File en memory streams, en lezen van input streams. Nog niet getest. Alle
authorfliep <fliep@ddfedd41-794f-dd11-ae45-00112f111e67>
Sat, 16 Aug 2008 16:19:02 +0000 (16:19 +0000)
committerfliep <fliep@ddfedd41-794f-dd11-ae45-00112f111e67>
Sat, 16 Aug 2008 16:19:02 +0000 (16:19 +0000)
stream I/O functies afgesplitst in strio.c.

glk_get_char_stream()
glk_get_buffer_stream()
glk_get_line_stream()
glk_stream_close()
glk_stream_get_position()
glk_stream_set_position()
glk_stream_open_memory()
glk_stream_open_memory_uni()

src/Makefile
src/model.c
src/stream.c
src/stream.h
src/strio.c [new file with mode: 0644]

index 1413a5f405cb63c26b56d389f12bfe356e16cbd1..60ca6f7a46dd046c4d882de6d0c542f1deb763e8 100644 (file)
@@ -8,7 +8,8 @@ SOURCES = main.c \
                  gestalt.c \
                  fileref.c fileref.h \
                  case.c \
-                 model.c
+                 model.c \
+                 strio.c
 OBJECTS = main.o \
                  callbacks.o \
                  error.o \
@@ -18,7 +19,8 @@ OBJECTS = main.o \
                  gestalt.o \
                  fileref.o \
                  case.o \
-                 model.o
+                 model.o \
+                 strio.o
 
 CFLAGS = -g -Wall -O0 -export-dynamic `pkg-config --cflags ${PKG_CONFIG}`
 LIBS = -export-dynamic `pkg-config --libs ${PKG_CONFIG}`
index 2de9f9bf7aab40bf93275eae3502bce98ec9ff34..6b8e758a9912db4582c801168e811425f0fecb5d 100644 (file)
@@ -15,21 +15,25 @@ void glk_main(void)
     /* Set the current output stream to print to it. */
     glk_set_window(mainwin);
     
-    unsigned char buffer[255];
+    unsigned char buffer[256];
     int i;
-    for(i = 0; i < 255; i++)
-       buffer[i] = glk_char_to_upper(i + 1);
+    for(i = 0; i < 256; i++)
+       buffer[i] = glk_char_to_upper(i);
     
     glk_put_string("Philip en Marijn zijn vet goed.\n");
-    glk_put_string(buffer);
+    glk_put_buffer((gchar *)buffer, 256);
     
-    frefid_t f = glk_fileref_create_by_prompt(fileusage_TextMode, filemode_Write, 0);
-    if( glk_fileref_does_file_exist(f) )
-       glk_put_string("\n\nFile exists!\n");
-    else
-       glk_put_string("\n\nFile does not exist!\n");
-    glk_fileref_destroy(f);
-
+    frefid_t f = 
+       glk_fileref_create_by_prompt(fileusage_TextMode, filemode_Write, 0);
+    if(f) {
+               if( glk_fileref_does_file_exist(f) )
+                       glk_put_string("\n\nFile exists!\n");
+               else
+                       glk_put_string("\n\nFile does not exist!\n");
+               glk_fileref_destroy(f);
+       } else
+               glk_put_string("\n\nCancel was clicked!\n");
+       
        /* Bye bye */
        glk_exit();
 }
index da470ba2b48b41514a3241b7385bba849a12439e..28ea3ec91933981bf7554897da0d22196fe6cf8d 100644 (file)
@@ -1,7 +1,6 @@
 #include "stream.h"
 #include "fileref.h"
-#include <string.h>
-#include <stdio.h>
+#include <glib.h>
 #include <glib/gstdio.h>
 
 /* Global current stream */
@@ -149,148 +148,104 @@ glk_put_buffer(char *buf, glui32 len)
 }
 
 /**
- * glk_put_char_stream:
- * @str: An output stream.
- * @ch: A character in Latin-1 encoding.
+ * glk_stream_open_memory:
+ * @buf: An allocated buffer, or %NULL.
+ * @buflen: Length of @buf.
+ * @fmode: Mode in which the buffer will be opened. Must be one of 
+ * #filemode_Read, #filemode_Write, or #filemode_ReadWrite.
+ * @rock: The new stream's rock value.
+ *
+ * Opens a stream which reads from or writes to a space in memory. @buf points
+ * to the buffer where output will be read from or written to. @buflen is the
+ * length of the buffer.
+ *
+ * When outputting, if more than @buflen characters are written to the stream,
+ * all of them beyond the buffer length will be thrown away, so as not to
+ * overwrite the buffer. (The character count of the stream will still be
+ * maintained correctly. That is, it will count the number of characters written
+ * into the stream, not the number that fit into the buffer.)
+ *
+ * If @buf is %NULL, or for that matter if @buflen is zero, then <emphasis>
+ * everything</emphasis> written to the stream is thrown away. This may be
+ * useful if you are interested in the character count.
+ *
+ * When inputting, if more than @buflen characters are read from the stream, the
+ * stream will start returning -1 (signalling end-of-file.) If @buf is %NULL,
+ * the stream will always return end-of-file.
  *
- * Prints one character @ch to the stream @str. It is illegal for @str to be
- * #NULL, or an input-only stream.
+ * The data is written to the buffer exactly as it was passed to the printing
+ * functions (glk_put_char(), etc.); input functions will read the data exactly
+ * as it exists in memory. No platform-dependent cookery will be done on it.
+ * [You can write a disk file in text mode, but a memory stream is effectively
+ * always in binary mode.]
+ *
+ * Unicode values (characters greater than 255) cannot be written to the buffer.
+ * If you try, they will be stored as 0x3F ("?") characters.
+ *
+ * Whether reading or writing, the contents of the buffer are undefined until
+ * the stream is closed. The library may store the data there as it is written,
+ * or deposit it all in a lump when the stream is closed. It is illegal to
+ * change the contents of the buffer while the stream is open.
  */
-void
-glk_put_char_stream(strid_t str, unsigned char ch)
-{
-       g_return_if_fail(str != NULL);
-       g_return_if_fail(str->file_mode != filemode_Read);
-       
-       /* Convert ch to a null-terminated string, call glk_put_string_stream() */
-       gchar *s = g_strndup((gchar *)&ch, 1);
-       glk_put_string_stream(str, s);
-       g_free(s);
-}
-
-/* Internal function: change illegal (control) characters in a string to a
-placeholder character. Must free returned string afterwards. */
-static gchar *
-remove_latin1_control_characters(gchar *s)
-{
-       gchar *retval = g_strdup(s);
-       unsigned char *ptr;
-       for(ptr = (unsigned char *)retval; *ptr != '\0'; ptr++)
-               if( (*ptr < 32 && *ptr != 10) || (*ptr >= 127 && *ptr <= 159) )
-                       *ptr = '?';
-                       /* Our placeholder character is '?'; other options are possible,
-                       like printing "0x7F" or something */
-       return retval;
-}
-
-/* Internal function: convert a Latin-1 string to a UTF-8 string, replacing
-Latin-1 control characters by a placeholder first. The UTF-8 string must be
-freed afterwards. Returns NULL on error. */
-static gchar *
-convert_latin1_to_utf8(gchar *s)
+strid_t
+glk_stream_open_memory(char *buf, glui32 buflen, glui32 fmode, glui32 rock)
 {
-       GError *error = NULL;
-       gchar *utf8;
-       gchar *canonical = remove_latin1_control_characters(s);
-       utf8 = g_convert(canonical, -1, "UTF-8", "ISO-8859-1", NULL, NULL, &error);
-       g_free(canonical);
-       
-       if(utf8 == NULL)
-       {
-               error_dialog(NULL, error, "Error during latin1->utf8 conversion: ");
-               return NULL;
-       }
+       g_return_val_if_fail(fmode != filemode_WriteAppend, NULL);
        
-       return utf8;
-}
+       strid_t s = g_new0(struct glk_stream_struct, 1);
+       s->rock = rock;
+       s->file_mode = fmode;
+       s->stream_type = STREAM_TYPE_MEMORY;
+       s->buffer = buf;
+       s->mark = 0;
+       s->buflen = buflen;
+       s->unicode = FALSE;
 
-/* Internal function: write a UTF-8 string to a window's text buffer. */
-static void
-write_utf8_to_window(winid_t win, gchar *s)
-{
-       GtkTextBuffer *buffer = 
-               gtk_text_view_get_buffer( GTK_TEXT_VIEW(win->widget) );
+       /* Add it to the global stream list */
+       stream_list = g_list_prepend(stream_list, s);
+       s->stream_list = stream_list;
 
-       GtkTextIter iter;
-       gtk_text_buffer_get_end_iter(buffer, &iter);
-       gtk_text_buffer_insert(buffer, &iter, s, -1);
+       return s;
 }
 
 /**
- * glk_put_string_stream:
- * @str: An output stream.
- * @s: A null-terminated string in Latin-1 encoding.
+ * glk_stream_open_memory_uni:
+ * @buf: An allocated buffer, or %NULL.
+ * @buflen: Length of @buf.
+ * @fmode: Mode in which the buffer will be opened. Must be one of 
+ * #filemode_Read, #filemode_Write, or #filemode_ReadWrite.
+ * @rock: The new stream's rock value.
  *
- * Prints @s to the stream @str. It is illegal for @str to be #NULL, or an
- * input-only stream.
+ * Works just like glk_stream_open_memory(), except that the buffer is an array
+ * of 32-bit words, instead of bytes. This allows you to write and read any
+ * Unicode character. The @buflen is the number of words, not the number of
+ * bytes.
  */
-void
-glk_put_string_stream(strid_t str, char *s)
+strid_t
+glk_stream_open_memory_uni(glui32 *buf, glui32 buflen, glui32 fmode, 
+       glui32 rock)
 {
-       g_return_if_fail(str != NULL);
-       g_return_if_fail(str->file_mode != filemode_Read);
+       g_return_val_if_fail(fmode != filemode_WriteAppend, NULL);
+       
+       strid_t s = g_new0(struct glk_stream_struct, 1);
+       s->rock = rock;
+       s->file_mode = fmode;
+       s->stream_type = STREAM_TYPE_MEMORY;
+       s->ubuffer = buf;
+       s->mark = 0;
+       s->buflen = buflen;
+       s->unicode = TRUE;
 
-       switch(str->stream_type)
-       {
-               case STREAM_TYPE_WINDOW:
-                       /* Each window type has a different way of printing to it */
-                       switch(str->window->window_type)
-                       {
-                               /* Printing to a these windows' streams does nothing */
-                               case wintype_Blank:
-                               case wintype_Pair:
-                               case wintype_Graphics:
-                                       current_stream->write_count += strlen(s);
-                                       break;
-                               /* Text buffer window */        
-                               case wintype_TextBuffer:
-                               {
-                                       gchar *utf8 = convert_latin1_to_utf8(s);
-                                       write_utf8_to_window(str->window, utf8);
-                                       g_free(utf8);
-                               }       
-                                       str->write_count += strlen(s);
-                                       break;
-                               default:
-                                       g_warning("glk_put_string: "
-                                               "Writing to this kind of window unsupported.");
-                       }
-                       
-                       /* Now write the same buffer to the window's echo stream */
-                       if(str->window->echo_stream != NULL)
-                               glk_put_string_stream(str->window->echo_stream, s);
-                       
-                       break;
-               default:
-                       g_warning("glk_put_string: "
-                               "Writing to this kind of stream unsupported."); 
-       }
-}
+       /* Add it to the global stream list */
+       stream_list = g_list_prepend(stream_list, s);
+       s->stream_list = stream_list;
 
-/**
- * glk_put_buffer_stream:
- * @str: An output stream.
- * @buf: An array of characters in Latin-1 encoding.
- * @len: Length of @buf.
- *
- * Prints @buf to the stream @str. It is illegal for @str to be #NULL, or an
- * input-only stream.
- */
-void
-glk_put_buffer_stream(strid_t str, char *buf, glui32 len)
-{
-       g_return_if_fail(str != NULL);
-       g_return_if_fail(str->file_mode != filemode_Read);
-       
-       /* Convert buf to a null-terminated string, call glk_put_string_stream() */
-       gchar *s = g_strndup(buf, len);
-       glk_put_string_stream(str, s);
-       g_free(s);
+       return s;
 }
 
 /* Internal function: create a stream using the given parameters. */
 static strid_t
-stream_new(frefid_t fileref, glui32 fmode, glui32 rock, gboolean unicode)
+file_stream_new(frefid_t fileref, glui32 fmode, glui32 rock, gboolean unicode)
 {
        g_return_val_if_fail(fileref != NULL, NULL);
        
@@ -342,10 +297,15 @@ stream_new(frefid_t fileref, glui32 fmode, glui32 rock, gboolean unicode)
        }
        
        strid_t s = g_new0(struct glk_stream_struct, 1);
+       s->rock = rock;
        s->file_mode = fmode;
-       s->stream_type = unicode? STREAM_TYPE_UNICODE_FILE : STREAM_TYPE_FILE;
+       s->stream_type = STREAM_TYPE_FILE;
        s->file_pointer = fp;
        s->binary = binary;
+       s->unicode = unicode;
+       s->filename = g_filename_to_utf8(fileref->filename, -1, NULL, NULL, NULL);
+       if(s->filename == NULL)
+               s->filename = g_strdup("Unknown file name"); /* fail silently */
        /* Add it to the global stream list */
        stream_list = g_list_prepend(stream_list, s);
        s->stream_list = stream_list;
@@ -380,7 +340,7 @@ stream_new(frefid_t fileref, glui32 fmode, glui32 rock, gboolean unicode)
 strid_t
 glk_stream_open_file(frefid_t fileref, glui32 fmode, glui32 rock)
 {
-       return stream_new(fileref, fmode, rock, FALSE);
+       return file_stream_new(fileref, fmode, rock, FALSE);
 }
 
 /**
@@ -401,6 +361,69 @@ glk_stream_open_file(frefid_t fileref, glui32 fmode, glui32 rock)
 strid_t
 glk_stream_open_file_uni(frefid_t fileref, glui32 fmode, glui32 rock)
 {
-       return stream_new(fileref, fmode, rock, TRUE);
+       return file_stream_new(fileref, fmode, rock, TRUE);
+}
+
+/**
+ * glk_stream_close:
+ * @str: Stream to close.
+ * @result: Pointer to a #stream_result_t, or %NULL.
+ *
+ * Closes the stream @str. The @result argument points to a structure which is
+ * filled in with the final character counts of the stream. If you do not care
+ * about these, you may pass %NULL as the @result argument.
+ *
+ * If @str is the current output stream, the current output stream is set to
+ * %NULL.
+ *
+ * You cannot close window streams; use glk_window_close() instead.
+ */
+void 
+glk_stream_close(strid_t str, stream_result_t *result)
+{
+       g_return_if_fail(str != NULL);
+       
+       /* Free resources associated with one specific type of stream */
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_WINDOW:
+                       g_warning("%s: Attempted to close a window stream. Use glk_window_"
+                               "close() instead.", __func__);
+                       return;
+                       
+               case STREAM_TYPE_MEMORY:
+                       /* Do nothing */
+                       break;
+                       
+               case STREAM_TYPE_FILE:
+                       if(fclose(str->file_pointer) != 0)
+                               g_warning("%s: Failed to close file '%s'.", __func__, 
+                                       str->filename);
+                       g_free(str->filename);
+                       break;
+               default:
+                       g_warning("%s: Closing this type of stream not supported.", 
+                               __func__);
+                       return;
+       }
+       
+       /* Remove the stream from the global stream list */
+       stream_list = g_list_delete_link(stream_list, str->stream_list);
+       /* If it was the current output stream, set that to NULL */
+       if(current_stream == str)
+               current_stream = NULL;
+       /* If it was one or more windows' echo streams, set those to NULL */
+       winid_t win;
+       for(win = glk_window_iterate(NULL, NULL); win; 
+               win = glk_window_iterate(win, NULL))
+               if(win->echo_stream == str)
+                       win->echo_stream = NULL;
+       /* Return the character counts */
+       if(result) 
+       {
+               result->readcount = str->read_count;
+               result->writecount = str->write_count;
+       }
+       g_free(str);
 }
 
index 1d7f131559cdee04be2321a3792c1829bfbd2196..73c46d706de08048a536abc57eef55a608c884be 100644 (file)
@@ -9,9 +9,7 @@ enum StreamType
 {
        STREAM_TYPE_WINDOW,
        STREAM_TYPE_MEMORY,
-       STREAM_TYPE_FILE,
-       STREAM_TYPE_UNICODE_MEMORY,
-       STREAM_TYPE_UNICODE_FILE
+       STREAM_TYPE_FILE
 };
 
 struct glk_stream_struct
@@ -27,13 +25,17 @@ struct glk_stream_struct
        enum StreamType stream_type;
        /* Specific to window stream: the window this stream is connected to */
        winid_t window;
+       /* For memory and file streams */
+       gboolean unicode;
        /* Specific to memory streams */
-       gchar *memory_buffer;
-       glui32 *memory_buffer_unicode;
-       glui32 buffer_len;
+       gchar *buffer;
+       glui32 *ubuffer;
+       glui32 mark;
+       glui32 buflen;
        /* Specific to file streams */
        FILE *file_pointer;
        gboolean binary;
+       gchar *filename; /* Displayable filename in UTF-8 for error handling */
 };
 
 strid_t window_stream_new(winid_t window);
diff --git a/src/strio.c b/src/strio.c
new file mode 100644 (file)
index 0000000..3db5e3e
--- /dev/null
@@ -0,0 +1,702 @@
+#include "stream.h"
+#include <stdio.h>
+#include <string.h>
+#include <glib.h>
+#include <glib/gstdio.h>
+
+#define min(x,y) ( (x > y)? y : x )
+
+/*
+ *
+ **************** WRITING FUNCTIONS ********************************************
+ *
+ */
+
+/* Internal function: change illegal (control) characters in a string to a
+placeholder character. Must free returned string afterwards. */
+static gchar *
+remove_latin1_control_characters(unsigned char *s, gssize len)
+{
+       gchar *retval = g_new0(gchar, len);
+       int i;
+       for(i = 0; i < len; i++)
+               if( (s[i] < 32 && s[i] != 10) || (s[i] >= 127 && s[i] <= 159) )
+                       retval[i] = '?';
+                       /* Our placeholder character is '?'; other options are possible,
+                       like printing "0x7F" or something */
+               else
+                       retval[i] = s[i];
+       return retval;
+}
+
+/* Internal function: convert a Latin-1 string to a UTF-8 string, replacing
+Latin-1 control characters by a placeholder first. The UTF-8 string must be
+freed afterwards. Returns NULL on error. */
+static gchar *
+convert_latin1_to_utf8(gchar *s, gssize len)
+{
+       GError *error = NULL;
+       gchar *utf8;
+       gchar *canonical = remove_latin1_control_characters( (unsigned char *)s,
+               len);
+       utf8 = g_convert(canonical, len, "UTF-8", "ISO-8859-1", NULL, NULL, &error);
+       g_free(canonical);
+       
+       if(utf8 == NULL)
+       {
+               error_dialog(NULL, error, "Error during latin1->utf8 conversion: ");
+               return NULL;
+       }
+       
+       return utf8;
+}
+
+/* Internal function: write a UTF-8 string to a window's text buffer. */
+static void
+write_utf8_to_window(winid_t win, gchar *s)
+{
+       GtkTextBuffer *buffer = 
+               gtk_text_view_get_buffer( GTK_TEXT_VIEW(win->widget) );
+
+       GtkTextIter iter;
+       gtk_text_buffer_get_end_iter(buffer, &iter);
+       gtk_text_buffer_insert(buffer, &iter, s, -1);
+}
+
+/* Internal function: write a UTF-8 buffer with length to a stream. */
+static void
+write_buffer_to_stream(strid_t str, gchar *buf, glui32 len)
+{
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_WINDOW:
+                       /* Each window type has a different way of printing to it */
+                       switch(str->window->window_type)
+                       {
+                               /* Printing to these windows' streams does nothing */
+                               case wintype_Blank:
+                               case wintype_Pair:
+                               case wintype_Graphics:
+                                       str->write_count += len;
+                                       break;
+                               /* Text buffer window */        
+                               case wintype_TextBuffer:
+                               {
+                                       gchar *utf8 = convert_latin1_to_utf8(buf, len);
+                                       write_utf8_to_window(str->window, utf8);
+                                       g_free(utf8);
+                               }       
+                                       str->write_count += len;
+                                       break;
+                               default:
+                                       g_warning("%s: Writing to this kind of window unsupported.",
+                                               __func__);
+                       }
+                       
+                       /* Now write the same buffer to the window's echo stream */
+                       if(str->window->echo_stream != NULL)
+                               write_buffer_to_stream(str->window->echo_stream, buf, len);
+                       
+                       break;
+                       
+               case STREAM_TYPE_MEMORY:
+                       if(str->unicode && str->ubuffer)
+                       {
+                               int foo = 0;
+                               while(str->mark < str->buflen && foo < len)
+                                       str->ubuffer[str->mark++] = (glui32)buf[foo++];
+                       }
+                       if(!str->unicode && str->buffer)
+                       {
+                               memmove(str->buffer + str->mark, buf, 
+                                       min(len, str->buflen - str->mark));
+                       }
+
+                       str->write_count += len;
+                       break;
+                       
+               case STREAM_TYPE_FILE:
+                       if(str->binary) 
+                       {
+                               if(str->unicode) 
+                               {
+                                       /* Convert to four-byte big-endian */
+                                       gchar *writebuffer = g_new0(gchar, len * 4);
+                                       int i;
+                                       for(i = 0; i < len; i++)
+                                               writebuffer[i * 4 + 3] = buf[i];
+                                       fwrite(writebuffer, sizeof(gchar), len * 4, 
+                                               str->file_pointer);
+                               } 
+                               else /* Regular file */
+                               {
+                                       fwrite(buf, sizeof(gchar), len, str->file_pointer);
+                               }
+                       }
+                       else /* Text mode is the same for Unicode and regular files */
+                       {
+                               gchar *utf8 = convert_latin1_to_utf8(buf, len);
+                               g_fprintf(str->file_pointer, "%s", utf8);
+                               g_free(utf8);
+                       }
+                       
+                       str->write_count += len;
+                       break;
+               default:
+                       g_warning("%s: Writing to this kind of stream unsupported.",
+                               __func__);
+       }
+}
+
+/**
+ * glk_put_char_stream:
+ * @str: An output stream.
+ * @ch: A character in Latin-1 encoding.
+ *
+ * Prints one character @ch to the stream @str. It is illegal for @str to be
+ * %NULL, or an input-only stream.
+ */
+void
+glk_put_char_stream(strid_t str, unsigned char ch)
+{
+       g_return_if_fail(str != NULL);
+       g_return_if_fail(str->file_mode != filemode_Read);
+       
+       write_buffer_to_stream(str, (gchar *)&ch, 1);
+}
+
+/**
+ * glk_put_string_stream:
+ * @str: An output stream.
+ * @s: A null-terminated string in Latin-1 encoding.
+ *
+ * Prints @s to the stream @str. It is illegal for @str to be %NULL, or an
+ * input-only stream.
+ */
+void
+glk_put_string_stream(strid_t str, char *s)
+{
+       g_return_if_fail(str != NULL);
+       g_return_if_fail(str->file_mode != filemode_Read);
+
+       write_buffer_to_stream(str, (gchar *)s, strlen(s));
+}
+
+/**
+ * glk_put_buffer_stream:
+ * @str: An output stream.
+ * @buf: An array of characters in Latin-1 encoding.
+ * @len: Length of @buf.
+ *
+ * Prints @buf to the stream @str. It is illegal for @str to be %NULL, or an
+ * input-only stream.
+ */
+void
+glk_put_buffer_stream(strid_t str, char *buf, glui32 len)
+{
+       g_return_if_fail(str != NULL);
+       g_return_if_fail(str->file_mode != filemode_Read);
+       
+       write_buffer_to_stream(str, (gchar *)buf, len);
+}
+
+/*
+ *
+ **************** READING FUNCTIONS ********************************************
+ *
+ */
+
+/* Internal function: Read one big-endian four-byte character from file fp and
+return it as a Unicode code point, or -1 on EOF */
+static glsi32
+read_ucs4be_char_from_file(FILE *fp)
+{
+       unsigned char readbuffer[4];
+       if(fread(readbuffer, sizeof(unsigned char), 4, fp) < 4)
+               return -1; /* EOF */
+       return
+               readbuffer[0] << 24 | 
+               readbuffer[1] << 16 | 
+               readbuffer[2] << 8  | 
+               readbuffer[3];
+}
+
+/* Internal function: Read one UTF-8 character, which may be more than one byte,
+from file fp and return it as a Unicode code point, or -1 on EOF */
+static glsi32
+read_utf8_char_from_file(FILE *fp)
+{
+       gchar readbuffer[4] = {0, 0, 0, 0}; /* Max UTF-8 width */
+       int foo;
+       gunichar charresult = (gunichar)-2;
+       for(foo = 0; foo < 4 && charresult == (gunichar)-2; foo++) 
+       {
+               int ch = fgetc(fp);
+               if(ch == EOF)
+                       return -1;
+               readbuffer[foo] = (gchar)ch;
+               charresult = g_utf8_get_char_validated(readbuffer, foo);
+               /* charresult is -1 if invalid, -2 if incomplete, and the unicode code
+               point otherwise */
+       }
+       /* Silently return unknown characters as 0xFFFD, Replacement Character */
+       if(charresult == (gunichar)-1 || charresult == (gunichar)-2) 
+               return 0xFFFD;
+       return charresult;
+}
+
+/* Internal function: Tell whether this code point is a Unicode newline. The
+file pointer and eight-bit flag are included in case the newline is a CR 
+(U+000D). If the next character is LF (U+000A) then it also belongs to the
+newline. */
+static gboolean
+is_unicode_newline(glsi32 ch, FILE *fp, gboolean utf8)
+{
+       if(ch == 0x0A || ch == 0x85 || ch == 0x0C || ch == 0x2028 || ch == 0x2029)
+               return TRUE;
+       if(ch == 0x0D) {
+               glsi32 ch2 = utf8? read_utf8_char_from_file(fp) : 
+                       read_ucs4be_char_from_file(fp);
+               if(ch2 != 0x0A)
+                       fseek(fp, utf8? -1 : -4, SEEK_CUR);
+               return TRUE;
+       }
+       return FALSE;
+}
+
+/**
+ * glk_get_char_stream:
+ * @str: An input stream.
+ *
+ * Reads one character from the stream @str. (There is no notion of a ``current
+ * input stream.'') It is illegal for @str to be %NULL, or an output-only
+ * stream.
+ *
+ * The result will be between 0 and 255. As with all basic text functions, Glk
+ * assumes the Latin-1 encoding. If the end of the stream has been reached, the
+ * result will be -1. Note that high-bit characters (128..255) are
+ * <emphasis>not</emphasis> returned as negative numbers.
+ *
+ * If the stream contains Unicode data --- for example, if it was created with
+ * glk_stream_open_file_uni() or glk_stream_open_memory_uni() --- then
+ * characters beyond 255 will be returned as 0x3F ("?").
+ *
+ * Returns: A character value between 0 and 255, or -1 on end of stream.
+ */
+glsi32
+glk_get_char_stream(strid_t str)
+{
+       g_return_val_if_fail(str != NULL, -1);
+       g_return_val_if_fail(str->file_mode == filemode_Read
+               || str->file_mode == filemode_ReadWrite, -1);
+       
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_MEMORY:
+                       if(str->unicode)
+                       {
+                               if(!str->ubuffer || str->mark >= str->buflen)
+                                       return -1;
+                               glui32 ch = str->ubuffer[str->mark++];
+                               str->read_count++;
+                               return (ch > 0xFF)? 0x3F : ch;
+                       }
+                       else
+                       {
+                               if(!str->buffer || str->mark >= str->buflen)
+                                       return -1;
+                               char ch = str->buffer[str->mark++];
+                               str->read_count++;
+                               return ch;
+                       }
+                       break;
+                       
+               case STREAM_TYPE_FILE:
+                       if(str->binary) 
+                       {
+                               if(str->unicode) 
+                               {
+                                       glsi32 ch = read_ucs4be_char_from_file(str->file_pointer);
+                                       if(ch == -1)
+                                               return -1;
+                                       str->read_count++;
+                                       return (ch > 0xFF)? 0x3F : ch;
+                               }
+                               else /* Regular file */
+                               {
+                                       int ch = fgetc(str->file_pointer);
+                                       if(ch == EOF)
+                                               return -1;
+                                       
+                                       str->read_count++;
+                                       return ch;
+                               }
+                       }
+                       else /* Text mode is the same for Unicode and regular files */
+                       {
+                               glsi32 ch = read_utf8_char_from_file(str->file_pointer);
+                               if(ch == -1)
+                                       return -1;
+                                       
+                               str->read_count++;
+                               return (ch > 0xFF)? 0x3F : ch;
+                       }
+               default:
+                       g_warning("%s: Reading from this kind of stream unsupported.",
+                               __func__);
+                       return -1;
+       }
+}
+
+/**
+ * glk_get_buffer_stream:
+ * @str: An input stream.
+ * @buf: A buffer with space for at least @len characters.
+ * @len: The number of characters to read.
+ *
+ * Reads @len characters from @str, unless the end of stream is reached first.
+ * No terminal null is placed in the buffer.
+ *
+ * Returns: The number of characters actually read.
+ */
+glui32
+glk_get_buffer_stream(strid_t str, char *buf, glui32 len)
+{
+       g_return_val_if_fail(str != NULL, 0);
+       g_return_val_if_fail(str->file_mode == filemode_Read
+               || str->file_mode == filemode_ReadWrite, 0);
+       g_return_val_if_fail(buf != NULL, 0);
+       
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_MEMORY:
+               {
+                       int copycount = 0;
+                       if(str->unicode)
+                       {
+                               while(copycount < len && str->ubuffer 
+                                       && str->mark < str->buflen) 
+                               {
+                                       glui32 ch = str->ubuffer[str->mark++];
+                                       buf[copycount++] = (ch > 0xFF)? '?' : (char)ch;
+                               }
+                       }
+                       else
+                       {
+                               if(str->buffer) /* if not, copycount stays 0 */
+                                       copycount = min(len, str->buflen - str->mark);
+                               memmove(buf, str->buffer + str->mark, copycount);
+                       }
+
+                       str->read_count += copycount;           
+                       return copycount;
+               }       
+               case STREAM_TYPE_FILE:
+                       if(str->binary) 
+                       {
+                               if(str->unicode) /* Binary file with 4-byte characters */
+                               {
+                                       /* Read len characters of 4 bytes each */
+                                       unsigned char *readbuffer = g_new0(unsigned char, 4 * len);
+                                       size_t count = fread(readbuffer, sizeof(unsigned char), 
+                                               4 * len, str->file_pointer);
+                                       /* If there was an incomplete character */
+                                       if(count % 4 != 0) 
+                                       {
+                                               count -= count % 4;
+                                               g_warning("%s: Incomplete character in binary Unicode "
+                                                       "file.", __func__);
+                                       }
+                                       
+                                       str->read_count += count / 4;
+                                       int foo;
+                                       for(foo = 0; foo < count; foo += 4)
+                                       {
+                                               glsi32 ch = readbuffer[foo] << 24
+                                                       | readbuffer[foo + 1] << 16
+                                                       | readbuffer[foo + 2] << 8
+                                                       | readbuffer[foo + 3];
+                                               buf[foo / 4] = (ch > 255)? 0x3F : (char)ch;
+                                       }
+                                       g_free(readbuffer);
+                                       return count / 4;
+                               }
+                               else /* Regular binary file */
+                               {
+                                       size_t count = fread(buf, sizeof(char), len, 
+                                               str->file_pointer);
+                                       str->read_count += count;
+                                       return count;
+                               }
+                       }
+                       else /* Text mode is the same for Unicode and regular files */
+                       {
+                               /* Do it character-by-character */
+                               int foo;
+                               for(foo = 0; foo < len; foo++)
+                               {
+                                       glsi32 ch = read_utf8_char_from_file(str->file_pointer);
+                                       if(ch == -1)
+                                               break;
+                                       str->read_count++;
+                                       buf[foo] = (ch > 0xFF)? 0x3F : (gchar)ch;
+                               }
+                               return foo;
+                       }
+               default:
+                       g_warning("%s: Reading from this kind of stream unsupported.",
+                               __func__);
+                       return 0;
+       }
+}
+
+/**
+ * glk_get_line_stream:
+ * @str: An input stream.
+ * @buf: A buffer with space for at least @len characters.
+ * @len: The number of characters to read, plus one.
+ *
+ * Reads characters from @str, until either @len - 1 characters have been read
+ * or a newline has been read. It then puts a terminal null ('\0') aracter on
+ * the end. It returns the number of characters actually read, including the
+ * newline (if there is one) but not including the terminal null.
+ *
+ * It is usually more efficient to read several characters at once with
+ * glk_get_buffer_stream() or glk_get_line_stream(), as opposed to calling
+ * glk_get_char_stream() several times.
+ *
+ * Returns: The number of characters actually read.
+ */
+glui32
+glk_get_line_stream(strid_t str, char *buf, glui32 len)
+{
+       g_return_val_if_fail(str != NULL, 0);
+       g_return_val_if_fail(str->file_mode == filemode_Read
+               || str->file_mode == filemode_ReadWrite, 0);
+       g_return_val_if_fail(buf != NULL, 0);
+
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_MEMORY:
+               {
+                       int copycount = 0;
+                       if(str->unicode)
+                       {
+                               /* Do it character-by-character */
+                               while(copycount < len - 1 && str->ubuffer 
+                                       && str->mark < str->buflen) 
+                               {
+                                       glui32 ch = str->ubuffer[str->mark++];
+                                       /* Check for Unicode newline; slightly different than
+                                       in file streams */
+                                       if(ch == 0x0A || ch == 0x85 || ch == 0x0C || ch == 0x2028 
+                                               || ch == 0x2029)
+                                       {
+                                               buf[copycount++] = '\n';
+                                               break;
+                                       }
+                                       if(ch == 0x0D)
+                                       {
+                                               if(str->ubuffer[str->mark] == 0x0A)
+                                                       str->mark++; /* skip past next newline */
+                                               buf[copycount++] = '\n';
+                                               break;
+                                       }
+                                       buf[copycount++] = (ch > 0xFF)? '?' : (char)ch;
+                               }
+                               buf[copycount] = '\0';
+                       }
+                       else
+                       {
+                               if(str->buffer) /* if not, copycount stays 0 */
+                                       copycount = min(len, str->buflen - str->mark);
+                               memccpy(buf, str->buffer + str->mark, '\n', copycount);
+                       }
+                       
+                       str->read_count += copycount;
+                       return copycount;
+               }       
+               case STREAM_TYPE_FILE:
+                       if(str->binary) 
+                       {
+                               if(str->unicode) /* Binary file with 4-byte characters */
+                               {
+                                       /* Do it character-by-character */
+                                       int foo;
+                                       for(foo = 0; foo < len - 1; foo++)
+                                       {
+                                               glsi32 ch = 
+                                                       read_ucs4be_char_from_file(str->file_pointer);
+                                               if(ch == -1) 
+                                               {
+                                                       buf[foo] = '\0';
+                                                       return foo - 1;
+                                               }
+                                               str->read_count++;
+                                               if(is_unicode_newline(ch, str->file_pointer, FALSE))
+                                               {
+                                                       buf[foo] = '\n';
+                                                       buf[foo + 1] = '\0';
+                                                       return foo;
+                                               }
+                                               buf[foo] = (ch > 0xFF)? '?' : (char)ch;
+                                       }
+                                       buf[len] = '\0';
+                                       return foo;
+                               }
+                               else /* Regular binary file */
+                               {
+                                       fgets(buf, len, str->file_pointer);
+                                       str->read_count += strlen(buf);
+                                       return strlen(buf);
+                               }
+                       }
+                       else /* Text mode is the same for Unicode and regular files */
+                       {
+                               /* Do it character-by-character */
+                               int foo;
+                               for(foo = 0; foo < len - 1; foo++)
+                               {
+                                       glsi32 ch = read_utf8_char_from_file(str->file_pointer);
+                                       if(ch == -1)
+                                       {
+                                               buf[foo] = '\0';
+                                               return foo - 1;
+                                       }
+                                       str->read_count++;
+                                       if(is_unicode_newline(ch, str->file_pointer, TRUE))
+                                       {
+                                               buf[foo] = '\n';
+                                               buf[foo + 1] = '\0';
+                                               return foo;
+                                       }
+                                       buf[foo] = (ch > 0xFF)? 0x3F : (char)ch;
+                               }
+                               buf[len] = '\0';
+                               return foo;
+                       }
+               default:
+                       g_warning("%s: Reading from this kind of stream unsupported.",
+                               __func__);
+                       return 0;
+       }
+}
+
+/*
+ *
+ **************** SEEKING FUNCTIONS ********************************************
+ *
+ */
+
+/**
+ * glk_stream_get_position:
+ * @str: A file or memory stream.
+ *
+ * Returns the position of the read/write mark in @str. For memory streams and
+ * binary file streams, this is exactly the number of characters read or written
+ * from the beginning of the stream (unless you have moved the mark with
+ * glk_stream_set_position().) For text file streams, matters are more 
+ * ambiguous, since (for example) writing one byte to a text file may store more
+ * than one character in the platform's native encoding. You can only be sure
+ * that the position increases as you read or write to the file.
+ *
+ * Additional complication: for Latin-1 memory and file streams, a character is
+ * a byte. For Unicode memory and file streams (those created by
+ * glk_stream_open_file_uni() and glk_stream_open_memory_uni()), a character is
+ * a 32-bit word. So in a binary Unicode file, positions are multiples of four
+ * bytes.
+ *
+ * Returns: position of the read/write mark in @str.
+ */
+glui32
+glk_stream_get_position(strid_t str)
+{
+       g_return_val_if_fail(str != NULL, 0);
+       
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_MEMORY:
+                       return str->mark;
+               case STREAM_TYPE_FILE:
+                       return ftell(str->file_pointer);
+               default:
+                       g_warning("%s: Seeking not supported on this type of stream.",
+                               __func__);
+                       return 0;
+       }
+}
+
+/**
+ * glk_stream_set_position:
+ * @str: A file or memory stream.
+ * @pos: The position to set the mark to, relative to @seekmode.
+ * @seekmode: One of #seekmode_Start, #seekmode_Current, or #seekmode_End.
+ *
+ * Sets the position of the read/write mark in @str. The position is controlled
+ * by @pos, and the meaning of @pos is controlled by @seekmode:
+ * <itemizedlist>
+ *  <listitem>#seekmode_Start: @pos characters after the beginning of the file.
+ *  </listitem>
+ *  <listitem>#seekmode_Current: @pos characters after the current position
+ *  (moving backwards if @pos is negative.)</listitem>
+ *  <listitem>#seekmode_End: @pos characters after the end of the file. (@pos
+ *  should always be zero or negative, so that this will move backwards to a
+ *  position within the file.</listitem>
+ * </itemizedlist>
+ * It is illegal to specify a position before the beginning or after the end of
+ * the file.
+ *
+ * In binary files, the mark position is exact --- it corresponds with the
+ * number of characters you have read or written. In text files, this mapping 
+ * can vary, because of linefeed conventions or other character-set 
+ * approximations. glk_stream_set_position() and glk_stream_get_position()
+ * measure positions in the platform's native encoding --- after character
+ * cookery. Therefore, in a text stream, it is safest to use
+ * glk_stream_set_position() only to move to the beginning or end of a file, or
+ * to a position determined by glk_stream_get_position().
+ *
+ * Again, in Latin-1 streams, characters are bytes. In Unicode streams,
+ * characters are 32-bit words, or four bytes each.
+ */
+void
+glk_stream_set_position(strid_t str, glsi32 pos, glui32 seekmode)
+{
+       g_return_if_fail(str != NULL);
+       g_return_if_fail(!(seekmode == seekmode_Start && pos < 0));
+       g_return_if_fail(!(seekmode == seekmode_End || pos > 0));
+       
+       switch(str->stream_type)
+       {
+               case STREAM_TYPE_MEMORY:
+                       switch(seekmode)
+                       {
+                               case seekmode_Start:   str->mark = pos;  break;
+                               case seekmode_Current: str->mark += pos; break;
+                               case seekmode_End:     str->mark = str->buflen + pos; break;
+                               default:
+                                       g_assert_not_reached();
+                                       return;
+                       }
+                       break;
+               case STREAM_TYPE_FILE:
+               {
+                       int whence;
+                       switch(seekmode)
+                       {
+                               case seekmode_Start:   whence = SEEK_SET; break;
+                               case seekmode_Current: whence = SEEK_CUR; break;
+                               case seekmode_End:     whence = SEEK_END; break;
+                               default:
+                                       g_assert_not_reached();
+                                       return;
+                       }
+                       fseek(str->file_pointer, pos, whence);
+                       break;
+               }
+               default:
+                       g_warning("%s: Seeking not supported on this type of stream.",
+                               __func__);
+                       return;
+       }
+}