/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/weaken.h"
#include "libc/fmt/conv.h"
#include "libc/fmt/fmt.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/oldutf16.internal.h"
#include "libc/str/str.h"
#include "libc/str/tpdecodecb.internal.h"
#include "libc/sysv/errfuns.h"
/**
* String / file / stream decoder.
*
* This scanf implementation is able to tokenize strings containing
* 8-bit through 128-bit integers (with validation), floating point
* numbers, etc. It can also be used to convert UTF-8 to UTF-16/32.
*
* - `%d` parses integer
* - `%ms` parses string allocating buffer assigning pointer
*
* @param callback supplies UTF-8 characters using -1 sentinel
* @param fmt is a computer program embedded inside a c string, written
* in a domain-specific programming language that, by design, lacks
* Turing-completeness
* @param va points to the variadic argument state
* @see libc/fmt/pflink.h (dynamic memory is not a requirement)
*/
int vcscanf(int callback(void *), int unget(int, void *), void *arg,
const char *fmt, va_list va) {
struct FreeMe {
struct FreeMe *next;
void *ptr;
} *freeme = NULL;
const unsigned char *p = (const unsigned char *)fmt;
unsigned i = 0;
int items = 0;
int c = callback(arg);
while (c != -1) {
switch (p[i++]) {
case '\0':
if (c != -1 && unget) {
unget(c, arg);
}
goto Done;
case ' ':
case '\t':
case '\n':
case '\r':
case '\v':
while (isspace(c)) {
c = callback(arg);
}
break;
case '%': {
uint128_t number;
void *buf;
size_t bufsize;
unsigned width = 0;
unsigned char bits = 32;
unsigned char charbytes = sizeof(char);
unsigned char diglet;
unsigned char base;
unsigned char prefix;
bool rawmode = false;
bool issigned = false;
bool ismalloc = false;
bool isneg = false;
bool thousands = false;
bool discard = false;
for (;;) {
switch (p[i++]) {
case '%': /* %% → % */
goto NonDirectiveCharacter;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
width *= 10;
width += p[i - 1] - '0';
break;
case '*':
discard = true;
break;
case 'm':
ismalloc = true;
break;
case 'c':
rawmode = true;
if (!width) width = 1;
/* εpsilon transition */
case 's':
goto DecodeString;
case '\'':
thousands = true;
break;
case 'j': /* j=64-bit jj=128-bit */
if (bits < 64) {
bits = 64;
} else {
bits = 128;
}
break;
case 'l': /* long */
case 'L': /* loooong */
charbytes = sizeof(wchar_t);
/* fallthrough */
case 't': /* ptrdiff_t */
case 'Z': /* size_t */
case 'z': /* size_t */
bits = 64;
break;
case 'h': /* short and char */
charbytes = sizeof(char16_t);
bits >>= 1;
break;
case 'b': /* binary */
base = 2;
prefix = 'b';
goto ConsumeBasePrefix;
case 'p': /* pointer (NexGen32e) */
bits = 48;
/* fallthrough */
case 'x':
case 'X': /* hexadecimal */
base = 16;
prefix = 'x';
goto ConsumeBasePrefix;
case 'o': /* octal */
base = 8;
goto DecodeNumber;
case 'd': /* decimal */
case 'n': /* TODO(jart): flexidecimal */
issigned = true;
if (c == '+' || (isneg = c == '-')) {
c = callback(arg);
}
/* εpsilon transition */
case 'u':
base = 10;
goto DecodeNumber;
default:
items = einval();
goto Done;
}
}
ConsumeBasePrefix:
if (c == '0') {
c = callback(arg);
if (c == prefix || c == prefix + ('a' - 'A')) {
c = callback(arg);
}
}
DecodeNumber:
if (c != -1) {
number = 0;
do {
diglet = kBase36[(unsigned char)c];
if (1 <= diglet && diglet <= base) {
number *= base;
number += diglet - 1;
} else if (thousands && diglet == ',') {
/* ignore */
} else {
break;
}
} while ((c = callback(arg)) != -1);
if (!discard) {
uint128_t bane = (uint128_t)1 << (bits - 1);
if (!(number & ~((bane - 1) | (issigned ? 0 : bane))) ||
(issigned && number == bane /* two's complement bane */)) {
++items;
} else {
items = erange();
goto Done;
}
if (issigned && isneg) {
number = ~number + 1;
}
void *out = va_arg(va, void *);
switch (bits) {
case sizeof(uint128_t) * CHAR_BIT:
*(uint128_t *)out = number;
break;
case 48:
case 64:
*(uint64_t *)out = (uint64_t)number;
break;
case 32:
*(uint32_t *)out = (uint32_t)number;
break;
case 16:
*(uint16_t *)out = (uint16_t)number;
break;
case 8:
default:
*(uint8_t *)out = (uint8_t)number;
break;
}
}
}
continue;
DecodeString:
bufsize = !width ? 32 : rawmode ? width : width + 1;
if (discard) {
buf = NULL;
} else if (ismalloc) {
buf = weaken(malloc)(bufsize * charbytes);
struct FreeMe *entry;
if (buf && (entry = weaken(calloc)(1, sizeof(struct FreeMe)))) {
entry->ptr = buf;
entry->next = freeme;
freeme = entry;
}
} else {
buf = va_arg(va, void *);
}
if (buf) {
size_t j = 0;
for (;;) {
if (ismalloc && !width && j + 2 + 1 >= bufsize &&
!weaken(__grow)(&buf, &bufsize, charbytes, 0)) {
width = bufsize - 1;
}
if (c != -1 && j + !rawmode < bufsize && (rawmode || !isspace(c))) {
if (charbytes == 1) {
((unsigned char *)buf)[j++] = (unsigned char)c;
c = callback(arg);
} else if (tpdecodecb((wint_t *)&c, c, (void *)callback, arg) !=
-1) {
if (charbytes == sizeof(char16_t)) {
j += abs(pututf16(&((char16_t *)buf)[j], bufsize - j - 1, c,
false));
} else {
((wchar_t *)buf)[j++] = (wchar_t)c;
}
c = callback(arg);
}
} else {
if (!rawmode && j < bufsize) {
if (charbytes == sizeof(char)) {
((unsigned char *)buf)[j] = '\0';
} else if (charbytes == sizeof(char16_t)) {
((char16_t *)buf)[j] = u'\0';
} else if (charbytes == sizeof(wchar_t)) {
((wchar_t *)buf)[j] = L'\0';
}
}
break;
}
}
++items;
if (ismalloc) {
*va_arg(va, char **) = buf;
}
} else {
do {
if (isspace(c)) break;
} while ((c = callback(arg)) != -1);
}
break;
}
default:
NonDirectiveCharacter:
c = (c == p[i - 1]) ? callback(arg) : -1;
break;
}
}
Done:
while (freeme && weaken(free)) {
struct FreeMe *entry = freeme;
freeme = entry->next;
if (items == -1) weaken(free)(entry->ptr);
weaken(free)(entry);
}
return items;
}