start_; // Start state + int64 numstates_; // # of states + int64 numarcs_; // # of arcs +}; + + +// Specifies matcher action. +enum MatchType { MATCH_INPUT, // Match input label. + MATCH_OUTPUT, // Match output label. + MATCH_BOTH, // Match input or output label. + MATCH_NONE, // Match nothing. + MATCH_UNKNOWN }; // Match type unknown. + +// +// Fst INTERFACE CLASS DEFINITION +// + +// A generic FST, templated on the arc definition, with +// common-demoninator methods (use StateIterator and ArcIterator to +// iterate over its states and arcs). +template <class A> +class Fst { + public: + typedef A Arc; + typedef typename A::Weight Weight; + typedef typename A::StateId StateId; + + virtual ~Fst() {} + + virtual StateId Start() const = 0; // Initial state + + virtual Weight Final(StateId) const = 0; // State's final weight + + virtual size_t NumArcs(StateId) const = 0; // State's arc count + + virtual size_t NumInputEpsilons(StateId) + const = 0; // State's input epsilon count + + virtual size_t NumOutputEpsilons(StateId) + const = 0; // State's output epsilon count + + // If test=false, return stored properties bits for mask (some poss. unknown) + // If test=true, return property bits for mask (computing o.w. unknown) + virtual uint64 Properties(uint64 mask, bool test) + const = 0; // Property bits + + virtual const string& Type() const = 0; // Fst type name + + // Get a copy of this Fst. The copying behaves as follows: + // + // (1) The copying is constant time if safe = false or if safe = true + // and is on an otherwise unaccessed Fst. + // + // (2) If safe = true, the copy is thread-safe in that the original + // and copy can be safely accessed (but not necessarily mutated) by + // separate threads. For some Fst types, 'Copy(true)' should only be + // called on an Fst that has not otherwise been accessed. Its behavior + // is undefined otherwise. + // + // (3) If a MutableFst is copied and then mutated, then the original is + // unmodified and vice versa (often by a copy-on-write on the initial + // mutation, which may not be constant time). + virtual Fst<A> *Copy(bool safe = false) const = 0; + + // Read an Fst from an input stream; returns NULL on error + static Fst<A> *Read(istream &strm, const FstReadOptions &opts) { + FstReadOptions ropts(opts); + FstHeader hdr; + if (ropts.header) + hdr = *opts.header; + else { + if (!hdr.Read(strm, opts.source)) + return 0; + ropts.header = &hdr; + } + FstRegister<A> *registr = FstRegister<A>::GetRegister(); + const typename FstRegister<A>::Reader reader = + registr->GetReader(hdr.FstType()); + if (!reader) { + LOG(ERROR) << "Fst::Read: Unknown FST type \"" << hdr.FstType() + << "\" (arc type = \"" << A::Type() + << "\"): " << ropts.source; + return 0; + } + return reader(strm, ropts); + }; + + // Read an Fst from a file; return NULL on error + // Empty filename reads from standard input + static Fst<A> *Read(const string &filename) { + if (!filename.empty()) { + ifstream strm(filename.c_str(), ifstream::in | ifstream::binary); + if (!strm) { + LOG(ERROR) << "Fst::Read: Can't open file: " << filename; + return 0; + } + return Read(strm, FstReadOptions(filename)); + } else { + return Read(cin, FstReadOptions("standard input")); + } + } + + // Write an Fst to an output stream; return false on error + virtual bool Write(ostream &strm, const FstWriteOptions &opts) const { + LOG(ERROR) << "Fst::Write: No write stream method for " << Type() + << " Fst type"; + return false; + } + + // Write an Fst to a file; return false on error + // Empty filename writes to standard output + virtual bool Write(const string &filename) const { + LOG(ERROR) << "Fst::Write: No write filename method for " << Type() + << " Fst type"; + return false; + } + + // Return input label symbol table; return NULL if not specified + virtual const SymbolTable* InputSymbols() const = 0; + + // Return output label symbol table; return NULL if not specified + virtual const SymbolTable* OutputSymbols() const = 0; + + // For generic state iterator construction; not normally called + // directly by users. + virtual void InitStateIterator(StateIteratorData<A> *) const = 0; + + // For generic arc iterator construction; not normally called + // directly by users. + virtual void InitArcIterator(StateId s, ArcIteratorData<A> *) const = 0; + + // For generic matcher construction; not normally called + // directly by users. + virtual MatcherBase<A> *InitMatcher(MatchType match_type) const; + + protected: + bool WriteFile(const string &filename) const { + if (!filename.empty()) { + ofstream strm(filename.c_str(), ofstream::out | ofstream::binary); + if (!strm) { + LOG(ERROR) << "Fst::Write: Can't open file: " << filename; + return false; + } + return Write(strm, FstWriteOptions(filename)); + } else { + return Write(cout, FstWriteOptions("standard output")); + } + } +}; + + +// +// STATE and ARC ITERATOR DEFINITIONS +// + +// State iterator interface templated on the Arc definition; used +// for StateIterator specializations returned by the InitStateIterator +// Fst method. +template <class A> +class StateIteratorBase { + public: + typedef A Arc; + typedef typename A::StateId StateId; + + virtual ~StateIteratorBase() {} + + bool Done() const { return Done_(); } // End of iterator? + StateId Value() const { return Value_(); } // Current state (when !Done) + void Next() { Next_(); } // Advance to next state (when !Done) + void Reset() { Reset_(); } // Return to initial condition + + private: + // This allows base class virtual access to non-virtual derived- + // class members of the same name. It makes the derived class more + // efficient to use but unsafe to further derive. + virtual bool Done_() const = 0; + virtual StateId Value_() const = 0; + virtual void Next_() = 0; + virtual void Reset_() = 0; +}; + + +// StateIterator initialization data + +template <class A> struct StateIteratorData { + StateIteratorBase<A> *base; // Specialized iterator if non-zero + typename A::StateId nstates; // O.w. total # of states +}; + + +// Generic state iterator, templated on the FST definition +// - a wrapper around pointer to specific one. +// Here is a typical use: \code +// for (StateIterator<StdFst> siter(fst); +// !siter.Done(); +// siter.Next()) { +// StateId s = siter.Value(); +// ... +// } \endcode +template <class F> +class StateIterator { + public: + typedef F FST; + typedef typename F::Arc Arc; + typedef typename Arc::StateId StateId; + + explicit StateIterator(const F &fst) : s_(0) { + fst.InitStateIterator(&data_); + } + + ~StateIterator() { if (data_.base) delete data_.base; } + + bool Done() const { + return data_.base ? data_.base->Done() : s_ >= data_.nstates; + } + + StateId Value() const { return data_.base ? data_.base->Value() : s_; } + + void Next() { + if (data_.base) + data_.base->Next(); + else + ++s_; + } + + void Reset() { + if (data_.base) + data_.base->Reset(); + else + s_ = 0; + } + + private: + StateIteratorData<Arc> data_; + StateId s_; + + DISALLOW_COPY_AND_ASSIGN(StateIterator); +}; + + +// Flags to control the behavior on an arc iterator: +static const uint32 kArcILabelValue = 0x0001; // Value() gives valid ilabel +static const uint32 kArcOLabelValue = 0x0002; // " " " olabel +static const uint32 kArcWeightValue = 0x0004; // " " " weight +static const uint32 kArcNextStateValue = 0x0008; // " " " nextstate +static const uint32 kArcNoCache = 0x0010; // No need to cache arcs + +static const uint32 kArcValueFlags = + kArcILabelValue | kArcOLabelValue | + kArcWeightValue | kArcNextStateValue; + +static const uint32 kArcFlags = kArcValueFlags | kArcNoCache; + + +// Arc iterator interface, templated on the Arc definition; used +// for Arc iterator specializations that are returned by the InitArcIterator +// Fst method. +template <class A> +class ArcIteratorBase { + public: + typedef A Arc; + typedef typename A::StateId StateId; + + virtual ~ArcIteratorBase() {} + + bool Done() const { return Done_(); } // End of iterator? + const A& Value() const { return Value_(); } // Current arc (when !Done) + void Next() { Next_(); } // Advance to next arc (when !Done) + size_t Position() const { return Position_(); } // Return current position + void Reset() { Reset_(); } // Return to initial condition + void Seek(size_t a) { Seek_(a); } // Random arc access by position + uint32 Flags() const { return Flags_(); } // Return current behavorial flags + void SetFlags(uint32 flags, uint32 mask) { // Set behavorial flags + SetFlags_(flags, mask); + } + + private: + // This allows base class virtual access to non-virtual derived- + // class members of the same name. It makes the derived class more + // efficient to use but unsafe to further derive. + virtual bool Done_() const = 0; + virtual const A& Value_() const = 0; + virtual void Next_() = 0; + virtual size_t Position_() const = 0; + virtual void Reset_() = 0; + virtual void Seek_(size_t a) = 0; + virtual uint32 Flags_() const = 0; + virtual void SetFlags_(uint32 flags, uint32 mask) = 0; +}; + + +// ArcIterator initialization data +template <class A> struct ArcIteratorData { + ArcIteratorBase<A> *base; // Specialized iterator if non-zero + const A *arcs; // O.w. arcs pointer + size_t narcs; // ... and arc count + int *ref_count; // ... and reference count if non-zero +}; + + +// Generic arc iterator, templated on the FST definition +// - a wrapper around pointer to specific one. +// Here is a typical use: \code +// for (ArcIterator<StdFst> aiter(fst, s)); +// !aiter.Done(); +// aiter.Next()) { +// StdArc &arc = aiter.Value(); +// ... +// } \endcode +template <class F> +class ArcIterator { + public: + typedef F FST; + typedef typename F::Arc Arc; + typedef typename Arc::StateId StateId; + + ArcIterator(const F &fst, StateId s) : i_(0) { + fst.InitArcIterator(s, &data_); + } + + explicit ArcIterator(const ArcIteratorData<Arc> &data) : data_(data), i_(0) { + if (data_.ref_count) + ++(*data_.ref_count); + } + + ~ArcIterator() { + if (data_.base) + delete data_.base; + else if (data_.ref_count) + --(*data_.ref_count); + } + + bool Done() const { + return data_.base ? data_.base->Done() : i_ >= data_.narcs; + } + + const Arc& Value() const { + return data_.base ? data_.base->Value() : data_.arcs[i_]; + } + + void Next() { + if (data_.base) + data_.base->Next(); + else + ++i_; + } + + void Reset() { + if (data_.base) + data_.base->Reset(); + else + i_ = 0; + } + + void Seek(size_t a) { + if (data_.base) + data_.base->Seek(a); + else + i_ = a; + } + + size_t Position() const { + return data_.base ? data_.base->Position() : i_; + } + + uint32 Flags() const { + if (data_.base) + return data_.base->Flags(); + else + return kArcValueFlags; + } + + void SetFlags(uint32 flags, uint32 mask) { + if (data_.base) + data_.base->SetFlags(flags, mask); + } + + private: + ArcIteratorData<Arc> data_; + size_t i_; + DISALLOW_COPY_AND_ASSIGN(ArcIterator); +}; + +// +// MATCHER DEFINITIONS +// + +template <class A> +MatcherBase<A> *Fst<A>::InitMatcher(MatchType match_type) const { + return 0; // Use the default matcher +} + + +// +// FST ACCESSORS - Useful functions in high-performance cases. +// + +namespace internal { + +// General case - requires non-abstract, 'final' methods. Use for inlining. +template <class F> inline +typename F::Arc::Weight Final(const F &fst, typename F::Arc::StateId s) { + return fst.F::Final(s); +} + +template <class F> inline +ssize_t NumArcs(const F &fst, typename F::Arc::StateId s) { + return fst.F::NumArcs(s); +} + +template <class F> inline +ssize_t NumInputEpsilons(const F &fst, typename F::Arc::StateId s) { + return fst.F::NumInputEpsilons(s); +} + +template <class F> inline +ssize_t NumOutputEpsilons(const F &fst, typename F::Arc::StateId s) { + return fst.F::NumOutputEpsilons(s); +} + + +// Fst<A> case - abstract methods. +template <class A> inline +typename A::Weight Final(const Fst<A> &fst, typename A::StateId s) { + return fst.Final(s); +} + +template <class A> inline +ssize_t NumArcs(const Fst<A> &fst, typename A::StateId s) { + return fst.NumArcs(s); +} + +template <class A> inline +ssize_t NumInputEpsilons(const Fst<A> &fst, typename A::StateId s) { + return fst.NumInputEpsilons(s); +} + +template <class A> inline +ssize_t NumOutputEpsilons(const Fst<A> &fst, typename A::StateId s) { + return fst.NumOutputEpsilons(s); +} + +} // namespace internal + +// A useful alias when using StdArc. +typedef Fst<StdArc> StdFst; + + +// +// CONSTANT DEFINITIONS +// + +const int kNoStateId = -1; // Not a valid state ID +const int kNoLabel = -1; // Not a valid label + +// +// Fst IMPLEMENTATION BASE +// +// This is the recommended Fst implementation base class. It will +// handle reference counts, property bits, type information and symbols. +// + +template <class A> class FstImpl { + public: + typedef typename A::Weight Weight; + typedef typename A::StateId StateId; + + FstImpl() + : properties_(0), type_("null"), isymbols_(0), osymbols_(0) {} + + FstImpl(const FstImpl<A> &impl) + : properties_(impl.properties_), type_(impl.type_), + isymbols_(impl.isymbols_ ? impl.isymbols_->Copy() : 0), + osymbols_(impl.osymbols_ ? impl.osymbols_->Copy() : 0) {} + + virtual ~FstImpl() { + delete isymbols_; + delete osymbols_; + } + + const string& Type() const { return type_; } + + void SetType(const string &type) { type_ = type; } + + virtual uint64 Properties() const { return properties_; } + + virtual uint64 Properties(uint64 mask) const { return properties_ & mask; } + + void SetProperties(uint64 props) { + properties_ &= kError; // kError can't be cleared + properties_ |= props; + } + + void SetProperties(uint64 props, uint64 mask) { + properties_ &= ~mask | kError; // kError can't be cleared + properties_ |= props & mask; + } + + // Allows (only) setting error bit on const FST impls + void SetProperties(uint64 props, uint64 mask) const { + if (mask != kError) + FSTERROR() << "FstImpl::SetProperties() const: can only set kError"; + properties_ |= kError; + } + + const SymbolTable* InputSymbols() const { return isymbols_; } + + const SymbolTable* OutputSymbols() const { return osymbols_; } + + SymbolTable* InputSymbols() { return isymbols_; } + + SymbolTable* OutputSymbols() { return osymbols_; } + + void SetInputSymbols(const SymbolTable* isyms) { + if (isymbols_) delete isymbols_; + isymbols_ = isyms ? isyms->Copy() : 0; + } + + void SetOutputSymbols(const SymbolTable* osyms) { + if (osymbols_) delete osymbols_; + osymbols_ = osyms ? osyms->Copy() : 0; + } + + int RefCount() const { + return ref_count_.count(); + } + + int IncrRefCount() { + return ref_count_.Incr(); + } + + int DecrRefCount() { + return ref_count_.Decr(); + } + + // Read-in header and symbols from input stream, initialize Fst, and + // return the header. If opts.header is non-null, skip read-in and + // use the option value. If opts.[io]symbols is non-null, read-in + // (if present), but use the option value. + bool ReadHeader(istream &strm, const FstReadOptions& opts, + int min_version, FstHeader *hdr); + + // Write-out header and symbols from output stream. + // If a opts.header is false, skip writing header. + // If opts.[io]symbols is false, skip writing those symbols. + // This method is needed for Impl's that implement Write methods. + void WriteHeader(ostream &strm, const FstWriteOptions& opts, + int version, FstHeader *hdr) const { + if (opts.write_header) { + hdr->SetFstType(type_); + hdr->SetArcType(A::Type()); + hdr->SetVersion(version); + hdr->SetProperties(properties_); + int32 file_flags = 0; + if (isymbols_ && opts.write_isymbols) + file_flags |= FstHeader::HAS_ISYMBOLS; + if (osymbols_ && opts.write_osymbols) + file_flags |= FstHeader::HAS_OSYMBOLS; + if (opts.align) + file_flags |= FstHeader::IS_ALIGNED; + hdr->SetFlags(file_flags); + hdr->Write(strm, opts.source); + } + if (isymbols_ && opts.write_isymbols) isymbols_->Write(strm); + if (osymbols_ && opts.write_osymbols) osymbols_->Write(strm); + } + + // Write-out header and symbols to output stream. + // If a opts.header is false, skip writing header. + // If opts.[io]symbols is false, skip writing those symbols. + // type is the Fst type being written. + // This method is used in the cross-type serialization methods Fst::WriteFst. + static void WriteFstHeader(const Fst<A> &fst, ostream &strm, + const FstWriteOptions& opts, int version, + const string &type, uint64 properties, + FstHeader *hdr) { + if (opts.write_header) { + hdr->SetFstType(type); + hdr->SetArcType(A::Type()); + hdr->SetVersion(version); + hdr->SetProperties(properties); + int32 file_flags = 0; + if (fst.InputSymbols() && opts.write_isymbols) + file_flags |= FstHeader::HAS_ISYMBOLS; + if (fst.OutputSymbols() && opts.write_osymbols) + file_flags |= FstHeader::HAS_OSYMBOLS; + if (opts.align) + file_flags |= FstHeader::IS_ALIGNED; + hdr->SetFlags(file_flags); + hdr->Write(strm, opts.source); + } + if (fst.InputSymbols() && opts.write_isymbols) { + fst.InputSymbols()->Write(strm); + } + if (fst.OutputSymbols() && opts.write_osymbols) { + fst.OutputSymbols()->Write(strm); + } + } + + // In serialization routines where the header cannot be written until after + // the machine has been serialized, this routine can be called to seek to + // the beginning of the file an rewrite the header with updated fields. + // It repositions the file pointer back at the end of the file. + // returns true on success, false on failure. + static bool UpdateFstHeader(const Fst<A> &fst, ostream &strm, + const FstWriteOptions& opts, int version, + const string &type, uint64 properties, + FstHeader *hdr, size_t header_offset) { + strm.seekp(header_offset); + if (!strm) { + LOG(ERROR) << "Fst::UpdateFstHeader: write failed: " << opts.source; + return false; + } + WriteFstHeader(fst, strm, opts, version, type, properties, hdr); + if (!strm) { + LOG(ERROR) << "Fst::UpdateFstHeader: write failed: " << opts.source; + return false; + } + strm.seekp(0, ios_base::end); + if (!strm) { + LOG(ERROR) << "Fst::UpdateFstHeader: write failed: " << opts.source; + return false; + } + return true; + } + + protected: + mutable uint64 properties_; // Property bits + + private: + string type_; // Unique name of Fst class + SymbolTable *isymbols_; // Ilabel symbol table + SymbolTable *osymbols_; // Olabel symbol table + RefCounter ref_count_; // Reference count + + void operator=(const FstImpl<A> &impl); // disallow +}; + +template <class A> inline +bool FstImpl<A>::ReadHeader(istream &strm, const FstReadOptions& opts, + int min_version, FstHeader *hdr) { + if (opts.header) + *hdr = *opts.header; + else if (!hdr->Read(strm, opts.source)) + return false; + + if (FLAGS_v >= 2) { + LOG(INFO) << "FstImpl::ReadHeader: source: " << opts.source + << ", fst_type: " << hdr->FstType() + << ", arc_type: " << A::Type() + << ", version: " << hdr->Version() + << ", flags: " << hdr->GetFlags(); + } + + if (hdr->FstType() != type_) { + LOG(ERROR) << "FstImpl::ReadHeader: Fst not of type \"" << type_ + << "\": " << opts.source; + return false; + } + if (hdr->ArcType() != A::Type()) { + LOG(ERROR) << "FstImpl::ReadHeader: Arc not of type \"" << A::Type() + << "\": " << opts.source; + return false; + } + if (hdr->Version() < min_version) { + LOG(ERROR) << "FstImpl::ReadHeader: Obsolete " << type_ + << " Fst version: " << opts.source; + return false; + } + properties_ = hdr->Properties(); + if (hdr->GetFlags() & FstHeader::HAS_ISYMBOLS) + isymbols_ = SymbolTable::Read(strm, opts.source); + if (hdr->GetFlags() & FstHeader::HAS_OSYMBOLS) + osymbols_ =SymbolTable::Read(strm, opts.source); + + if (opts.isymbols) { + delete isymbols_; + isymbols_ = opts.isymbols->Copy(); + } + if (opts.osymbols) { + delete osymbols_; + osymbols_ = opts.osymbols->Copy(); + } + return true; +} + + +template<class Arc> +uint64 TestProperties(const Fst<Arc> &fst, uint64 mask, uint64 *known); + + +// This is a helper class template useful for attaching an Fst interface to +// its implementation, handling reference counting. +template < class I, class F = Fst<typename I::Arc> > +class ImplToFst : public F { + public: + typedef typename I::Arc Arc; + typedef typename Arc::Weight Weight; + typedef typename Arc::StateId StateId; + + virtual ~ImplToFst() { if (!impl_->DecrRefCount()) delete impl_; } + + virtual StateId Start() const { return impl_->Start(); } + + virtual Weight Final(StateId s) const { return impl_->Final(s); } + + virtual size_t NumArcs(StateId s) const { return impl_->NumArcs(s); } + + virtual size_t NumInputEpsilons(StateId s) const { + return impl_->NumInputEpsilons(s); + } + + virtual size_t NumOutputEpsilons(StateId s) const { + return impl_->NumOutputEpsilons(s); + } + + virtual uint64 Properties(uint64 mask, bool test) const { + if (test) { + uint64 knownprops, testprops = TestProperties(*this, mask, &knownprops); + impl_->SetProperties(testprops, knownprops); + return testprops & mask; + } else { + return impl_->Properties(mask); + } + } + + virtual const string& Type() const { return impl_->Type(); } + + virtual const SymbolTable* InputSymbols() const { + return impl_->InputSymbols(); + } + + virtual const SymbolTable* OutputSymbols() const { + return impl_->OutputSymbols(); + } + + protected: + ImplToFst() : impl_(0) {} + + ImplToFst(I *impl) : impl_(impl) {} + + ImplToFst(const ImplToFst<I, F> &fst) { + impl_ = fst.impl_; + impl_->IncrRefCount(); + } + + // This constructor presumes there is a copy constructor for the + // implementation. + ImplToFst(const ImplToFst<I, F> &fst, bool safe) { + if (safe) { + impl_ = new I(*(fst.impl_)); + } else { + impl_ = fst.impl_; + impl_->IncrRefCount(); + } + } + + I *GetImpl() const { return impl_; } + + // Change Fst implementation pointer. If 'own_impl' is true, + // ownership of the input implementation is given to this + // object; otherwise, the input implementation's reference count + // should be incremented. + void SetImpl(I *impl, bool own_impl = true) { + if (!own_impl) + impl->IncrRefCount(); + if (impl_ && !impl_->DecrRefCount()) delete impl_; + impl_ = impl; + } + + private: + // Disallow + ImplToFst<I, F> &operator=(const ImplToFst<I, F> &fst); + + ImplToFst<I, F> &operator=(const Fst<Arc> &fst) { + FSTERROR() << "ImplToFst: Assignment operator disallowed"; + GetImpl()->SetProperties(kError, kError); + return *this; + } + + I *impl_; +}; + + +// Converts FSTs by casting their implementations, where this makes +// sense (which excludes implementations with weight-dependent virtual +// methods). Must be a friend of the Fst classes involved (currently +// the concrete Fsts: VectorFst, ConstFst, CompactFst). +template<class F, class G> void Cast(const F &ifst, G *ofst) { + ofst->SetImpl(reinterpret_cast<typename G::Impl *>(ifst.GetImpl()), false); +} + +// Fst Serialization +template <class A> +void FstToString(const Fst<A> &fst, string *result) { + ostringstream ostrm; + fst.Write(ostrm, FstWriteOptions("FstToString")); + *result = ostrm.str(); +} + +template <class A> +Fst<A> *StringToFst(const string &s) { + istringstream istrm(s); + return Fst<A>::Read(istrm, FstReadOptions("StringToFst")); +} + +} // namespace fst + +#endif // FST_LIB_FST_H__ |