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utf: use unsigned types

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Turns out the people warning about doing signed bitshifts were right
This commit is contained in:
anna 2021-07-14 21:15:07 +02:00
parent befc18f8ff
commit 06d538bc4a
Signed by: fef
GPG key ID: EC22E476DC2D3D84
1 changed files with 6 additions and 3 deletions
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9
src/string/utf.c
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@ -74,7 +74,7 @@ usize utf8_nchr_size(nchar c, error *err)
usize utf8_from_nchr(char *restrict dest, nchar c, error *err)
{
static const char prefixes[] = { 0x00, 0x00, 0xc0, 0xe0, 0xf0 };
static const u8 prefixes[] = { 0x00, 0x00, 0xc0, 0xe0, 0xf0 };
usize utf8_size = utf8_nchr_size(c, err);
catch(err) {
@ -119,7 +119,7 @@ usize utf8_from_nchr(char *restrict dest, nchar c, error *err)
* worth the considerable speed gain from this design.
*/
usize utf8_to_nchr(nchar *dest, const char *restrict utf8chr, error *err)
usize utf8_to_nchr(nchar *dest, const char *restrict _utf8chr, error *err)
{
/* Expected sequence length per the 5 MSBs of the start byte */
static const uint_fast8_t lengths[] = {
@ -133,12 +133,15 @@ usize utf8_to_nchr(nchar *dest, const char *restrict utf8chr, error *err)
/* Error bitmasks for (unused) bytes 2-4 per sequence length */
static const uint_fast8_t emasks[] = { 0x00, 0x03, 0x07, 0x3f, 0xff };
/* signed bitshifts are a bad idea, trust me */
const u8 *restrict utf8chr = (const u8 *restrict)_utf8chr;
uint_fast8_t cshift = 0;
/*
* 0xff bitmask just in case we are on a really odd
* architecture where char is more than one byte
*/
uint_fast8_t len = lengths[(utf8chr[0] >> 3) & 0xff];
uint_fast8_t len = lengths[utf8chr[0] >> 3];
/*
* 7-6: two MSBs of the fourth byte in the sequence, must be 0b10
* 5-4: two MSBs of the third byte in the sequence, must be 0b10