From e58dcfbcd127e00bec22141387037bc58ce8bec8 Mon Sep 17 00:00:00 2001 From: stkhan Date: Mon, 27 Mar 2023 20:57:44 -0500 Subject: init --- utils/nsxiv/utf8.h | 68 ------------------------------------------------------ 1 file changed, 68 deletions(-) delete mode 100644 utils/nsxiv/utf8.h (limited to 'utils/nsxiv/utf8.h') diff --git a/utils/nsxiv/utf8.h b/utils/nsxiv/utf8.h deleted file mode 100644 index a9be2d4..0000000 --- a/utils/nsxiv/utf8.h +++ /dev/null @@ -1,68 +0,0 @@ -/* Branchless UTF-8 decoder - * - * This is free and unencumbered software released into the public domain. - */ -#ifndef UTF8_H -#define UTF8_H - -#include - -/* Decode the next character, C, from BUF, reporting errors in E. - * - * Since this is a branchless decoder, four bytes will be read from the - * buffer regardless of the actual length of the next character. This - * means the buffer _must_ have at least three bytes of zero padding - * following the end of the data stream. - * - * Errors are reported in E, which will be non-zero if the parsed - * character was somehow invalid: invalid byte sequence, non-canonical - * encoding, or a surrogate half. - * - * The function returns a pointer to the next character. When an error - * occurs, this pointer will be a guess that depends on the particular - * error, but it will always advance at least one byte. - */ -static void * -utf8_decode(void *buf, uint32_t *c, int *e) -{ - static const char lengths[] = { - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 3, 3, 4, 0 - }; - static const int masks[] = {0x00, 0x7f, 0x1f, 0x0f, 0x07}; - static const uint32_t mins[] = {4194304, 0, 128, 2048, 65536}; - static const int shiftc[] = {0, 18, 12, 6, 0}; - static const int shifte[] = {0, 6, 4, 2, 0}; - - unsigned char *s = buf; - int len = lengths[s[0] >> 3]; - - /* Compute the pointer to the next character early so that the next - * iteration can start working on the next character. Neither Clang - * nor GCC figure out this reordering on their own. - */ - unsigned char *next = s + len + !len; - - /* Assume a four-byte character and load four bytes. Unused bits are - * shifted out. - */ - *c = (uint32_t)(s[0] & masks[len]) << 18; - *c |= (uint32_t)(s[1] & 0x3f) << 12; - *c |= (uint32_t)(s[2] & 0x3f) << 6; - *c |= (uint32_t)(s[3] & 0x3f) << 0; - *c >>= shiftc[len]; - - /* Accumulate the various error conditions. */ - *e = (*c < mins[len]) << 6; /* non-canonical encoding */ - *e |= ((*c >> 11) == 0x1b) << 7; /* surrogate half? */ - *e |= (*c > 0x10FFFF) << 8; /* out of range? */ - *e |= (s[1] & 0xc0) >> 2; - *e |= (s[2] & 0xc0) >> 4; - *e |= (s[3] ) >> 6; - *e ^= 0x2a; /* top two bits of each tail byte correct? */ - *e >>= shifte[len]; - - return next; -} - -#endif -- cgit v1.2.3