X-Git-Url: http://www.average.org/gitweb/?p=pam_pcsc_cr.git;a=blobdiff_plain;f=base64.c;fp=base64.c;h=d90a927cc42a4a399c028d7d14706e058db21f78;hp=0000000000000000000000000000000000000000;hb=b4ed664ffb6e3f3764fa2b2f4b05437df43d7f19;hpb=b4bd8dfd5d7780bc00f820c3dec7b2a06f47b514 diff --git a/base64.c b/base64.c new file mode 100644 index 0000000..d90a927 --- /dev/null +++ b/base64.c @@ -0,0 +1,262 @@ +/* +cencoder.c - c source to a base64 encoding 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 +*/ + +/* + Modified by Eugene Crosser to fit pam_pcsc_cr project, 2013 +*/ + +#include +#include +/* +cencode.h - c header for a base64 encoding algorithm + +This is part of the libb64 project, and has been placed in the public domain. +For details, see http://sourceforge.net/projects/libb64 +*/ + +/* + Modified by Eugene Crosser to fit pam_pcsc_cr project, 2013 +*/ + +typedef enum +{ + step_A, step_B, step_C +} base64_encodestep; + +typedef struct +{ + base64_encodestep step; + char result; + int stepcount; +} base64_encodestate; + +/* +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 +*/ + +typedef enum +{ + step_a, step_b, step_c, step_d +} base64_decodestep; + +typedef struct +{ + base64_decodestep step; + char plainchar; +} base64_decodestate; + +static void base64_init_encodestate(base64_encodestate* state_in) +{ + state_in->step = step_A; + state_in->result = 0; + state_in->stepcount = 0; +} + +static char base64_encode_value(char value_in) +{ + static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; + if (value_in > 63) return '='; + return encoding[(int)value_in]; +} + +static int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in) +{ + const char* plainchar = plaintext_in; + const char* const plaintextend = plaintext_in + length_in; + char* codechar = code_out; + char result; + char fragment; + + result = state_in->result; + + switch (state_in->step) + { + while (1) + { + case step_A: + if (plainchar == plaintextend) + { + state_in->result = result; + state_in->step = step_A; + return codechar - code_out; + } + fragment = *plainchar++; + result = (fragment & 0x0fc) >> 2; + *codechar++ = base64_encode_value(result); + result = (fragment & 0x003) << 4; + case step_B: + if (plainchar == plaintextend) + { + state_in->result = result; + state_in->step = step_B; + return codechar - code_out; + } + fragment = *plainchar++; + result |= (fragment & 0x0f0) >> 4; + *codechar++ = base64_encode_value(result); + result = (fragment & 0x00f) << 2; + case step_C: + if (plainchar == plaintextend) + { + state_in->result = result; + state_in->step = step_C; + return codechar - code_out; + } + fragment = *plainchar++; + result |= (fragment & 0x0c0) >> 6; + *codechar++ = base64_encode_value(result); + result = (fragment & 0x03f) >> 0; + *codechar++ = base64_encode_value(result); + + ++(state_in->stepcount); + } + } + /* control should not reach here */ + return codechar - code_out; +} + +static int base64_encode_blockend(char* code_out, base64_encodestate* state_in) +{ + char* codechar = code_out; + + switch (state_in->step) + { + case step_B: + *codechar++ = base64_encode_value(state_in->result); + *codechar++ = '='; + *codechar++ = '='; + break; + case step_C: + *codechar++ = base64_encode_value(state_in->result); + *codechar++ = '='; + break; + case step_A: + break; + } + *codechar++ = '\n'; + + return codechar - code_out; +} + +/* +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 +*/ + +static 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]; +} + +static void base64_init_decodestate(base64_decodestate* state_in) +{ + state_in->step = step_a; + state_in->plainchar = 0; +} + +static 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; +} + +int b64_encode(const char *src, const int ssize, + char *const b64, int *const bsize) +{ + base64_encodestate s; + int cnt1, cnt2; + char *c = b64; + + /* FIXME check size */ + base64_init_encodestate(&s); + cnt1 = base64_encode_block(src, ssize, c, &s); + c += cnt1; + cnt2 = base64_encode_blockend(c, &s); + c += cnt2; + *c = 0; + *bsize = cnt1 + cnt2; + return 0; +} + +int b64_decode(const char *b64, char *const dst, int *const dsize) +{ + base64_decodestate s; + int cnt; + + /* FIXME check size */ + base64_init_decodestate(&s); + cnt = base64_decode_block(b64, strlen(b64), dst, &s); + *dsize = cnt; + return 0; +}