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96 lines
3.0 KiB
96 lines
3.0 KiB
2 years ago
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/*!
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\file b64.c
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\brief This file contains some simple 8bit-to-6bit encoding/deconding routines
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Most of these routines are outdated and should be converted using glibc's equivalent
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routines.
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\date Started 2/22/05
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\author George
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\version\verbatim $Id: b64.c 10711 2011-08-31 22:23:04Z karypis $ \endverbatim
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\verbatim
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$Copyright$
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$License$
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\endverbatim
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*/
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#include "GKlib.h"
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#define B64OFFSET 48 /* This is the '0' number */
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/******************************************************************************
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* Encode 3 '8-bit' binary bytes as 4 '6-bit' characters
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*******************************************************************************/
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void encodeblock(unsigned char *in, unsigned char *out)
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{
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out[0] = (in[0] >> 2);
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out[1] = (((in[0] & 0x03) << 4) | (in[1] >> 4));
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out[2] = (((in[1] & 0x0f) << 2) | (in[2] >> 6));
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out[3] = (in[2] & 0x3f);
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out[0] += B64OFFSET;
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out[1] += B64OFFSET;
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out[2] += B64OFFSET;
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out[3] += B64OFFSET;
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// printf("%c %c %c %c %2x %2x %2x %2x %2x %2x %2x\n", out[0], out[1], out[2], out[3], out[0], out[1], out[2], out[3], in[0], in[1], in[2]);
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}
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/******************************************************************************
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* Decode 4 '6-bit' characters into 3 '8-bit' binary bytes
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*******************************************************************************/
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void decodeblock(unsigned char *in, unsigned char *out)
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{
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in[0] -= B64OFFSET;
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in[1] -= B64OFFSET;
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in[2] -= B64OFFSET;
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in[3] -= B64OFFSET;
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out[0] = (in[0] << 2 | in[1] >> 4);
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out[1] = (in[1] << 4 | in[2] >> 2);
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out[2] = (in[2] << 6 | in[3]);
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}
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/******************************************************************************
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* This function encodes an input array of bytes into a base64 encoding. Memory
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* for the output array is assumed to have been allocated by the calling program
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* and be sufficiently large. The output string is NULL terminated.
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*******************************************************************************/
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void GKEncodeBase64(int nbytes, unsigned char *inbuffer, unsigned char *outbuffer)
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{
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int i, j;
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if (nbytes%3 != 0)
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gk_errexit(SIGERR, "GKEncodeBase64: Input buffer size should be a multiple of 3! (%d)\n", nbytes);
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for (j=0, i=0; i<nbytes; i+=3, j+=4)
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encodeblock(inbuffer+i, outbuffer+j);
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//printf("%d %d\n", nbytes, j);
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outbuffer[j] = '\0';
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}
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/******************************************************************************
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* This function decodes an input array of base64 characters into their actual
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* 8-bit codes. Memory * for the output array is assumed to have been allocated
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* by the calling program and be sufficiently large. The padding is discarded.
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*******************************************************************************/
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void GKDecodeBase64(int nbytes, unsigned char *inbuffer, unsigned char *outbuffer)
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{
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int i, j;
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if (nbytes%4 != 0)
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gk_errexit(SIGERR, "GKDecodeBase64: Input buffer size should be a multiple of 4! (%d)\n", nbytes);
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for (j=0, i=0; i<nbytes; i+=4, j+=3)
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decodeblock(inbuffer+i, outbuffer+j);
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}
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