| 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 | |
| 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 | |
| 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 | } |