cread.c 1.9 KB

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  1. #include <u.h>
  2. #include <libc.h>
  3. #include <draw.h>
  4. #include <memdraw.h>
  5. Memimage*
  6. creadmemimage(int fd)
  7. {
  8. char hdr[5*12+1];
  9. Rectangle r;
  10. int m, nb, miny, maxy, new, ldepth, ncblock;
  11. uchar *buf;
  12. Memimage *i;
  13. ulong chan;
  14. if(readn(fd, hdr, 5*12) != 5*12){
  15. werrstr("readmemimage: short header (2)");
  16. return nil;
  17. }
  18. /*
  19. * distinguish new channel descriptor from old ldepth.
  20. * channel descriptors have letters as well as numbers,
  21. * while ldepths are a single digit formatted as %-11d.
  22. */
  23. new = 0;
  24. for(m=0; m<10; m++){
  25. if(hdr[m] != ' '){
  26. new = 1;
  27. break;
  28. }
  29. }
  30. if(hdr[11] != ' '){
  31. werrstr("creadimage: bad format");
  32. return nil;
  33. }
  34. if(new){
  35. hdr[11] = '\0';
  36. if((chan = strtochan(hdr)) == 0){
  37. werrstr("creadimage: bad channel string %s", hdr);
  38. return nil;
  39. }
  40. }else{
  41. ldepth = ((int)hdr[10])-'0';
  42. if(ldepth<0 || ldepth>3){
  43. werrstr("creadimage: bad ldepth %d", ldepth);
  44. return nil;
  45. }
  46. chan = drawld2chan[ldepth];
  47. }
  48. r.min.x=atoi(hdr+1*12);
  49. r.min.y=atoi(hdr+2*12);
  50. r.max.x=atoi(hdr+3*12);
  51. r.max.y=atoi(hdr+4*12);
  52. if(r.min.x>r.max.x || r.min.y>r.max.y){
  53. werrstr("creadimage: bad rectangle");
  54. return nil;
  55. }
  56. i = allocmemimage(r, chan);
  57. if(i == nil)
  58. return nil;
  59. ncblock = _compblocksize(r, i->depth);
  60. buf = malloc(ncblock);
  61. if(buf == nil)
  62. goto Errout;
  63. miny = r.min.y;
  64. while(miny != r.max.y){
  65. if(readn(fd, hdr, 2*12) != 2*12){
  66. Shortread:
  67. werrstr("readmemimage: short read");
  68. Errout:
  69. freememimage(i);
  70. free(buf);
  71. return nil;
  72. }
  73. maxy = atoi(hdr+0*12);
  74. nb = atoi(hdr+1*12);
  75. if(maxy<=miny || r.max.y<maxy){
  76. werrstr("readimage: bad maxy %d", maxy);
  77. goto Errout;
  78. }
  79. if(nb<=0 || ncblock<nb){
  80. werrstr("readimage: bad count %d", nb);
  81. goto Errout;
  82. }
  83. if(readn(fd, buf, nb)!=nb)
  84. goto Shortread;
  85. if(!new) /* old image: flip the data bits */
  86. _twiddlecompressed(buf, nb);
  87. cloadmemimage(i, Rect(r.min.x, miny, r.max.x, maxy), buf, nb);
  88. miny = maxy;
  89. }
  90. free(buf);
  91. return i;
  92. }