| 1 | /* |
| 2 | * shiftjis.c - multibyte encoding of Shift-JIS |
| 3 | */ |
| 4 | |
| 5 | #ifndef ENUM_CHARSETS |
| 6 | |
| 7 | #include "charset.h" |
| 8 | #include "internal.h" |
| 9 | |
| 10 | /* |
| 11 | * Shift-JIS has no associated data, so `charset' may be ignored. |
| 12 | */ |
| 13 | |
| 14 | static void read_sjis(charset_spec const *charset, long int input_chr, |
| 15 | charset_state *state, |
| 16 | void (*emit)(void *ctx, long int output), void *emitctx) |
| 17 | { |
| 18 | UNUSEDARG(charset); |
| 19 | |
| 20 | /* |
| 21 | * For reading Shift-JIS, state->s0 simply contains the single |
| 22 | * stored lead byte when we are half way through a double-byte |
| 23 | * character, or 0 if we aren't. |
| 24 | */ |
| 25 | |
| 26 | if (state->s0 == 0) { |
| 27 | if ((input_chr >= 0x81 && input_chr <= 0x9F) || |
| 28 | (input_chr >= 0xE0 && input_chr <= 0xEF)) { |
| 29 | /* |
| 30 | * Lead byte. Just store it. |
| 31 | */ |
| 32 | state->s0 = input_chr; |
| 33 | } else { |
| 34 | /* |
| 35 | * Anything else we translate through JIS X 0201. |
| 36 | */ |
| 37 | if (input_chr == 0x5C) |
| 38 | input_chr = 0xA5; |
| 39 | else if (input_chr == 0x7E) |
| 40 | input_chr = 0x203E; |
| 41 | else if (input_chr >= 0xA1 && input_chr <= 0xDF) |
| 42 | input_chr += 0xFF61 - 0xA1; |
| 43 | else if (input_chr < 0x80) |
| 44 | /* do nothing */; |
| 45 | else |
| 46 | input_chr = ERROR; |
| 47 | emit(emitctx, input_chr); |
| 48 | } |
| 49 | } else { |
| 50 | /* |
| 51 | * We have a stored lead byte. We expect a valid followup |
| 52 | * byte. |
| 53 | */ |
| 54 | if (input_chr >= 0x40 && input_chr <= 0xFC && input_chr != 0x7F) { |
| 55 | int r, c; |
| 56 | r = state->s0; |
| 57 | if (r >= 0xE0) r -= (0xE0 - 0xA0); |
| 58 | r -= 0x81; |
| 59 | c = input_chr; |
| 60 | if (c > 0x7F) c--; |
| 61 | c -= 0x40; |
| 62 | r *= 2; |
| 63 | if (c >= 94) |
| 64 | r++, c -= 94; |
| 65 | emit(emitctx, jisx0208_to_unicode(r, c)); |
| 66 | } else { |
| 67 | emit(emitctx, ERROR); |
| 68 | } |
| 69 | state->s0 = 0; |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | /* |
| 74 | * Shift-JIS is a stateless multi-byte encoding (in the sense that |
| 75 | * just after any character has been completed, the state is always |
| 76 | * the same); hence when writing it, there is no need to use the |
| 77 | * charset_state. |
| 78 | */ |
| 79 | |
| 80 | static int write_sjis(charset_spec const *charset, long int input_chr, |
| 81 | charset_state *state, |
| 82 | void (*emit)(void *ctx, long int output), void *emitctx) |
| 83 | { |
| 84 | UNUSEDARG(charset); |
| 85 | UNUSEDARG(state); |
| 86 | |
| 87 | if (input_chr == -1) |
| 88 | return TRUE; /* stateless; no cleanup required */ |
| 89 | |
| 90 | if (input_chr < 0x80 && input_chr != 0x5C && input_chr != 0x7E) { |
| 91 | emit(emitctx, input_chr); |
| 92 | return TRUE; |
| 93 | } else if (input_chr == 0xA5) { |
| 94 | emit(emitctx, 0x5C); |
| 95 | return TRUE; |
| 96 | } else if (input_chr == 0x203E) { |
| 97 | emit(emitctx, 0x7E); |
| 98 | return TRUE; |
| 99 | } else if (input_chr >= 0xFF61 && input_chr <= 0xFF9F) { |
| 100 | emit(emitctx, input_chr - (0xFF61 - 0xA1)); |
| 101 | return TRUE; |
| 102 | } else { |
| 103 | int r, c; |
| 104 | if (unicode_to_jisx0208(input_chr, &r, &c)) { |
| 105 | c += 94 * (r % 2); |
| 106 | r /= 2; |
| 107 | r += 0x81; |
| 108 | if (r >= 0xA0) r += 0xE0 - 0xA0; |
| 109 | c += 0x40; |
| 110 | if (c >= 0x7F) c++; |
| 111 | emit(emitctx, r); |
| 112 | emit(emitctx, c); |
| 113 | return TRUE; |
| 114 | } else { |
| 115 | return FALSE; |
| 116 | } |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | const charset_spec charset_CS_SHIFT_JIS = { |
| 121 | CS_SHIFT_JIS, read_sjis, write_sjis, NULL |
| 122 | }; |
| 123 | |
| 124 | #else /* ENUM_CHARSETS */ |
| 125 | |
| 126 | ENUM_CHARSET(CS_SHIFT_JIS) |
| 127 | |
| 128 | #endif /* ENUM_CHARSETS */ |