json print/parse from/to PVStructure

src/json/print.cpp

@@ -0,0 +1,160 @@
+/*
+ * Copyright information and license terms for this software can be
+ * found in the file LICENSE that is included with the distribution
+ */
+
+#include <vector>
+#include <sstream>
+
+#include <pv/pvdVersion.h>
+#include <pv/pvData.h>
+#include <pv/valueBuilder.h>
+
+#if EPICS_VERSION_INT>=VERSION_INT(3,15,0,1)
+
+#include <yajl_parse.h>
+
+#define epicsExportSharedSymbols
+#include "pv/json.h"
+
+namespace pvd = epics::pvData;
+
+namespace {
+
+struct args {
+    std::ostream& strm;
+    const pvd::JSONPrintOptions& opts;
+
+    unsigned indent;
+
+    args(std::ostream& strm,
+         const pvd::JSONPrintOptions& opts)
+        :strm(strm)
+        ,opts(opts)
+        ,indent(opts.indent)
+    {}
+
+    void doIntent() {
+        if(!opts.multiLine) return;
+        strm.put('\n');
+        unsigned i=indent;
+        while(i--) strm.put(' ');
+    }
+};
+
+void show_field(args& A, const pvd::PVField* fld);
+
+void show_struct(args& A, const pvd::PVStructure* fld)
+{
+    const pvd::StructureConstPtr& type = fld->getStructure();
+    const pvd::PVFieldPtrArray& children = fld->getPVFields();
+
+    const pvd::StringArray& names = type->getFieldNames();
+
+    A.strm.put('{');
+    A.indent++;
+
+    for(size_t i=0, N=names.size(); i<N; i++)
+    {
+        if(i!=0)
+            A.strm.put(',');
+        A.doIntent();
+        A.strm<<'\"'<<names[i]<<"\": ";
+        show_field(A, children[i].get());
+    }
+
+    A.indent--;
+    A.doIntent();
+    A.strm.put('}');
+}
+
+void show_field(args& A, const pvd::PVField* fld)
+{
+    switch(fld->getField()->getType())
+    {
+    case pvd::scalar:
+    {
+        const pvd::PVScalar *scalar=static_cast<const pvd::PVScalar*>(fld);
+        if(scalar->getScalar()->getScalarType()==pvd::pvString) {
+            A.strm<<'\"'<<scalar->getAs<std::string>()<<'\"';
+        } else {
+            A.strm<<scalar->getAs<std::string>();
+        }
+    }
+        break;
+    case pvd::scalarArray:
+    {
+        const pvd::PVScalarArray *scalar=static_cast<const pvd::PVScalarArray*>(fld);
+        const bool isstring = scalar->getScalarArray()->getElementType()==pvd::pvString;
+
+        pvd::shared_vector<const void> arr;
+        scalar->getAs<void>(arr);
+
+        pvd::shared_vector<const std::string> sarr(pvd::shared_vector_convert<const std::string>(arr));
+
+        A.strm.put('[');
+        for(size_t i=0, N=sarr.size(); i<N; i++) {
+            if(i!=0)
+                A.strm.put(',');
+            if(isstring)
+                A.strm.put('\"');
+            A.strm<<sarr[i];
+            if(isstring)
+                A.strm.put('\"');
+        }
+        A.strm.put(']');
+    }
+        break;
+    case pvd::structure:
+        show_struct(A, static_cast<const pvd::PVStructure*>(fld));
+        break;
+    case pvd::structureArray:
+    {
+        pvd::PVStructureArray::const_svector arr(static_cast<const pvd::PVStructureArray*>(fld)->view());
+        A.strm.put('[');
+        A.indent++;
+
+        for(size_t i=0, N=arr.size(); i<N; i++) {
+            if(i!=0)
+                A.strm.put(',');
+            A.doIntent();
+            if(arr[i])
+                show_struct(A, arr[i].get());
+            else
+                A.strm<<"NULL";
+        }
+
+        A.indent--;
+        A.doIntent();
+        A.strm.put(']');
+    }
+        break;
+    default:
+        if(A.opts.ignoreUnprintable)
+            A.strm<<"// unprintable field type";
+        else
+            throw std::runtime_error("Encountered unprintable field type");
+    }
+}
+
+} // namespace
+
+namespace epics{namespace pvData{
+
+JSONPrintOptions::JSONPrintOptions()
+    :multiLine(true)
+    ,ignoreUnprintable(true)
+    ,indent(0)
+{}
+
+void printJSON(std::ostream& strm,
+               const PVField::const_shared_pointer& val,
+               const JSONPrintOptions& opts)
+{
+    args A(strm, opts);
+    show_field(A, val.get());
+}
+
+}} // namespace epics::pvData
+
+#endif // EPICS_VERSION_INT