ios - What algorithm is used in [NSString containString:] this function in ObjC? -

i want make app addressbook, needs add search feature. hope search feature can support string matching, , found [nsstring containstring:] function in nsstring class. in order efficiently, want use string matching algorithm achieve it, kmp. want know algorithm used in function. , can on source code of nsstring function?

thx.

the assembly following:

foundation`-[nsstring containsstring:]: ->  0x10a128954 <+0>:  pushq  %rbp     0x10a128955 <+1>:  movq   %rsp, %rbp     0x10a128958 <+4>:  pushq  %r15     0x10a12895a <+6>:  pushq  %r14     0x10a12895c <+8>:  pushq  %rbx     0x10a12895d <+9>:  pushq  %rax     0x10a12895e <+10>: movq   %rdx, %r14     0x10a128961 <+13>: movq   %rdi, %rbx     0x10a128964 <+16>: movq   0x1836d5(%rip), %rsi      ; "length"     0x10a12896b <+23>: movq   0x19ddee(%rip), %r15      ; (void *)0x000000010a4bb800: objc_msgsend     0x10a128972 <+30>: callq  *%r15     0x10a128975 <+33>: movq   0x185dc4(%rip), %rsi      ; "rangeofstring:options:range:locale:"     0x10a12897c <+40>: movq   $0x0, (%rsp)     0x10a128984 <+48>: xorl   %ecx, %ecx     0x10a128986 <+50>: xorl   %r8d, %r8d     0x10a128989 <+53>: movq   %rbx, %rdi     0x10a12898c <+56>: movq   %r14, %rdx     0x10a12898f <+59>: movq   %rax, %r9     0x10a128992 <+62>: callq  *%r15     0x10a128995 <+65>: movabsq $0x7fffffffffffffff, %rcx ; imm = 0x7fffffffffffffff      0x10a12899f <+75>: cmpq   %rcx, %rax     0x10a1289a2 <+78>: setne  %al     0x10a1289a5 <+81>: addq   $0x8, %rsp     0x10a1289a9 <+85>: popq   %rbx     0x10a1289aa <+86>: popq   %r14     0x10a1289ac <+88>: popq   %r15     0x10a1289ae <+90>: popq   %rbp     0x10a1289af <+91>: retq    

it following algorithm:

- (bool)containsstring:(nsstring *)stringtofind {      if (stringtofind && stringtofind.length < self) {         return (typeof(nsnotfound))[self rangeofstring:stringtofind options:nsliteralsearch range:nsmakerange(0, self.length) locale:nil].location != nsnotfound;     }     return false; } 

p.s. not check if string nil or check length. exactly:

- (bool)containsstring:(nsstring *)stringtofind {      return (typeof(nsnotfound))[self rangeofstring:stringtofind options:nsliteralsearch range:nsmakerange(0, self.length) locale:nil].location != nsnotfound; } 

with no safety checks. don't know why decided add checks w/e..

range of string has following assembly:

foundation`-[nsstring rangeofstring:options:range:locale:]: ->  0x10a031cfd <+0>:   pushq  %rbp     0x10a031cfe <+1>:   movq   %rsp, %rbp     0x10a031d01 <+4>:   pushq  %r15     0x10a031d03 <+6>:   pushq  %r14     0x10a031d05 <+8>:   pushq  %r13     0x10a031d07 <+10>:  pushq  %r12     0x10a031d09 <+12>:  pushq  %rbx     0x10a031d0a <+13>:  subq   $0x48, %rsp     0x10a031d0e <+17>:  movq   %r9, %r15     0x10a031d11 <+20>:  movq   %r8, %r14     0x10a031d14 <+23>:  movq   %rcx, -0x40(%rbp)     0x10a031d18 <+27>:  movq   %rdx, %r13     0x10a031d1b <+30>:  movq   %rsi, -0x48(%rbp)     0x10a031d1f <+34>:  movq   %rdi, %r12     0x10a031d22 <+37>:  movq   0x27a317(%rip), %rsi      ; "length"     0x10a031d29 <+44>:  movq   0x294a30(%rip), %rbx      ; (void *)0x000000010a4bb800: objc_msgsend     0x10a031d30 <+51>:  movq   %r13, %rdi     0x10a031d33 <+54>:  callq  *%rbx     0x10a031d35 <+56>:  movq   %rax, -0x50(%rbp)     0x10a031d39 <+60>:  movq   0x27a300(%rip), %rsi      ; "length"     0x10a031d40 <+67>:  movq   %r12, %rdi     0x10a031d43 <+70>:  callq  *%rbx     0x10a031d45 <+72>:  movq   %rax, %rbx     0x10a031d48 <+75>:  subq   %r15, %rax     0x10a031d4b <+78>:  jb     0x10a031d56               ; <+89>     0x10a031d4d <+80>:  cmpq   %r14, %rax     0x10a031d50 <+83>:  jae    0x10a031e07               ; <+266>     0x10a031d56 <+89>:  callq  0x10a239912               ; symbol stub for: __cfstringnoteerrors     0x10a031d5b <+94>:  testb  %al, %al     0x10a031d5d <+96>:  je     0x10a031e07               ; <+266>     0x10a031d63 <+102>: movl   $0x6, %edi     0x10a031d68 <+107>: callq  0x10a2396b4               ; symbol stub for: _cfexecutablelinkedonorafter     0x10a031d6d <+112>: testb  %al, %al     0x10a031d6f <+114>: je     0x10a031dc5               ; <+200>     0x10a031d71 <+116>: movq   0x281420(%rip), %rax      ; (void *)0x000000010ac5a358: nsexception     0x10a031d78 <+123>: movq   %rax, -0x58(%rbp)     0x10a031d7c <+127>: movq   0x294325(%rip), %rax      ; (void *)0x000000010ac74b38: nsrangeexception     0x10a031d83 <+134>: movq   (%rax), %rax     0x10a031d86 <+137>: movq   %rax, -0x60(%rbp)     0x10a031d8a <+141>: movq   %r12, %rdi     0x10a031d8d <+144>: movq   -0x48(%rbp), %rsi     0x10a031d91 <+148>: callq  0x10a11f7e0               ; _nsmethodexceptionproem     0x10a031d96 <+153>: movq   %rax, %r8     0x10a031d99 <+156>: movq   0x27a288(%rip), %rsi      ; "raise:format:"     0x10a031da0 <+163>: movq   %rbx, 0x8(%rsp)     0x10a031da5 <+168>: movq   %r15, (%rsp)     0x10a031da9 <+172>: leaq   0x2a4e40(%rip), %rcx      ; @"%@: range {%lu, %lu} out of bounds; string length %lu"     0x10a031db0 <+179>: xorl   %eax, %eax     0x10a031db2 <+181>: movq   -0x58(%rbp), %rdi     0x10a031db6 <+185>: movq   -0x60(%rbp), %rdx     0x10a031dba <+189>: movq   %r14, %r9     0x10a031dbd <+192>: callq  *0x29499d(%rip)           ; (void *)0x000000010a4bb800: objc_msgsend     0x10a031dc3 <+198>: jmp    0x10a031e07               ; <+266>     0x10a031dc5 <+200>: movb   0x29326d(%rip), %al       ; rangeofstring:options:range:locale:.warnonce     0x10a031dcb <+206>: testb  %al, %al     0x10a031dcd <+208>: jne    0x10a031e07               ; <+266>     0x10a031dcf <+210>: movb   $0x1, 0x293262(%rip)      ; compare:options:range:locale:.localeclass + 7     0x10a031dd6 <+217>: movq   %r12, %rdi     0x10a031dd9 <+220>: movq   -0x48(%rbp), %rsi     0x10a031ddd <+224>: callq  0x10a11f7e0               ; _nsmethodexceptionproem     0x10a031de2 <+229>: movq   %rax, %rbx     0x10a031de5 <+232>: movq   %r14, %rdi     0x10a031de8 <+235>: movq   %r15, %rsi     0x10a031deb <+238>: callq  0x10a1212f0               ; nsstringfromrange     0x10a031df0 <+243>: movq   %rax, %rcx     0x10a031df3 <+246>: leaq   0x2a4e36(%rip), %rdi      ; @"*** %@: invalid range %@; become exception apps linked on snowleopard. warning shown once per app execution."     0x10a031dfa <+253>: xorl   %eax, %eax     0x10a031dfc <+255>: movq   %rbx, %rsi     0x10a031dff <+258>: movq   %rcx, %rdx     0x10a031e02 <+261>: callq  0x10a06c78a               ; nslog     0x10a031e07 <+266>: testq  %r13, %r13     0x10a031e0a <+269>: jne    0x10a031e5e               ; <+353>     0x10a031e0c <+271>: callq  0x10a239912               ; symbol stub for: __cfstringnoteerrors     0x10a031e11 <+276>: testb  %al, %al     0x10a031e13 <+278>: je     0x10a031e5e               ; <+353>     0x10a031e15 <+280>: movq   0x28137c(%rip), %rax      ; (void *)0x000000010ac5a358: nsexception     0x10a031e1c <+287>: movq   %rax, -0x58(%rbp)     0x10a031e20 <+291>: movq   0x294241(%rip), %rax      ; (void *)0x000000010ac74b40: nsinvalidargumentexception     0x10a031e27 <+298>: movq   (%rax), %rax     0x10a031e2a <+301>: movq   %rax, -0x60(%rbp)     0x10a031e2e <+305>: movq   %r12, %rdi     0x10a031e31 <+308>: movq   -0x48(%rbp), %rsi     0x10a031e35 <+312>: callq  0x10a11f7e0               ; _nsmethodexceptionproem     0x10a031e3a <+317>: movq   %rax, %rbx     0x10a031e3d <+320>: movq   0x27a1e4(%rip), %rsi      ; "raise:format:"     0x10a031e44 <+327>: leaq   0x2a4dc5(%rip), %rcx      ; @"%@: nil argument"     0x10a031e4b <+334>: xorl   %eax, %eax     0x10a031e4d <+336>: movq   -0x58(%rbp), %rdi     0x10a031e51 <+340>: movq   -0x60(%rbp), %rdx     0x10a031e55 <+344>: movq   %rbx, %r8     0x10a031e58 <+347>: callq  *0x294902(%rip)           ; (void *)0x000000010a4bb800: objc_msgsend     0x10a031e5e <+353>: movq   0x10(%rbp), %r9     0x10a031e62 <+357>: movq   -0x40(%rbp), %rcx     0x10a031e66 <+361>: testb  $0x4, %ch     0x10a031e69 <+364>: jne    0x10a031ebe               ; <+449>     0x10a031e6b <+366>: movabsq $0x7fffffffffffffff, %rbx ; imm = 0x7fffffffffffffff      0x10a031e75 <+376>: xorl   %edx, %edx     0x10a031e77 <+378>: testq  %r15, %r15     0x10a031e7a <+381>: je     0x10a031ede               ; <+481>     0x10a031e7c <+383>: cmpq   $0x0, -0x50(%rbp)     0x10a031e81 <+388>: je     0x10a031ede               ; <+481>     0x10a031e83 <+390>: leaq   (,%rcx,8), %r8     0x10a031e8b <+398>: notl   %r8d     0x10a031e8e <+401>: andq   $0x10, %r8     0x10a031e92 <+405>: orq    %rcx, %r8     0x10a031e95 <+408>: leaq   -0x38(%rbp), %rax     0x10a031e99 <+412>: movq   %rax, (%rsp)     0x10a031e9d <+416>: movq   %r12, %rdi     0x10a031ea0 <+419>: movq   %r13, %rsi     0x10a031ea3 <+422>: movq   %r14, %rdx     0x10a031ea6 <+425>: movq   %r15, %rcx     0x10a031ea9 <+428>: callq  0x10a239354               ; symbol stub for: cfstringfindwithoptionsandlocale     0x10a031eae <+433>: xorl   %edx, %edx     0x10a031eb0 <+435>: testb  %al, %al     0x10a031eb2 <+437>: je     0x10a031ede               ; <+481>     0x10a031eb4 <+439>: movq   -0x38(%rbp), %rbx     0x10a031eb8 <+443>: movq   -0x30(%rbp), %rdx     0x10a031ebc <+447>: jmp    0x10a031ede               ; <+481>     0x10a031ebe <+449>: movq   0x27c873(%rip), %rsi      ; "_rangeofregularexpressionpattern:options:range:locale:"     0x10a031ec5 <+456>: movq   %r9, (%rsp)     0x10a031ec9 <+460>: movq   %r12, %rdi     0x10a031ecc <+463>: movq   %r13, %rdx     0x10a031ecf <+466>: movq   %r14, %r8     0x10a031ed2 <+469>: movq   %r15, %r9     0x10a031ed5 <+472>: callq  *0x294885(%rip)           ; (void *)0x000000010a4bb800: objc_msgsend     0x10a031edb <+478>: movq   %rax, %rbx     0x10a031ede <+481>: movq   %rbx, %rax     0x10a031ee1 <+484>: addq   $0x48, %rsp     0x10a031ee5 <+488>: popq   %rbx     0x10a031ee6 <+489>: popq   %r12     0x10a031ee8 <+491>: popq   %r13     0x10a031eea <+493>: popq   %r14     0x10a031eec <+495>: popq   %r15     0x10a031eee <+497>: popq   %rbp     0x10a031eef <+498>: retq    

it runs regular expression check if 1 string has , has safety checks..