mirror of
https://github.com/fumiama/go-base16384.git
synced 2026-06-05 00:32:52 +08:00
107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
#ifdef __cosmopolitan // always le
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# define be16toh(x) bswap_16(x)
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# define be32toh(x) bswap_32(x)
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# define htobe16(x) bswap_16(x)
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# define htobe32(x) bswap_32(x)
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#else
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#ifdef __linux__
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# include <endian.h>
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#endif
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#ifdef __FreeBSD__
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# include <sys/endian.h>
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#endif
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#ifdef __NetBSD__
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# include <sys/endian.h>
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#endif
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#ifdef __OpenBSD__
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# include <sys/types.h>
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# define be16toh(x) betoh16(x)
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# define be32toh(x) betoh32(x)
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#endif
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#ifdef __MAC_10_0
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# define be16toh(x) ntohs(x)
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# define be32toh(x) ntohl(x)
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# define htobe16(x) ntohs(x)
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# define htobe32(x) htonl(x)
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#endif
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#ifdef _WIN32
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#ifdef WORDS_BIGENDIAN
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# define be16toh(x) (x)
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# define be32toh(x) (x)
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# define htobe16(x) (x)
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# define htobe32(x) (x)
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#else
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# define be16toh(x) _byteswap_ushort(x)
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# define be32toh(x) _byteswap_ulong(x)
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# define htobe16(x) _byteswap_ushort(x)
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# define htobe32(x) _byteswap_ulong(x)
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#endif
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#endif
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#endif
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int base16384_encode(int offset, int outlen, const char* data, int dlen, int dcap, char* buf, int blen, int bcap) {
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uint32_t* vals = (uint32_t*)buf;
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uint32_t n = 0;
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int32_t i = 0;
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for(; i <= dlen - 7; i += 7) {
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register uint32_t sum = 0;
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register uint32_t shift = htobe32(*(uint32_t*)(data+i));
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sum |= (shift>>2) & 0x3fff0000;
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sum |= (shift>>4) & 0x00003fff;
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sum += 0x4e004e00;
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vals[n++] = be32toh(sum);
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shift <<= 26;
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shift &= 0x3c000000;
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sum = 0;
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shift |= (htobe32(*(uint32_t*)(data+i+4))>>6)&0x03fffffc;
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sum |= shift & 0x3fff0000;
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shift >>= 2;
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sum |= shift & 0x00003fff;
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sum += 0x4e004e00;
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vals[n++] = be32toh(sum);
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}
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uint8_t o = offset;
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if(o--) {
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register uint32_t sum = 0x0000003f & (data[i] >> 2);
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sum |= ((uint32_t)data[i] << 14) & 0x0000c000;
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if(o--) {
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sum |= ((uint32_t)data[i + 1] << 6) & 0x00003f00;
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sum |= ((uint32_t)data[i + 1] << 20) & 0x00300000;
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if(o--) {
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sum |= ((uint32_t)data[i + 2] << 12) & 0x000f0000;
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sum |= ((uint32_t)data[i + 2] << 28) & 0xf0000000;
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if(o--) {
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sum |= ((uint32_t)data[i + 3] << 20) & 0x0f000000;
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sum += 0x004e004e;
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#ifdef WORDS_BIGENDIAN
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vals[n++] = __builtin_bswap32(sum);
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#else
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vals[n++] = sum;
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#endif
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sum = (((uint32_t)data[i + 3] << 2)) & 0x0000003c;
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if(o--) {
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sum |= (((uint32_t)data[i + 4] >> 6)) & 0x00000003;
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sum |= ((uint32_t)data[i + 4] << 10) & 0x0000fc00;
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if(o--) {
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sum |= ((uint32_t)data[i + 5] << 2) & 0x00000300;
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sum |= ((uint32_t)data[i + 5] << 16) & 0x003f0000;
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}
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}
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}
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}
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}
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sum += 0x004e004e;
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#ifdef WORDS_BIGENDIAN
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vals[n] = __builtin_bswap32(sum);
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#else
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vals[n] = sum;
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#endif
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buf[outlen - 2] = '=';
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buf[outlen - 1] = offset;
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}
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return outlen;
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}
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