1 /*
2 * sbcs.c - routines to handle single-byte character sets.
3 */
4
5 #include "charset.h"
6 #include "internal.h"
7
8 /*
9 * The charset_spec for any single-byte character set should
10 * provide read_sbcs() as its read function, and its `data' field
11 * should be a wchar_t string constant containing the 256 entries
12 * of the translation table.
13 */
14
read_sbcs(charset_spec const * charset,long int input_chr,charset_state * state,void (* emit)(void * ctx,long int output),void * emitctx)15 void read_sbcs(charset_spec const *charset, long int input_chr,
16 charset_state *state,
17 void (*emit)(void *ctx, long int output), void *emitctx)
18 {
19 const struct sbcs_data *sd = charset->data;
20
21 UNUSEDARG(state);
22
23 emit(emitctx, sd->sbcs2ucs[input_chr]);
24 }
25
write_sbcs(charset_spec const * charset,long int input_chr,charset_state * state,void (* emit)(void * ctx,long int output),void * emitctx)26 void write_sbcs(charset_spec const *charset, long int input_chr,
27 charset_state *state,
28 void (*emit)(void *ctx, long int output), void *emitctx)
29 {
30 const struct sbcs_data *sd = charset->data;
31 int i, j, k, c;
32
33 UNUSEDARG(state);
34
35 /*
36 * Binary-search in the ucs2sbcs table.
37 */
38 i = -1;
39 j = sd->nvalid;
40 while (i+1 < j) {
41 k = (i+j)/2;
42 c = sd->ucs2sbcs[k];
43 if (input_chr < sd->sbcs2ucs[c])
44 j = k;
45 else if (input_chr > sd->sbcs2ucs[c])
46 i = k;
47 else {
48 emit(emitctx, c);
49 return;
50 }
51 }
52 emit(emitctx, ERROR);
53 }
54