Mirror of :pserver:anonymous@cvs.schmorp.de/schmorpforge libev http://software.schmorp.de/pkg/libev.html
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  1. /*
  2. * libev select fd activity backend
  3. *
  4. * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
  5. * All rights reserved.
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions are
  9. * met:
  10. *
  11. * * Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. *
  14. * * Redistributions in binary form must reproduce the above
  15. * copyright notice, this list of conditions and the following
  16. * disclaimer in the documentation and/or other materials provided
  17. * with the distribution.
  18. *
  19. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22. * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23. * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26. * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27. * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29. * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30. */
  31. /* for broken bsd's */
  32. #include <sys/time.h>
  33. #include <sys/types.h>
  34. #include <unistd.h>
  35. /* for unix systems */
  36. #ifndef WIN32
  37. # include <sys/select.h>
  38. #endif
  39. #include <string.h>
  40. #include <inttypes.h>
  41. static void
  42. select_modify (EV_P_ int fd, int oev, int nev)
  43. {
  44. int offs = fd >> 3;
  45. int mask = 1 << (fd & 7);
  46. if (oev == nev)
  47. return;
  48. if (vec_max < (fd >> 5) + 1)
  49. {
  50. int new_max = (fd >> 5) + 1;
  51. vec_ri = (unsigned char *)ev_realloc (vec_ri, new_max * 4);
  52. vec_ro = (unsigned char *)ev_realloc (vec_ro, new_max * 4); /* could free/malloc */
  53. vec_wi = (unsigned char *)ev_realloc (vec_wi, new_max * 4);
  54. vec_wo = (unsigned char *)ev_realloc (vec_wo, new_max * 4); /* could free/malloc */
  55. for (; vec_max < new_max; ++vec_max)
  56. ((uint32_t *)vec_ri)[vec_max] =
  57. ((uint32_t *)vec_wi)[vec_max] = 0;
  58. }
  59. vec_ri [offs] |= mask;
  60. if (!(nev & EV_READ))
  61. vec_ri [offs] &= ~mask;
  62. vec_wi [offs] |= mask;
  63. if (!(nev & EV_WRITE))
  64. vec_wi [offs] &= ~mask;
  65. }
  66. static void
  67. select_poll (EV_P_ ev_tstamp timeout)
  68. {
  69. int word, offs;
  70. struct timeval tv;
  71. int res;
  72. memcpy (vec_ro, vec_ri, vec_max * 4);
  73. memcpy (vec_wo, vec_wi, vec_max * 4);
  74. tv.tv_sec = (long)timeout;
  75. tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
  76. res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
  77. if (res < 0)
  78. {
  79. if (errno == EBADF)
  80. fd_ebadf (EV_A);
  81. else if (errno == ENOMEM && !syserr_cb)
  82. fd_enomem (EV_A);
  83. else if (errno != EINTR)
  84. syserr ("(libev) select");
  85. return;
  86. }
  87. for (word = vec_max; word--; )
  88. {
  89. if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word])
  90. for (offs = 4; offs--; )
  91. {
  92. int idx = word * 4 + offs;
  93. unsigned char byte_r = vec_ro [idx];
  94. unsigned char byte_w = vec_wo [idx];
  95. int bit;
  96. if (byte_r | byte_w)
  97. for (bit = 8; bit--; )
  98. {
  99. int events = 0;
  100. events |= byte_r & (1 << bit) ? EV_READ : 0;
  101. events |= byte_w & (1 << bit) ? EV_WRITE : 0;
  102. if (events)
  103. fd_event (EV_A_ idx * 8 + bit, events);
  104. }
  105. }
  106. }
  107. }
  108. static int
  109. select_init (EV_P_ int flags)
  110. {
  111. method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
  112. method_modify = select_modify;
  113. method_poll = select_poll;
  114. vec_max = 0;
  115. vec_ri = 0;
  116. vec_ri = 0;
  117. vec_wo = 0;
  118. vec_wo = 0;
  119. return EVMETHOD_SELECT;
  120. }
  121. static void
  122. select_destroy (EV_P)
  123. {
  124. ev_free (vec_ri);
  125. ev_free (vec_ro);
  126. ev_free (vec_wi);
  127. ev_free (vec_wo);
  128. }