diff options
Diffstat (limited to 'wcsmbs/c8rtomb.c')
| -rw-r--r-- | wcsmbs/c8rtomb.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/wcsmbs/c8rtomb.c b/wcsmbs/c8rtomb.c new file mode 100644 index 0000000000..b564770eb5 --- /dev/null +++ b/wcsmbs/c8rtomb.c @@ -0,0 +1,132 @@ +/* UTF-8 to multibyte conversion. + Copyright (C) 2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <uchar.h> +#include <wchar.h> + + +/* This is the private state used if PS is NULL. */ +static mbstate_t state; + +size_t +c8rtomb (char *s, char8_t c8, mbstate_t *ps) +{ + /* This implementation depends on the converter invoked by wcrtomb not + needing to retain state in either the top most bit of ps->__count or + in ps->__value between invocations. This implementation uses the + top most bit of ps->__count to indicate that trailing code units are + expected and uses ps->__value to store previously seen code units. */ + + wchar_t wc; + + if (ps == NULL) + ps = &state; + + if (s == NULL) + { + /* if 's' is a null pointer, behave as if u8'\0' was passed as 'c8'. If + this occurs for an incomplete code unit sequence, then an error will + be reported below. */ + c8 = u8""[0]; + } + + if (! (ps->__count & 0x80000000)) + { + /* Initial state. */ + if ((c8 >= 0x80 && c8 <= 0xC1) || c8 >= 0xF5) + { + /* An invalid lead code unit. */ + __set_errno (EILSEQ); + return -1; + } + if (c8 >= 0xC2) + { + /* A valid lead code unit. */ + ps->__count |= 0x80000000; + ps->__value.__wchb[0] = c8; + ps->__value.__wchb[3] = 1; + return 0; + } + /* A single byte (ASCII) code unit. */ + wc = c8; + } + else + { + char8_t cu1 = ps->__value.__wchb[0]; + if (ps->__value.__wchb[3] == 1) + { + /* A single lead code unit was previously seen. */ + if ((c8 < 0x80 || c8 > 0xBF) + || (cu1 == 0xE0 && c8 < 0xA0) + || (cu1 == 0xED && c8 > 0x9F) + || (cu1 == 0xF0 && c8 < 0x90) + || (cu1 == 0xF4 && c8 > 0x8F)) + { + /* An invalid second code unit. */ + __set_errno (EILSEQ); + return -1; + } + if (cu1 >= 0xE0) + { + /* A three or four code unit sequence. */ + ps->__value.__wchb[1] = c8; + ++ps->__value.__wchb[3]; + return 0; + } + wc = ((cu1 & 0x1F) << 6) + + (c8 & 0x3F); + } + else + { + char8_t cu2 = ps->__value.__wchb[1]; + /* A three or four byte code unit sequence. */ + if (c8 < 0x80 || c8 > 0xBF) + { + /* An invalid third or fourth code unit. */ + __set_errno (EILSEQ); + return -1; + } + if (ps->__value.__wchb[3] == 2 && cu1 >= 0xF0) + { + /* A four code unit sequence. */ + ps->__value.__wchb[2] = c8; + ++ps->__value.__wchb[3]; + return 0; + } + if (cu1 < 0xF0) + { + wc = ((cu1 & 0x0F) << 12) + + ((cu2 & 0x3F) << 6) + + (c8 & 0x3F); + } + else + { + char8_t cu3 = ps->__value.__wchb[2]; + wc = ((cu1 & 0x07) << 18) + + ((cu2 & 0x3F) << 12) + + ((cu3 & 0x3F) << 6) + + (c8 & 0x3F); + } + } + ps->__count &= 0x7fffffff; + ps->__value.__wch = 0; + } + + return wcrtomb (s, wc, ps); +} |