post-scarcity/src/io/io.c
2019-01-28 18:46:24 +00:00

320 lines
9.8 KiB
C

/*
* io.c
*
* Communication between PSSE and the outside world, via libcurl.
*
* (c) 2019 Simon Brooke <simon@journeyman.cc>
* Licensed under GPL version 2.0, or, at your option, any later version.
*/
#include <stdlib.h>
#include "conspage.h"
#include "consspaceobject.h"
#include "debug.h"
#include "fopen.h"
#include "lispops.h"
/**
* Allow a one-character unget facility. This may not be enough - we may need
* to allocate a buffer.
*/
wint_t ungotten = 0;
/**
* Convert this lisp string-like-thing (also works for symbols, and, later
* keywords) into a UTF-8 string. NOTE that the returned value has been
* malloced and must be freed. TODO: candidate to moving into a utilities
* file.
*
* @param s the lisp string or symbol;
* @return the c string.
*/
char *lisp_string_to_c_string( struct cons_pointer s ) {
char *result = NULL;
if ( stringp( s ) || symbolp( s ) ) {
int len = 0;
for ( struct cons_pointer c = s; !nilp( c );
c = pointer2cell( c ).payload.string.cdr ) {
len++;
}
wchar_t *buffer = calloc( len + 1, sizeof( wchar_t ) );
/* worst case, one wide char = four utf bytes */
result = calloc( ( len * 4 ) + 1, sizeof( char ) );
int i = 0;
for ( struct cons_pointer c = s; !nilp( c );
c = pointer2cell( c ).payload.string.cdr ) {
buffer[i++] = pointer2cell( c ).payload.string.character;
}
wcstombs( result, buffer, len );
free( buffer );
}
debug_print( L"lisp_string_to_c_string( ", DEBUG_IO );
debug_print_object( s, DEBUG_IO );
debug_printf( DEBUG_IO, L") => '%s'\n", result );
return result;
}
/**
* given this file handle f, return a new url_file handle wrapping it.
*
* @param f the file to be wrapped;
* @return the new handle, or null if no such handle could be allocated.
*/
URL_FILE *file_to_url_file( FILE * f ) {
URL_FILE *result = ( URL_FILE * ) malloc( sizeof( URL_FILE ) );
if ( result != NULL ) {
result->type = CFTYPE_FILE, result->handle.file = f;
}
return result;
}
/**
* get one wide character from the buffer.
*
* @param file the stream to read from;
* @return the next wide character on the stream, or zero if no more.
*/
wint_t url_fgetwc( URL_FILE * input ) {
wint_t result = -1;
if ( ungotten != 0 ) {
/* TODO: not thread safe */
result = ungotten;
ungotten = 0;
} else {
switch ( input->type ) {
case CFTYPE_FILE:
fwide( input->handle.file, 1 ); /* wide characters */
result = fgetwc( input->handle.file ); /* passthrough */
break;
case CFTYPE_CURL:{
char *cbuff =
calloc( sizeof( wchar_t ) + 2, sizeof( char ) );
wchar_t *wbuff = calloc( 2, sizeof( wchar_t ) );
size_t count = 0;
debug_print( L"url_fgetwc: about to call url_fgets\n", DEBUG_IO );
url_fgets( cbuff, 2, input );
debug_print( L"url_fgetwc: back from url_fgets\n", DEBUG_IO );
int c = ( int ) cbuff[0];
debug_printf( DEBUG_IO,
L"url_fgetwc: cbuff is '%s'; (first) character = %d (%c)\n",
cbuff, c, c & 0xf7 );
/* The value of each individual byte indicates its UTF-8 function, as follows:
*
* 00 to 7F hex (0 to 127): first and only byte of a sequence.
* 80 to BF hex (128 to 191): continuing byte in a multi-byte sequence.
* C2 to DF hex (194 to 223): first byte of a two-byte sequence.
* E0 to EF hex (224 to 239): first byte of a three-byte sequence.
* F0 to FF hex (240 to 255): first byte of a four-byte sequence.
*/
if ( c <= 0x07 ) {
count = 1;
} else if ( c >= '0xc2' && c <= '0xdf' ) {
count = 2;
} else if ( c >= '0xe0' && c <= '0xef' ) {
count = 3;
} else if ( c >= '0xf0' && c <= '0xff' ) {
count = 4;
}
if ( count > 1 ) {
url_fgets( (char *)&cbuff[1], count, input );
}
mbstowcs( wbuff, cbuff, 1 ); //(char *)(&input->buffer[input->buffer_pos]), 1 );
result = wbuff[0];
free( wbuff );
free( cbuff );
}
break;
case CFTYPE_NONE:
break;
}
}
debug_printf( DEBUG_IO, L"url_fgetwc returning %d (%C)\n", result,
result );
return result;
}
wint_t url_ungetwc( wint_t wc, URL_FILE * input ) {
wint_t result = -1;
switch ( input->type ) {
case CFTYPE_FILE:
fwide( input->handle.file, 1 ); /* wide characters */
result = ungetwc( wc, input->handle.file ); /* passthrough */
break;
case CFTYPE_CURL:{
ungotten = wc;
// wchar_t *wbuff = calloc( 2, sizeof( wchar_t ) );
// char *cbuff = calloc( 5, sizeof( char ) );
//
// wbuff[0] = wc;
// result = wcstombs( cbuff, wbuff, 1 );
//
// input->buffer_pos -= strlen( cbuff );
//
// free( cbuff );
// free( wbuff );
//
// result = result > 0 ? wc : result;
break;
case CFTYPE_NONE:
break;
}
}
return result;
}
/**
* Function, sort-of: close the file indicated by my first arg, and return
* nil. If the first arg is not a stream, does nothing. All other args are
* ignored.
*
* * (close stream)
*
* @param frame my stack_frame.
* @param frame_pointer a pointer to my stack_frame.
* @param env my environment.
* @return T if the stream was successfully closed, else NIL.
*/
struct cons_pointer
lisp_close( struct stack_frame *frame, struct cons_pointer frame_pointer,
struct cons_pointer env ) {
struct cons_pointer result = NIL;
if ( readp( frame->arg[0] ) || writep( frame->arg[0] ) ) {
if ( url_fclose( pointer2cell( frame->arg[0] ).payload.stream.stream )
== 0 ) {
result = TRUE;
}
}
return result;
}
/**
* Function: return a stream open on the URL indicated by the first argument;
* if a second argument is present and is non-nil, open it for reading. At
* present, further arguments are ignored and there is no mechanism to open
* to append, or error if the URL is faulty or indicates an unavailable
* resource.
*
* * (read-char stream)
*
* @param frame my stack_frame.
* @param frame_pointer a pointer to my stack_frame.
* @param env my environment.
* @return a string of one character, namely the next available character
* on my stream, if any, else NIL.
*/
struct cons_pointer
lisp_open( struct stack_frame *frame, struct cons_pointer frame_pointer,
struct cons_pointer env ) {
struct cons_pointer result = NIL;
if ( stringp( frame->arg[0] ) ) {
char *url = lisp_string_to_c_string( frame->arg[0] );
if ( nilp( frame->arg[1] ) ) {
result = make_read_stream( url_fopen( url, "r" ) );
} else {
// TODO: anything more complex is a problem for another day.
result = make_write_stream( url_fopen( url, "w" ) );
}
free( url );
if ( pointer2cell( result ).payload.stream.stream == NULL ) {
result = NIL;
}
}
return result;
}
/**
* Function: return the next character from the stream indicated by arg 0;
* further arguments are ignored.
*
* * (read-char stream)
*
* @param frame my stack_frame.
* @param frame_pointer a pointer to my stack_frame.
* @param env my environment.
* @return a string of one character, namely the next available character
* on my stream, if any, else NIL.
*/
struct cons_pointer
lisp_read_char( struct stack_frame *frame, struct cons_pointer frame_pointer,
struct cons_pointer env ) {
struct cons_pointer result = NIL;
if ( readp( frame->arg[0] ) ) {
result =
make_string( url_fgetwc
( pointer2cell( frame->arg[0] ).payload.stream.
stream ), NIL );
}
return result;
}
/**
* Function: return a string representing all characters from the stream
* indicated by arg 0; further arguments are ignored.
*
* * (slurp stream)
*
* @param frame my stack_frame.
* @param frame_pointer a pointer to my stack_frame.
* @param env my environment.
* @return a string of one character, namely the next available character
* on my stream, if any, else NIL.
*/
struct cons_pointer
lisp_slurp( struct stack_frame *frame, struct cons_pointer frame_pointer,
struct cons_pointer env ) {
struct cons_pointer result = NIL;
if ( readp( frame->arg[0] ) ) {
URL_FILE *stream = pointer2cell( frame->arg[0] ).payload.stream.stream;
struct cons_pointer cursor = make_string( url_fgetwc( stream ), NIL );
result = cursor;
for ( wint_t c = url_fgetwc( stream ); !url_feof( stream ) && c != 0;
c = url_fgetwc( stream ) ) {
debug_print( L"slurp: cursor is: ", DEBUG_IO );
debug_dump_object( cursor, DEBUG_IO );
debug_print( L"; result is: ", DEBUG_IO );
debug_dump_object( result, DEBUG_IO );
debug_println( DEBUG_IO );
struct cons_space_object *cell = &pointer2cell( cursor );
cursor = make_string( ( wchar_t ) c, NIL );
cell->payload.string.cdr = cursor;
}
}
return result;
}