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 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 typedef enum scm_t_port_encoding_mode {
  52   SCM_PORT_ENCODING_MODE_UTF8,
  53   SCM_PORT_ENCODING_MODE_ICONV
  54 } scm_t_port_encoding_mode;
  55
  56 /* This is a separate object so that only those ports that use iconv
  57    cause finalizers to be registered.  */
  58 typedef struct scm_t_iconv_descriptors
  59 {
  60   /* input/output iconv conversion descriptors */
  61   void *input_cd;
  62   void *output_cd;
  63 } scm_t_iconv_descriptors;
  64
  65 /* C representation of a Scheme port.  */
  66
  67 typedef struct
  68 {
  69   SCM port;                     /* Link back to the port object.  */
  70   scm_i_pthread_mutex_t *lock;  /* A recursive lock for this port.  */
  71
  72   /* data for the underlying port implementation as a raw C value. */
  73   scm_t_bits stream;
  74
  75   SCM file_name;                /* debugging support.  */
  76   long line_number;             /* debugging support.  */
  77   int column_number;            /* debugging support.  */
  78
  79   /* port buffers.  the buffer(s) are set up for all ports.
  80      in the case of string ports, the buffer is the string itself.
  81      in the case of unbuffered file ports, the buffer is a
  82      single char: shortbuf.  */
  83
  84   /* this buffer is filled from read_buf to read_end using the ptob
  85      buffer_fill.  then input requests are taken from read_pos until
  86      it reaches read_end.  */
  87
  88   unsigned char *read_buf;      /* buffer start.  */
  89   const unsigned char *read_pos;/* the next unread char.  */
  90   unsigned char *read_end;      /* pointer to last buffered char + 1.  */
  91   scm_t_off read_buf_size;              /* size of the buffer.  */
  92
  93   /* when chars are put back into the buffer, e.g., using peek-char or
  94      unread-string, the read-buffer pointers are switched to cbuf.
  95      the original pointers are saved here and restored when the put-back
  96      chars have been consumed.  */
  97   unsigned char *saved_read_buf;
  98   const unsigned char *saved_read_pos;
  99   unsigned char *saved_read_end;
 100   scm_t_off saved_read_buf_size;
 101
 102   /* write requests are saved into this buffer at write_pos until it
 103      reaches write_buf + write_buf_size, then the ptob flush is
 104      called.  */
 105
 106   unsigned char *write_buf;     /* buffer start.  */
 107   unsigned char *write_pos;     /* pointer to last buffered char + 1.  */
 108   unsigned char *write_end;     /* pointer to end of buffer + 1.  */
 109   scm_t_off write_buf_size;             /* size of the buffer.  */
 110
 111   unsigned char shortbuf;       /* buffer for "unbuffered" streams.  */
 112
 113   int rw_random;                /* true if the port is random access.
 114                                    implies that the buffers must be
 115                                    flushed before switching between
 116                                    reading and writing, seeking, etc.  */
 117
 118   scm_t_port_rw_active rw_active; /* for random access ports,
 119                                      indicates which of the buffers
 120                                      is currently in use.  can be
 121                                      SCM_PORT_WRITE, SCM_PORT_READ,
 122                                      or SCM_PORT_NEITHER.  */
 123
 124
 125   /* a buffer for un-read chars and strings.  */
 126   unsigned char *putback_buf;
 127   size_t putback_buf_size;        /* allocated size of putback_buf.  */
 128
 129   /* Character encoding support  */
 130   char *encoding;
 131   scm_t_port_encoding_mode encoding_mode;
 132   scm_t_string_failed_conversion_handler ilseq_handler;
 133   scm_t_iconv_descriptors *iconv_descriptors;
 134 } scm_t_port;
 135
 136
 137 SCM_INTERNAL SCM scm_i_port_weak_set;
 138
 139
 140 #define SCM_READ_BUFFER_EMPTY_P(c_port) (c_port->read_pos >= c_port->read_end)
 141
 142 \f
 143
 144 #define SCM_EOF_OBJECT_P(x) (scm_is_eq ((x), SCM_EOF_VAL))
 145
 146 /* PORT FLAGS
 147  * A set of flags characterizes a port.
 148  * Note that we reserve the bits 1 << 24 and above for use by the
 149  * routines in the port's scm_ptobfuns structure.
 150  */
 151 #define SCM_OPN         (1L<<16) /* Is the port open? */
 152 #define SCM_RDNG        (2L<<16) /* Is it a readable port? */
 153 #define SCM_WRTNG       (4L<<16) /* Is it writable? */
 154 #define SCM_BUF0        (8L<<16) /* Is it unbuffered? */
 155 #define SCM_BUFLINE     (64L<<16) /* Is it line-buffered? */
 156
 157 #define SCM_PORTP(x) (SCM_HAS_TYP7 (x, scm_tc7_port))
 158 #define SCM_OPPORTP(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_OPN))
 159 #define SCM_INPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_RDNG))
 160 #define SCM_OUTPUT_PORT_P(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_WRTNG))
 161 #define SCM_OPINPORTP(x) (SCM_OPPORTP (x) && SCM_INPUT_PORT_P (x))
 162 #define SCM_OPOUTPORTP(x) (SCM_OPPORTP (x) && SCM_OUTPUT_PORT_P (x))
 163 #define SCM_OPENP(x) (SCM_OPPORTP (x))
 164 #define SCM_CLOSEDP(x) (!SCM_OPENP (x))
 165 #define SCM_CLR_PORT_OPEN_FLAG(p) \
 166   SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) & ~SCM_OPN)
 167
 168 #define SCM_PTAB_ENTRY(x)         ((scm_t_port *) SCM_CELL_WORD_1 (x))
 169 #define SCM_PORT_DESCRIPTOR(port) ((scm_t_ptob_descriptor *) SCM_CELL_WORD_2 (port))
 170 #define SCM_SETPTAB_ENTRY(x, ent)  (SCM_SET_CELL_WORD_1 ((x), (scm_t_bits) (ent)))
 171 #define SCM_STREAM(x)             (SCM_PTAB_ENTRY(x)->stream)
 172 #define SCM_SETSTREAM(x, s)        (SCM_PTAB_ENTRY(x)->stream = (scm_t_bits) (s))
 173 #define SCM_FILENAME(x)           (SCM_PTAB_ENTRY(x)->file_name)
 174 #define SCM_SET_FILENAME(x, n)    (SCM_PTAB_ENTRY(x)->file_name = (n))
 175 #define SCM_LINUM(x)              (SCM_PTAB_ENTRY(x)->line_number)
 176 #define SCM_COL(x)                (SCM_PTAB_ENTRY(x)->column_number)
 177
 178 #define SCM_INCLINE(port)       do {SCM_LINUM (port) += 1; SCM_COL (port) = 0;} while (0)
 179 #define SCM_ZEROCOL(port)       do {SCM_COL (port) = 0;} while (0)
 180 #define SCM_INCCOL(port)        do {SCM_COL (port) += 1;} while (0)
 181 #define SCM_DECCOL(port)        do {if (SCM_COL (port) > 0) SCM_COL (port) -= 1;} while (0)
 182 #define SCM_TABCOL(port)        do {SCM_COL (port) += 8 - SCM_COL (port) % 8;} while (0)
 183
 184 /* Maximum number of port types.  */
 185 #define SCM_I_MAX_PORT_TYPE_COUNT  256
 186
 187 \f
 188
 189 typedef enum scm_t_port_type_flags {
 190   SCM_PORT_TYPE_HAS_FLUSH = 1 << 0
 191 } scm_t_port_type_flags;
 192
 193 /* port-type description.  */
 194 typedef struct scm_t_ptob_descriptor
 195 {
 196   char *name;
 197   SCM (*mark) (SCM);
 198   size_t (*free) (SCM);
 199   int (*print) (SCM exp, SCM port, scm_print_state *pstate);
 200   SCM (*equalp) (SCM, SCM);
 201   int (*close) (SCM port);
 202
 203   void (*write) (SCM port, const void *data, size_t size);
 204   void (*flush) (SCM port);
 205
 206   void (*end_input) (SCM port, int offset);
 207   int (*fill_input) (SCM port);
 208   int (*input_waiting) (SCM port);
 209
 210   scm_t_off (*seek) (SCM port, scm_t_off OFFSET, int WHENCE);
 211   void (*truncate) (SCM port, scm_t_off length);
 212
 213   unsigned flags;
 214 } scm_t_ptob_descriptor;
 215
 216 #define SCM_TC2PTOBNUM(x) (0x0ff & ((x) >> 8))
 217 #define SCM_PTOBNUM(x) (SCM_TC2PTOBNUM (SCM_CELL_TYPE (x)))
 218 /* SCM_PTOBNAME can be 0 if name is missing */
 219 #define SCM_PTOBNAME(ptobnum) (scm_c_port_type_ref (ptobnum)->name)
 220
 221 /* Port types, and their vtables.  */
 222 SCM_INTERNAL long scm_c_num_port_types (void);
 223 SCM_API scm_t_ptob_descriptor* scm_c_port_type_ref (long ptobnum);
 224 SCM_API long scm_c_port_type_add_x (scm_t_ptob_descriptor *desc);
 225 SCM_API scm_t_bits scm_make_port_type (char *name,
 226                                        int (*fill_input) (SCM port),
 227                                        void (*write) (SCM port,
 228                                                       const void *data,
 229                                                       size_t size));
 230 SCM_API void scm_set_port_mark (scm_t_bits tc, SCM (*mark) (SCM));
 231 SCM_API void scm_set_port_free (scm_t_bits tc, size_t (*free) (SCM));
 232 SCM_API void scm_set_port_print (scm_t_bits tc,
 233                                  int (*print) (SCM exp,
 234                                                SCM port,
 235                                                scm_print_state *pstate));
 236 SCM_API void scm_set_port_equalp (scm_t_bits tc, SCM (*equalp) (SCM, SCM));
 237 SCM_API void scm_set_port_close (scm_t_bits tc, int (*close) (SCM));
 238
 239 SCM_API void scm_set_port_flush (scm_t_bits tc, void (*flush) (SCM port));
 240 SCM_API void scm_set_port_end_input (scm_t_bits tc,
 241                                      void (*end_input) (SCM port,
 242                                                         int offset));
 243 SCM_API void scm_set_port_seek (scm_t_bits tc,
 244                                 scm_t_off (*seek) (SCM port,
 245                                                    scm_t_off OFFSET,
 246                                                    int WHENCE));
 247 SCM_API void scm_set_port_truncate (scm_t_bits tc,
 248                                     void (*truncate) (SCM port,
 249                                                       scm_t_off length));
 250 SCM_API void scm_set_port_input_waiting (scm_t_bits tc, int (*input_waiting) (SCM));
 251
 252 /* The input, output, error, and load ports.  */
 253 SCM_API SCM scm_current_input_port (void);
 254 SCM_API SCM scm_current_output_port (void);
 255 SCM_API SCM scm_current_error_port (void);
 256 SCM_API SCM scm_current_warning_port (void);
 257 SCM_API SCM scm_current_load_port (void);
 258 SCM_API SCM scm_set_current_input_port (SCM port);
 259 SCM_API SCM scm_set_current_output_port (SCM port);
 260 SCM_API SCM scm_set_current_error_port (SCM port);
 261 SCM_API SCM scm_set_current_warning_port (SCM port);
 262 SCM_API void scm_dynwind_current_input_port (SCM port);
 263 SCM_API void scm_dynwind_current_output_port (SCM port);
 264 SCM_API void scm_dynwind_current_error_port (SCM port);
 265 SCM_INTERNAL void scm_i_dynwind_current_load_port (SCM port);
 266
 267 /* Mode bits.  */
 268 SCM_INTERNAL long scm_i_mode_bits (SCM modes);
 269 SCM_API long scm_mode_bits (char *modes);
 270 SCM_API SCM scm_port_mode (SCM port);
 271
 272 /* Low-level constructors.  */
 273 SCM_API SCM
 274 scm_c_make_port_with_encoding (scm_t_bits tag,
 275                                unsigned long mode_bits,
 276                                const char *encoding,
 277                                scm_t_string_failed_conversion_handler handler,
 278                                scm_t_bits stream);
 279 SCM_API SCM scm_c_make_port (scm_t_bits tag, unsigned long mode_bits,
 280                              scm_t_bits stream);
 281 SCM_API SCM scm_new_port_table_entry (scm_t_bits tag);
 282
 283 /* Predicates.  */
 284 SCM_API SCM scm_port_p (SCM x);
 285 SCM_API SCM scm_input_port_p (SCM x);
 286 SCM_API SCM scm_output_port_p (SCM x);
 287 SCM_API SCM scm_port_closed_p (SCM port);
 288 SCM_API SCM scm_eof_object_p (SCM x);
 289
 290 /* Closing ports.  */
 291 SCM_API SCM scm_close_port (SCM port);
 292 SCM_API SCM scm_close_input_port (SCM port);
 293 SCM_API SCM scm_close_output_port (SCM port);
 294
 295 /* Encoding characters to byte streams, and decoding byte streams to
 296    characters.  */
 297 SCM_INTERNAL const char *scm_i_default_port_encoding (void);
 298 SCM_INTERNAL void scm_i_set_default_port_encoding (const char *);
 299 SCM_INTERNAL scm_t_iconv_descriptors *scm_i_port_iconv_descriptors (SCM port);
 300 SCM_INTERNAL void scm_i_set_port_encoding_x (SCM port, const char *str);
 301 SCM_API SCM scm_port_encoding (SCM port);
 302 SCM_API SCM scm_set_port_encoding_x (SCM port, SCM encoding);
 303 SCM_INTERNAL scm_t_string_failed_conversion_handler scm_i_get_conversion_strategy (SCM port);
 304 SCM_INTERNAL void scm_i_set_conversion_strategy_x (SCM port,
 305                                                    scm_t_string_failed_conversion_handler h);
 306 SCM_API SCM scm_port_conversion_strategy (SCM port);
 307 SCM_API SCM scm_set_port_conversion_strategy_x (SCM port, SCM behavior);
 308
 309 /* Acquiring and releasing the port lock.  */
 310 SCM_API void scm_dynwind_lock_port (SCM port);
 311 SCM_INLINE int scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 312 SCM_INLINE int scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock);
 313
 314 /* Input.  */
 315 SCM_API int scm_get_byte_or_eof (SCM port);
 316 SCM_INLINE int scm_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 size_t scm_c_read (SCM port, void *buffer, size_t size);
 320 SCM_API size_t scm_c_read_unlocked (SCM port, void *buffer, size_t size);
 321 SCM_API scm_t_wchar scm_getc (SCM port);
 322 SCM_API scm_t_wchar scm_getc_unlocked (SCM port);
 323 SCM_API SCM scm_read_char (SCM port);
 324
 325 /* Pushback.  */
 326 SCM_INTERNAL void scm_unget_byte (int c, SCM port);
 327 SCM_INTERNAL void scm_unget_byte_unlocked (int c, SCM port);
 328 SCM_API void scm_ungetc (scm_t_wchar c, SCM port);
 329 SCM_API void scm_ungetc_unlocked (scm_t_wchar c, SCM port);
 330 SCM_API void scm_ungets (const char *s, int n, SCM port);
 331 SCM_API void scm_ungets_unlocked (const char *s, int n, SCM port);
 332 SCM_API SCM scm_peek_char (SCM port);
 333 SCM_API SCM scm_unread_char (SCM cobj, SCM port);
 334 SCM_API SCM scm_unread_string (SCM str, SCM port);
 335
 336 /* Manipulating the buffers.  */
 337 SCM_API void scm_port_non_buffer (scm_t_port *pt);
 338 SCM_API int scm_fill_input (SCM port);
 339 SCM_API int scm_fill_input_unlocked (SCM port);
 340 SCM_INTERNAL size_t scm_take_from_input_buffers (SCM port, char *dest, size_t read_len);
 341 SCM_API SCM scm_drain_input (SCM port);
 342 SCM_API void scm_end_input (SCM port);
 343 SCM_API void scm_end_input_unlocked (SCM port);
 344 SCM_API SCM scm_force_output (SCM port);
 345 SCM_API void scm_flush (SCM port);
 346 SCM_API void scm_flush_unlocked (SCM port);
 347
 348 /* Output.  */
 349 SCM_API void scm_putc (char c, SCM port);
 350 SCM_INLINE void scm_putc_unlocked (char c, SCM port);
 351 SCM_API void scm_puts (const char *str_data, SCM port);
 352 SCM_INLINE void scm_puts_unlocked (const char *str_data, SCM port);
 353 SCM_API void scm_c_write (SCM port, const void *buffer, size_t size);
 354 SCM_API void scm_c_write_unlocked (SCM port, const void *buffer, size_t size);
 355 SCM_API void scm_lfwrite (const char *ptr, size_t size, SCM port);
 356 SCM_API void scm_lfwrite_unlocked (const char *ptr, size_t size, SCM port);
 357 SCM_INTERNAL void scm_lfwrite_substr (SCM str, size_t start, size_t end,
 358                                       SCM port);
 359
 360 /* Querying and setting positions, and character availability.  */
 361 SCM_API SCM scm_char_ready_p (SCM port);
 362 SCM_API SCM scm_seek (SCM object, SCM offset, SCM whence);
 363 SCM_API SCM scm_truncate_file (SCM object, SCM length);
 364 SCM_API SCM scm_port_line (SCM port);
 365 SCM_API SCM scm_set_port_line_x (SCM port, SCM line);
 366 SCM_API SCM scm_port_column (SCM port);
 367 SCM_API SCM scm_set_port_column_x (SCM port, SCM line);
 368 SCM_API SCM scm_port_filename (SCM port);
 369 SCM_API SCM scm_set_port_filename_x (SCM port, SCM filename);
 370
 371 /* Implementation helpers for port printing functions.  */
 372 SCM_API int scm_port_print (SCM exp, SCM port, scm_print_state *);
 373 SCM_API void scm_print_port_mode (SCM exp, SCM port);
 374
 375 /* Iterating over all ports.  */
 376 SCM_API SCM scm_port_for_each (SCM proc);
 377 SCM_API void scm_c_port_for_each (void (*proc)(void *data, SCM p), void *data);
 378 SCM_API SCM scm_flush_all_ports (void);
 379
 380 /* Void ports.  */
 381 SCM_API SCM scm_void_port (char * mode_str);
 382 SCM_API SCM scm_sys_make_void_port (SCM mode);
 383
 384 /* Initialization.  */
 385 SCM_INTERNAL void scm_init_ports (void);
 386
 387
 388 /* Inline function implementations.  */
 389
 390 #if SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES
 391 SCM_INLINE_IMPLEMENTATION int
 392 scm_c_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 393 {
 394   *lock = SCM_PTAB_ENTRY (port)->lock;
 395
 396   if (*lock)
 397     return scm_i_pthread_mutex_lock (*lock);
 398   else
 399     return 0;
 400 }
 401
 402 SCM_INLINE_IMPLEMENTATION int
 403 scm_c_try_lock_port (SCM port, scm_i_pthread_mutex_t **lock)
 404 {
 405   *lock = SCM_PTAB_ENTRY (port)->lock;
 406   if (*lock)
 407     {
 408       int ret = scm_i_pthread_mutex_trylock (*lock);
 409       if (ret != 0)
 410         *lock = NULL;
 411       return ret;
 412     }
 413   else
 414     return 0;
 415 }
 416
 417 SCM_INLINE_IMPLEMENTATION int
 418 scm_get_byte_or_eof_unlocked (SCM port)
 419 {
 420   int c;
 421   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 422
 423   if (pt->rw_active == SCM_PORT_WRITE)
 424     /* may be marginally faster than calling scm_flush.  */
 425     SCM_PORT_DESCRIPTOR (port)->flush (port);
 426
 427   if (pt->rw_random)
 428     pt->rw_active = SCM_PORT_READ;
 429
 430   if (pt->read_pos >= pt->read_end)
 431     {
 432       if (SCM_UNLIKELY (scm_fill_input_unlocked (port) == EOF))
 433         return EOF;
 434     }
 435
 436   c = *(pt->read_pos++);
 437
 438   return c;
 439 }
 440
 441 /* Like `scm_get_byte_or_eof' but does not change PORT's `read_pos'.  */
 442 SCM_INLINE_IMPLEMENTATION int
 443 scm_peek_byte_or_eof_unlocked (SCM port)
 444 {
 445   int c;
 446   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 447
 448   if (pt->rw_active == SCM_PORT_WRITE)
 449     /* may be marginally faster than calling scm_flush.  */
 450     SCM_PORT_DESCRIPTOR (port)->flush (port);
 451
 452   if (pt->rw_random)
 453     pt->rw_active = SCM_PORT_READ;
 454
 455   if (pt->read_pos >= pt->read_end)
 456     {
 457       if (SCM_UNLIKELY (scm_fill_input_unlocked (port) == EOF))
 458         return EOF;
 459     }
 460
 461   c = *pt->read_pos;
 462
 463   return c;
 464 }
 465
 466 SCM_INLINE_IMPLEMENTATION void
 467 scm_putc_unlocked (char c, SCM port)
 468 {
 469   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 470   scm_lfwrite_unlocked (&c, 1, port);
 471 }
 472
 473 SCM_INLINE_IMPLEMENTATION void
 474 scm_puts_unlocked (const char *s, SCM port)
 475 {
 476   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 477   scm_lfwrite_unlocked (s, strlen (s), port);
 478 }
 479 #endif  /* SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES */
 480
 481 #endif  /* SCM_PORTS_H */
 482
 483 /*
 484   Local Variables:
 485   c-file-style: "gnu"
 486   End:
 487 */