| /* |
| * Copyright (c) 2005, 2006 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| * Redistribution and modifications are permitted subject to BSD license. |
| */ |
| #include <asn_system.h> |
| #include <asn_internal.h> |
| #include <per_support.h> |
| |
| /* |
| * Extract a small number of bits (<= 31) from the specified PER data pointer. |
| */ |
| int32_t |
| per_get_few_bits(asn_per_data_t *pd, int nbits) { |
| size_t off; /* Next after last bit offset */ |
| uint32_t accum; |
| const uint8_t *buf; |
| |
| if(nbits < 0 || pd->nboff + nbits > pd->nbits) |
| return -1; |
| |
| /* |
| * Normalize position indicator. |
| */ |
| if(pd->nboff >= 8) { |
| pd->buffer += (pd->nboff >> 3); |
| pd->nbits -= (pd->nboff & ~0x07); |
| pd->nboff &= 0x07; |
| } |
| off = (pd->nboff += nbits); |
| buf = pd->buffer; |
| |
| /* |
| * Extract specified number of bits. |
| */ |
| if(off <= 8) |
| accum = nbits ? (buf[0]) >> (8 - off) : 0; |
| else if(off <= 16) |
| accum = ((buf[0] << 8) + buf[1]) >> (16 - off); |
| else if(off <= 24) |
| accum = ((buf[0] << 16) + (buf[1] << 8) + buf[2]) >> (24 - off); |
| else if(off <= 31) |
| accum = ((buf[0] << 24) + (buf[1] << 16) |
| + (buf[2] << 8) + (buf[3])) >> (32 - off); |
| else if(nbits <= 31) { |
| asn_per_data_t tpd = *pd; |
| /* Here are we with our 31-bits limit plus 1..7 bits offset. */ |
| tpd.nboff -= nbits; |
| accum = per_get_few_bits(&tpd, nbits - 24) << 24; |
| accum |= per_get_few_bits(&tpd, 24); |
| } else { |
| pd->nboff -= nbits; /* Oops, revert back */ |
| return -1; |
| } |
| |
| return (accum & (((uint32_t)1 << nbits) - 1)); |
| } |
| |
| /* |
| * Extract a large number of bits from the specified PER data pointer. |
| */ |
| int |
| per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int alright, int nbits) { |
| int32_t value; |
| |
| if(alright && (nbits & 7)) { |
| /* Perform right alignment of a first few bits */ |
| value = per_get_few_bits(pd, nbits & 0x07); |
| if(value < 0) return -1; |
| *dst++ = value; /* value is already right-aligned */ |
| nbits &= ~7; |
| } |
| |
| while(nbits) { |
| if(nbits >= 24) { |
| value = per_get_few_bits(pd, 24); |
| if(value < 0) return -1; |
| *(dst++) = value >> 16; |
| *(dst++) = value >> 8; |
| *(dst++) = value; |
| nbits -= 24; |
| } else { |
| value = per_get_few_bits(pd, nbits); |
| if(value < 0) return -1; |
| if(nbits & 7) { /* implies left alignment */ |
| value <<= 8 - (nbits & 7), |
| nbits += 8 - (nbits & 7); |
| if(nbits > 24) |
| *dst++ = value >> 24; |
| } |
| if(nbits > 16) |
| *dst++ = value >> 16; |
| if(nbits > 8) |
| *dst++ = value >> 8; |
| *dst++ = value; |
| break; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Get the length "n" from the stream. |
| */ |
| ssize_t |
| uper_get_length(asn_per_data_t *pd, int ebits, int *repeat) { |
| ssize_t value; |
| |
| *repeat = 0; |
| |
| if(ebits >= 0) return per_get_few_bits(pd, ebits); |
| |
| value = per_get_few_bits(pd, 8); |
| if(value < 0) return -1; |
| if((value & 128) == 0) /* #10.9.3.6 */ |
| return (value & 0x7F); |
| if((value & 64) == 0) { /* #10.9.3.7 */ |
| value = ((value & 63) << 8) | per_get_few_bits(pd, 8); |
| if(value < 0) return -1; |
| return value; |
| } |
| value &= 63; /* this is "m" from X.691, #10.9.3.8 */ |
| if(value < 1 || value > 4) |
| return -1; |
| *repeat = 1; |
| return (16384 * value); |
| } |
| |
| /* |
| * Get the normally small non-negative whole number. |
| * X.691, #10.6 |
| */ |
| ssize_t |
| uper_get_nsnnwn(asn_per_data_t *pd) { |
| ssize_t value; |
| |
| value = per_get_few_bits(pd, 7); |
| if(value & 64) { /* implicit (value < 0) */ |
| value &= 63; |
| value <<= 2; |
| value |= per_get_few_bits(pd, 2); |
| if(value & 128) /* implicit (value < 0) */ |
| return -1; |
| if(value == 0) |
| return 0; |
| if(value >= 3) |
| return -1; |
| value = per_get_few_bits(pd, 8 * value); |
| return value; |
| } |
| |
| return value; |
| } |
| |
| /* |
| * Put the normally small non-negative whole number. |
| * X.691, #10.6 |
| */ |
| int |
| uper_put_nsnnwn(asn_per_outp_t *po, int n) { |
| int bytes; |
| |
| if(n <= 63) { |
| if(n < 0) return -1; |
| return per_put_few_bits(po, n, 7); |
| } |
| if(n < 256) |
| bytes = 1; |
| else if(n < 65536) |
| bytes = 2; |
| else if(n < 256 * 65536) |
| bytes = 3; |
| else |
| return -1; /* This is not a "normally small" value */ |
| if(per_put_few_bits(po, bytes, 8)) |
| return -1; |
| |
| return per_put_few_bits(po, n, 8 * bytes); |
| } |
| |
| |
| /* |
| * Put a small number of bits (<= 31). |
| */ |
| int |
| per_put_few_bits(asn_per_outp_t *po, uint32_t bits, int obits) { |
| size_t off; /* Next after last bit offset */ |
| size_t omsk; /* Existing last byte meaningful bits mask */ |
| uint8_t *buf; |
| |
| if(obits <= 0 || obits >= 32) return obits ? -1 : 0; |
| |
| /* |
| * Normalize position indicator. |
| */ |
| if(po->nboff >= 8) { |
| po->buffer += (po->nboff >> 3); |
| po->nbits -= (po->nboff & ~0x07); |
| po->nboff &= 0x07; |
| } |
| |
| /* |
| * Flush whole-bytes output, if necessary. |
| */ |
| if(po->nboff + obits > po->nbits) { |
| int complete_bytes = (po->buffer - po->tmpspace); |
| if(po->outper(po->buffer, complete_bytes, po->op_key) < 0) |
| return -1; |
| if(po->nboff) |
| po->tmpspace[0] = po->buffer[0]; |
| po->buffer = po->tmpspace; |
| po->nbits = 8 * sizeof(po->tmpspace); |
| } |
| |
| /* |
| * Now, due to sizeof(tmpspace), we are guaranteed large enough space. |
| */ |
| buf = po->buffer; |
| omsk = ~((1 << (8 - po->nboff)) - 1); |
| off = (po->nboff += obits); |
| |
| /* Clear data of debris before meaningful bits */ |
| bits &= (((uint32_t)1 << obits) - 1); |
| |
| ASN_DEBUG("[PER out %d %u/%x (t=%d,o=%d) %x&%x=%x]", obits, bits, bits, |
| po->nboff - obits, off, buf[0], omsk&0xff, buf[0] & omsk); |
| |
| if(off <= 8) /* Completely within 1 byte */ |
| bits <<= (8 - off), |
| buf[0] = (buf[0] & omsk) | bits; |
| else if(off <= 16) |
| bits <<= (16 - off), |
| buf[0] = (buf[0] & omsk) | (bits >> 8), |
| buf[1] = bits; |
| else if(off <= 24) |
| bits <<= (24 - off), |
| buf[0] = (buf[0] & omsk) | (bits >> 16), |
| buf[1] = bits >> 8, |
| buf[2] = bits; |
| else if(off <= 31) |
| bits <<= (32 - off), |
| buf[0] = (buf[0] & omsk) | (bits >> 24), |
| buf[1] = bits >> 16, |
| buf[2] = bits >> 8, |
| buf[3] = bits; |
| else { |
| ASN_DEBUG("->[PER out split %d]", obits); |
| per_put_few_bits(po, bits >> 8, 24); |
| per_put_few_bits(po, bits, obits - 24); |
| ASN_DEBUG("<-[PER out split %d]", obits); |
| } |
| |
| ASN_DEBUG("[PER out %u/%x => %02x buf+%d]", |
| bits, bits, buf[0], po->buffer - po->tmpspace); |
| |
| return 0; |
| } |
| |
| |
| /* |
| * Output a large number of bits. |
| */ |
| int |
| per_put_many_bits(asn_per_outp_t *po, const uint8_t *src, int nbits) { |
| |
| while(nbits) { |
| uint32_t value; |
| |
| if(nbits >= 24) { |
| value = (src[0] << 16) | (src[1] << 8) | src[2]; |
| src += 3; |
| nbits -= 24; |
| if(per_put_few_bits(po, value, 24)) |
| return -1; |
| } else { |
| value = src[0]; |
| if(nbits > 8) |
| value = (value << 8) | src[1]; |
| if(nbits > 16) |
| value = (value << 8) | src[2]; |
| if(nbits & 0x07) |
| value >>= (8 - (nbits & 0x07)); |
| if(per_put_few_bits(po, value, nbits)) |
| return -1; |
| break; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Put the length "n" (or part of it) into the stream. |
| */ |
| ssize_t |
| uper_put_length(asn_per_outp_t *po, size_t length) { |
| |
| if(length <= 127) /* #10.9.3.6 */ |
| return per_put_few_bits(po, length, 8) |
| ? -1 : (ssize_t)length; |
| else if(length < 16384) /* #10.9.3.7 */ |
| return per_put_few_bits(po, length|0x8000, 16) |
| ? -1 : (ssize_t)length; |
| |
| length >>= 14; |
| if(length > 4) length = 4; |
| |
| return per_put_few_bits(po, 0xC0 | length, 8) |
| ? -1 : (ssize_t)(length << 14); |
| } |
| |