CODEWITHSUNDEEP
c
Koldar
Koldar

Reputation: 1407

how can I make a char buffer acting as a file?

I'm having trouble converting a char buffer in a FILE* (if this is even possible, of course!). I have an enumeration defines as such:

typedef enum SchemaType{
 SCHEMA_INT,
 SCHEMA_REAL,
 SCHEMA_STRING,
 SCHEMA_BOOLEAN,
 SCHEMA_CHAR,
 SCHEMA_SIMPLE,
 SCHEMA_RECORD,
 SCHEMA_ARRAY
} SchemaType;

I have a perfectly functioning function that prints out the enumeration itself (for debugging purposes):

void printSchemaType(FILE* f,SchemaType schemaType){
 switch (schemaType){
  case SCHEMA_INT: fprintf(f,"int"); break;
  case SCHEMA_ARRAY: fprintf(f,"array"); break;
  case SCHEMA_BOOLEAN: fprintf(f,"boolean"); break;
  case SCHEMA_CHAR: fprintf(f,"char"); break;
  case SCHEMA_REAL: fprintf(f,"real"); break;
  case SCHEMA_RECORD: fprintf(f,"record"); break;
  case SCHEMA_STRING: fprintf(f,"string"); break;
 }
}

Now the problem: I need to use the string printed out by fprintf (i.e. "int", "char", "real", ex cetera) as key in an hashtable; for this purpose i would like to store the printed string of printSchemaType() inside a variable, maybe by using sprintf:

char buffer[25];
sprintf(buffer,"%s",printSchemaType_output);

The problem is that I need to get the function output inside a variable! I know I could:

The solution I was thinking is to transform a char buffer into a FILE* variable: in this way I would be able to do something like this:

SchemaType=SCHEMA_INT;
char buffer[25];
FILE* bufferActingAsAFile=make_buffer_acts_as_a_File(buffer);
fprintf(bufferActingAsAFile,type); //now in the buffer there is stored "int"

Is something like this even possible in C? If yes, how can I do that?

Upvotes: 1

Views: 282

Answers (2)

Zan Lynx
Zan Lynx

Reputation: 54325

Not what you asked for, but I would rewrite your printSchemaType function.

Create a new function called SchemaTypeStr (or some other name that fits your naming scheme) like this:

const char* SchemaTypeStr(enum SchemaType type) {
    switch(type) {
        case SCHEMA_INT:     return "int"; break;
        case SCHEMA_ARRAY:   return "array"; break;
        case SCHEMA_BOOLEAN: return "boolean"; break;
        case SCHEMA_CHAR:    return "char"; break;
        case SCHEMA_REAL:    return "real"; break;
        case SCHEMA_RECORD:  return "record"; break;
        case SCHEMA_STRING:  return "string"; break;
        default: abort();
    }
}

void printSchemaType(FILE* f,SchemaType schemaType) {
    fputs(SchemaTypeStr(schemaType), f);
}

Upvotes: 1

user3820547
user3820547

Reputation: 359

There doesn't seem to be a portable solution. For linux, you can use fmemopen, but for Windows you'll need to use CreateFile, CreateFileMapping and MapViewOfFile.

See similar question here.

Upvotes: 0

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