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Fix decryption of UTF-16 strings (Issue #42)
This commit is contained in:
Michael R Sweet
parent
cfdd6f55d9
commit
3ae95f1545
@ -12,7 +12,8 @@ v1.6.0 - YYYY-MM-DD
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v1.5.3 - YYYY-MM-DD
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-------------------
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- Fixed decryption of PDF files "protected" by 40-bit RC4.
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- Fixed decryption of PDF files "protected" by 40-bit RC4 (Issue #42)
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- Fixed decryption of UTF-16 strings (Issue #42)
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v1.5.2 - 2025-04-12
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123
pdfio-dict.c
123
pdfio-dict.c
@ -465,127 +465,12 @@ pdfioDictGetString(pdfio_dict_t *dict, // I - Dictionary
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else if (value && value->type == PDFIO_VALTYPE_BINARY && value->value.binary.datalen < 4096)
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{
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// Convert binary string to regular string...
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char temp[4096], // Temporary string
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*tempptr; // Pointer into temporary string
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unsigned char *dataptr; // Pointer into the data string
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char temp[4096]; // Temporary UTF-8 string
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if (!(value->value.binary.datalen & 1) && !memcmp(value->value.binary.data, "\376\377", 2))
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if (!(value->value.binary.datalen & 1) && (!memcmp(value->value.binary.data, "\376\377", 2) || !memcmp(value->value.binary.data, "\377\376", 2)))
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{
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// Copy UTF-16 BE
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int ch; // Unicode character
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size_t remaining; // Remaining bytes
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for (dataptr = value->value.binary.data + 2, remaining = value->value.binary.datalen - 2, tempptr = temp; remaining > 1 && tempptr < (temp + sizeof(temp) - 5); dataptr += 2, remaining -= 2)
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{
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ch = (dataptr[0] << 8) | dataptr[1];
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if (ch >= 0xd800 && ch <= 0xdbff && remaining > 3)
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{
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// Multi-word UTF-16 char...
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int lch; // Lower bits
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lch = (dataptr[2] << 8) | dataptr[3];
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if (lch < 0xdc00 || lch >= 0xdfff)
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break;
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ch = (((ch & 0x3ff) << 10) | (lch & 0x3ff)) + 0x10000;
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dataptr += 2;
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remaining -= 2;
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}
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else if (ch >= 0xfffe)
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{
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continue;
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}
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if (ch < 128)
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{
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// ASCII
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*tempptr++ = (char)ch;
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}
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else if (ch < 4096)
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{
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// 2-byte UTF-8
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*tempptr++ = (char)(0xc0 | (ch >> 6));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else if (ch < 65536)
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{
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// 3-byte UTF-8
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*tempptr++ = (char)(0xe0 | (ch >> 12));
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*tempptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else
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{
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// 4-byte UTF-8
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*tempptr++ = (char)(0xe0 | (ch >> 18));
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*tempptr++ = (char)(0x80 | ((ch >> 12) & 0x3f));
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*tempptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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}
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*tempptr = '\0';
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}
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else if (!(value->value.binary.datalen & 1) && !memcmp(value->value.binary.data, "\377\376", 2))
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{
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// Copy UTF-16 LE
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int ch; // Unicode character
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size_t remaining; // Remaining bytes
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for (dataptr = value->value.binary.data + 2, remaining = value->value.binary.datalen - 2, tempptr = temp; remaining > 1 && tempptr < (temp + sizeof(temp) - 5); dataptr += 2, remaining -= 2)
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{
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ch = (dataptr[1] << 8) | dataptr[0];
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if (ch >= 0xd800 && ch <= 0xdbff && remaining > 3)
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{
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// Multi-word UTF-16 char...
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int lch; // Lower bits
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lch = (dataptr[3] << 8) | dataptr[2];
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if (lch < 0xdc00 || lch >= 0xdfff)
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break;
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ch = (((ch & 0x3ff) << 10) | (lch & 0x3ff)) + 0x10000;
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dataptr += 2;
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remaining -= 2;
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}
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else if (ch >= 0xfffe)
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{
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continue;
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}
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if (ch < 128)
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{
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// ASCII
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*tempptr++ = (char)ch;
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}
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else if (ch < 4096)
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{
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// 2-byte UTF-8
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*tempptr++ = (char)(0xc0 | (ch >> 6));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else if (ch < 65536)
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{
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// 3-byte UTF-8
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*tempptr++ = (char)(0xe0 | (ch >> 12));
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*tempptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else
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{
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// 4-byte UTF-8
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*tempptr++ = (char)(0xe0 | (ch >> 18));
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*tempptr++ = (char)(0x80 | ((ch >> 12) & 0x3f));
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*tempptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*tempptr++ = (char)(0x80 | (ch & 0x3f));
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}
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}
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*tempptr = '\0';
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// Copy UTF-16...
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_pdfio_utf16cpy(temp, value->value.binary.data, value->value.binary.datalen, sizeof(temp));
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}
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else
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{
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@ -339,6 +339,7 @@ struct _pdfio_stream_s // Stream
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extern size_t _pdfio_strlcpy(char *dst, const char *src, size_t dstsize) _PDFIO_INTERNAL;
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extern double _pdfio_strtod(pdfio_file_t *pdf, const char *s) _PDFIO_INTERNAL;
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extern void _pdfio_utf16cpy(char *dst, const unsigned char *src, size_t srclen, size_t dstsize) _PDFIO_INTERNAL;
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extern ssize_t _pdfio_vsnprintf(pdfio_file_t *pdf, char *buffer, size_t bufsize, const char *format, va_list ap) _PDFIO_INTERNAL;
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extern bool _pdfioArrayDecrypt(pdfio_file_t *pdf, pdfio_obj_t *obj, pdfio_array_t *a, size_t depth) _PDFIO_INTERNAL;
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@ -158,6 +158,89 @@ _pdfio_strtod(pdfio_file_t *pdf, // I - PDF file
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}
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//
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// '_pdfio_utf16cpy()' - Convert UTF-16 to UTF-8.
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//
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void
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_pdfio_utf16cpy(
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char *dst, // I - Destination buffer for UTF-8
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const unsigned char *src, // I - Source UTF-16
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size_t srclen, // I - Length of UTF-16
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size_t dstsize) // I - Destination buffer size
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{
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char *dstptr = dst, // Pointer into buffer
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*dstend = dst + dstsize - 5; // End of buffer
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int ch; // Unicode character
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bool is_be = !memcmp(src, "\376\377", 2);
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// Big-endian strings?
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// Loop through the UTF-16 string, converting to Unicode then UTF-8...
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for (src += 2, srclen -= 2; srclen > 1 && dstptr < dstend; src += 2, srclen -= 2)
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{
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// Initial character...
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if (is_be)
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ch = (src[0] << 8) | src[1];
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else
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ch = (src[1] << 8) | src[0];
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if (ch >= 0xd800 && ch <= 0xdbff && srclen > 3)
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{
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// Multi-word UTF-16 char...
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int lch; // Lower bits
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if (is_be)
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lch = (src[2] << 8) | src[3];
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else
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lch = (src[3] << 8) | src[2];
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if (lch < 0xdc00 || lch >= 0xdfff)
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break;
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ch = (((ch & 0x3ff) << 10) | (lch & 0x3ff)) + 0x10000;
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src += 2;
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srclen -= 2;
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}
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else if (ch >= 0xfffe)
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{
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continue;
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}
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// Convert Unicode to UTF-8...
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if (ch < 128)
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{
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// ASCII
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*dstptr++ = (char)ch;
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}
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else if (ch < 4096)
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{
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// 2-byte UTF-8
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*dstptr++ = (char)(0xc0 | (ch >> 6));
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*dstptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else if (ch < 65536)
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{
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// 3-byte UTF-8
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*dstptr++ = (char)(0xe0 | (ch >> 12));
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*dstptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*dstptr++ = (char)(0x80 | (ch & 0x3f));
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}
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else
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{
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// 4-byte UTF-8
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*dstptr++ = (char)(0xe0 | (ch >> 18));
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*dstptr++ = (char)(0x80 | ((ch >> 12) & 0x3f));
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*dstptr++ = (char)(0x80 | ((ch >> 6) & 0x3f));
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*dstptr++ = (char)(0x80 | (ch & 0x3f));
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}
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}
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// Nul-terminate the UTF-8 string...
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*dstptr = '\0';
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}
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//
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// '_pdfio_vsnprintf()' - Format a string.
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//
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@ -205,7 +205,26 @@ _pdfioValueDecrypt(pdfio_file_t *pdf, // I - PDF file
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temp[templen] = '\0';
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if ((timeval = get_date_time((char *)temp)) != 0)
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if ((templen & 1) == 0 && (!memcmp(temp, "\376\377", 2) || !memcmp(temp, "\377\376", 2)))
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{
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// Convert UTF-16 to UTF-8...
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char utf8[4096]; // Temporary string
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_pdfio_utf16cpy(utf8, temp, templen, sizeof(utf8));
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if ((timeval = get_date_time((char *)utf8)) != 0)
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{
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// Change the type to date...
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v->type = PDFIO_VALTYPE_DATE;
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v->value.date = timeval;
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}
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else
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{
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// Copy the decrypted string back to the value...
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v->value.string = pdfioStringCreate(pdf, utf8);
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}
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}
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else if ((timeval = get_date_time((char *)temp)) != 0)
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{
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// Change the type to date...
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v->type = PDFIO_VALTYPE_DATE;
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