rosapps/smartpdf/fitz/stream/filt_ahxd.c

   1 #include "fitz-base.h"
   2 #include "fitz-stream.h"
   3
   4 typedef struct fz_ahxd_s fz_ahxd;
   5
   6 struct fz_ahxd_s
   7 {
   8         fz_filter super;
   9         int odd;
  10         int a;
  11 };
  12
  13 static inline int iswhite(int a)
  14 {
  15         switch (a) {
  16         case '\n': case '\r': case '\t': case ' ':
  17         case '\0': case '\f': case '\b': case 0177:
  18                 return 1;
  19         }
  20         return 0;
  21 }
  22
  23 static inline int ishex(int a)
  24 {
  25         return (a >= 'A' && a <= 'F') ||
  26                 (a >= 'a' && a <= 'f') ||
  27                 (a >= '0' && a <= '9');
  28 }
  29
  30 static inline int fromhex(int a)
  31 {
  32         if (a >= 'A' && a <= 'F')
  33                 return a - 'A' + 0xA;
  34         if (a >= 'a' && a <= 'f')
  35                 return a - 'a' + 0xA;
  36         if (a >= '0' && a <= '9')
  37                 return a - '0';
  38         return 0;
  39 }
  40
  41 fz_error *
  42 fz_newahxd(fz_filter **fp, fz_obj *params)
  43 {
  44         FZ_NEWFILTER(fz_ahxd, f, ahxd);
  45         f->odd = 0;
  46         f->a = 0;
  47         return nil;
  48 }
  49
  50 void
  51 fz_dropahxd(fz_filter *f)
  52 {
  53 }
  54
  55 fz_error *
  56 fz_processahxd(fz_filter *filter, fz_buffer *in, fz_buffer *out)
  57 {
  58         fz_ahxd *f = (fz_ahxd*)filter;
  59         int b, c;
  60
  61         while (1)
  62         {
  63                 if (in->rp == in->wp)
  64                         return fz_ioneedin;
  65
  66                 if (out->wp == out->ep)
  67                         return fz_ioneedout;
  68
  69                 c = *in->rp++;
  70
  71                 if (ishex(c)) {
  72                         if (!f->odd) {
  73                                 f->a = fromhex(c);
  74                                 f->odd = 1;
  75                         }
  76                         else {
  77                                 b = fromhex(c);
  78                                 *out->wp++ = (f->a << 4) | b;
  79                                 f->odd = 0;
  80                         }
  81                 }
  82
  83                 else if (c == '>') {
  84                         if (f->odd)
  85                                 *out->wp++ = (f->a << 4);
  86                         out->eof = 1;
  87                         return fz_iodone;
  88                 }
  89
  90                 else if (!iswhite(c)) {
  91                         return fz_throw("ioerror: bad data in ahxd: '%c'", c);
  92                 }
  93         }
  94 }
  95
  96 void
  97 fz_pushbackahxd(fz_filter *filter, fz_buffer *in, fz_buffer *out, int n)
  98 {
  99         int k;
 100
 101         assert(filter->process == fz_processahxd);
 102         assert(out->wp - n >= out->rp);
 103
 104         k = 0;
 105         while (k < n * 2) {
 106                 in->rp --;
 107                 if (ishex(*in->rp))
 108                         k ++;
 109         }
 110
 111         out->wp -= n;
 112 }
 113