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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 | { |
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19 | const struct sbcs_data *sd = charset->data; |
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20 | |
21 | UNUSEDARG(state); |
22 | |
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23 | emit(emitctx, sd->sbcs2ucs[input_chr]); |
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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 | { |
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30 | const struct sbcs_data *sd = charset->data; |
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31 | int i, j, k, c; |
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32 | |
33 | UNUSEDARG(state); |
34 | |
35 | /* |
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36 | * Binary-search in the ucs2sbcs table. |
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37 | */ |
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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); |
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49 | return; |
50 | } |
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51 | } |
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52 | emit(emitctx, ERROR); |
53 | } |