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/*
* Copyright (C) 2020-2021 Tomasz Kramkowski <tk@the-tk.com>
* SPDX-License-Identifier: MIT
*/
#include <ctype.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include "common.h"
#include "pack.h"
#include "trace.h"
static void write_val(unsigned char *buf, size_t size, enum pack_endian e, uintmax_t val)
{
for (size_t i = 0; i < size; i++)
buf[i] = (val >> (e == PACK_ENDIAN_LITTLE ? i : size - i - 1) * 8) & 0xff;
}
enum pack_status pack(void *buf_, size_t size, const char *fmt, ...)
{
enum pack_endian endianness = PACK_ENDIAN_BIG;
unsigned char *buf = buf_;
enum pack_status ret = PACK_OK;
size_t offset = 0;
va_list ap;
tr_call("pack(%p, %" PRIuSIZE ", %s, ...)", (void *)buf, size, fmt);
va_start(ap, fmt);
for (int i = 0; fmt[i] != '\0'; i++) {
bool sign;
size_t s;
union { uintmax_t unsigned_; intmax_t signed_; } v;
tr_debug("i: %d, fmt[i]: %c", i, fmt[i]);
sign = islower(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: \
v.sign##_ = va_arg(ap, sign va_type); \
break;
ITYPE_MACROS
#undef T
case PACK_TYPE_PADDING: v.unsigned_ = 0; sign = false; break;
default: SET_AND_GOTO(ret, PACK_FMTINVAL, stop);
}
tr_debug("i: %d, fmt[i]: %c, sign: %ssigned", i, fmt[i], sign ? "" : "un");
s = getsize(fmt[i]);
tr_debug("s: %" PRIuSIZE, s);
if (s == (size_t)-1) SET_AND_GOTO(ret, PACK_FMTINVAL, stop);
if (size - offset < s) SET_AND_GOTO(ret, PACK_TOOSMALL, stop);
if (sign) {
intmax_t n = v.signed_;
tr_debug("val.s: %" PRIdMAX, v.signed_);
if (v.signed_ >= 0) {
v.unsigned_ = n;
} else {
uintmax_t offt = BITMASK(s * 8);
n += 1;
v.unsigned_ = offt + n;
}
}
tr_debug("val.u: %" PRIuMAX, v.unsigned_);
write_val(&buf[offset], s, endianness, v.unsigned_);
offset += s;
}
stop:
va_end(ap);
return ret;
}
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