diff --git a/README.md b/README.md index a4bb029..c1771ad 100644 --- a/README.md +++ b/README.md @@ -1,7 +1,10 @@ -libb64: Base64 Encoding C Routine -================================= +libb64: Base64 C Routines +========================= -From project: (latest CVS source from ) +From projects: + +- +- (latest CVS source from ) LICENSE: -------- @@ -18,8 +21,8 @@ Major changes: -------------- - Use macro instead of function to encode each value -- Line breaks disabled by default -- Include fixed for iOS build +- Line breaks disabled in cencode.c by default +- Flatter include statements to make iOS build easier Other versions: --------------- diff --git a/cdecode.c b/cdecode.c new file mode 100644 index 0000000..5e5f588 --- /dev/null +++ b/cdecode.c @@ -0,0 +1,88 @@ +/* +cdecoder.c - c source to a base64 decoding algorithm implementation + +This is part of the libb64 project, and has been placed in the public domain. +For details, see http://sourceforge.net/projects/libb64 +*/ + +#include "cdecode.h" + +int base64_decode_value(char value_in) +{ + static const char decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51}; + static const char decoding_size = sizeof(decoding); + value_in -= 43; + if (value_in < 0 || value_in >= decoding_size) return -1; + return decoding[(int)value_in]; +} + +void base64_init_decodestate(base64_decodestate* state_in) +{ + state_in->step = step_a; + state_in->plainchar = 0; +} + +int base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in) +{ + const char* codechar = code_in; + char* plainchar = plaintext_out; + char fragment; + + *plainchar = state_in->plainchar; + + switch (state_in->step) + { + while (1) + { + case step_a: + do { + if (codechar == code_in+length_in) + { + state_in->step = step_a; + state_in->plainchar = *plainchar; + return plainchar - plaintext_out; + } + fragment = (char)base64_decode_value(*codechar++); + } while (fragment < 0); + *plainchar = (fragment & 0x03f) << 2; + case step_b: + do { + if (codechar == code_in+length_in) + { + state_in->step = step_b; + state_in->plainchar = *plainchar; + return plainchar - plaintext_out; + } + fragment = (char)base64_decode_value(*codechar++); + } while (fragment < 0); + *plainchar++ |= (fragment & 0x030) >> 4; + *plainchar = (fragment & 0x00f) << 4; + case step_c: + do { + if (codechar == code_in+length_in) + { + state_in->step = step_c; + state_in->plainchar = *plainchar; + return plainchar - plaintext_out; + } + fragment = (char)base64_decode_value(*codechar++); + } while (fragment < 0); + *plainchar++ |= (fragment & 0x03c) >> 2; + *plainchar = (fragment & 0x003) << 6; + case step_d: + do { + if (codechar == code_in+length_in) + { + state_in->step = step_d; + state_in->plainchar = *plainchar; + return plainchar - plaintext_out; + } + fragment = (char)base64_decode_value(*codechar++); + } while (fragment < 0); + *plainchar++ |= (fragment & 0x03f); + } + } + /* control should not reach here */ + return plainchar - plaintext_out; +} + diff --git a/cdecode.h b/cdecode.h new file mode 100644 index 0000000..5729853 --- /dev/null +++ b/cdecode.h @@ -0,0 +1,29 @@ +/* +cdecode.h - c header for a base64 decoding algorithm + +This is part of the libb64 project, and has been placed in the public domain. +For details, see http://sourceforge.net/projects/libb64 +*/ + +#ifndef BASE64_CDECODE_H +#define BASE64_CDECODE_H + +typedef enum +{ + step_a, step_b, step_c, step_d +} base64_decodestep; + +typedef struct +{ + base64_decodestep step; + char plainchar; +} base64_decodestate; + +void base64_init_decodestate(base64_decodestate* state_in); + +int base64_decode_value(char value_in); + +int base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in); + +#endif /* BASE64_CDECODE_H */ +