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, 2014 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   /* When non-NULL, this is the method called by 'setvbuf' for this port.
 204      It must create read and write buffers for PORT with the specified
 205      sizes (a size of 0 is for unbuffered ports, which should use the
 206      'shortbuf' field.)  Size -1 means to use the port's preferred buffer
 207      size.  */
 208   void (*setvbuf) (SCM port, long read_size, long write_size);
 209
 210   unsigned flags;
 211 } scm_t_ptob_descriptor;
 212
 213 #define SCM_TC2PTOBNUM(x) (0x0ff & ((x) >> 8))
 214 #define SCM_PTOBNUM(x) (SCM_TC2PTOBNUM (SCM_CELL_TYPE (x)))
 215 /* SCM_PTOBNAME can be 0 if name is missing */
 216 #define SCM_PTOBNAME(ptobnum) (scm_c_port_type_ref (ptobnum)->name)
 217
 218 /* Port types, and their vtables.  */
 219 SCM_INTERNAL long scm_c_num_port_types (void);
 220 SCM_API scm_t_ptob_descriptor* scm_c_port_type_ref (long ptobnum);
 221 SCM_API long scm_c_port_type_add_x (scm_t_ptob_descriptor *desc);
 222 SCM_API scm_t_bits scm_make_port_type (char *name,
 223                                        int (*fill_input) (SCM port),
 224                                        void (*write) (SCM port,
 225                                                       const void *data,
 226                                                       size_t size));
 227 SCM_API void scm_set_port_mark (scm_t_bits tc, SCM (*mark) (SCM));
 228 SCM_API void scm_set_port_free (scm_t_bits tc, size_t (*free) (SCM));
 229 SCM_API void scm_set_port_print (scm_t_bits tc,
 230                                  int (*print) (SCM exp,
 231                                                SCM port,
 232                                                scm_print_state *pstate));
 233 SCM_API void scm_set_port_equalp (scm_t_bits tc, SCM (*equalp) (SCM, SCM));
 234 SCM_API void scm_set_port_close (scm_t_bits tc, int (*close) (SCM));
 235
 236 SCM_API void scm_set_port_flush (scm_t_bits tc, void (*flush) (SCM port));
 237 SCM_API void scm_set_port_end_input (scm_t_bits tc,
 238                                      void (*end_input) (SCM port,
 239                                                         int offset));
 240 SCM_API void scm_set_port_seek (scm_t_bits tc,
 241                                 scm_t_off (*seek) (SCM port,
 242                                                    scm_t_off OFFSET,
 243                                                    int WHENCE));
 244 SCM_API void scm_set_port_truncate (scm_t_bits tc,
 245                                     void (*truncate) (SCM port,
 246                                                       scm_t_off length));
 247 SCM_API void scm_set_port_input_waiting (scm_t_bits tc, int (*input_waiting) (SCM));
 248 SCM_API void scm_set_port_setvbuf (scm_t_bits tc,
 249                                    void (*setvbuf) (SCM, long, long));
 250
 251 /* The input, output, error, and load ports.  */
 252 SCM_API SCM scm_current_input_port (void);
 253 SCM_API SCM scm_current_output_port (void);
 254 SCM_API SCM scm_current_error_port (void);
 255 SCM_API SCM scm_current_warning_port (void);
 256 SCM_API SCM scm_current_load_port (void);
 257 SCM_API SCM scm_set_current_input_port (SCM port);
 258 SCM_API SCM scm_set_current_output_port (SCM port);
 259 SCM_API SCM scm_set_current_error_port (SCM port);
 260 SCM_API SCM scm_set_current_warning_port (SCM port);
 261 SCM_API void scm_dynwind_current_input_port (SCM port);
 262 SCM_API void scm_dynwind_current_output_port (SCM port);
 263 SCM_API void scm_dynwind_current_error_port (SCM port);
 264 SCM_INTERNAL void scm_i_dynwind_current_load_port (SCM port);
 265
 266 /* Mode bits.  */
 267 SCM_INTERNAL long scm_i_mode_bits (SCM modes);
 268 SCM_API long scm_mode_bits (char *modes);
 269 SCM_API SCM scm_port_mode (SCM port);
 270
 271 /* Low-level constructors.  */
 272 SCM_API SCM
 273 scm_c_make_port_with_encoding (scm_t_bits tag,
 274                                unsigned long mode_bits,
 275                                const char *encoding,
 276                                scm_t_string_failed_conversion_handler handler,
 277                                scm_t_bits stream);
 278 SCM_API SCM scm_c_make_port (scm_t_bits tag, unsigned long mode_bits,
 279                              scm_t_bits stream);
 280 SCM_API SCM scm_new_port_table_entry (scm_t_bits tag);
 281
 282 /* Predicates.  */
 283 SCM_API SCM scm_port_p (SCM x);
 284 SCM_API SCM scm_input_port_p (SCM x);
 285 SCM_API SCM scm_output_port_p (SCM x);
 286 SCM_API SCM scm_port_closed_p (SCM port);
 287 SCM_API SCM scm_eof_object_p (SCM x);
 288
 289 /* Closing ports.  */
 290 SCM_API SCM scm_close_port (SCM port);
 291 SCM_API SCM scm_close_input_port (SCM port);
 292 SCM_API SCM scm_close_output_port (SCM port);
 293
 294 /* Encoding characters to byte streams, and decoding byte streams to
 295    characters.  */
 296 SCM_INTERNAL const char *scm_i_default_port_encoding (void);
 297 SCM_INTERNAL void scm_i_set_default_port_encoding (const char *);
 298 SCM_INTERNAL scm_t_string_failed_conversion_handler
 299 scm_i_default_port_conversion_handler (void);
 300 SCM_INTERNAL void
 301 scm_i_set_default_port_conversion_handler (scm_t_string_failed_conversion_handler);
 302 SCM_INTERNAL void scm_i_set_port_encoding_x (SCM port, const char *str);
 303 SCM_API SCM scm_port_encoding (SCM port);
 304 SCM_API SCM scm_set_port_encoding_x (SCM port, SCM encoding);
 305 SCM_API SCM scm_port_conversion_strategy (SCM port);
 306 SCM_API SCM scm_set_port_conversion_strategy_x (SCM port, SCM behavior);
 307
 308 /* Acquiring and releasing the port lock.  */
 309 SCM_API void scm_dynwind_lock_port (SCM port);
 310 SCM_INLINE int scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 311 SCM_INLINE int scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 312
 313 /* Input.  */
 314 SCM_API int scm_get_byte_or_eof (SCM port);
 315 SCM_INLINE int scm_get_byte_or_eof_unlocked (SCM port);
 316 SCM_API int scm_slow_get_byte_or_eof_unlocked (SCM port);
 317 SCM_API int scm_peek_byte_or_eof (SCM port);
 318 SCM_INLINE int scm_peek_byte_or_eof_unlocked (SCM port);
 319 SCM_API int scm_slow_peek_byte_or_eof_unlocked (SCM port);
 320 SCM_API size_t scm_c_read (SCM port, void *buffer, size_t size);
 321 SCM_API size_t scm_c_read_unlocked (SCM port, void *buffer, size_t size);
 322 SCM_API scm_t_wchar scm_getc (SCM port);
 323 SCM_API scm_t_wchar scm_getc_unlocked (SCM port);
 324 SCM_API SCM scm_read_char (SCM port);
 325
 326 /* Pushback.  */
 327 SCM_API void scm_unget_bytes (const unsigned char *buf, size_t len, SCM port);
 328 SCM_API void scm_unget_bytes_unlocked (const unsigned char *buf, size_t len, SCM port);
 329 SCM_API void scm_unget_byte (int c, SCM port);
 330 SCM_API void scm_unget_byte_unlocked (int c, SCM port);
 331 SCM_API void scm_ungetc (scm_t_wchar c, SCM port);
 332 SCM_API void scm_ungetc_unlocked (scm_t_wchar c, SCM port);
 333 SCM_API void scm_ungets (const char *s, int n, SCM port);
 334 SCM_API void scm_ungets_unlocked (const char *s, int n, SCM port);
 335 SCM_API SCM scm_peek_char (SCM port);
 336 SCM_API SCM scm_unread_char (SCM cobj, SCM port);
 337 SCM_API SCM scm_unread_string (SCM str, SCM port);
 338
 339 /* Manipulating the buffers.  */
 340 SCM_API void scm_port_non_buffer (scm_t_port *pt);
 341 SCM_API int scm_fill_input (SCM port);
 342 SCM_API int scm_fill_input_unlocked (SCM port);
 343 SCM_INTERNAL size_t scm_take_from_input_buffers (SCM port, char *dest, size_t read_len);
 344 SCM_API SCM scm_drain_input (SCM port);
 345 SCM_API void scm_end_input (SCM port);
 346 SCM_API void scm_end_input_unlocked (SCM port);
 347 SCM_API SCM scm_force_output (SCM port);
 348 SCM_API void scm_flush (SCM port);
 349 SCM_API void scm_flush_unlocked (SCM port);
 350
 351 /* Output.  */
 352 SCM_API void scm_putc (char c, SCM port);
 353 SCM_INLINE void scm_putc_unlocked (char c, SCM port);
 354 SCM_API void scm_puts (const char *str_data, SCM port);
 355 SCM_INLINE void scm_puts_unlocked (const char *str_data, SCM port);
 356 SCM_API void scm_c_write (SCM port, const void *buffer, size_t size);
 357 SCM_API void scm_c_write_unlocked (SCM port, const void *buffer, size_t size);
 358 SCM_API void scm_lfwrite (const char *ptr, size_t size, SCM port);
 359 SCM_API void scm_lfwrite_unlocked (const char *ptr, size_t size, SCM port);
 360 SCM_INTERNAL void scm_lfwrite_substr (SCM str, size_t start, size_t end,
 361                                       SCM port);
 362
 363 /* Querying and setting positions, and character availability.  */
 364 SCM_API SCM scm_char_ready_p (SCM port);
 365 SCM_API SCM scm_seek (SCM object, SCM offset, SCM whence);
 366 SCM_API SCM scm_truncate_file (SCM object, SCM length);
 367 SCM_API SCM scm_port_line (SCM port);
 368 SCM_API SCM scm_set_port_line_x (SCM port, SCM line);
 369 SCM_API SCM scm_port_column (SCM port);
 370 SCM_API SCM scm_set_port_column_x (SCM port, SCM line);
 371 SCM_API SCM scm_port_filename (SCM port);
 372 SCM_API SCM scm_set_port_filename_x (SCM port, SCM filename);
 373
 374 /* Port properties.  */
 375 SCM_INTERNAL SCM scm_i_port_property (SCM port, SCM key);
 376 SCM_INTERNAL SCM scm_i_set_port_property_x (SCM port, SCM key, SCM value);
 377
 378 /* Implementation helpers for port printing functions.  */
 379 SCM_API int scm_port_print (SCM exp, SCM port, scm_print_state *);
 380 SCM_API void scm_print_port_mode (SCM exp, SCM port);
 381
 382 /* Iterating over all ports.  */
 383 SCM_API SCM scm_port_for_each (SCM proc);
 384 SCM_API void scm_c_port_for_each (void (*proc)(void *data, SCM p), void *data);
 385 SCM_API SCM scm_flush_all_ports (void);
 386
 387 /* Void ports.  */
 388 SCM_API SCM scm_void_port (char * mode_str);
 389 SCM_API SCM scm_sys_make_void_port (SCM mode);
 390
 391 /* Initialization.  */
 392 SCM_INTERNAL void scm_init_ports (void);
 393
 394
 395 /* Inline function implementations.  */
 396
 397 #if SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES
 398 SCM_INLINE_IMPLEMENTATION int
 399 scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 400 {
 401   *lock = SCM_PTAB_ENTRY (port)->lock;
 402
 403   if (*lock)
 404     return scm_i_pthread_mutex_lock (*lock);
 405   else
 406     return 0;
 407 }
 408
 409 SCM_INLINE_IMPLEMENTATION int
 410 scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 411 {
 412   *lock = SCM_PTAB_ENTRY (port)->lock;
 413   if (*lock)
 414     {
 415       int ret = scm_i_pthread_mutex_trylock (*lock);
 416       if (ret != 0)
 417         *lock = NULL;
 418       return ret;
 419     }
 420   else
 421     return 0;
 422 }
 423
 424 SCM_INLINE_IMPLEMENTATION int
 425 scm_get_byte_or_eof_unlocked (SCM port)
 426 {
 427   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 428
 429   if (SCM_LIKELY ((pt->rw_active == SCM_PORT_READ || !pt->rw_random)
 430                   && pt->read_pos < pt->read_end))
 431     return *pt->read_pos++;
 432   else
 433     return scm_slow_get_byte_or_eof_unlocked (port);
 434 }
 435
 436 /* Like `scm_get_byte_or_eof' but does not change PORT's `read_pos'.  */
 437 SCM_INLINE_IMPLEMENTATION int
 438 scm_peek_byte_or_eof_unlocked (SCM port)
 439 {
 440   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 441
 442   if (SCM_LIKELY ((pt->rw_active == SCM_PORT_READ || !pt->rw_random)
 443                   && pt->read_pos < pt->read_end))
 444     return *pt->read_pos;
 445   else
 446     return scm_slow_peek_byte_or_eof_unlocked (port);
 447 }
 448
 449 SCM_INLINE_IMPLEMENTATION void
 450 scm_putc_unlocked (char c, SCM port)
 451 {
 452   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 453   scm_lfwrite_unlocked (&c, 1, port);
 454 }
 455
 456 SCM_INLINE_IMPLEMENTATION void
 457 scm_puts_unlocked (const char *s, SCM port)
 458 {
 459   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 460   scm_lfwrite_unlocked (s, strlen (s), port);
 461 }
 462 #endif  /* SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES */
 463
 464 #endif  /* SCM_PORTS_H */
 465
 466 /*
 467   Local Variables:
 468   c-file-style: "gnu"
 469   End:
 470 */