lzio.c 1.7 KB

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  1. /*
  2. ** $Id: lzio.c,v 1.31.1.1 2007/12/27 13:02:25 roberto Exp $
  3. ** a generic input stream interface
  4. ** See Copyright Notice in lua.h
  5. */
  6. #define lzio_c
  7. #define LUA_CORE
  8. #define LUAC_CROSS_FILE
  9. #include "lua.h"
  10. #include C_HEADER_STRING
  11. #include "llimits.h"
  12. #include "lmem.h"
  13. #include "lstate.h"
  14. #include "lzio.h"
  15. int luaZ_fill (ZIO *z) {
  16. size_t size;
  17. lua_State *L = z->L;
  18. const char *buff;
  19. lua_unlock(L);
  20. buff = z->reader(L, z->data, &size);
  21. lua_lock(L);
  22. if (buff == NULL || size == 0) return EOZ;
  23. z->n = size - 1;
  24. z->p = buff;
  25. return char2int(*(z->p++));
  26. }
  27. int luaZ_lookahead (ZIO *z) {
  28. if (z->n == 0) {
  29. if (luaZ_fill(z) == EOZ)
  30. return EOZ;
  31. else {
  32. z->n++; /* luaZ_fill removed first byte; put back it */
  33. z->p--;
  34. }
  35. }
  36. return char2int(*z->p);
  37. }
  38. void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
  39. z->L = L;
  40. z->reader = reader;
  41. z->data = data;
  42. z->n = z->i = 0;
  43. z->p = NULL;
  44. }
  45. /* --------------------------------------------------------------- read --- */
  46. size_t luaZ_read (ZIO *z, void *b, size_t n) {
  47. while (n) {
  48. size_t m;
  49. if (luaZ_lookahead(z) == EOZ)
  50. return n; /* return number of missing bytes */
  51. m = (n <= z->n) ? n : z->n; /* min. between n and z->n */
  52. if (b)
  53. c_memcpy(b, z->p, m);
  54. z->n -= m;
  55. z->i += m;
  56. z->p += m;
  57. if (b)
  58. b = (char *)b + m;
  59. n -= m;
  60. }
  61. return 0;
  62. }
  63. /* ------------------------------------------------------------------------ */
  64. char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
  65. if (n > buff->buffsize) {
  66. if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
  67. luaZ_resizebuffer(L, buff, n);
  68. }
  69. return buff->buffer;
  70. }