Add some basic field width support to printf().

Use it to make "ls" output a bit better. Also sys$spawn now fails with EACCES if the path is not a file that's executable by the current uid/gid.
2025-07-28 04:57:45 +00:00 · 2018-10-27 16:43:03 +02:00 · 2018-10-27 16:43:03 +02:00 · 8f91a47aeb
commit 8f91a47aeb
parent de2fb183cc
8 changed files with 212 additions and 272 deletions
--- a/AK/printf.cpp
+++ b/AK/printf.cpp
@ -0,0 +1,181 @@
+typedef unsigned char byte;
+typedef unsigned short word;
+typedef unsigned int dword;
+
+inline size_t strlen(const char* str)
+{
+    size_t len = 0;
+    while (*(str++))
+        ++len;
+    return len;
+}
+
+static constexpr const char* h = "0123456789abcdef";
+
+template<typename PutChFunc>
+int printHex(PutChFunc putch, char*& bufptr, dword number, byte fields)
+{
+    int ret = 0;
+    byte shr_count = fields * 4;
+    while (shr_count) {
+        shr_count -= 4;
+        putch(bufptr, h[(number >> shr_count) & 0x0F]);
+        ++ret;
+    }
+    return ret;
+}
+
+template<typename PutChFunc>
+int printNumber(PutChFunc putch, char*& bufptr, dword number, bool leftPad, bool zeroPad, dword fieldWidth)
+{
+    dword divisor = 1000000000;
+    char ch;
+    char padding = 1;
+    char buf[16];
+    char* p = buf;
+
+    for (;;) {
+        ch = '0' + (number / divisor);
+        number %= divisor;
+        if (ch != '0')
+            padding = 0;
+        if (!padding || divisor == 1)
+            *(p++) = ch;
+        if (divisor == 1)
+            break;
+        divisor /= 10;
+    }
+
+    size_t numlen = p - buf;
+    if (!fieldWidth)
+        fieldWidth = numlen;
+    if (!leftPad) {
+        for (unsigned i = 0; i < fieldWidth - numlen; ++i) {
+            putch(bufptr, zeroPad ? '0' : ' ');
+        }
+    }
+    for (unsigned i = 0; i < numlen; ++i) {
+        putch(bufptr, buf[i]);
+    }
+    if (leftPad) {
+        for (unsigned i = 0; i < fieldWidth - numlen; ++i) {
+            putch(bufptr, ' ');
+        }
+    }
+
+    return fieldWidth;
+}
+
+template<typename PutChFunc>
+int printString(PutChFunc putch, char*& bufptr, const char* str, bool leftPad, dword fieldWidth)
+{
+    size_t len = strlen(str);
+    if (!fieldWidth)
+        fieldWidth = len;
+    if (!leftPad) {
+        for (unsigned i = 0; i < fieldWidth - len; ++i)
+            putch(bufptr, ' ');
+    }
+    for (unsigned i = 0; i < len; ++i) {
+        putch(bufptr, str[i]);
+    }
+    if (leftPad) {
+        for (unsigned i = 0; i < fieldWidth - len; ++i)
+            putch(bufptr, ' ');
+    }
+    return fieldWidth;
+}
+
+
+template<typename PutChFunc>
+int printSignedNumber(PutChFunc putch, char*& bufptr, int number, bool leftPad, bool zeroPad, dword fieldWidth)
+{
+    if (number < 0) {
+        putch(bufptr, '-');
+        return printNumber(putch, bufptr, 0 - number, leftPad, zeroPad, fieldWidth) + 1;
+    }
+    return printNumber(putch, bufptr, number, leftPad, zeroPad, fieldWidth);
+}
+
+template<typename PutChFunc>
+int printfInternal(PutChFunc putch, char* buffer, const char*& fmt, char*& ap)
+{
+    const char *p;
+
+    int ret = 0;
+    char* bufptr = buffer;
+
+    for (p = fmt; *p; ++p) {
+        bool leftPad = false;
+        bool zeroPad = false;
+        unsigned fieldWidth = 0;
+        if (*p == '%' && *(p + 1)) {
+one_more:
+            ++p;
+            if (*p == ' ') {
+                leftPad = true;
+                if (*(p + 1))
+                    goto one_more;
+            }
+            if (!zeroPad && !fieldWidth && *p == '0') {
+                zeroPad = true;
+                if (*(p + 1))
+                    goto one_more;
+            }
+            if (*p >= '0' && *p <= '9') {
+                fieldWidth *= 10;
+                fieldWidth += *p - '0';
+                if (*(p + 1))
+                    goto one_more;
+            }
+            switch( *p )
+            {
+                case 's':
+                    {
+                        const char* sp = va_arg(ap, const char*);
+                        ret += printString(putch, bufptr, sp ? sp : "(null)", leftPad, fieldWidth);
+                    }
+                    break;
+
+                case 'd':
+                    ret += printSignedNumber(putch, bufptr, va_arg(ap, int), leftPad, zeroPad, fieldWidth);
+                    break;
+
+                case 'u':
+                    ret += printNumber(putch, bufptr, va_arg(ap, dword), leftPad, zeroPad, fieldWidth);
+                    break;
+
+                case 'x':
+                    ret += printHex(putch, bufptr, va_arg(ap, dword), 8);
+                    break;
+
+                case 'w':
+                    ret += printHex(putch, bufptr, va_arg(ap, int), 4);
+                    break;
+
+                case 'b':
+                    ret += printHex(putch, bufptr, va_arg(ap, int), 2);
+                    break;
+
+                case 'c':
+                    putch(bufptr, (char)va_arg(ap, int));
+                    ++ret;
+                    break;
+
+                case 'p':
+                    putch(bufptr, '0');
+                    putch(bufptr, 'x');
+                    ret += 2;
+                    ret += printHex(putch, bufptr, va_arg(ap, dword), 8);
+                    break;
+            }
+        }
+        else {
+            putch(bufptr, *p);
+            ++ret;
+        }
+    }
+    return ret;
+}
+
+