Algorithm-base64 and uiimage Conversion

Link: http://qzc770707.blog.163.com/blog/static/34082753201022442356502/

 

String storage and reading of uiimage

 

//

// Nsdataadditions. h

// Iostestpro

//

// Created by infohold infohold_mac3 on 13-2-22.

// Copy right (c) 2013YearInfohold infohold_mac3. All rights reserved.

//

 

# Import<Foundation/Foundation. h>

 @ InterfaceNsdata (mbbase64)

// Get nsdata from base64 string

+ (ID) Datawithbase64encodedstring :(Nsstring*) String;// Padding '= 'characters are optional. whitespace is ignored.

// Turn nsdata into base64 string

-(Nsstring*) Base64encoding;

@ End

 

 

 

 

 

// Implementation file

//

// Nsdataadditions. m

// Iostestpro

//

// Created by infohold infohold_mac3 on 13-2-22.

// Copy right (c) 2013YearInfohold infohold_mac3. All rights reserved.

//

 

# Import"Nsdataadditions. H"

 

StaticConstCharEncodingtable [] ="Abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789 + /";

// Encodingtable. Length = 64 = 26 + 26 + 10 + 2

 

@ ImplementationNsdata (mbbase64)

+ (Nsdata*) Datawithbase64encodedstring :(Nsstring*) String

{

// Create a memory buffer containing base64 encoded string data

If(String =Nil)

[NsexceptionRaise:NsinvalidargumentexceptionFormat:Nil];

If([StringLength] =0)

Return[Nsdata Data];

Static Char* Decodingtable =Null;

If(Decodingtable =Null)

{

Decodingtable =Malloc(256);

If(Decodingtable =Null)

Return Nil;

Memset(Decodingtable,Char_max,256);

NsuintegerI;

For(I =0; I <64; I ++)

Decodingtable [(Short)Encodingtable[I] = I;

}

ConstChar* Characters = [StringCstringusingencoding:Nsasciistringencoding];

If(Characters =Null)// Not an ASCII string!

Return Nil;

Char* Bytes =Malloc([StringLength] +3)/4)*3);

If(Bytes =Null)

Return Nil;

NsuintegerLength =0;

NsuintegerI =0;

While(Yes)

{

CharBuffer [4];

ShortBufferlength;

For(Bufferlength =0; Bufferlength <4; I ++)

{

If(Characters [I] ='\ 0')

Break;

If(Isspace(Characters [I]) | characters [I] ='=')

Continue;

Buffer [bufferlength] = decodingtable [(Short) Characters [I];

If(Buffer [bufferlength ++] =Char_max)// Illegal character!

{

Free(Bytes );

Return Nil;

}

}

If(Bufferlength =0)

Break;

If(Bufferlength =1)// At least two characters are needed to produce one byte!

{

Free(Bytes );

Return Nil;

}

// Decode the characters in the buffer to bytes.

Bytes [length ++] = (buffer [0] <2) | (Buffer [1]>4);

If(Bufferlength>2)

Bytes [length ++] = (buffer [1] <4) | (Buffer [2]>2);

If(Bufferlength>3)

Bytes [length ++] = (buffer [2] <6) | Buffer [3];

}

Realloc(Bytes, length );

Return[NsdataDatawithbytesnocopy: BytesLength: Length];

}

 

 

-(Nsstring*) Base64encoding;

{

If([Self Length] =0)

Return @"";

Char* Characters =Malloc((([Self Length] +2)/3)*4);

If(Characters =Null)

Return Nil;

NsuintegerLength =0;

NsuintegerI =0;

While(I <[Self Length])

{

CharBuffer [3] = {0,0,0};

ShortBufferlength =0;

While(Bufferlength <3& I <[Self Length])

Buffer [bufferlength ++] = ((Char*)[Self Bytes]) [I ++];

// Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.

Characters [length ++] =Encodingtable[(Buffer [0] &0xfc)>2];

Characters [length ++] =Encodingtable[(Buffer [0] &0x03) <4) | (Buffer [1] &0xf0)>4)];

If(Bufferlength>1)

Characters [length ++] =Encodingtable[(Buffer [1] &0x0f) <2) | (Buffer [2] &0xc0)>6)];

ElseCharacters [length ++] ='=';

If(Bufferlength>2)

Characters [length ++] =Encodingtable[Buffer [2] &0x3f];

ElseCharacters [length ++] ='=';

}

Return[[[NsstringAlloc]Initwithbytesnocopy: CharactersLength: LengthEncoding:Nsasciistringencodingfreewhendone:Yes]Autorelease];

}

@ End

 

 

TestCode:

-(Void) Viewdidload

{

[SuperViewdidload];

 

Uiimage* M_image = [Uiimage Imagenamed:@ "Pic_1.jpg"];

Nsdata* M_imagedata =Uiimagejpegrepresentation(M_image,1.0f);

Nsstring* M_base64str = [m_imagedataBase64encoding];

Nsdata* M_imagedatafromstring = [Nsdata Datawithbase64encodedstring: M_base64str];

Uiimage* M_imagen = [Uiimage Imagewithdata: M_imagedatafromstring];

Uiimageview* M_imageview = [[Uiimageview Alloc]Initwithimage: M_imagen];

M_imageview.Frame=Cgrectmake(0,0,320,460);

[Self.View Addsubview: M_imageview];

[M_imageviewRelease];

}

 

The end!

2013-02-22