C++ Var::isVoid方法代码示例

static void writeVarEncodingExpression(Var& var, FILE* fp)
{
    const char* varname = var.name().c_str();

    if (var.isPointer()) {
        // encode a pointer header
        fprintf(fp, "\t*(unsigned int *)(ptr) = __size_%s; ptr += 4;\n", varname);

        Var::PointerDir dir = var.pointerDir();
        if (dir == Var::POINTER_INOUT || dir == Var::POINTER_IN) {
            if (var.nullAllowed()) {
                fprintf(fp, "\tif (%s != NULL) ", varname);
            } else {
                fprintf(fp, "\t");
            }

            if (var.packExpression().size() != 0) {
                fprintf(fp, "%s;", var.packExpression().c_str());
            } else {
                fprintf(fp, "memcpy(ptr, %s, __size_%s);",
                        varname, varname);
            }

            fprintf(fp, "ptr += __size_%s;\n", varname);
        }
    } else {
        // encode a non pointer variable
        if (!var.isVoid()) {
            fprintf(fp, "\t\tmemcpy(ptr, &%s, %u); ptr += %u;\n",
                    varname,
                    (unsigned) var.type()->bytes(),
                    (unsigned) var.type()->bytes());
        }
    }
}

int ApiGen::genDecoderImpl(const std::string &filename)
{
    FILE *fp = fopen(filename.c_str(), "wt");
    if (fp == NULL) {
        perror(filename.c_str());
        return -1;
    }

    printHeader(fp);

    std::string classname = m_basename + "_decoder_context_t";

    size_t n = size();

    fprintf(fp, "\n\n#include <string.h>\n");
    fprintf(fp, "#include \"%s_opcodes.h\"\n\n", m_basename.c_str());
    fprintf(fp, "#include \"%s_dec.h\"\n\n\n", m_basename.c_str());
    fprintf(fp, "#include \"ProtocolUtils.h\"\n\n");
    fprintf(fp, "#include <stdio.h>\n\n");
    fprintf(fp, "typedef unsigned int tsize_t; // Target \"size_t\", which is 32-bit for now. It may or may not be the same as host's size_t when emugen is compiled.\n\n");

    // helper macros
    fprintf(fp,
            "#ifdef DEBUG_PRINTOUT\n"
            "#  define DEBUG(...) fprintf(stderr, __VA_ARGS__)\n"
            "#else\n"
            "#  define DEBUG(...)  ((void)0)\n"
            "#endif\n\n");

    fprintf(fp,
            "#ifdef CHECK_GLERROR\n"
            "#  define SET_LASTCALL(name)  sprintf(lastCall, #name)\n"
            "#else\n"
            "#  define SET_LASTCALL(name)  ((void)0)\n"
            "#endif\n\n");

    // helper templates
    fprintf(fp, "using namespace emugl;\n\n");

    // decoder switch;
    fprintf(fp, "size_t %s::decode(void *buf, size_t len, IOStream *stream)\n{\n", classname.c_str());
    fprintf(fp,
            "                           \n\
\tsize_t pos = 0;\n\
\tif (len < 8) return pos; \n\
\tunsigned char *ptr = (unsigned char *)buf;\n\
\tbool unknownOpcode = false;  \n\
#ifdef CHECK_GL_ERROR \n\
\tchar lastCall[256] = {0}; \n\
#endif \n\
\twhile ((len - pos >= 8) && !unknownOpcode) {   \n\
\t\tuint32_t opcode = *(uint32_t *)ptr;   \n\
\t\tsize_t packetLen = *(uint32_t *)(ptr + 4);\n\
\t\tif (len - pos < packetLen)  return pos; \n\
\t\tswitch(opcode) {\n");

    for (size_t f = 0; f < n; f++) {
        enum Pass_t {
            PASS_FIRST = 0,
            PASS_VariableDeclarations = PASS_FIRST,
            PASS_TmpBuffAlloc,
            PASS_MemAlloc,
            PASS_DebugPrint,
            PASS_FunctionCall,
            PASS_FlushOutput,
            PASS_Epilog,
            PASS_LAST
        };
        EntryPoint *e = &at(f);

        // construct a printout string;
        std::string printString = "";
        for (size_t i = 0; i < e->vars().size(); i++) {
            Var *v = &e->vars()[i];
            if (!v->isVoid())  printString += (v->isPointer() ? "%p(%u)" : v->type()->printFormat()) + " ";
        }
        printString += "";
        // TODO - add for return value;

        fprintf(fp, "\t\tcase OP_%s: {\n", e->name().c_str());

        bool totalTmpBuffExist = false;
        std::string totalTmpBuffOffset = "0";
        std::string *tmpBufOffset = new std::string[e->vars().size()];

        // construct retval type string
        std::string retvalType;
        if (!e->retval().isVoid()) {
            retvalType = e->retval().type()->name();
        }

        for (int pass = PASS_FIRST; pass < PASS_LAST; pass++) {
            if (pass == PASS_FunctionCall &&
                    !e->retval().isVoid() &&
                    !e->retval().isPointer()) {
                fprintf(fp, "\t\t\t*(%s *)(&tmpBuf[%s]) = ", retvalType.c_str(),
                        totalTmpBuffOffset.c_str());
            }


//.........这里部分代码省略.........