diff options
Diffstat (limited to 'base64.c')
| -rw-r--r-- | base64.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/base64.c b/base64.c new file mode 100644 index 0000000..55b482f --- /dev/null +++ b/base64.c @@ -0,0 +1,133 @@ +#include <stdlib.h> + +/* + base64.c - by Joe DF (joedf@ahkscript.org) + Released under the MIT License + + Revision: 00:06 2014-09-22 + + Thank you for inspiration: + http://www.codeproject.com/Tips/813146/Fast-base-functions-for-encode-decode +*/ + + +unsigned int b64_int(unsigned int ch); +unsigned int b64e_size(unsigned int in_size); +unsigned int b64d_size(unsigned int in_size); +unsigned int b64_encode(const unsigned int* in, unsigned int in_len, unsigned char* out); +unsigned int b64_decode(const unsigned char* in, unsigned int in_len, unsigned int* out); + + +//Base64 char table - used internally for encoding +unsigned char b64_chr[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; + +//Base64 char table functions - used internally for decoding +unsigned int b64_int(unsigned int ch) { + + // ASCII to base64_int + // 65-90 Upper Case >> 0-25 + // 97-122 Lower Case >> 26-51 + // 48-57 Numbers >> 52-61 + // 43 Plus (+) >> 62 + // 47 Slash (/) >> 63 + // 61 Equal (=) >> 64~ + if (ch==43) + return 62; + if (ch==47) + return 63; + if (ch==61) + return 64; + if ((ch>47) && (ch<58)) + return ch + 4; + if ((ch>64) && (ch<91)) + return ch - 'A'; + if ((ch>96) && (ch<123)) + return (ch - 'a') + 26; + return 0; +} + +// in_size : the number bytes to be encoded. +// Returns the recommended memory size to be allocated for the output buffer excluding the null byte +unsigned int b64e_size(unsigned int in_size) { + + // size equals 4*floor((1/3)*(in_size+2)); + int i, j = 0; + for (i=0;i<in_size;i++) { + if (i % 3 == 0) + j += 1; + } + return (4*j); +} + +// in_size : the number bytes to be decoded. +// Returns the recommended memory size to be allocated for the output buffer excluding the null byte +unsigned int b64d_size(unsigned int in_size) { + + return ((3*in_size)/4); +} + +// in : buffer of "raw" binary to be encoded. +// in_len : number of bytes to be encoded. +// out : pointer to buffer with enough memory, user is responsible for memory allocation, receives null-terminated string +// returns size of output including null byte +unsigned int b64_encode(const unsigned int* in, unsigned int in_len, unsigned char* out) { + + unsigned int i=0, j=0, k=0, s[3]; + + for (i=0;i<in_len;i++) { + s[j++]=*(in+i); + if (j==3) { + out[k+0] = b64_chr[ s[0]>>2 ]; + out[k+1] = b64_chr[ ((s[0]&0x03)<<4)+((s[1]&0xF0)>>4) ]; + out[k+2] = b64_chr[ ((s[1]&0x0F)<<2)+((s[2]&0xC0)>>6) ]; + out[k+3] = b64_chr[ s[2]&0x3F ]; + j=0; k+=4; + } + } + + if (j) { + if (j==1) + s[1] = 0; + out[k+0] = b64_chr[ s[0]>>2 ]; + out[k+1] = b64_chr[ ((s[0]&0x03)<<4)+((s[1]&0xF0)>>4) ]; + if (j==2) + out[k+2] = b64_chr[ ((s[1]&0x0F)<<2) ]; + else + out[k+2] = '='; + out[k+3] = '='; + k+=4; + } + + out[k] = '\0'; + + return k; +} + +// in : buffer of base64 string to be decoded. +// in_len : number of bytes to be decoded. +// out : pointer to buffer with enough memory, user is responsible for memory allocation, receives "raw" binary +// returns size of output excluding null byte +unsigned int b64_decode(const unsigned char* in, unsigned int in_len, unsigned int* out) { + + unsigned int i=0, j=0, k=0, s[4]; + + for (i=0;i<in_len;i++) { + s[j++]=b64_int(*(in+i)); + if (j==4) { + out[k+0] = (s[0]<<2)+((s[1]&0x30)>>4); + if (s[2]!=64) { + out[k+1] = ((s[1]&0x0F)<<4)+((s[2]&0x3C)>>2); + if ((s[3]!=64)) { + out[k+2] = ((s[2]&0x03)<<6)+(s[3]); k+=3; + } else { + k+=2; + } + } else { + k+=1; + } + j=0; + } + } + + return k; +} |