boehm-gc/include/ec.h

   1 # ifndef EC_H
   2 # define EC_H
   3
   4 # ifndef CORD_H
   5 #  include "cord.h"
   6 # endif
   7
   8 /* Extensible cords are strings that may be destructively appended to.  */
   9 /* They allow fast construction of cords from characters that are       */
  10 /* being read from a stream.                                            */
  11 /*
  12  * A client might look like:
  13  *
  14  *      {
  15  *          CORD_ec x;
  16  *          CORD result;
  17  *          char c;
  18  *          FILE *f;
  19  *
  20  *          ...
  21  *          CORD_ec_init(x);
  22  *          while(...) {
  23  *              c = getc(f);
  24  *              ...
  25  *              CORD_ec_append(x, c);
  26  *          }
  27  *          result = CORD_balance(CORD_ec_to_cord(x));
  28  *
  29  * If a C string is desired as the final result, the call to CORD_balance
  30  * may be replaced by a call to CORD_to_char_star.
  31  */
  32
  33 # ifndef CORD_BUFSZ
  34 #   define CORD_BUFSZ 128
  35 # endif
  36
  37 typedef struct CORD_ec_struct {
  38     CORD ec_cord;
  39     char * ec_bufptr;
  40     char ec_buf[CORD_BUFSZ+1];
  41 } CORD_ec[1];
  42
  43 /* This structure represents the concatenation of ec_cord with          */
  44 /* ec_buf[0 ... (ec_bufptr-ec_buf-1)]                                   */
  45
  46 /* Flush the buffer part of the extended chord into ec_cord.    */
  47 /* Note that this is almost the only real function, and it is   */
  48 /* implemented in 6 lines in cordxtra.c                         */
  49 void CORD_ec_flush_buf(CORD_ec x);
  50
  51 /* Convert an extensible cord to a cord. */
  52 # define CORD_ec_to_cord(x) (CORD_ec_flush_buf(x), (x)[0].ec_cord)
  53
  54 /* Initialize an extensible cord. */
  55 # define CORD_ec_init(x) ((x)[0].ec_cord = 0, (x)[0].ec_bufptr = (x)[0].ec_buf)
  56
  57 /* Append a character to an extensible cord.    */
  58 # define CORD_ec_append(x, c) \
  59     {  \
  60         if ((x)[0].ec_bufptr == (x)[0].ec_buf + CORD_BUFSZ) { \
  61                 CORD_ec_flush_buf(x); \
  62         } \
  63         *((x)[0].ec_bufptr)++ = (c); \
  64     }
  65
  66 /* Append a cord to an extensible cord.  Structure remains shared with  */
  67 /* original.                                                            */
  68 void CORD_ec_append_cord(CORD_ec x, CORD s);
  69
  70 # endif /* EC_H */