stack.h 3.0 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667
  1. /*====================================================================*
  2. - Copyright (C) 2001 Leptonica. All rights reserved.
  3. -
  4. - Redistribution and use in source and binary forms, with or without
  5. - modification, are permitted provided that the following conditions
  6. - are met:
  7. - 1. Redistributions of source code must retain the above copyright
  8. - notice, this list of conditions and the following disclaimer.
  9. - 2. Redistributions in binary form must reproduce the above
  10. - copyright notice, this list of conditions and the following
  11. - disclaimer in the documentation and/or other materials
  12. - provided with the distribution.
  13. -
  14. - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  15. - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  16. - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  17. - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
  18. - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19. - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20. - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21. - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22. - OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  23. - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  24. - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25. *====================================================================*/
  26. #ifndef LEPTONICA_STACK_H
  27. #define LEPTONICA_STACK_H
  28. /*
  29. * stack.h
  30. *
  31. * Expandable pointer stack for arbitrary void* data.
  32. *
  33. * The L_Stack is an array of void * ptrs, onto which arbitrary
  34. * objects can be stored. At any time, the number of
  35. * stored objects is stack->n. The object at the bottom
  36. * of the stack is at array[0]; the object at the top of
  37. * the stack is at array[n-1]. New objects are added
  38. * to the top of the stack, at the first available location,
  39. * which is array[n]. Objects are removed from the top of the
  40. * stack. When an attempt is made to remove an object from an
  41. * empty stack, the result is null. When the stack becomes
  42. * filled, so that n = nalloc, the size is doubled.
  43. *
  44. * The auxiliary stack can be used to store and remove
  45. * objects for re-use. It must be created by a separate
  46. * call to pstackCreate(). [Just imagine the chaos if
  47. * pstackCreate() created the auxiliary stack!]
  48. * pstackDestroy() checks for the auxiliary stack and removes it.
  49. */
  50. /* Note that array[n] is the first null ptr in the array */
  51. struct L_Stack
  52. {
  53. l_int32 nalloc; /* size of ptr array */
  54. l_int32 n; /* number of stored elements */
  55. void **array; /* ptr array */
  56. struct L_Stack *auxstack; /* auxiliary stack */
  57. };
  58. typedef struct L_Stack L_STACK;
  59. #endif /* LEPTONICA_STACK_H */