55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
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/*
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* Convert an 8-bit input string (e.g. ISO-8859-1) into CESU-8.
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* Calling code supplies the "code page" as a 256-entry array of
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* codepoints for the conversion.
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*
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* This is useful when input data is in non-UTF-8 format and must
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* be converted at runtime, e.g. when compiling non-UTF-8 source
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* code. Another alternative is to use e.g. iconv.
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*/
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#include "duktape.h"
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/* Decode an 8-bit string using 'codepage' into Unicode codepoints and
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* re-encode into CESU-8. Codepage argument must point to a 256-entry
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* table. Only supports BMP (codepoints U+0000 to U+FFFF).
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*/
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void duk_decode_string_codepage(duk_context *ctx, const char *str, size_t len, unsigned int *codepage) {
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unsigned char *tmp;
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size_t tmplen, i;
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unsigned char *p;
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unsigned int cp;
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tmplen = 3 * len; /* max expansion is 1 input byte -> 3 output bytes */
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if (tmplen / 3 != len) {
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/* Temporary buffer length wraps. */
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(void) duk_error(ctx, DUK_ERR_RANGE_ERROR, "input string too long");
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return;
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}
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tmp = (unsigned char *) duk_push_fixed_buffer(ctx, tmplen);
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for (i = 0, p = tmp; i < len; i++) {
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cp = codepage[((unsigned char *) str)[i]] & 0xffffUL;
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if (cp < 0x80UL) {
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*p++ = (unsigned char) cp;
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} else if (cp < 0x800UL) {
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*p++ = (unsigned char) (0xc0 + ((cp >> 6) & 0x1f));
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*p++ = (unsigned char) (0x80 + (cp & 0x3f));
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} else {
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/* In CESU-8 all codepoints in [0x0000,0xFFFF] are
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* allowed, including surrogates.
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*/
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*p++ = (unsigned char) (0xe0 + ((cp >> 12) & 0x0f));
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*p++ = (unsigned char) (0x80 + ((cp >> 6) & 0x3f));
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*p++ = (unsigned char) (0x80 + (cp & 0x3f));
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}
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}
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duk_push_lstring(ctx, (const char *) tmp, (duk_size_t) (p - tmp));
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/* [ ... tmp res ] */
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duk_remove(ctx, -2);
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}
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