libguile/ports.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_PORTS_H
   4 #define SCM_PORTS_H
   5
   6 /* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004,
   7  *   2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 3 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  22  * 02110-1301 USA
  23  */
  24
  25 \f
  26
  27 #include "libguile/__scm.h"
  28
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include "libguile/gc.h"
  33 #include "libguile/tags.h"
  34 #include "libguile/error.h"
  35 #include "libguile/print.h"
  36 #include "libguile/struct.h"
  37 #include "libguile/threads.h"
  38 #include "libguile/strings.h"
  39
  40 \f
  41
  42 #define SCM_INITIAL_PUTBACK_BUF_SIZE 4
  43
  44 /* values for the rw_active flag.  */
  45 typedef enum scm_t_port_rw_active {
  46   SCM_PORT_NEITHER = 0,
  47   SCM_PORT_READ = 1,
  48   SCM_PORT_WRITE = 2
  49 } scm_t_port_rw_active;
  50
  51 /* C representation of a Scheme port.  */
  52
  53 typedef struct
  54 {
  55   SCM port;                     /* Link back to the port object.  */
  56 #if SCM_USE_PTHREAD_THREADS
  57   scm_i_pthread_mutex_t lock;   /* A recursive lock for this port.  */
  58 #endif
  59
  60   int revealed;                 /* 0 not revealed, > 1 revealed.
  61                                  * Revealed ports do not get GC'd.
  62                                  */
  63   /* data for the underlying port implementation as a raw C value. */
  64   scm_t_bits stream;
  65
  66   SCM file_name;                /* debugging support.  */
  67   long line_number;             /* debugging support.  */
  68   int column_number;            /* debugging support.  */
  69
  70   /* Character encoding support  */
  71   char *encoding;
  72   scm_t_string_failed_conversion_handler ilseq_handler;
  73
  74   /* port buffers.  the buffer(s) are set up for all ports.
  75      in the case of string ports, the buffer is the string itself.
  76      in the case of unbuffered file ports, the buffer is a
  77      single char: shortbuf.  */
  78
  79   /* this buffer is filled from read_buf to read_end using the ptob
  80      buffer_fill.  then input requests are taken from read_pos until
  81      it reaches read_end.  */
  82
  83   unsigned char *read_buf;      /* buffer start.  */
  84   const unsigned char *read_pos;/* the next unread char.  */
  85   unsigned char *read_end;      /* pointer to last buffered char + 1.  */
  86   scm_t_off read_buf_size;              /* size of the buffer.  */
  87
  88   /* when chars are put back into the buffer, e.g., using peek-char or
  89      unread-string, the read-buffer pointers are switched to cbuf.
  90      the original pointers are saved here and restored when the put-back
  91      chars have been consumed.  */
  92   unsigned char *saved_read_buf;
  93   const unsigned char *saved_read_pos;
  94   unsigned char *saved_read_end;
  95   scm_t_off saved_read_buf_size;
  96
  97   /* write requests are saved into this buffer at write_pos until it
  98      reaches write_buf + write_buf_size, then the ptob flush is
  99      called.  */
 100
 101   unsigned char *write_buf;     /* buffer start.  */
 102   unsigned char *write_pos;     /* pointer to last buffered char + 1.  */
 103   unsigned char *write_end;     /* pointer to end of buffer + 1.  */
 104   scm_t_off write_buf_size;             /* size of the buffer.  */
 105
 106   unsigned char shortbuf;       /* buffer for "unbuffered" streams.  */
 107
 108   int rw_random;                /* true if the port is random access.
 109                                    implies that the buffers must be
 110                                    flushed before switching between
 111                                    reading and writing, seeking, etc.  */
 112
 113   scm_t_port_rw_active rw_active; /* for random access ports,
 114                                      indicates which of the buffers
 115                                      is currently in use.  can be
 116                                      SCM_PORT_WRITE, SCM_PORT_READ,
 117                                      or SCM_PORT_NEITHER.  */
 118
 119
 120   /* a buffer for un-read chars and strings.  */
 121   unsigned char *putback_buf;
 122   size_t putback_buf_size;        /* allocated size of putback_buf.  */
 123
 124   /* input/output iconv conversion descriptors */
 125   void *input_cd;
 126   void *output_cd;
 127 } scm_t_port;
 128
 129
 130 SCM_INTERNAL SCM scm_i_port_weak_set;
 131
 132
 133 #define SCM_READ_BUFFER_EMPTY_P(c_port) (c_port->read_pos >= c_port->read_end)
 134
 135 \f
 136
 137 #define SCM_EOF_OBJECT_P(x) (scm_is_eq ((x), SCM_EOF_VAL))
 138
 139 /* PORT FLAGS
 140  * A set of flags characterizes a port.
 141  * Note that we reserve the bits 1 << 24 and above for use by the
 142  * routines in the port's scm_ptobfuns structure.
 143  */
 144 #define SCM_OPN         (1L<<16) /* Is the port open? */
 145 #define SCM_RDNG        (2L<<16) /* Is it a readable port? */
 146 #define SCM_WRTNG       (4L<<16) /* Is it writable? */
 147 #define SCM_BUF0        (8L<<16) /* Is it unbuffered? */
 148 #define SCM_BUFLINE     (64L<<16) /* Is it line-buffered? */
 149
 150 #define SCM_PORTP(x) (SCM_HAS_TYP7 (x, scm_tc7_port))
 151 #define SCM_OPPORTP(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_OPN))
 152 #define SCM_INPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_RDNG))
 153 #define SCM_OUTPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_WRTNG))
 154 #define SCM_OPINPORTP(x) (SCM_OPPORTP (x) && SCM_INPUT_PORT_P (x))
 155 #define SCM_OPOUTPORTP(x) (SCM_OPPORTP (x) && SCM_OUTPUT_PORT_P (x))
 156 #define SCM_OPENP(x) (SCM_OPPORTP (x))
 157 #define SCM_CLOSEDP(x) (!SCM_OPENP (x))
 158 #define SCM_CLR_PORT_OPEN_FLAG(p) \
 159   SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) & ~SCM_OPN)
 160
 161 #define SCM_PTAB_ENTRY(x)         ((scm_t_port *) SCM_CELL_WORD_1 (x))
 162 #define SCM_PORT_DESCRIPTOR(port) ((scm_t_ptob_descriptor *) SCM_CELL_WORD_2 (port))
 163 #define SCM_SETPTAB_ENTRY(x, ent)  (SCM_SET_CELL_WORD_1 ((x), (scm_t_bits) (ent)))
 164 #define SCM_STREAM(x)             (SCM_PTAB_ENTRY(x)->stream)
 165 #define SCM_SETSTREAM(x, s)        (SCM_PTAB_ENTRY(x)->stream = (scm_t_bits) (s))
 166 #define SCM_FILENAME(x)           (SCM_PTAB_ENTRY(x)->file_name)
 167 #define SCM_SET_FILENAME(x, n)    (SCM_PTAB_ENTRY(x)->file_name = (n))
 168 #define SCM_LINUM(x)              (SCM_PTAB_ENTRY(x)->line_number)
 169 #define SCM_COL(x)                (SCM_PTAB_ENTRY(x)->column_number)
 170 #define SCM_REVEALED(x)           (SCM_PTAB_ENTRY(x)->revealed)
 171 #define SCM_SETREVEALED(x, s)      (SCM_PTAB_ENTRY(x)->revealed = (s))
 172
 173 #define SCM_INCLINE(port)       do {SCM_LINUM (port) += 1; SCM_COL (port) = 0;} while (0)
 174 #define SCM_ZEROCOL(port)       do {SCM_COL (port) = 0;} while (0)
 175 #define SCM_INCCOL(port)        do {SCM_COL (port) += 1;} while (0)
 176 #define SCM_DECCOL(port)        do {if (SCM_COL (port) > 0) SCM_COL (port) -= 1;} while (0)
 177 #define SCM_TABCOL(port)        do {SCM_COL (port) += 8 - SCM_COL (port) % 8;} while (0)
 178
 179 /* Maximum number of port types.  */
 180 #define SCM_I_MAX_PORT_TYPE_COUNT  256
 181
 182 \f
 183
 184 /* port-type description.  */
 185 typedef struct scm_t_ptob_descriptor
 186 {
 187   char *name;
 188   SCM (*mark) (SCM);
 189   size_t (*free) (SCM);
 190   int (*print) (SCM exp, SCM port, scm_print_state *pstate);
 191   SCM (*equalp) (SCM, SCM);
 192   int (*close) (SCM port);
 193
 194   void (*write) (SCM port, const void *data, size_t size);
 195   void (*flush) (SCM port);
 196
 197   void (*end_input) (SCM port, int offset);
 198   int (*fill_input) (SCM port);
 199   int (*input_waiting) (SCM port);
 200
 201   scm_t_off (*seek) (SCM port, scm_t_off OFFSET, int WHENCE);
 202   void (*truncate) (SCM port, scm_t_off length);
 203
 204 } scm_t_ptob_descriptor;
 205
 206 #define SCM_TC2PTOBNUM(x) (0x0ff & ((x) >> 8))
 207 #define SCM_PTOBNUM(x) (SCM_TC2PTOBNUM (SCM_CELL_TYPE (x)))
 208 /* SCM_PTOBNAME can be 0 if name is missing */
 209 #define SCM_PTOBNAME(ptobnum) (scm_c_port_type_ref (ptobnum)->name)
 210
 211 /* Port types, and their vtables.  */
 212 SCM_INTERNAL long scm_c_num_port_types (void);
 213 SCM_API scm_t_ptob_descriptor* scm_c_port_type_ref (long ptobnum);
 214 SCM_API long scm_c_port_type_add_x (scm_t_ptob_descriptor *desc);
 215 SCM_API scm_t_bits scm_make_port_type (char *name,
 216                                        int (*fill_input) (SCM port),
 217                                        void (*write) (SCM port,
 218                                                       const void *data,
 219                                                       size_t size));
 220 SCM_API void scm_set_port_mark (scm_t_bits tc, SCM (*mark) (SCM));
 221 SCM_API void scm_set_port_free (scm_t_bits tc, size_t (*free) (SCM));
 222 SCM_API void scm_set_port_print (scm_t_bits tc,
 223                                  int (*print) (SCM exp,
 224                                                SCM port,
 225                                                scm_print_state *pstate));
 226 SCM_API void scm_set_port_equalp (scm_t_bits tc, SCM (*equalp) (SCM, SCM));
 227 SCM_API void scm_set_port_close (scm_t_bits tc, int (*close) (SCM));
 228
 229 SCM_API void scm_set_port_flush (scm_t_bits tc, void (*flush) (SCM port));
 230 SCM_API void scm_set_port_end_input (scm_t_bits tc,
 231                                      void (*end_input) (SCM port,
 232                                                         int offset));
 233 SCM_API void scm_set_port_seek (scm_t_bits tc,
 234                                 scm_t_off (*seek) (SCM port,
 235                                                    scm_t_off OFFSET,
 236                                                    int WHENCE));
 237 SCM_API void scm_set_port_truncate (scm_t_bits tc,
 238                                     void (*truncate) (SCM port,
 239                                                       scm_t_off length));
 240 SCM_API void scm_set_port_input_waiting (scm_t_bits tc, int (*input_waiting) (SCM));
 241
 242 /* The input, output, error, and load ports.  */
 243 SCM_API SCM scm_current_input_port (void);
 244 SCM_API SCM scm_current_output_port (void);
 245 SCM_API SCM scm_current_error_port (void);
 246 SCM_API SCM scm_current_load_port (void);
 247 SCM_API SCM scm_set_current_input_port (SCM port);
 248 SCM_API SCM scm_set_current_output_port (SCM port);
 249 SCM_API SCM scm_set_current_error_port (SCM port);
 250 SCM_API void scm_dynwind_current_input_port (SCM port);
 251 SCM_API void scm_dynwind_current_output_port (SCM port);
 252 SCM_API void scm_dynwind_current_error_port (SCM port);
 253 SCM_INTERNAL void scm_i_dynwind_current_load_port (SCM port);
 254
 255 /* Mode bits.  */
 256 SCM_INTERNAL long scm_i_mode_bits (SCM modes);
 257 SCM_API long scm_mode_bits (char *modes);
 258 SCM_API SCM scm_port_mode (SCM port);
 259
 260 /* Low-level constructors.  */
 261 SCM_API SCM
 262 scm_c_make_port_with_encoding (scm_t_bits tag,
 263                                unsigned long mode_bits,
 264                                const char *encoding,
 265                                scm_t_string_failed_conversion_handler handler,
 266                                scm_t_bits stream);
 267 SCM_API SCM scm_c_make_port (scm_t_bits tag, unsigned long mode_bits,
 268                              scm_t_bits stream);
 269 SCM_API SCM scm_new_port_table_entry (scm_t_bits tag);
 270
 271 /* Predicates.  */
 272 SCM_API SCM scm_port_p (SCM x);
 273 SCM_API SCM scm_input_port_p (SCM x);
 274 SCM_API SCM scm_output_port_p (SCM x);
 275 SCM_API SCM scm_port_closed_p (SCM port);
 276 SCM_API SCM scm_eof_object_p (SCM x);
 277
 278 /* Closing ports.  */
 279 SCM_API SCM scm_close_port (SCM port);
 280 SCM_API SCM scm_close_input_port (SCM port);
 281 SCM_API SCM scm_close_output_port (SCM port);
 282
 283 /* Encoding characters to byte streams, and decoding byte streams to
 284    characters.  */
 285 SCM_INTERNAL const char *scm_i_default_port_encoding (void);
 286 SCM_INTERNAL void scm_i_set_default_port_encoding (const char *);
 287 SCM_INTERNAL void scm_i_set_port_encoding_x (SCM port, const char *str);
 288 SCM_API SCM scm_port_encoding (SCM port);
 289 SCM_API SCM scm_set_port_encoding_x (SCM port, SCM encoding);
 290 SCM_INTERNAL scm_t_string_failed_conversion_handler scm_i_get_conversion_strategy (SCM port);
 291 SCM_INTERNAL void scm_i_set_conversion_strategy_x (SCM port,
 292                                                    scm_t_string_failed_conversion_handler h);
 293 SCM_API SCM scm_port_conversion_strategy (SCM port);
 294 SCM_API SCM scm_set_port_conversion_strategy_x (SCM port, SCM behavior);
 295
 296 /* Acquiring and releasing the port lock.  */
 297 SCM_INLINE int scm_c_lock_port (scm_t_port *entry);
 298 SCM_INLINE int scm_c_try_lock_port (scm_t_port *entry);
 299 SCM_INLINE int scm_c_unlock_port (scm_t_port *entry);
 300
 301 /* Meta.  */
 302 SCM_API int scm_revealed_count (SCM port);
 303 SCM_API SCM scm_port_revealed (SCM port);
 304 SCM_API SCM scm_set_port_revealed_x (SCM port, SCM rcount);
 305
 306 /* Input.  */
 307 SCM_INLINE int scm_get_byte_or_eof (SCM port);
 308 SCM_INLINE int scm_peek_byte_or_eof (SCM port);
 309 SCM_API size_t scm_c_read (SCM port, void *buffer, size_t size);
 310 SCM_API scm_t_wchar scm_getc (SCM port);
 311 SCM_API SCM scm_peek_char (SCM port);
 312 SCM_API SCM scm_read_char (SCM port);
 313
 314 /* Pushback.  */
 315 SCM_INTERNAL void scm_unget_byte (int c, SCM port);
 316 SCM_API void scm_ungetc (scm_t_wchar c, SCM port);
 317 SCM_API void scm_ungets (const char *s, int n, SCM port);
 318 SCM_API SCM scm_unread_char (SCM cobj, SCM port);
 319 SCM_API SCM scm_unread_string (SCM str, SCM port);
 320
 321 /* Manipulating the buffers.  */
 322 SCM_API void scm_port_non_buffer (scm_t_port *pt);
 323 SCM_API int scm_fill_input (SCM port);
 324 SCM_INTERNAL size_t scm_take_from_input_buffers (SCM port, char *dest, size_t read_len);
 325 SCM_API SCM scm_drain_input (SCM port);
 326 SCM_API void scm_end_input (SCM port);
 327 SCM_API SCM scm_force_output (SCM port);
 328 SCM_API void scm_flush (SCM port);
 329
 330 /* Output.  */
 331 SCM_INLINE void scm_putc (char c, SCM port);
 332 SCM_INLINE void scm_puts (const char *str_data, SCM port);
 333 SCM_API void scm_c_write (SCM port, const void *buffer, size_t size);
 334 SCM_API void scm_lfwrite (const char *ptr, size_t size, SCM port);
 335 SCM_INTERNAL void scm_lfwrite_substr (SCM str, size_t start, size_t end,
 336                                       SCM port);
 337
 338 /* Querying and setting positions, and character availability.  */
 339 SCM_API SCM scm_char_ready_p (SCM port);
 340 SCM_API SCM scm_seek (SCM object, SCM offset, SCM whence);
 341 SCM_API SCM scm_truncate_file (SCM object, SCM length);
 342 SCM_API SCM scm_port_line (SCM port);
 343 SCM_API SCM scm_set_port_line_x (SCM port, SCM line);
 344 SCM_API SCM scm_port_column (SCM port);
 345 SCM_API SCM scm_set_port_column_x (SCM port, SCM line);
 346 SCM_API SCM scm_port_filename (SCM port);
 347 SCM_API SCM scm_set_port_filename_x (SCM port, SCM filename);
 348
 349 /* Implementation helpers for port printing functions.  */
 350 SCM_API int scm_port_print (SCM exp, SCM port, scm_print_state *);
 351 SCM_API void scm_print_port_mode (SCM exp, SCM port);
 352
 353 /* Iterating over all ports.  */
 354 SCM_API SCM scm_port_for_each (SCM proc);
 355 SCM_API void scm_c_port_for_each (void (*proc)(void *data, SCM p), void *data);
 356 SCM_API SCM scm_flush_all_ports (void);
 357
 358 /* Void ports.  */
 359 SCM_API SCM scm_void_port (char * mode_str);
 360 SCM_API SCM scm_sys_make_void_port (SCM mode);
 361
 362 /* Initialization.  */
 363 SCM_INTERNAL void scm_init_ports (void);
 364
 365
 366 /* Inline function implementations.  */
 367
 368 #if SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES
 369 SCM_INLINE_IMPLEMENTATION int
 370 scm_c_lock_port (scm_t_port *entry)
 371 {
 372 #if SCM_USE_PTHREAD_THREADS
 373   return scm_i_pthread_mutex_lock (&entry->lock);
 374 #else
 375   return 0;
 376 #endif
 377 }
 378
 379 SCM_INLINE_IMPLEMENTATION int
 380 scm_c_try_lock_port (scm_t_port *entry)
 381 {
 382 #if SCM_USE_PTHREAD_THREADS
 383   return scm_i_pthread_mutex_trylock (&entry->lock);
 384 #else
 385   return 0;
 386 #endif
 387 }
 388
 389 SCM_INLINE_IMPLEMENTATION int
 390 scm_c_unlock_port (scm_t_port *entry)
 391 {
 392 #if SCM_USE_PTHREAD_THREADS
 393   return scm_i_pthread_mutex_unlock (&entry->lock);
 394 #else
 395   return 0;
 396 #endif
 397 }
 398
 399 SCM_INLINE_IMPLEMENTATION int
 400 scm_get_byte_or_eof (SCM port)
 401 {
 402   int c;
 403   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 404
 405   if (pt->rw_active == SCM_PORT_WRITE)
 406     /* may be marginally faster than calling scm_flush.  */
 407     SCM_PORT_DESCRIPTOR (port)->flush (port);
 408
 409   if (pt->rw_random)
 410     pt->rw_active = SCM_PORT_READ;
 411
 412   if (pt->read_pos >= pt->read_end)
 413     {
 414       if (SCM_UNLIKELY (scm_fill_input (port) == EOF))
 415         return EOF;
 416     }
 417
 418   c = *(pt->read_pos++);
 419
 420   return c;
 421 }
 422
 423 /* Like `scm_get_byte_or_eof' but does not change PORT's `read_pos'.  */
 424 SCM_INLINE_IMPLEMENTATION int
 425 scm_peek_byte_or_eof (SCM port)
 426 {
 427   int c;
 428   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 429
 430   if (pt->rw_active == SCM_PORT_WRITE)
 431     /* may be marginally faster than calling scm_flush.  */
 432     SCM_PORT_DESCRIPTOR (port)->flush (port);
 433
 434   if (pt->rw_random)
 435     pt->rw_active = SCM_PORT_READ;
 436
 437   if (pt->read_pos >= pt->read_end)
 438     {
 439       if (SCM_UNLIKELY (scm_fill_input (port) == EOF))
 440         return EOF;
 441     }
 442
 443   c = *pt->read_pos;
 444
 445   return c;
 446 }
 447
 448 SCM_INLINE_IMPLEMENTATION void
 449 scm_putc (char c, SCM port)
 450 {
 451   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 452   scm_lfwrite (&c, 1, port);
 453 }
 454
 455 SCM_INLINE_IMPLEMENTATION void
 456 scm_puts (const char *s, SCM port)
 457 {
 458   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 459   scm_lfwrite (s, strlen (s), port);
 460 }
 461 #endif  /* SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES */
 462
 463 #endif  /* SCM_PORTS_H */
 464
 465 /*
 466   Local Variables:
 467   c-file-style: "gnu"
 468   End:
 469 */