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, 2012, 2013 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 /* An internal-only structure defined in ports-internal.h. */
  52 struct scm_port_internal;
  53
  54 /* C representation of a Scheme port.  */
  55
  56 typedef struct
  57 {
  58   SCM port;                     /* Link back to the port object.  */
  59   scm_i_pthread_mutex_t *lock;  /* A recursive lock for this port.  */
  60
  61   /* pointer to internal-only port structure */
  62   struct scm_port_internal *internal;
  63
  64   /* data for the underlying port implementation as a raw C value. */
  65   scm_t_bits stream;
  66
  67   SCM file_name;                /* debugging support.  */
  68   long line_number;             /* debugging support.  */
  69   int column_number;            /* debugging support.  */
  70
  71   /* port buffers.  the buffer(s) are set up for all ports.
  72      in the case of string ports, the buffer is the string itself.
  73      in the case of unbuffered file ports, the buffer is a
  74      single char: shortbuf.  */
  75
  76   /* this buffer is filled from read_buf to read_end using the ptob
  77      buffer_fill.  then input requests are taken from read_pos until
  78      it reaches read_end.  */
  79
  80   unsigned char *read_buf;      /* buffer start.  */
  81   const unsigned char *read_pos;/* the next unread char.  */
  82   unsigned char *read_end;      /* pointer to last buffered char + 1.  */
  83   scm_t_off read_buf_size;              /* size of the buffer.  */
  84
  85   /* when chars are put back into the buffer, e.g., using peek-char or
  86      unread-string, the read-buffer pointers are switched to cbuf.
  87      the original pointers are saved here and restored when the put-back
  88      chars have been consumed.  */
  89   unsigned char *saved_read_buf;
  90   const unsigned char *saved_read_pos;
  91   unsigned char *saved_read_end;
  92   scm_t_off saved_read_buf_size;
  93
  94   /* write requests are saved into this buffer at write_pos until it
  95      reaches write_buf + write_buf_size, then the ptob flush is
  96      called.  */
  97
  98   unsigned char *write_buf;     /* buffer start.  */
  99   unsigned char *write_pos;     /* pointer to last buffered char + 1.  */
 100   unsigned char *write_end;     /* pointer to end of buffer + 1.  */
 101   scm_t_off write_buf_size;             /* size of the buffer.  */
 102
 103   unsigned char shortbuf;       /* buffer for "unbuffered" streams.  */
 104
 105   int rw_random;                /* true if the port is random access.
 106                                    implies that the buffers must be
 107                                    flushed before switching between
 108                                    reading and writing, seeking, etc.  */
 109
 110   scm_t_port_rw_active rw_active; /* for random access ports,
 111                                      indicates which of the buffers
 112                                      is currently in use.  can be
 113                                      SCM_PORT_WRITE, SCM_PORT_READ,
 114                                      or SCM_PORT_NEITHER.  */
 115
 116
 117   /* a buffer for un-read chars and strings.  */
 118   unsigned char *putback_buf;
 119   size_t putback_buf_size;        /* allocated size of putback_buf.  */
 120
 121   /* Character encoding support  */
 122   char *encoding;
 123   scm_t_string_failed_conversion_handler ilseq_handler;
 124 } scm_t_port;
 125
 126
 127 SCM_INTERNAL SCM scm_i_port_weak_set;
 128
 129
 130 #define SCM_READ_BUFFER_EMPTY_P(c_port) (c_port->read_pos >= c_port->read_end)
 131
 132 \f
 133
 134 #define SCM_EOF_OBJECT_P(x) (scm_is_eq ((x), SCM_EOF_VAL))
 135
 136 /* PORT FLAGS
 137  * A set of flags characterizes a port.
 138  * Note that we reserve the bits 1 << 24 and above for use by the
 139  * routines in the port's scm_ptobfuns structure.
 140  */
 141 #define SCM_OPN         (1L<<16) /* Is the port open? */
 142 #define SCM_RDNG        (2L<<16) /* Is it a readable port? */
 143 #define SCM_WRTNG       (4L<<16) /* Is it writable? */
 144 #define SCM_BUF0        (8L<<16) /* Is it unbuffered? */
 145 #define SCM_BUFLINE     (64L<<16) /* Is it line-buffered? */
 146
 147 #define SCM_PORTP(x) (SCM_HAS_TYP7 (x, scm_tc7_port))
 148 #define SCM_OPPORTP(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_OPN))
 149 #define SCM_INPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_RDNG))
 150 #define SCM_OUTPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_WRTNG))
 151 #define SCM_OPINPORTP(x) (SCM_OPPORTP (x) && SCM_INPUT_PORT_P (x))
 152 #define SCM_OPOUTPORTP(x) (SCM_OPPORTP (x) && SCM_OUTPUT_PORT_P (x))
 153 #define SCM_OPENP(x) (SCM_OPPORTP (x))
 154 #define SCM_CLOSEDP(x) (!SCM_OPENP (x))
 155 #define SCM_CLR_PORT_OPEN_FLAG(p) \
 156   SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) & ~SCM_OPN)
 157
 158 #define SCM_PTAB_ENTRY(x)         ((scm_t_port *) SCM_CELL_WORD_1 (x))
 159 #define SCM_PORT_DESCRIPTOR(port) ((scm_t_ptob_descriptor *) SCM_CELL_WORD_2 (port))
 160 #define SCM_SETPTAB_ENTRY(x, ent)  (SCM_SET_CELL_WORD_1 ((x), (scm_t_bits) (ent)))
 161 #define SCM_STREAM(x)             (SCM_PTAB_ENTRY(x)->stream)
 162 #define SCM_SETSTREAM(x, s)        (SCM_PTAB_ENTRY(x)->stream = (scm_t_bits) (s))
 163 #define SCM_FILENAME(x)           (SCM_PTAB_ENTRY(x)->file_name)
 164 #define SCM_SET_FILENAME(x, n)    (SCM_PTAB_ENTRY(x)->file_name = (n))
 165 #define SCM_LINUM(x)              (SCM_PTAB_ENTRY(x)->line_number)
 166 #define SCM_COL(x)                (SCM_PTAB_ENTRY(x)->column_number)
 167
 168 #define SCM_INCLINE(port)       do {SCM_LINUM (port) += 1; SCM_COL (port) = 0;} while (0)
 169 #define SCM_ZEROCOL(port)       do {SCM_COL (port) = 0;} while (0)
 170 #define SCM_INCCOL(port)        do {SCM_COL (port) += 1;} while (0)
 171 #define SCM_DECCOL(port)        do {if (SCM_COL (port) > 0) SCM_COL (port) -= 1;} while (0)
 172 #define SCM_TABCOL(port)        do {SCM_COL (port) += 8 - SCM_COL (port) % 8;} while (0)
 173
 174 /* Maximum number of port types.  */
 175 #define SCM_I_MAX_PORT_TYPE_COUNT  256
 176
 177 \f
 178
 179 typedef enum scm_t_port_type_flags {
 180   SCM_PORT_TYPE_HAS_FLUSH = 1 << 0
 181 } scm_t_port_type_flags;
 182
 183 /* port-type description.  */
 184 typedef struct scm_t_ptob_descriptor
 185 {
 186   char *name;
 187   SCM (*mark) (SCM);
 188   size_t (*free) (SCM);
 189   int (*print) (SCM exp, SCM port, scm_print_state *pstate);
 190   SCM (*equalp) (SCM, SCM);
 191   int (*close) (SCM port);
 192
 193   void (*write) (SCM port, const void *data, size_t size);
 194   void (*flush) (SCM port);
 195
 196   void (*end_input) (SCM port, int offset);
 197   int (*fill_input) (SCM port);
 198   int (*input_waiting) (SCM port);
 199
 200   scm_t_off (*seek) (SCM port, scm_t_off OFFSET, int WHENCE);
 201   void (*truncate) (SCM port, scm_t_off length);
 202
 203   unsigned flags;
 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_warning_port (void);
 247 SCM_API SCM scm_current_load_port (void);
 248 SCM_API SCM scm_set_current_input_port (SCM port);
 249 SCM_API SCM scm_set_current_output_port (SCM port);
 250 SCM_API SCM scm_set_current_error_port (SCM port);
 251 SCM_API SCM scm_set_current_warning_port (SCM port);
 252 SCM_API void scm_dynwind_current_input_port (SCM port);
 253 SCM_API void scm_dynwind_current_output_port (SCM port);
 254 SCM_API void scm_dynwind_current_error_port (SCM port);
 255 SCM_INTERNAL void scm_i_dynwind_current_load_port (SCM port);
 256
 257 /* Mode bits.  */
 258 SCM_INTERNAL long scm_i_mode_bits (SCM modes);
 259 SCM_API long scm_mode_bits (char *modes);
 260 SCM_API SCM scm_port_mode (SCM port);
 261
 262 /* Low-level constructors.  */
 263 SCM_API SCM
 264 scm_c_make_port_with_encoding (scm_t_bits tag,
 265                                unsigned long mode_bits,
 266                                const char *encoding,
 267                                scm_t_string_failed_conversion_handler handler,
 268                                scm_t_bits stream);
 269 SCM_API SCM scm_c_make_port (scm_t_bits tag, unsigned long mode_bits,
 270                              scm_t_bits stream);
 271 SCM_API SCM scm_new_port_table_entry (scm_t_bits tag);
 272
 273 /* Predicates.  */
 274 SCM_API SCM scm_port_p (SCM x);
 275 SCM_API SCM scm_input_port_p (SCM x);
 276 SCM_API SCM scm_output_port_p (SCM x);
 277 SCM_API SCM scm_port_closed_p (SCM port);
 278 SCM_API SCM scm_eof_object_p (SCM x);
 279
 280 /* Closing ports.  */
 281 SCM_API SCM scm_close_port (SCM port);
 282 SCM_API SCM scm_close_input_port (SCM port);
 283 SCM_API SCM scm_close_output_port (SCM port);
 284
 285 /* Encoding characters to byte streams, and decoding byte streams to
 286    characters.  */
 287 SCM_INTERNAL const char *scm_i_default_port_encoding (void);
 288 SCM_INTERNAL void scm_i_set_default_port_encoding (const char *);
 289 SCM_INTERNAL scm_t_string_failed_conversion_handler
 290 scm_i_default_port_conversion_handler (void);
 291 SCM_INTERNAL void
 292 scm_i_set_default_port_conversion_handler (scm_t_string_failed_conversion_handler);
 293 SCM_INTERNAL void scm_i_set_port_encoding_x (SCM port, const char *str);
 294 SCM_API SCM scm_port_encoding (SCM port);
 295 SCM_API SCM scm_set_port_encoding_x (SCM port, SCM encoding);
 296 SCM_API SCM scm_port_conversion_strategy (SCM port);
 297 SCM_API SCM scm_set_port_conversion_strategy_x (SCM port, SCM behavior);
 298
 299 /* Acquiring and releasing the port lock.  */
 300 SCM_API void scm_dynwind_lock_port (SCM port);
 301 SCM_INLINE int scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 302 SCM_INLINE int scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 303
 304 /* Input.  */
 305 SCM_API int scm_get_byte_or_eof (SCM port);
 306 SCM_INLINE int scm_get_byte_or_eof_unlocked (SCM port);
 307 SCM_API int scm_slow_get_byte_or_eof_unlocked (SCM port);
 308 SCM_API int scm_peek_byte_or_eof (SCM port);
 309 SCM_INLINE int scm_peek_byte_or_eof_unlocked (SCM port);
 310 SCM_API int scm_slow_peek_byte_or_eof_unlocked (SCM port);
 311 SCM_API size_t scm_c_read (SCM port, void *buffer, size_t size);
 312 SCM_API size_t scm_c_read_unlocked (SCM port, void *buffer, size_t size);
 313 SCM_API scm_t_wchar scm_getc (SCM port);
 314 SCM_API scm_t_wchar scm_getc_unlocked (SCM port);
 315 SCM_API SCM scm_read_char (SCM port);
 316
 317 /* Pushback.  */
 318 SCM_API void scm_unget_bytes (const unsigned char *buf, size_t len, SCM port);
 319 SCM_API void scm_unget_bytes_unlocked (const unsigned char *buf, size_t len, SCM port);
 320 SCM_API void scm_unget_byte (int c, SCM port);
 321 SCM_API void scm_unget_byte_unlocked (int c, SCM port);
 322 SCM_API void scm_ungetc (scm_t_wchar c, SCM port);
 323 SCM_API void scm_ungetc_unlocked (scm_t_wchar c, SCM port);
 324 SCM_API void scm_ungets (const char *s, int n, SCM port);
 325 SCM_API void scm_ungets_unlocked (const char *s, int n, SCM port);
 326 SCM_API SCM scm_peek_char (SCM port);
 327 SCM_API SCM scm_unread_char (SCM cobj, SCM port);
 328 SCM_API SCM scm_unread_string (SCM str, SCM port);
 329
 330 /* Manipulating the buffers.  */
 331 SCM_API void scm_port_non_buffer (scm_t_port *pt);
 332 SCM_API int scm_fill_input (SCM port);
 333 SCM_API int scm_fill_input_unlocked (SCM port);
 334 SCM_INTERNAL size_t scm_take_from_input_buffers (SCM port, char *dest, size_t read_len);
 335 SCM_API SCM scm_drain_input (SCM port);
 336 SCM_API void scm_end_input (SCM port);
 337 SCM_API void scm_end_input_unlocked (SCM port);
 338 SCM_API SCM scm_force_output (SCM port);
 339 SCM_API void scm_flush (SCM port);
 340 SCM_API void scm_flush_unlocked (SCM port);
 341
 342 /* Output.  */
 343 SCM_API void scm_putc (char c, SCM port);
 344 SCM_INLINE void scm_putc_unlocked (char c, SCM port);
 345 SCM_API void scm_puts (const char *str_data, SCM port);
 346 SCM_INLINE void scm_puts_unlocked (const char *str_data, SCM port);
 347 SCM_API void scm_c_write (SCM port, const void *buffer, size_t size);
 348 SCM_API void scm_c_write_unlocked (SCM port, const void *buffer, size_t size);
 349 SCM_API void scm_lfwrite (const char *ptr, size_t size, SCM port);
 350 SCM_API void scm_lfwrite_unlocked (const char *ptr, size_t size, SCM port);
 351 SCM_INTERNAL void scm_lfwrite_substr (SCM str, size_t start, size_t end,
 352                                       SCM port);
 353
 354 /* Querying and setting positions, and character availability.  */
 355 SCM_API SCM scm_char_ready_p (SCM port);
 356 SCM_API SCM scm_seek (SCM object, SCM offset, SCM whence);
 357 SCM_API SCM scm_truncate_file (SCM object, SCM length);
 358 SCM_API SCM scm_port_line (SCM port);
 359 SCM_API SCM scm_set_port_line_x (SCM port, SCM line);
 360 SCM_API SCM scm_port_column (SCM port);
 361 SCM_API SCM scm_set_port_column_x (SCM port, SCM line);
 362 SCM_API SCM scm_port_filename (SCM port);
 363 SCM_API SCM scm_set_port_filename_x (SCM port, SCM filename);
 364
 365 /* Port alist.  */
 366 SCM_INTERNAL SCM scm_i_port_alist (SCM port);
 367 SCM_INTERNAL void scm_i_set_port_alist_x (SCM port, SCM alist);
 368
 369 /* Implementation helpers for port printing functions.  */
 370 SCM_API int scm_port_print (SCM exp, SCM port, scm_print_state *);
 371 SCM_API void scm_print_port_mode (SCM exp, SCM port);
 372
 373 /* Iterating over all ports.  */
 374 SCM_API SCM scm_port_for_each (SCM proc);
 375 SCM_API void scm_c_port_for_each (void (*proc)(void *data, SCM p), void *data);
 376 SCM_API SCM scm_flush_all_ports (void);
 377
 378 /* Void ports.  */
 379 SCM_API SCM scm_void_port (char * mode_str);
 380 SCM_API SCM scm_sys_make_void_port (SCM mode);
 381
 382 /* Initialization.  */
 383 SCM_INTERNAL void scm_init_ports (void);
 384
 385
 386 /* Inline function implementations.  */
 387
 388 #if SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES
 389 SCM_INLINE_IMPLEMENTATION int
 390 scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 391 {
 392   *lock = SCM_PTAB_ENTRY (port)->lock;
 393
 394   if (*lock)
 395     return scm_i_pthread_mutex_lock (*lock);
 396   else
 397     return 0;
 398 }
 399
 400 SCM_INLINE_IMPLEMENTATION int
 401 scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 402 {
 403   *lock = SCM_PTAB_ENTRY (port)->lock;
 404   if (*lock)
 405     {
 406       int ret = scm_i_pthread_mutex_trylock (*lock);
 407       if (ret != 0)
 408         *lock = NULL;
 409       return ret;
 410     }
 411   else
 412     return 0;
 413 }
 414
 415 SCM_INLINE_IMPLEMENTATION int
 416 scm_get_byte_or_eof_unlocked (SCM port)
 417 {
 418   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 419
 420   if (SCM_LIKELY ((pt->rw_active == SCM_PORT_READ || !pt->rw_random)
 421                   && pt->read_pos < pt->read_end))
 422     return *pt->read_pos++;
 423   else
 424     return scm_slow_get_byte_or_eof_unlocked (port);
 425 }
 426
 427 /* Like `scm_get_byte_or_eof' but does not change PORT's `read_pos'.  */
 428 SCM_INLINE_IMPLEMENTATION int
 429 scm_peek_byte_or_eof_unlocked (SCM port)
 430 {
 431   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 432
 433   if (SCM_LIKELY ((pt->rw_active == SCM_PORT_READ || !pt->rw_random)
 434                   && pt->read_pos < pt->read_end))
 435     return *pt->read_pos;
 436   else
 437     return scm_slow_peek_byte_or_eof_unlocked (port);
 438 }
 439
 440 SCM_INLINE_IMPLEMENTATION void
 441 scm_putc_unlocked (char c, SCM port)
 442 {
 443   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 444   scm_lfwrite_unlocked (&c, 1, port);
 445 }
 446
 447 SCM_INLINE_IMPLEMENTATION void
 448 scm_puts_unlocked (const char *s, SCM port)
 449 {
 450   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 451   scm_lfwrite_unlocked (s, strlen (s), port);
 452 }
 453 #endif  /* SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES */
 454
 455 #endif  /* SCM_PORTS_H */
 456
 457 /*
 458   Local Variables:
 459   c-file-style: "gnu"
 460   End:
 461 */