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Diffstat (limited to 'spectro/base64.c')
| -rw-r--r-- | spectro/base64.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/spectro/base64.c b/spectro/base64.c new file mode 100644 index 0000000..388d121 --- /dev/null +++ b/spectro/base64.c @@ -0,0 +1,215 @@ + +/* + * Argyll Color Correction System + * + * Very simple & concise base64 encoder/decoder + * + * Author: Graeme W. Gill + * + * Copyright 2014, Graeme W. Gill + * All rights reserved. + * + * This material is licenced under the GNU GENERAL PUBLIC LICENSE Version 2 or later :- + * see the License2.txt file for licencing details. + */ + + +#include <stdio.h> +# define DLL_LOCAL +#include "base64.h" + +static int enc(int val) { + val &= 0x3f; + + if (val <= 25) + return ('A' + val); + if (val <= 51) + return ('a' + val - 26); + if (val <= 61) + return ('0' + val - 52); + if (val == 62) + return '+'; + return '/'; +} + +/* Encode slen bytes into nul terminated string. */ +/* if dlen is !NULL, then set it to resulting string length excluding nul */ +/* We assume that the destination buffer is long enough at EBASE64LEN */ +void DLL_LOCAL ebase64(int *dlen, char *dst, unsigned char *src, int slen) { + unsigned char buf[3]; + int i, j; + + /* Do this 3 characters at a time */ + for (j = i = 0; i < slen; i += 3) { + int ib; + + /* Grab 3 bytes or zero pad, and count bits */ + buf[0] = src[i]; ib = 8; + buf[1] = (i+1) < slen ? (ib += 8, src[i+1]) : 0; + buf[2] = (i+2) < slen ? (ib += 8, src[i+2]) : 0; + + /* Output up to 4 encoded characters */ + dst[j] = enc(buf[0] >> 2), j++; + if (ib > 6) { + dst[j] = enc(buf[0] << 4 | buf[1] >> 4), j++; + if (ib > 12) { + dst[j] = enc(buf[1] << 2 | buf[2] >> 6), j++; + if (ib > 18) + dst[j] = enc(buf[2]), j++; + } + } + } + if (dlen != NULL) + *dlen = j; + + dst[j++] = '\000'; +} + +/* Return binary value corresponding to encoded character, */ +/* -1 for invalid character, -2 if nul terminator */ +/* (We're assuming ASCII encoding) */ +static int dec(int val) { + val &= 0xff; + + if (val == 0) + return -2; + if (val == '+') + return 62; + if (val == '/') + return 63; + if (val < '0') + return -1; + if (val <= '9') + return val - '0' + 52; + if (val < 'A') + return -1; + if (val <= 'Z') + return val - 'A'; + if (val < 'a') + return -1; + if (val <= 'z') + return val - 'a' + 26; + return -1; +} + +/* Decode nul terminated string into bytes, ignoring illegal characters. */ +/* if dlen is !NULL, then set it to resulting byte length */ +/* We assume that the destination buffer is long enough at DBASE64LEN */ +void DLL_LOCAL dbase64(int *dlen, unsigned char *dst, char *src) { + int buf[4]; + int j; + + /* Do this 4 characters at a time */ + for (j = 0;;) { + int v, ib; + + /* Grab 4 characters skipping illegals, and count bits */ + while ((buf[0] = dec(*src++)) == -1) + ; + if (buf[0] == -2) + break; + ib = 6; + while ((buf[1] = dec(*src++)) == -1) + ; + if (buf[1] != -2) { + ib += 6; + while ((buf[2] = dec(*src++)) == -1) + ; + if (buf[2] != -2) { + ib += 6; + while ((buf[3] = dec(*src++)) == -1) + ; + if (buf[3] != -2) + ib += 6; + else + buf[3] = 0; + } else + buf[2] = 0; + } else + buf[1] = 0; + + /* Output up to 3 decoded bytes */ + dst[j] = buf[0] << 2 | buf[1] >> 4, j++; + if (ib > 12) { + dst[j] = buf[1] << 4 | buf[2] >> 2, j++; + if (ib > 18) { + dst[j] = buf[2] << 6 | buf[3], j++; + continue; /* We didn't run out */ + } + } + break; /* Must be done if didn't continue */ + } + if (dlen != NULL) + *dlen = j; +} + + +#ifdef STANDALONE_TEST +/* test base64 code */ + +#include <numlib.h> + +#define MAXLEN 30 + +int main() { + unsigned char src[MAXLEN], check[MAXLEN]; + char dst[EBASE64LEN(MAXLEN) + 1]; + int n, slen, dlen, chlen, i, j; + + printf("Testing base64 encode/decode:\n"); + + for (n = 0; n < 10000000; n++) { + + /* Create a random binary */ + slen = i_rand(0, MAXLEN); + for (i = 0; i < slen; i++) + src[i] = i_rand(0, 255); + + /* Encode it */ + ebase64(&dlen, dst, src, slen); + + if (dlen != EBASE64LEN(slen)) { + error("%d: Wrong encoded length, src %d, is %d should be %d\n",n,slen,dlen,EBASE64LEN(slen)); + } + + /* Decode it */ + dbase64(&chlen, check, dst); + + if (chlen != DBASE64LEN(dlen)) { + error("%d: Wrong decoded length, enc %d, is %d should be %d\n",n,dlen,chlen,DBASE64LEN(dlen)); + } + + /* Check characters match */ + for (i = 0; i < slen; i++) { + if (src[i] != check[i]) { + for (j = 0; j < slen; j++) { + printf("%02X ",src[j]); + if ((j % 3) == 2) + printf(" "); + } + printf("\n"); + + for (j = 0; j < dlen; j++) { + printf("%c ",dst[j]); + if ((j % 4) == 3) + printf(" "); + } + printf("\n"); + for (j = 0; j < slen; j++) { + printf("%02X ",check[j]); + if ((j % 3) == 2) + printf(" "); + } + printf("\n\n"); + printf("src len %d, dst len %d\n",slen, dlen); + error("%d: Verify error at byte %d, is 0x%x should be 0x%x\n",n,i,check[i],src[i]); + } + } + + if ((n % 10000) == 0) + printf("done %d tests\n",n); + } + printf("Testing %d conversions base64 complete\n",n); +} + +#endif /* STANDALONE_TEST */ |