src/complex/input/cl_N_read_stream.cc

   1 // read_complex().
   2
   3 // General includes.
   4 #include "cl_sysdep.h"
   5
   6 // Specification.
   7 #include "cl_complex_io.h"
   8
   9
  10 // Implementation.
  11
  12 #include "cl_io.h"
  13 #include "cl_spushstring.h"
  14 #include "cl_input.h"
  15
  16 // We read an entire token (or even more, if it begins with #C) into a
  17 // buffer and then call read_complex() on the buffer.
  18
  19 class pushstring_hack : public cl_spushstring {
  20 public:
  21         char* start_pointer (void) { return buffer; }
  22         char* end_pointer (void) { return buffer+index; }
  23 };
  24
  25 static cl_boolean number_char_p (char c)
  26 {
  27         if ((c >= '0') && (c <= '9'))
  28                 return cl_true;
  29         if (((c >= 'A') && (c <= 'Z')) || ((c >= 'a') && (c <= 'z')))
  30                 return cl_true;
  31         switch (c) {
  32                 case '+': case '-': case '.': case '/':
  33                         return cl_true;
  34                 default:
  35                         return cl_false;
  36         }
  37 }
  38
  39 const cl_N read_complex (cl_istream stream, const cl_read_flags& flags)
  40 {
  41         // One pre-allocated buffer. This reduces the allocation/free cost.
  42         static pushstring_hack buffer;
  43
  44         var int c;
  45         // Skip whitespace at the beginning.
  46         loop {
  47                 c = freadchar(stream);
  48                 if (c == cl_EOF) goto eof;
  49                 if ((c == ' ') || (c == '\t') || (c == '\n'))
  50                         continue;
  51                 else
  52                         break;
  53         }
  54         // Found first non-whitespace character.
  55         // Numbers cannot cross lines. We can treat EOF and '\n' the same way.
  56         buffer.reset();
  57         if (c == '#') {
  58                 if (!(flags.lsyntax & lsyntax_commonlisp))
  59                         goto syntax1;
  60                 buffer.push(c);
  61                 // Read some digits, then a letter, then a list or token.
  62                 loop {
  63                         c = freadchar(stream);
  64                         if (c == cl_EOF) goto eof;
  65                         buffer.push(c);
  66                         if ((c >= '0') && (c <= '9'))
  67                                 continue;
  68                         else
  69                                 break;
  70                 }
  71                 if (!(((c >= 'A') && (c <= 'Z')) || ((c >= 'a') && (c <= 'z'))))
  72                         goto syntax1;
  73                 buffer.push(c);
  74                 c = freadchar(stream);
  75                 if (c == cl_EOF) goto eof;
  76                 if (c == '(') {
  77                         var uintL paren_level = 0;
  78                         loop {
  79                                 buffer.push(c);
  80                                 if (c == '(') paren_level++;
  81                                 else if (c == ')') paren_level--;
  82                                 if (paren_level == 0) goto done;
  83                                 c = freadchar(stream);
  84                                 if ((c == cl_EOF) || (c == '\n')) goto syntax;
  85                         }
  86                 }
  87         }
  88         // Read a number token.
  89         if (!number_char_p(c))
  90                 goto syntax1;
  91         loop {
  92                 buffer.push(c);
  93                 c = freadchar(stream);
  94                 if (c == cl_EOF)
  95                         break;
  96                 if (!number_char_p(c)) {
  97                         funreadchar(stream,c);
  98                         break;
  99                 }
 100         }
 101 done:
 102         // Parse the number.
 103         return read_complex(flags,
 104                             buffer.start_pointer(), buffer.end_pointer(),
 105                             NULL
 106                            );
 107
 108         // Handle syntax error.
 109 syntax1:        buffer.push(c);
 110 syntax: read_number_bad_syntax(buffer.start_pointer(),buffer.end_pointer());
 111
 112         // Handle premature EOF.
 113 eof:    read_number_eof();
 114 }