mirror of https://gerrit.osmocom.org/asn1c
256 lines
6.0 KiB
C
256 lines
6.0 KiB
C
/*-
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* Copyright (c) 2003 Lev Walkin <vlm@lionet.info>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <asn_internal.h>
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#include <INTEGER.h>
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#include <ber_codec_prim.h> /* Encoder and decoder of a primitive */
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#include <assert.h>
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#include <errno.h>
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/*
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* INTEGER basic type description.
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*/
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static ber_tlv_tag_t asn_DEF_INTEGER_tags[] = {
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(ASN_TAG_CLASS_UNIVERSAL | (2 << 2))
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};
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asn_TYPE_descriptor_t asn_DEF_INTEGER = {
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"INTEGER",
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ASN__PRIMITIVE_TYPE_free,
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INTEGER_print,
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asn_generic_no_constraint,
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ber_decode_primitive,
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INTEGER_encode_der,
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0, /* Not implemented yet */
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INTEGER_encode_xer,
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0, /* Use generic outmost tag fetcher */
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asn_DEF_INTEGER_tags,
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sizeof(asn_DEF_INTEGER_tags) / sizeof(asn_DEF_INTEGER_tags[0]),
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asn_DEF_INTEGER_tags, /* Same as above */
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sizeof(asn_DEF_INTEGER_tags) / sizeof(asn_DEF_INTEGER_tags[0]),
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0, 0, /* No members */
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0 /* No specifics */
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};
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/*
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* Encode INTEGER type using DER.
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*/
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asn_enc_rval_t
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INTEGER_encode_der(asn_TYPE_descriptor_t *td, void *sptr,
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int tag_mode, ber_tlv_tag_t tag,
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asn_app_consume_bytes_f *cb, void *app_key) {
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INTEGER_t *st = (INTEGER_t *)sptr;
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ASN_DEBUG("%s %s as INTEGER (tm=%d)",
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cb?"Encoding":"Estimating", td->name, tag_mode);
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/*
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* Canonicalize integer in the buffer.
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* (Remove too long sign extension, remove some first 0x00 bytes)
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*/
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if(st->buf) {
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uint8_t *buf = st->buf;
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uint8_t *end1 = buf + st->size - 1;
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int shift;
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/* Compute the number of superfluous leading bytes */
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for(; buf < end1; buf++) {
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/*
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* If the contents octets of an integer value encoding
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* consist of more than one octet, then the bits of the
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* first octet and bit 8 of the second octet:
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* a) shall not all be ones; and
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* b) shall not all be zero.
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*/
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switch(*buf) {
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case 0x00: if((buf[1] & 0x80) == 0)
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continue;
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break;
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case 0xff: if((buf[1] & 0x80))
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continue;
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break;
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}
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break;
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}
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/* Remove leading superfluous bytes from the integer */
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shift = buf - st->buf;
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if(shift) {
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uint8_t *nb = st->buf;
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uint8_t *end;
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st->size -= shift; /* New size, minus bad bytes */
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end = nb + st->size;
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for(; nb < end; nb++, buf++)
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*nb = *buf;
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}
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} /* if(1) */
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return der_encode_primitive(td, sptr, tag_mode, tag, cb, app_key);
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}
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/*
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* INTEGER specific human-readable output.
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*/
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static ssize_t
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INTEGER__dump(const INTEGER_t *st, asn_app_consume_bytes_f *cb, void *app_key) {
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char scratch[32]; /* Enough for 64-bit integer */
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uint8_t *buf = st->buf;
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uint8_t *buf_end = st->buf + st->size;
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signed long accum;
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ssize_t wrote = 0;
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char *p;
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int ret;
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if(st->size == 0) {
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return (cb("0", 1, app_key) < 0) ? -1 : 1;
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}
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/*
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* Advance buf pointer until the start of the value's body.
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* This will make us able to process large integers using simple case,
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* when the actual value is small
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* (0x0000000000abcdef would yield a fine 0x00abcdef)
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*/
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/* Skip the insignificant leading bytes */
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for(; buf < buf_end-1; buf++) {
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switch(*buf) {
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case 0x00: if((buf[1] & 0x80) == 0) continue; break;
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case 0xff: if((buf[1] & 0x80) != 0) continue; break;
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}
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break;
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}
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/* Simple case: the integer size is small */
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if((size_t)(buf_end - buf) <= sizeof(accum)) {
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accum = (*buf & 0x80) ? -1 : 0;
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for(; buf < buf_end; buf++)
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accum = (accum << 8) | *buf;
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ret = snprintf(scratch, sizeof(scratch), "%ld", accum);
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assert(ret > 0 && ret < (int)sizeof(scratch));
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return (cb(scratch, ret, app_key) < 0) ? -1 : ret;
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}
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/* Output in the long xx:yy:zz... format */
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/* TODO: replace with generic algorithm (Knuth TAOCP Vol 2, 4.3.1) */
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for(p = scratch; buf < buf_end; buf++) {
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static const char *h2c = "0123456789ABCDEF";
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if((p - scratch) >= (ssize_t)(sizeof(scratch) - 4)) {
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/* Flush buffer */
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if(cb(scratch, p - scratch, app_key) < 0)
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return -1;
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wrote += p - scratch;
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p = scratch;
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}
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*p++ = h2c[*buf >> 4];
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*p++ = h2c[*buf & 0x0F];
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*p++ = 0x3a; /* ":" */
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}
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if(p != scratch)
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p--; /* Remove the last ":" */
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wrote += p - scratch;
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return (cb(scratch, p - scratch, app_key) < 0) ? -1 : wrote;
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}
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/*
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* INTEGER specific human-readable output.
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*/
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int
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INTEGER_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
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asn_app_consume_bytes_f *cb, void *app_key) {
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const INTEGER_t *st = (const INTEGER_t *)sptr;
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ssize_t ret;
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(void)td;
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(void)ilevel;
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if(!st && !st->buf)
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ret = cb("<absent>", 8, app_key);
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else
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ret = INTEGER__dump(st, cb, app_key);
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return (ret < 0) ? -1 : 0;
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}
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asn_enc_rval_t
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INTEGER_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
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int ilevel, enum xer_encoder_flags_e flags,
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asn_app_consume_bytes_f *cb, void *app_key) {
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const INTEGER_t *st = (const INTEGER_t *)sptr;
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asn_enc_rval_t er;
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(void)ilevel;
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(void)flags;
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if(!st && !st->buf)
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_ASN_ENCODE_FAILED;
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er.encoded = INTEGER__dump(st, cb, app_key);
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if(er.encoded < 0) _ASN_ENCODE_FAILED;
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return er;
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}
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int
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asn_INTEGER2long(const INTEGER_t *iptr, long *lptr) {
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uint8_t *b, *end;
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size_t size;
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long l;
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/* Sanity checking */
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if(!iptr || !iptr->buf || !lptr) {
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errno = EINVAL;
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return -1;
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}
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/* Cache the begin/end of the buffer */
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b = iptr->buf; /* Start of the INTEGER buffer */
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size = iptr->size;
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end = b + size; /* Where to stop */
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if(size > sizeof(long)) {
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uint8_t *end1 = end - 1;
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/*
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* Slightly more advanced processing,
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* able to >sizeof(long) bytes,
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* when the actual value is small
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* (0x0000000000abcdef would yield a fine 0x00abcdef)
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*/
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/* Skip out the insignificant leading bytes */
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for(; b < end1; b++) {
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switch(*b) {
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case 0x00: if((b[1] & 0x80) == 0) continue; break;
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case 0xff: if((b[1] & 0x80) != 0) continue; break;
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}
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break;
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}
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size = end - b;
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if(size > sizeof(long)) {
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/* Still cannot fit the long */
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errno = ERANGE;
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return -1;
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}
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}
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/* Shortcut processing of a corner case */
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if(end == b) {
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*lptr = 0;
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return 0;
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}
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/* Perform the sign initialization */
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/* Actually l = -(*b >> 7); gains nothing, yet unreadable! */
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if((*b >> 7)) l = -1; else l = 0;
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/* Conversion engine */
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for(; b < end; b++)
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l = (l << 8) | *b;
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*lptr = l;
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return 0;
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}
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