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-rw-r--r--src/per_support.c318
1 files changed, 318 insertions, 0 deletions
diff --git a/src/per_support.c b/src/per_support.c
new file mode 100644
index 0000000..c834419
--- /dev/null
+++ b/src/per_support.c
@@ -0,0 +1,318 @@
+/*
+ * 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;
+
+ ASN_DEBUG("[PER get %d bits from %p+%d bits]",
+ nbits, pd->buffer, pd->nboff);
+
+ /*
+ * 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;
+
+ ASN_DEBUG("[PER put %d bits to %p+%d bits]",
+ obits, po->buffer, po->nboff);
+
+ /*
+ * 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);
+ po->flushed_bytes += complete_bytes;
+ }
+
+ /*
+ * 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);
+}
+
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