initial commit, 4.5 stable

thirdparty/icu4c/common/bytestrieiterator.cpp

@@ -0,0 +1,214 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+*   Copyright (C) 2010-2012, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*******************************************************************************
+*   file name:  bytestrieiterator.cpp
+*   encoding:   UTF-8
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2010nov03
+*   created by: Markus W. Scherer
+*/
+
+#include "unicode/utypes.h"
+#include "unicode/bytestrie.h"
+#include "unicode/stringpiece.h"
+#include "charstr.h"
+#include "uvectr32.h"
+
+U_NAMESPACE_BEGIN
+
+BytesTrie::Iterator::Iterator(const void *trieBytes, int32_t maxStringLength,
+                              UErrorCode &errorCode)
+        : bytes_(static_cast<const uint8_t *>(trieBytes)),
+          pos_(bytes_), initialPos_(bytes_),
+          remainingMatchLength_(-1), initialRemainingMatchLength_(-1),
+          str_(nullptr), maxLength_(maxStringLength), value_(0), stack_(nullptr) {
+    if(U_FAILURE(errorCode)) {
+        return;
+    }
+    // str_ and stack_ are pointers so that it's easy to turn bytestrie.h into
+    // a public API header for which we would want it to depend only on
+    // other public headers.
+    // Unlike BytesTrie itself, its Iterator performs memory allocations anyway
+    // via the CharString and UVector32 implementations, so this additional
+    // cost is minimal.
+    str_=new CharString();
+    stack_=new UVector32(errorCode);
+    if(U_SUCCESS(errorCode) && (str_==nullptr || stack_==nullptr)) {
+        errorCode=U_MEMORY_ALLOCATION_ERROR;
+    }
+}
+
+BytesTrie::Iterator::Iterator(const BytesTrie &trie, int32_t maxStringLength,
+                              UErrorCode &errorCode)
+        : bytes_(trie.bytes_), pos_(trie.pos_), initialPos_(trie.pos_),
+          remainingMatchLength_(trie.remainingMatchLength_),
+          initialRemainingMatchLength_(trie.remainingMatchLength_),
+          str_(nullptr), maxLength_(maxStringLength), value_(0), stack_(nullptr) {
+    if(U_FAILURE(errorCode)) {
+        return;
+    }
+    str_=new CharString();
+    stack_=new UVector32(errorCode);
+    if(U_FAILURE(errorCode)) {
+        return;
+    }
+    if(str_==nullptr || stack_==nullptr) {
+        errorCode=U_MEMORY_ALLOCATION_ERROR;
+        return;
+    }
+    int32_t length=remainingMatchLength_;  // Actual remaining match length minus 1.
+    if(length>=0) {
+        // Pending linear-match node, append remaining bytes to str_.
+        ++length;
+        if(maxLength_>0 && length>maxLength_) {
+            length=maxLength_;  // This will leave remainingMatchLength>=0 as a signal.
+        }
+        str_->append(reinterpret_cast<const char *>(pos_), length, errorCode);
+        pos_+=length;
+        remainingMatchLength_-=length;
+    }
+}
+
+BytesTrie::Iterator::~Iterator() {
+    delete str_;
+    delete stack_;
+}
+
+BytesTrie::Iterator &
+BytesTrie::Iterator::reset() {
+    pos_=initialPos_;
+    remainingMatchLength_=initialRemainingMatchLength_;
+    int32_t length=remainingMatchLength_+1;  // Remaining match length.
+    if(maxLength_>0 && length>maxLength_) {
+        length=maxLength_;
+    }
+    str_->truncate(length);
+    pos_+=length;
+    remainingMatchLength_-=length;
+    stack_->setSize(0);
+    return *this;
+}
+
+UBool
+BytesTrie::Iterator::hasNext() const { return pos_!=nullptr || !stack_->isEmpty(); }
+
+UBool
+BytesTrie::Iterator::next(UErrorCode &errorCode) {
+    if(U_FAILURE(errorCode)) {
+        return false;
+    }
+    const uint8_t *pos=pos_;
+    if(pos==nullptr) {
+        if(stack_->isEmpty()) {
+            return false;
+        }
+        // Pop the state off the stack and continue with the next outbound edge of
+        // the branch node.
+        int32_t stackSize=stack_->size();
+        int32_t length=stack_->elementAti(stackSize-1);
+        pos=bytes_+stack_->elementAti(stackSize-2);
+        stack_->setSize(stackSize-2);
+        str_->truncate(length&0xffff);
+        length = static_cast<int32_t>(static_cast<uint32_t>(length) >> 16);
+        if(length>1) {
+            pos=branchNext(pos, length, errorCode);
+            if(pos==nullptr) {
+                return true;  // Reached a final value.
+            }
+        } else {
+            str_->append(static_cast<char>(*pos++), errorCode);
+        }
+    }
+    if(remainingMatchLength_>=0) {
+        // We only get here if we started in a pending linear-match node
+        // with more than maxLength remaining bytes.
+        return truncateAndStop();
+    }
+    for(;;) {
+        int32_t node=*pos++;
+        if(node>=kMinValueLead) {
+            // Deliver value for the byte sequence so far.
+            UBool isFinal = static_cast<UBool>(node & kValueIsFinal);
+            value_=readValue(pos, node>>1);
+            if(isFinal || (maxLength_>0 && str_->length()==maxLength_)) {
+                pos_=nullptr;
+            } else {
+                pos_=skipValue(pos, node);
+            }
+            return true;
+        }
+        if(maxLength_>0 && str_->length()==maxLength_) {
+            return truncateAndStop();
+        }
+        if(node<kMinLinearMatch) {
+            if(node==0) {
+                node=*pos++;
+            }
+            pos=branchNext(pos, node+1, errorCode);
+            if(pos==nullptr) {
+                return true;  // Reached a final value.
+            }
+        } else {
+            // Linear-match node, append length bytes to str_.
+            int32_t length=node-kMinLinearMatch+1;
+            if(maxLength_>0 && str_->length()+length>maxLength_) {
+                str_->append(reinterpret_cast<const char *>(pos),
+                            maxLength_-str_->length(), errorCode);
+                return truncateAndStop();
+            }
+            str_->append(reinterpret_cast<const char *>(pos), length, errorCode);
+            pos+=length;
+        }
+    }
+}
+
+StringPiece
+BytesTrie::Iterator::getString() const {
+    return str_ == nullptr ? StringPiece() : str_->toStringPiece();
+}
+
+UBool
+BytesTrie::Iterator::truncateAndStop() {
+    pos_=nullptr;
+    value_=-1;  // no real value for str
+    return true;
+}
+
+// Branch node, needs to take the first outbound edge and push state for the rest.
+const uint8_t *
+BytesTrie::Iterator::branchNext(const uint8_t *pos, int32_t length, UErrorCode &errorCode) {
+    while(length>kMaxBranchLinearSubNodeLength) {
+        ++pos;  // ignore the comparison byte
+        // Push state for the greater-or-equal edge.
+        stack_->addElement(static_cast<int32_t>(skipDelta(pos) - bytes_), errorCode);
+        stack_->addElement(((length-(length>>1))<<16)|str_->length(), errorCode);
+        // Follow the less-than edge.
+        length>>=1;
+        pos=jumpByDelta(pos);
+    }
+    // List of key-value pairs where values are either final values or jump deltas.
+    // Read the first (key, value) pair.
+    uint8_t trieByte=*pos++;
+    int32_t node=*pos++;
+    UBool isFinal = static_cast<UBool>(node & kValueIsFinal);
+    int32_t value=readValue(pos, node>>1);
+    pos=skipValue(pos, node);
+    stack_->addElement(static_cast<int32_t>(pos - bytes_), errorCode);
+    stack_->addElement(((length-1)<<16)|str_->length(), errorCode);
+    str_->append(static_cast<char>(trieByte), errorCode);
+    if(isFinal) {
+        pos_=nullptr;
+        value_=value;
+        return nullptr;
+    } else {
+        return pos+value;
+    }
+}
+
+U_NAMESPACE_END