/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "mysys_priv.h" #include "my_sys.h" #include "mysys_err.h" #include #include #include #include #include "mysql/psi/mysql_file.h" #include "sql_chars.h" /* The code below implements this functionality: - Initializing charset related structures - Loading dynamic charsets - Searching for a proper CHARSET_INFO using charset name, collation name or collation ID - Setting server default character set */ my_bool my_charset_same(const CHARSET_INFO *cs1, const CHARSET_INFO *cs2) { return ((cs1 == cs2) || !strcmp(cs1->csname,cs2->csname)); } static uint get_collation_number_internal(const char *name) { CHARSET_INFO **cs; for (cs= all_charsets; cs < all_charsets + array_elements(all_charsets); cs++) { if ( cs[0] && cs[0]->name && !my_strcasecmp(&my_charset_latin1, cs[0]->name, name)) return cs[0]->number; } return 0; } static void simple_cs_init_functions(CHARSET_INFO *cs) { if (cs->state & MY_CS_BINSORT) cs->coll= &my_collation_8bit_bin_handler; else cs->coll= &my_collation_8bit_simple_ci_handler; cs->cset= &my_charset_8bit_handler; } static int cs_copy_data(CHARSET_INFO *to, CHARSET_INFO *from) { to->number= from->number ? from->number : to->number; if (from->csname) if (!(to->csname= my_once_strdup(from->csname,MYF(MY_WME)))) goto err; if (from->name) if (!(to->name= my_once_strdup(from->name,MYF(MY_WME)))) goto err; if (from->comment) if (!(to->comment= my_once_strdup(from->comment,MYF(MY_WME)))) goto err; if (from->ctype) { if (!(to->ctype= (uchar*) my_once_memdup((char*) from->ctype, MY_CS_CTYPE_TABLE_SIZE, MYF(MY_WME)))) goto err; if (init_state_maps(to)) goto err; } if (from->to_lower) if (!(to->to_lower= (uchar*) my_once_memdup((char*) from->to_lower, MY_CS_TO_LOWER_TABLE_SIZE, MYF(MY_WME)))) goto err; if (from->to_upper) if (!(to->to_upper= (uchar*) my_once_memdup((char*) from->to_upper, MY_CS_TO_UPPER_TABLE_SIZE, MYF(MY_WME)))) goto err; if (from->sort_order) { if (!(to->sort_order= (uchar*) my_once_memdup((char*) from->sort_order, MY_CS_SORT_ORDER_TABLE_SIZE, MYF(MY_WME)))) goto err; } if (from->tab_to_uni) { uint sz= MY_CS_TO_UNI_TABLE_SIZE*sizeof(uint16); if (!(to->tab_to_uni= (uint16*) my_once_memdup((char*)from->tab_to_uni, sz, MYF(MY_WME)))) goto err; } if (from->tailoring) if (!(to->tailoring= my_once_strdup(from->tailoring,MYF(MY_WME)))) goto err; return 0; err: return 1; } static my_bool simple_cs_is_full(CHARSET_INFO *cs) { return ((cs->csname && cs->tab_to_uni && cs->ctype && cs->to_upper && cs->to_lower) && (cs->number && cs->name && (cs->sort_order || (cs->state & MY_CS_BINSORT) ))); } static void copy_uca_collation(CHARSET_INFO *to, CHARSET_INFO *from) { to->cset= from->cset; to->coll= from->coll; to->strxfrm_multiply= from->strxfrm_multiply; to->min_sort_char= from->min_sort_char; to->max_sort_char= from->max_sort_char; to->mbminlen= from->mbminlen; to->mbmaxlen= from->mbmaxlen; to->caseup_multiply= from->caseup_multiply; to->casedn_multiply= from->casedn_multiply; to->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_STRNXFRM | MY_CS_UNICODE; } static int add_collation(CHARSET_INFO *cs) { if (cs->name && (cs->number || (cs->number=get_collation_number_internal(cs->name))) && cs->number < array_elements(all_charsets)) { if (!all_charsets[cs->number]) { if (!(all_charsets[cs->number]= (CHARSET_INFO*) my_once_alloc(sizeof(CHARSET_INFO),MYF(0)))) return MY_XML_ERROR; memset(all_charsets[cs->number], 0, sizeof(CHARSET_INFO)); } if (cs->primary_number == cs->number) cs->state |= MY_CS_PRIMARY; if (cs->binary_number == cs->number) cs->state |= MY_CS_BINSORT; all_charsets[cs->number]->state|= cs->state; if (!(all_charsets[cs->number]->state & MY_CS_COMPILED)) { CHARSET_INFO *newcs= all_charsets[cs->number]; if (cs_copy_data(all_charsets[cs->number],cs)) return MY_XML_ERROR; newcs->caseup_multiply= newcs->casedn_multiply= 1; newcs->levels_for_compare= 1; newcs->levels_for_order= 1; if (!strcmp(cs->csname,"ucs2") ) { #if defined(HAVE_CHARSET_ucs2) && defined(HAVE_UCA_COLLATIONS) copy_uca_collation(newcs, &my_charset_ucs2_unicode_ci); newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII; #endif } else if (!strcmp(cs->csname, "utf8") || !strcmp(cs->csname, "utf8mb3")) { #if defined (HAVE_CHARSET_utf8) && defined(HAVE_UCA_COLLATIONS) copy_uca_collation(newcs, &my_charset_utf8_unicode_ci); newcs->ctype= my_charset_utf8_unicode_ci.ctype; if (init_state_maps(newcs)) return MY_XML_ERROR; #endif } else if (!strcmp(cs->csname, "utf8mb4")) { #if defined (HAVE_CHARSET_utf8mb4) && defined(HAVE_UCA_COLLATIONS) copy_uca_collation(newcs, &my_charset_utf8mb4_unicode_ci); newcs->ctype= my_charset_utf8mb4_unicode_ci.ctype; newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED; #endif } else if (!strcmp(cs->csname, "utf16")) { #if defined (HAVE_CHARSET_utf16) && defined(HAVE_UCA_COLLATIONS) copy_uca_collation(newcs, &my_charset_utf16_unicode_ci); newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII; #endif } else if (!strcmp(cs->csname, "utf32")) { #if defined (HAVE_CHARSET_utf32) && defined(HAVE_UCA_COLLATIONS) copy_uca_collation(newcs, &my_charset_utf32_unicode_ci); newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII; #endif } else { const uchar *sort_order= all_charsets[cs->number]->sort_order; simple_cs_init_functions(all_charsets[cs->number]); newcs->mbminlen= 1; newcs->mbmaxlen= 1; if (simple_cs_is_full(all_charsets[cs->number])) { all_charsets[cs->number]->state |= MY_CS_LOADED; } all_charsets[cs->number]->state|= MY_CS_AVAILABLE; /* Check if case sensitive sort order: A < a < B. We need MY_CS_FLAG for regex library, and for case sensitivity flag for 5.0 client protocol, to support isCaseSensitive() method in JDBC driver */ if (sort_order && sort_order['A'] < sort_order['a'] && sort_order['a'] < sort_order['B']) all_charsets[cs->number]->state|= MY_CS_CSSORT; if (my_charset_is_8bit_pure_ascii(all_charsets[cs->number])) all_charsets[cs->number]->state|= MY_CS_PUREASCII; if (!my_charset_is_ascii_compatible(cs)) all_charsets[cs->number]->state|= MY_CS_NONASCII; } } else { /* We need the below to make get_charset_name() and get_charset_number() working even if a character set has not been really incompiled. The above functions are used for example in error message compiler extra/comp_err.c. If a character set was compiled, this information will get lost and overwritten in add_compiled_collation(). */ CHARSET_INFO *dst= all_charsets[cs->number]; dst->number= cs->number; if (cs->comment) if (!(dst->comment= my_once_strdup(cs->comment,MYF(MY_WME)))) return MY_XML_ERROR; if (cs->csname) if (!(dst->csname= my_once_strdup(cs->csname,MYF(MY_WME)))) return MY_XML_ERROR; if (cs->name) if (!(dst->name= my_once_strdup(cs->name,MYF(MY_WME)))) return MY_XML_ERROR; } cs->number= 0; cs->primary_number= 0; cs->binary_number= 0; cs->name= NULL; cs->state= 0; cs->sort_order= NULL; cs->state= 0; } return MY_XML_OK; } /** Report character set initialization errors and warnings. Be silent by default: no warnings on the client side. */ static void default_reporter(enum loglevel level MY_ATTRIBUTE ((unused)), const char *format MY_ATTRIBUTE ((unused)), ...) { } my_error_reporter my_charset_error_reporter= default_reporter; /** Wrappers for memory functions my_malloc (and friends) with C-compatbile API without extra "myf" argument. */ static void * my_once_alloc_c(size_t size) { return my_once_alloc(size, MYF(MY_WME)); } static void * my_malloc_c(size_t size) { return my_malloc(key_memory_charset_loader, size, MYF(MY_WME)); } static void * my_realloc_c(void *old, size_t size) { return my_realloc(key_memory_charset_loader, old, size, MYF(MY_WME)); } static void my_free_c(void *ptr) { my_free(ptr); } /** Initialize character set loader to use mysys memory management functions. @param loader Loader to initialize */ void my_charset_loader_init_mysys(MY_CHARSET_LOADER *loader) { loader->error[0]= '\0'; loader->once_alloc= my_once_alloc_c; loader->mem_malloc= my_malloc_c; loader->mem_realloc= my_realloc_c; loader->mem_free= my_free_c; loader->reporter= my_charset_error_reporter; loader->add_collation= add_collation; } #define MY_MAX_ALLOWED_BUF 1024*1024 #define MY_CHARSET_INDEX "Index.xml" const char *charsets_dir= NULL; static my_bool my_read_charset_file(MY_CHARSET_LOADER *loader, const char *filename, myf myflags) { uchar *buf; int fd; size_t len, tmp_len; MY_STAT stat_info; if (!my_stat(filename, &stat_info, MYF(myflags)) || ((len= (uint)stat_info.st_size) > MY_MAX_ALLOWED_BUF) || !(buf= (uchar*) my_malloc(key_memory_charset_file, len,myflags))) return TRUE; if ((fd= mysql_file_open(key_file_charset, filename, O_RDONLY, myflags)) < 0) goto error; tmp_len= mysql_file_read(fd, buf, len, myflags); mysql_file_close(fd, myflags); if (tmp_len != len) goto error; if (my_parse_charset_xml(loader, (char *) buf, len)) { my_printf_error(EE_UNKNOWN_CHARSET, "Error while parsing '%s': %s\n", MYF(0), filename, loader->error); goto error; } my_free(buf); return FALSE; error: my_free(buf); return TRUE; } char *get_charsets_dir(char *buf) { const char *sharedir= SHAREDIR; char *res; DBUG_ENTER("get_charsets_dir"); if (charsets_dir != NULL) strmake(buf, charsets_dir, FN_REFLEN-1); else { if (test_if_hard_path(sharedir) || is_prefix(sharedir, DEFAULT_CHARSET_HOME)) strxmov(buf, sharedir, "/", CHARSET_DIR, NullS); else strxmov(buf, DEFAULT_CHARSET_HOME, "/", sharedir, "/", CHARSET_DIR, NullS); } res= convert_dirname(buf,buf,NullS); DBUG_PRINT("info",("charsets dir: '%s'", buf)); DBUG_RETURN(res); } CHARSET_INFO *all_charsets[MY_ALL_CHARSETS_SIZE]={NULL}; CHARSET_INFO *default_charset_info = &my_charset_latin1; void add_compiled_collation(CHARSET_INFO *cs) { DBUG_ASSERT(cs->number < array_elements(all_charsets)); all_charsets[cs->number]= cs; cs->state|= MY_CS_AVAILABLE; } static my_thread_once_t charsets_initialized= MY_THREAD_ONCE_INIT; static my_thread_once_t charsets_template= MY_THREAD_ONCE_INIT; static void init_available_charsets(void) { char fname[FN_REFLEN + sizeof(MY_CHARSET_INDEX)]; MY_CHARSET_LOADER loader; memset(&all_charsets, 0, sizeof(all_charsets)); init_compiled_charsets(MYF(0)); /* Copy compiled charsets */ my_charset_loader_init_mysys(&loader); my_stpcpy(get_charsets_dir(fname), MY_CHARSET_INDEX); my_read_charset_file(&loader, fname, MYF(0)); } void free_charsets(void) { charsets_initialized= charsets_template; } static const char* get_collation_name_alias(const char *name, char *buf, size_t bufsize) { if (!native_strncasecmp(name, "utf8mb3_", 8)) { my_snprintf(buf, bufsize, "utf8_%s", name + 8); return buf; } return NULL; } uint get_collation_number(const char *name) { uint id; char alias[64]; my_thread_once(&charsets_initialized, init_available_charsets); if ((id= get_collation_number_internal(name))) return id; if ((name= get_collation_name_alias(name, alias, sizeof(alias)))) return get_collation_number_internal(name); return 0; } static uint get_charset_number_internal(const char *charset_name, uint cs_flags) { CHARSET_INFO **cs; for (cs= all_charsets; cs < all_charsets + array_elements(all_charsets); cs++) { if ( cs[0] && cs[0]->csname && (cs[0]->state & cs_flags) && !my_strcasecmp(&my_charset_latin1, cs[0]->csname, charset_name)) return cs[0]->number; } return 0; } static const char* get_charset_name_alias(const char *name) { if (!my_strcasecmp(&my_charset_latin1, name, "utf8mb3")) return "utf8"; return NULL; } uint get_charset_number(const char *charset_name, uint cs_flags) { uint id; my_thread_once(&charsets_initialized, init_available_charsets); if ((id= get_charset_number_internal(charset_name, cs_flags))) return id; if ((charset_name= get_charset_name_alias(charset_name))) return get_charset_number_internal(charset_name, cs_flags); return 0; } const char *get_charset_name(uint charset_number) { my_thread_once(&charsets_initialized, init_available_charsets); if (charset_number < array_elements(all_charsets)) { CHARSET_INFO *cs= all_charsets[charset_number]; if (cs && (cs->number == charset_number) && cs->name) return (char*) cs->name; } return "?"; /* this mimics find_type() */ } static CHARSET_INFO * get_internal_charset(MY_CHARSET_LOADER *loader, uint cs_number, myf flags) { char buf[FN_REFLEN]; CHARSET_INFO *cs; DBUG_ASSERT(cs_number < array_elements(all_charsets)); if ((cs= all_charsets[cs_number])) { if (cs->state & MY_CS_READY) /* if CS is already initialized */ return cs; /* To make things thread safe we are not allowing other threads to interfere while we may changing the cs_info_table */ mysql_mutex_lock(&THR_LOCK_charset); if (!(cs->state & (MY_CS_COMPILED|MY_CS_LOADED))) /* if CS is not in memory */ { MY_CHARSET_LOADER loader; strxmov(get_charsets_dir(buf), cs->csname, ".xml", NullS); my_charset_loader_init_mysys(&loader); my_read_charset_file(&loader, buf, flags); } if (cs->state & MY_CS_AVAILABLE) { if (!(cs->state & MY_CS_READY)) { if ((cs->cset->init && cs->cset->init(cs, loader)) || (cs->coll->init && cs->coll->init(cs, loader))) { cs= NULL; } else cs->state|= MY_CS_READY; } } else cs= NULL; mysql_mutex_unlock(&THR_LOCK_charset); } return cs; } CHARSET_INFO *get_charset(uint cs_number, myf flags) { CHARSET_INFO *cs; MY_CHARSET_LOADER loader; if (cs_number == default_charset_info->number) return default_charset_info; my_thread_once(&charsets_initialized, init_available_charsets); if (cs_number >= array_elements(all_charsets)) return NULL; my_charset_loader_init_mysys(&loader); cs= get_internal_charset(&loader, cs_number, flags); if (!cs && (flags & MY_WME)) { char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)], cs_string[23]; my_stpcpy(get_charsets_dir(index_file),MY_CHARSET_INDEX); cs_string[0]='#'; int10_to_str(cs_number, cs_string+1, 10); my_error(EE_UNKNOWN_CHARSET, MYF(0), cs_string, index_file); } return cs; } /** Find collation by name: extended version of get_charset_by_name() to return error messages to the caller. @param loader Character set loader @param name Collation name @param flags Flags @return NULL on error, pointer to collation on success */ CHARSET_INFO * my_collation_get_by_name(MY_CHARSET_LOADER *loader, const char *name, myf flags) { uint cs_number; CHARSET_INFO *cs; my_thread_once(&charsets_initialized, init_available_charsets); cs_number= get_collation_number(name); my_charset_loader_init_mysys(loader); cs= cs_number ? get_internal_charset(loader, cs_number, flags) : NULL; if (!cs && (flags & MY_WME)) { char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)]; my_stpcpy(get_charsets_dir(index_file),MY_CHARSET_INDEX); my_error(EE_UNKNOWN_COLLATION, MYF(0), name, index_file); } return cs; } CHARSET_INFO *get_charset_by_name(const char *cs_name, myf flags) { MY_CHARSET_LOADER loader; my_charset_loader_init_mysys(&loader); return my_collation_get_by_name(&loader, cs_name, flags); } /** Find character set by name: extended version of get_charset_by_csname() to return error messages to the caller. @param loader Character set loader @param name Collation name @param cs_flags Character set flags (e.g. default or binary collation) @param flags Flags @return NULL on error, pointer to collation on success */ CHARSET_INFO * my_charset_get_by_name(MY_CHARSET_LOADER *loader, const char *cs_name, uint cs_flags, myf flags) { uint cs_number; CHARSET_INFO *cs; DBUG_ENTER("get_charset_by_csname"); DBUG_PRINT("enter",("name: '%s'", cs_name)); my_thread_once(&charsets_initialized, init_available_charsets); cs_number= get_charset_number(cs_name, cs_flags); cs= cs_number ? get_internal_charset(loader, cs_number, flags) : NULL; if (!cs && (flags & MY_WME)) { char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)]; my_stpcpy(get_charsets_dir(index_file),MY_CHARSET_INDEX); my_error(EE_UNKNOWN_CHARSET, MYF(0), cs_name, index_file); } DBUG_RETURN(cs); } CHARSET_INFO * get_charset_by_csname(const char *cs_name, uint cs_flags, myf flags) { MY_CHARSET_LOADER loader; my_charset_loader_init_mysys(&loader); return my_charset_get_by_name(&loader, cs_name, cs_flags, flags); } /** Resolve character set by the character set name (utf8, latin1, ...). The function tries to resolve character set by the specified name. If there is character set with the given name, it is assigned to the "cs" parameter and FALSE is returned. If there is no such character set, "default_cs" is assigned to the "cs" and TRUE is returned. @param[in] cs_name Character set name. @param[in] default_cs Default character set. @param[out] cs Variable to store character set. @return FALSE if character set was resolved successfully; TRUE if there is no character set with given name. */ my_bool resolve_charset(const char *cs_name, const CHARSET_INFO *default_cs, const CHARSET_INFO **cs) { *cs= get_charset_by_csname(cs_name, MY_CS_PRIMARY, MYF(0)); if (*cs == NULL) { *cs= default_cs; return TRUE; } return FALSE; } /** Resolve collation by the collation name (utf8_general_ci, ...). The function tries to resolve collation by the specified name. If there is collation with the given name, it is assigned to the "cl" parameter and FALSE is returned. If there is no such collation, "default_cl" is assigned to the "cl" and TRUE is returned. @param[out] cl Variable to store collation. @param[in] cl_name Collation name. @param[in] default_cl Default collation. @return FALSE if collation was resolved successfully; TRUE if there is no collation with given name. */ my_bool resolve_collation(const char *cl_name, const CHARSET_INFO *default_cl, const CHARSET_INFO **cl) { *cl= get_charset_by_name(cl_name, MYF(0)); if (*cl == NULL) { *cl= default_cl; return TRUE; } return FALSE; } /* Escape string with backslashes (\) SYNOPSIS escape_string_for_mysql() charset_info Charset of the strings to Buffer for escaped string to_length Length of destination buffer, or 0 from The string to escape length The length of the string to escape DESCRIPTION This escapes the contents of a string by adding backslashes before special characters, and turning others into specific escape sequences, such as turning newlines into \n and null bytes into \0. NOTE To maintain compatibility with the old C API, to_length may be 0 to mean "big enough" RETURN VALUES (size_t) -1 The escaped string did not fit in the to buffer # The length of the escaped string */ size_t escape_string_for_mysql(const CHARSET_INFO *charset_info, char *to, size_t to_length, const char *from, size_t length) { const char *to_start= to; const char *end, *to_end=to_start + (to_length ? to_length-1 : 2*length); my_bool overflow= FALSE; my_bool use_mb_flag= use_mb(charset_info); for (end= from + length; from < end; from++) { char escape= 0; int tmp_length; if (use_mb_flag && (tmp_length= my_ismbchar(charset_info, from, end))) { if (to + tmp_length > to_end) { overflow= TRUE; break; } while (tmp_length--) *to++= *from++; from--; continue; } /* If the next character appears to begin a multi-byte character, we escape that first byte of that apparent multi-byte character. (The character just looks like a multi-byte character -- if it were actually a multi-byte character, it would have been passed through in the test above.) Without this check, we can create a problem by converting an invalid multi-byte character into a valid one. For example, 0xbf27 is not a valid GBK character, but 0xbf5c is. (0x27 = ', 0x5c = \) */ tmp_length= use_mb_flag ? my_mbcharlen_ptr(charset_info, from, end) : 0; if (tmp_length > 1) escape= *from; else switch (*from) { case 0: /* Must be escaped for 'mysql' */ escape= '0'; break; case '\n': /* Must be escaped for logs */ escape= 'n'; break; case '\r': escape= 'r'; break; case '\\': escape= '\\'; break; case '\'': escape= '\''; break; case '"': /* Better safe than sorry */ escape= '"'; break; case '\032': /* This gives problems on Win32 */ escape= 'Z'; break; } if (escape) { if (to + 2 > to_end) { overflow= TRUE; break; } *to++= '\\'; *to++= escape; } else { if (to + 1 > to_end) { overflow= TRUE; break; } *to++= *from; } } *to= 0; return overflow ? (size_t) -1 : (size_t) (to - to_start); } #ifdef _WIN32 static CHARSET_INFO *fs_cset_cache= NULL; CHARSET_INFO *fs_character_set() { if (!fs_cset_cache) { char buf[10]= "cp"; GetLocaleInfo(LOCALE_SYSTEM_DEFAULT, LOCALE_IDEFAULTANSICODEPAGE, buf+2, sizeof(buf)-3); /* We cannot call get_charset_by_name here because fs_character_set() is executed before LOCK_THD_charset mutex initialization, which is used inside get_charset_by_name. As we're now interested in cp932 only, let's just detect it using strcmp(). */ fs_cset_cache= #ifdef HAVE_CHARSET_cp932 !strcmp(buf, "cp932") ? &my_charset_cp932_japanese_ci : #endif &my_charset_bin; } return fs_cset_cache; } #endif /* Escape apostrophes by doubling them up SYNOPSIS escape_quotes_for_mysql() charset_info Charset of the strings to Buffer for escaped string to_length Length of destination buffer, or 0 from The string to escape length The length of the string to escape quote The quote the buffer will be escaped against DESCRIPTION This escapes the contents of a string by doubling up any character specified by the quote parameter. This is used when the NO_BACKSLASH_ESCAPES SQL_MODE is in effect on the server. NOTE To be consistent with escape_string_for_mysql(), to_length may be 0 to mean "big enough" RETURN VALUES ~0 The escaped string did not fit in the to buffer >=0 The length of the escaped string */ size_t escape_quotes_for_mysql(CHARSET_INFO *charset_info, char *to, size_t to_length, const char *from, size_t length, char quote) { const char *to_start= to; const char *end, *to_end=to_start + (to_length ? to_length-1 : 2*length); my_bool overflow= FALSE; my_bool use_mb_flag= use_mb(charset_info); for (end= from + length; from < end; from++) { int tmp_length; if (use_mb_flag && (tmp_length= my_ismbchar(charset_info, from, end))) { if (to + tmp_length > to_end) { overflow= TRUE; break; } while (tmp_length--) *to++= *from++; from--; continue; } /* We don't have the same issue here with a non-multi-byte character being turned into a multi-byte character by the addition of an escaping character, because we are only escaping the ' character with itself. */ if (*from == quote) { if (to + 2 > to_end) { overflow= TRUE; break; } *to++= quote; *to++= quote; } else { if (to + 1 > to_end) { overflow= TRUE; break; } *to++= *from; } } *to= 0; return overflow ? (ulong)~0 : (ulong) (to - to_start); }