diff options
Diffstat (limited to 'strings/ctype.c')
| -rw-r--r-- | strings/ctype.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/strings/ctype.c b/strings/ctype.c index 6b6983ada60..adff69ad680 100644 --- a/strings/ctype.c +++ b/strings/ctype.c @@ -428,3 +428,144 @@ my_charset_is_ascii_compatible(CHARSET_INFO *cs) } return 1; } + + +/* + Convert a string between two character sets. + 'to' must be large enough to store (form_length * to_cs->mbmaxlen) bytes. + + @param to[OUT] Store result here + @param to_length Size of "to" buffer + @param to_cs Character set of result string + @param from Copy from here + @param from_length Length of the "from" string + @param from_cs Character set of the "from" string + @param errors[OUT] Number of conversion errors + + @return Number of bytes copied to 'to' string +*/ + +static uint32 +my_convert_internal(char *to, uint32 to_length, + const CHARSET_INFO *to_cs, + const char *from, uint32 from_length, + const CHARSET_INFO *from_cs, uint *errors) +{ + int cnvres; + my_wc_t wc; + const uchar *from_end= (const uchar*) from + from_length; + char *to_start= to; + uchar *to_end= (uchar*) to + to_length; + my_charset_conv_mb_wc mb_wc= from_cs->cset->mb_wc; + my_charset_conv_wc_mb wc_mb= to_cs->cset->wc_mb; + uint error_count= 0; + + while (1) + { + if ((cnvres= (*mb_wc)(from_cs, &wc, (uchar*) from, from_end)) > 0) + from+= cnvres; + else if (cnvres == MY_CS_ILSEQ) + { + error_count++; + from++; + wc= '?'; + } + else if (cnvres > MY_CS_TOOSMALL) + { + /* + A correct multibyte sequence detected + But it doesn't have Unicode mapping. + */ + error_count++; + from+= (-cnvres); + wc= '?'; + } + else + break; // Not enough characters + +outp: + if ((cnvres= (*wc_mb)(to_cs, wc, (uchar*) to, to_end)) > 0) + to+= cnvres; + else if (cnvres == MY_CS_ILUNI && wc != '?') + { + error_count++; + wc= '?'; + goto outp; + } + else + break; + } + *errors= error_count; + return (uint32) (to - to_start); +} + + +/* + Convert a string between two character sets. + Optimized for quick copying of ASCII characters in the range 0x00..0x7F. + 'to' must be large enough to store (form_length * to_cs->mbmaxlen) bytes. + + @param to[OUT] Store result here + @param to_length Size of "to" buffer + @param to_cs Character set of result string + @param from Copy from here + @param from_length Length of the "from" string + @param from_cs Character set of the "from" string + @param errors[OUT] Number of conversion errors + + @return Number of bytes copied to 'to' string +*/ + +uint32 +my_convert(char *to, uint32 to_length, const CHARSET_INFO *to_cs, + const char *from, uint32 from_length, + const CHARSET_INFO *from_cs, uint *errors) +{ + uint32 length, length2; + /* + If any of the character sets is not ASCII compatible, + immediately switch to slow mb_wc->wc_mb method. + */ + if ((to_cs->state | from_cs->state) & MY_CS_NONASCII) + return my_convert_internal(to, to_length, to_cs, + from, from_length, from_cs, errors); + + length= length2= MY_MIN(to_length, from_length); + +#if defined(__i386__) + /* + Special loop for i386, it allows to refer to a + non-aligned memory block as UINT32, which makes + it possible to copy four bytes at once. This + gives about 10% performance improvement comparing + to byte-by-byte loop. + */ + for ( ; length >= 4; length-= 4, from+= 4, to+= 4) + { + if ((*(uint32*)from) & 0x80808080) + break; + *((uint32*) to)= *((const uint32*) from); + } +#endif /* __i386__ */ + + for (; ; *to++= *from++, length--) + { + if (!length) + { + *errors= 0; + return length2; + } + if (*((unsigned char*) from) > 0x7F) /* A non-ASCII character */ + { + uint32 copied_length= length2 - length; + to_length-= copied_length; + from_length-= copied_length; + return copied_length + my_convert_internal(to, to_length, to_cs, + from, from_length, from_cs, + errors); + } + } + + DBUG_ASSERT(FALSE); // Should never get to here + return 0; // Make compiler happy +} |