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/*
* Copyright (C) 2020-2021 Tomasz Kramkowski <tk@the-tk.com>
* SPDX-License-Identifier: MIT
*/
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include "common.h"
#include "ieee754b.h"
#include "pack.h"
#include "trace.h"
struct dest {
enum pack_type type;
union ptr {
#define T(type, sign, c_type, va_type) sign c_type *type;
ITYPE_MACROS
#undef T
float *f;
double *d;
} ptr;
size_t count;
};
static uintmax_t read_val(const unsigned char *buf, size_t size, enum pack_endian e)
{
uintmax_t val = 0;
for (size_t i = 0; i < size; i++) {
val |= (uintmax_t)(buf[i] & 0xff) << (e == PACK_ENDIAN_LITTLE ? i : size - i - 1) * 8;
}
return val;
}
static intmax_t minval(size_t s)
{
switch (s) {
case 1: return INTMAX_C(-128);
case 2: return INTMAX_C(-32768);
case 4: return INTMAX_C(-2147483648);
default: return -INTMAX_C(9223372036854775807) - 1;
}
}
static void read_fields(struct dest dest, const void *src_, enum pack_endian endianness)
{
union {
uintmax_t unsigned_;
intmax_t signed_;
float f;
double d;
} val;
const unsigned char *src = src_;
size_t s = getsize(dest.type);
for (size_t i = 0; i < dest.count; i++) {
val.unsigned_ =
read_val(&src[s * i], s, endianness);
tr_debug("val.u: %" PRIuMAX ", at: %" PRIuSIZE,
val.unsigned_, s * i);
if (dest.type == PACK_TYPE_FLOAT) {
float f = ieee754b32_deserialise(val.unsigned_);
val.f = f;
tr_debug("val.f: %f", val.f);
} else if (dest.type == PACK_TYPE_DOUBLE) {
double d = ieee754b64_deserialise(val.unsigned_);
val.d = d;
tr_debug("val.d: %f", val.d);
} else if (islower((char)dest.type)) {
intmax_t vals;
if (!(val.unsigned_ & (UINTMAX_C(1) << (s * 8 - 1)))) {
vals = val.unsigned_;
} else {
vals = minval(s);
vals += val.unsigned_ ^ (UINTMAX_C(1) << (s * 8 - 1));
}
val.signed_ = vals;
tr_debug("val.s: %" PRIdMAX, val.signed_);
}
switch (dest.type) {
#define T(type, sign, c_type, va_type) \
case (char)PACK_TYPE_##type: \
dest.ptr.type[i] = val.sign##_; \
break;
ITYPE_MACROS
#undef T
case PACK_TYPE_FLOAT: dest.ptr.f[i] = val.f; break;
case PACK_TYPE_DOUBLE: dest.ptr.d[i] = val.d; break;
case PACK_TYPE_PADDING: break;
case PACK_TYPE_COUNT: return;
}
}
}
enum pack_status unpack(const void *buf_, size_t size, const char *fmt, ...)
{
enum pack_endian endianness = PACK_ENDIAN_BIG;
const unsigned char *buf = buf_;
enum pack_status ret = PACK_OK;
size_t offset = 0;
va_list ap;
tr_call("unpack(%p, %" PRIuSIZE ", %s, ...)", (const void *)buf, size, fmt);
va_start(ap, fmt);
for (int i = 0; fmt[i] != '\0'; i++) {
size_t s;
struct dest dest = { .count = 1 };
tr_debug("i: %d, fmt[i]: %c", i, fmt[i]);
if (isdigit(fmt[i])) {
unsigned long long c;
char *end;
errno = 0;
c = strtoull(&fmt[i], &end, 10);
if ((c == ULLONG_MAX && errno == ERANGE) || c > SIZE_MAX)
SET_AND_GOTO(ret, PACK_FMTINVAL, stop);
dest.count = c;
i += end - &fmt[i];
} else if (fmt[i] == PACK_TYPE_COUNT) {
dest.count = va_arg(ap, size_t);
i++;
}
tr_debug("dest.count: %" PRIuSIZE ", i: %d, fmt[i]: %c", dest.count, i, fmt[i]);
switch (fmt[i]) {
case '>': endianness = PACK_ENDIAN_BIG; continue;
case '<': endianness = PACK_ENDIAN_LITTLE; continue;
#define T(type, sign, c_type, va_type) \
case (char)PACK_TYPE_##type: \
dest.ptr.type = va_arg(ap, sign c_type *); \
break;
ITYPE_MACROS
#undef T
case PACK_TYPE_FLOAT: dest.ptr.f = va_arg(ap, float *); break;
case PACK_TYPE_DOUBLE: dest.ptr.d = va_arg(ap, double *); break;
case PACK_TYPE_PADDING: break;
default: SET_AND_GOTO(ret, PACK_FMTINVAL, stop);
}
dest.type = fmt[i];
s = getsize(dest.type);
tr_debug("s: %" PRIuSIZE, s);
if (s == (size_t)-1) SET_AND_GOTO(ret, PACK_FMTINVAL, stop);
if (size - offset < s * dest.count)
SET_AND_GOTO(ret, PACK_TOOSMALL, stop);
if (dest.type != PACK_TYPE_PADDING)
read_fields(dest, &buf[offset], endianness);
offset += s * dest.count;
}
stop:
va_end(ap);
return ret;
}
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