strformat.c

#include <strformat.h>

#define HAVE_DOUBLE

#define HAVE_LONGLONG
#ifndef LARGEST_SIGNED
#ifdef HAVE_LONGLONG
#define LARGEST_SIGNED long long int
#else
#define LARGEST_UNSIGNED long int
#endif
#endif

#ifndef LARGEST_UNSIGNED
#ifdef HAVE_LONGLONG
#define LARGEST_UNSIGNED unsigned long long int
#else
#define LARGEST_UNSIGNED unsigned long int
#endif
#endif

#ifndef POINTER_INT
#define POINTER_INT unsigned long
#endif

typedef unsigned int FormatFlags;

#define MAKE_MASK(shift,size) (((1 << size) - 1) << (shift))

#define JUSTIFY_SHIFT   0
#define JUSTIFY_SIZE    1
#define JUSTIFY_RIGHT   0x0000
#define JUSTIFY_LEFT    0x0001
#define JUSTIFY_MASK    MAKE_MASK(JUSTIFY_SHIFT,JUSTIFY_SIZE)


/* How a positive number is prefixed */
#define POSITIVE_SHIFT  (JUSTIFY_SHIFT + JUSTIFY_SIZE)
#define POSITIVE_NONE   (0x0000 << POSITIVE_SHIFT)
#define POSITIVE_SPACE  (0x0001 << POSITIVE_SHIFT)
#define POSITIVE_PLUS   (0x0003 << POSITIVE_SHIFT)
#define POSITIVE_MASK   MAKE_MASK(POSITIVE_SHIFT, POSITIVE_SIZE)

#define POSITIVE_SIZE   2

#define ALTERNATE_FORM_SHIFT (POSITIVE_SHIFT + POSITIVE_SIZE)
#define ALTERNATE_FORM_SIZE 1
#define ALTERNATE_FORM  (0x0001 << ALTERNATE_FORM_SHIFT)


#define PAD_SHIFT       (ALTERNATE_FORM_SHIFT + ALTERNATE_FORM_SIZE)
#define PAD_SIZE        1
#define PAD_SPACE       (0x0000 << PAD_SHIFT)
#define PAD_ZERO        (0x0001 << PAD_SHIFT)

#define SIZE_SHIFT      (PAD_SHIFT + PAD_SIZE)
#define SIZE_SIZE       3
#define SIZE_CHAR       (0x0001 << SIZE_SHIFT)
#define SIZE_SHORT      (0x0002 << SIZE_SHIFT)
#define SIZE_INT        (0x0000 << SIZE_SHIFT)
#define SIZE_LONG       (0x0003 << SIZE_SHIFT)
#define SIZE_LONGLONG   (0x0004 << SIZE_SHIFT)
#define SIZE_MASK       MAKE_MASK(SIZE_SHIFT,SIZE_SIZE)

#define CONV_SHIFT      (SIZE_SHIFT + SIZE_SIZE)
#define CONV_SIZE       3
#define CONV_INTEGER    (0x0001 << CONV_SHIFT)
#define CONV_FLOAT      (0x0002 << CONV_SHIFT)
#define CONV_POINTER    (0x0003 << CONV_SHIFT)
#define CONV_STRING     (0x0004 << CONV_SHIFT)
#define CONV_CHAR       (0x0005 << CONV_SHIFT)
#define CONV_PERCENT    (0x0006 << CONV_SHIFT)
#define CONV_WRITTEN    (0x0007 << CONV_SHIFT)
#define CONV_MASK       MAKE_MASK(CONV_SHIFT, CONV_SIZE)

#define RADIX_SHIFT     (CONV_SHIFT + CONV_SIZE)
#define RADIX_SIZE      2
#define RADIX_DECIMAL   (0x0001 << RADIX_SHIFT)
#define RADIX_OCTAL     (0x0002 << RADIX_SHIFT)
#define RADIX_HEX       (0x0003 << RADIX_SHIFT)
#define RADIX_MASK      MAKE_MASK(RADIX_SHIFT,RADIX_SIZE)

#define SIGNED_SHIFT    (RADIX_SHIFT + RADIX_SIZE)
#define SIGNED_SIZE     1
#define SIGNED_NO       (0x0000 << SIGNED_SHIFT)
#define SIGNED_YES      (0x0001 << SIGNED_SHIFT)
#define SIGNED_MASK     MAKE_MASK(SIGNED_SHIFT,SIGNED_SIZE)

#define CAPS_SHIFT      (SIGNED_SHIFT + SIGNED_SIZE)
#define CAPS_SIZE       1
#define CAPS_NO         (0x0000 << CAPS_SHIFT)
#define CAPS_YES        (0x0001 << CAPS_SHIFT)
#define CAPS_MASK       MAKE_MASK(CAPS_SHIFT,CAPS_SIZE)

#define FLOAT_SHIFT     (CAPS_SHIFT + CAPS_SIZE)
#define FLOAT_SIZE      2
#define FLOAT_NORMAL    (0x0000 << FLOAT_SHIFT)
#define FLOAT_EXPONENT  (0x0001 << FLOAT_SHIFT)
#define FLOAT_DEPENDANT (0x0002 << FLOAT_SHIFT)
#define FLOAT_HEX       (0x0003 << FLOAT_SHIFT)
#define FLOAT_MASK      MAKE_MASK(FLOAT_SHIFT, FLOAT_SIZE)

static FormatFlags
parse_flags(const char **posp)
{
  FormatFlags flags = 0;
  const char *pos = *posp;
  while (1) {
    switch(*pos) {
    case '-':
      flags |= JUSTIFY_LEFT;
      break;
    case '+':
      flags |= POSITIVE_PLUS;
      break;
    case ' ':
      flags |= POSITIVE_SPACE;
      break;
    case '#':
      flags |= ALTERNATE_FORM;
      break;
    case '0':
      flags |= PAD_ZERO;
      break;
    default:
      *posp = pos;
      return flags;
    }
    pos++;
  }
      
}

static unsigned int
parse_uint(const char **posp)
{
  unsigned v = 0;
  const char *pos = *posp;
  char ch;
  while((ch = *pos) >= '0' && ch <= '9') {
    v = v * 10 + (ch - '0');
    pos++;
  }
  *posp = pos;
  return v;
}

#define MAXCHARS_HEX ((sizeof(LARGEST_UNSIGNED) * 8) / 4 )

/* Largest number of characters needed for converting an unsigned integer.
 */
#define MAXCHARS ((sizeof(LARGEST_UNSIGNED) * 8  + 2) / 3 )

static unsigned int
output_uint_decimal(char **posp, LARGEST_UNSIGNED v)
{
  unsigned int len;
  char *pos = *posp;
  while (v > 0) {
    *--pos = (v % 10) + '0';
    v /= 10;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static unsigned int
output_uint_hex(char **posp, LARGEST_UNSIGNED v, unsigned int flags)
{
  unsigned int len;
  const char *hex = (flags & CAPS_YES) ?"0123456789ABCDEF":"0123456789abcdef";
  char *pos = *posp;
  while (v > 0) {
    *--pos = hex[(v % 16)];
    v /= 16;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static unsigned int
output_uint_octal(char **posp, LARGEST_UNSIGNED v)
{
  unsigned int len;
  char *pos = *posp;
  while (v > 0) {
    *--pos = (v % 8) + '0';
    v /= 8;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static StrFormatResult
fill_space(const StrFormatContext *ctxt, unsigned int len)
{
  StrFormatResult res;
  static const char buffer[16] = "                ";
  while(len > 16) {
    res = ctxt->write_str(ctxt->user_data, buffer, 16);
    if (res != STRFORMAT_OK) return res;
    len -= 16;
  }
  if (len == 0) return STRFORMAT_OK;
  return ctxt->write_str(ctxt->user_data, buffer, len);
}

static StrFormatResult
fill_zero(const StrFormatContext *ctxt, unsigned int len)
{
  StrFormatResult res;
  static const char buffer[16] = "0000000000000000";
  while(len > 16) {
    res = ctxt->write_str(ctxt->user_data, buffer, 16);
    if (res != STRFORMAT_OK) return res;
    len -= 16;
  }
  if (len == 0) return STRFORMAT_OK;
  return ctxt->write_str(ctxt->user_data, buffer, len);
}

#define CHECKCB(res) {if ((res) != STRFORMAT_OK) {va_end(ap); return -1;}}

int
format_str(const StrFormatContext *ctxt, const char *format, ...)
{
  int ret;
  va_list ap;
  va_start(ap, format);
  ret = format_str_v(ctxt, format, ap);
  va_end(ap);
  return ret;
}

int
format_str_v(const StrFormatContext *ctxt, const char *format, va_list ap)
{
  unsigned int written = 0;
  const char *pos = format;
  while(*pos != '\0') {
    FormatFlags flags;
    unsigned int minwidth = 0;
    int precision = -1; /* Negative means no precision */
    char ch;
    const char *start = pos;
    while( (ch = *pos) != '\0' && ch != '%') pos++;
    if (pos != start) {
      CHECKCB(ctxt->write_str(ctxt->user_data, start, pos - start));
      written += pos - start;
    }
    if (*pos == '\0') {
      va_end(ap);
      return written;
    }
    pos++;
    if (*pos == '\0') {
      va_end(ap);
      return written;
    }
    flags = parse_flags(&pos);

    /* parse width */
    if (*pos >= '1' && *pos <= '9') {
      minwidth = parse_uint(&pos);
    } else if (*pos == '*') {
      int w = va_arg(ap,int);
      if (w < 0) {
        flags |= JUSTIFY_LEFT;
        minwidth = w;
      } else {
        minwidth = w;
      }
      pos ++;
    }

    /* parse precision */
    if (*pos == '.') {
      pos++;
      if (*pos >= '0' && *pos <= '9') {
        precision = parse_uint(&pos);
      } else if (*pos == '*') {
        precision = va_arg(ap,int);
      }
    }
    if (*pos == 'l') {
      pos++;
      if (*pos == 'l') {
        flags |= SIZE_LONGLONG;
        pos++;
      } else {
        flags |= SIZE_LONG;
      }
    } else if (*pos == 'h') {
      pos++;
      if (*pos == 'h') {
        flags |= SIZE_CHAR;
        pos++;
      } else {
        flags |= SIZE_SHORT;
      }
    }

    /* parse conversion specifier */
    switch(*pos) {
    case 'd':
    case 'i':
      flags |= CONV_INTEGER | RADIX_DECIMAL | SIGNED_YES;
      break;
    case 'u':
      flags |= CONV_INTEGER | RADIX_DECIMAL | SIGNED_NO;
      break;
    case 'o':
      flags |= CONV_INTEGER | RADIX_OCTAL | SIGNED_NO;
      break;
    case 'x':
      flags |= CONV_INTEGER | RADIX_HEX | SIGNED_NO;
      break;
    case 'X':
      flags |= CONV_INTEGER | RADIX_HEX | SIGNED_NO | CAPS_YES;
      break;
#ifdef HAVE_DOUBLE
    case 'f':
      flags |= CONV_FLOAT | FLOAT_NORMAL;
      break;
    case 'F':
      flags |= CONV_FLOAT | FLOAT_NORMAL | CAPS_YES;
      break;
    case 'e':
      flags |= CONV_FLOAT | FLOAT_EXPONENT;
      break;
    case 'E':
      flags |= CONV_FLOAT | FLOAT_EXPONENT | CAPS_YES;
      break;
    case 'g':
      flags |= CONV_FLOAT | FLOAT_DEPENDANT;
      break;
    case 'G':
      flags |= CONV_FLOAT | FLOAT_DEPENDANT | CAPS_YES;
      break;
    case 'a':
      flags |= CONV_FLOAT | FLOAT_HEX;
      break;
    case 'A':
      flags |= CONV_FLOAT | FLOAT_HEX | CAPS_YES;
      break;
#endif
    case 'c':
      flags |= CONV_CHAR;
      break;
    case 's':
      flags |= CONV_STRING;
      break;
    case 'p':
      flags |= CONV_POINTER;
      break;
    case 'n':
      flags |= CONV_WRITTEN;
      break;
    case '%':
      flags |= CONV_PERCENT;
      break;
    case '\0':
      va_end(ap);
      return written;
    }
    pos++;
    switch(flags & CONV_MASK) {
    case CONV_PERCENT:
      CHECKCB(ctxt->write_str(ctxt->user_data, "%", 1));
      written++;
      break;
    case CONV_INTEGER:
      {
        /* unsigned integers */
        char *prefix = 0; /* sign, "0x" or "0X" */
        unsigned int prefix_len = 0;
        char buffer[MAXCHARS];
        char *conv_pos = buffer + MAXCHARS;
        unsigned int conv_len = 0;
        unsigned int width = 0;
        unsigned int precision_fill;
        unsigned int field_fill;
        LARGEST_UNSIGNED uvalue = 0;
        int negative = 0;
      
        if (precision < 0) precision = 1;
        else flags &= ~PAD_ZERO;
      
        if (flags & SIGNED_YES) {
          /* signed integers */
          LARGEST_SIGNED value = 0;
          switch(flags & SIZE_MASK) {
          case SIZE_CHAR:
            value = (signed char)va_arg(ap, int);
            break;
          case SIZE_SHORT:
            value = (short)va_arg(ap, int);
            break;
          case SIZE_INT:
            value = va_arg(ap, int);
            break;
#ifndef HAVE_LONGLONG
          case SIZE_LONGLONG:   /* Treat long long the same as long */
#endif
          case SIZE_LONG:
            value = va_arg(ap, long);
            break;
#ifdef HAVE_LONGLONG
          case SIZE_LONGLONG:
            value = va_arg(ap, long long);
            break;
#endif
          }
          if (value < 0) {
            uvalue = -value;
            negative = 1;
          } else {
            uvalue = value;
          }
        } else {
        
          switch(flags & SIZE_MASK) {
          case SIZE_CHAR:
            uvalue = (unsigned char)va_arg(ap,unsigned int);
            break;
          case SIZE_SHORT:
            uvalue = (unsigned short)va_arg(ap,unsigned int);
            break;
          case SIZE_INT:
            uvalue = va_arg(ap,unsigned int);
            break;
#ifndef HAVE_LONGLONG
          case SIZE_LONGLONG:   /* Treat long long the same as long */
#endif
          case SIZE_LONG:
            uvalue = va_arg(ap,unsigned long);
            break;
#ifdef HAVE_LONGLONG
          case SIZE_LONGLONG:
            uvalue = va_arg(ap,unsigned long long);
            break;
#endif
          }
        }
        
        switch(flags & (RADIX_MASK)) {
        case RADIX_DECIMAL:
          conv_len = output_uint_decimal(&conv_pos,uvalue);
          break;
        case RADIX_OCTAL:
          conv_len = output_uint_octal(&conv_pos,uvalue);
          break;
        case RADIX_HEX:
          conv_len = output_uint_hex(&conv_pos,uvalue, flags);
          break;
        }

        width += conv_len;
        precision_fill = (precision > conv_len) ? precision - conv_len : 0;
        if ((flags & (RADIX_MASK | ALTERNATE_FORM))
            == (RADIX_OCTAL | ALTERNATE_FORM)) {
          if (precision_fill < 1) precision_fill = 1;
        }

        width += precision_fill;
        
        if ((flags & (RADIX_MASK | ALTERNATE_FORM))
            == (RADIX_HEX | ALTERNATE_FORM) && uvalue != 0) {
          prefix_len = 2;
          if (flags & CAPS_YES) {
            prefix = "0X";
          } else {
            prefix = "0x";
          }
        }

        if (flags & SIGNED_YES) {
          if (negative) {
            prefix = "-";
            prefix_len = 1;
          } else {
            switch(flags & POSITIVE_MASK) {
            case POSITIVE_SPACE:
              prefix = " ";
              prefix_len = 1;
              break;
            case POSITIVE_PLUS:
              prefix = "+";
              prefix_len = 1;
              break;
            }
          }
        }

        width += prefix_len;

        field_fill = (minwidth > width) ? minwidth - width : 0;

        if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
          if (flags & PAD_ZERO) {
            precision_fill += field_fill;
          } else {
            CHECKCB(fill_space(ctxt,field_fill));
          }
        }

        if (prefix_len > 0)
          CHECKCB(ctxt->write_str(ctxt->user_data, prefix, prefix_len));
        written += prefix_len;
        
        CHECKCB(fill_zero(ctxt,precision_fill));
        written += precision_fill;
        
        CHECKCB(ctxt->write_str(ctxt->user_data, conv_pos,conv_len));
        written += conv_len;
        
        if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        written += field_fill;
      }
      break;
    case CONV_STRING:
      {
        unsigned int field_fill;
        unsigned int len;
        char *str = va_arg(ap,char *);
        if (str) {
          char *pos = str;
          while(*pos != '\0') pos++;
          len = pos - str;
        } else {
          str = "(null)";
          len = 6;
        }
        if (precision >= 0 && precision < len) len = precision;
        field_fill = (minwidth > len) ? minwidth - len : 0;
        if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        CHECKCB(ctxt->write_str(ctxt->user_data, str,len));
        written += len;
        if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        written += field_fill;
      }
      break;
    case CONV_POINTER:
      {
        LARGEST_UNSIGNED uvalue =
          (LARGEST_UNSIGNED)(POINTER_INT)va_arg(ap,void *);
        char buffer[MAXCHARS_HEX + 3];
        char *conv_pos = buffer + MAXCHARS_HEX+3;
        unsigned int conv_len;
        unsigned int field_fill;
        
        conv_len = output_uint_hex(&conv_pos,uvalue,flags);
        if (conv_len == 0) {
          *--conv_pos = '0';
          conv_len++;
        }
        *--conv_pos = 'x';
        *--conv_pos = '0';
        *--conv_pos = '#';
        conv_len += 3;

        field_fill = (minwidth > conv_len) ? minwidth - conv_len : 0;
        
        if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        
        CHECKCB(ctxt->write_str(ctxt->user_data, conv_pos,conv_len));
        written += conv_len;
        
        if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        written += field_fill;
      }
      break;
    case CONV_CHAR:
      {
        char ch = va_arg(ap,int);
        unsigned int field_fill = (minwidth > 1) ? minwidth - 1 : 0;
        if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
          CHECKCB(fill_space(ctxt,field_fill));
          written += field_fill;
        }
        
        CHECKCB(ctxt->write_str(ctxt->user_data, &ch, 1));
        written++;
        
        if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
          CHECKCB(fill_space(ctxt,field_fill));
        }
        written+= field_fill;
      }
      break;
    case CONV_WRITTEN:
      {
        int *p = va_arg(ap,int*);
        *p = written;
      }
      break;

    }
  }
  
  return written;
}