s/stringport.c

#include <stdio.h>
#include <stdlib.h>

#include "stringport.h"

// from stackoverflow.com/questions/2082743/c-equivalent-to-fstreams-peek
int fpeek(FILE *stream)
{
	int c;

	c = fgetc(stream);
	ungetc(c, stream);

	return c;
}

int port_peek(string_port *port)
{
  switch(port->kind) {
    
  case STRPORT_CHAR:
    return port->text[port->place];
    break;

  case STRPORT_FILE:
    return fpeek(port->fptr);

  default:
    exit(-1);
  }
}

int port_eof(string_port *port)
{
  switch(port->kind) {
    
  case STRPORT_CHAR:
    return port->text[port->place] == '\0';
    break;

  case STRPORT_FILE:
    return feof(port->fptr);

  default:
    exit(-1);
  }
}

int port_getc(string_port *port)
{
  int c;
  
  switch(port->kind) {
    
  case STRPORT_CHAR:
    c = port->text[port->place];

    if(c != '\0') {
      port->place++;
    }
    
    return c;

  case STRPORT_FILE:
    return fgetc(port->fptr);

  default:
    exit(-1);
  }
}