/cln-1.3.2/src/rational/input/cl_RA_read.cc
C++ | 153 lines | 129 code | 10 blank | 14 comment | 112 complexity | 12b8b7669d710c4cd8177de6311191d7 MD5 | raw file
Possible License(s): GPL-2.0
- // read_rational().
- // This file contains a slimmed down version of read_real().
- // It does not pull in all the floating-point, complex and transcendental
- // function code.
- // General includes.
- #include "base/cl_sysdep.h"
- // Specification.
- #include "cln/rational_io.h"
- // Implementation.
- #include <cstring>
- #include <sstream>
- #include "cln/input.h"
- #include "cln/integer.h"
- #include "cln/integer_io.h"
- #include "integer/cl_I.h"
- #include "cln/exception.h"
- namespace cln {
- // Step forward over all digits, to the end of string or to the next non-digit.
- static const char * skip_digits (const char * ptr, const char * string_limit, unsigned int base)
- {
- for ( ; ptr != string_limit; ptr++) {
- var char ch = *ptr;
- if ((ch >= '0') && (ch <= '9'))
- if (ch < '0' + (int)base)
- continue;
- else
- break;
- else {
- if (base <= 10)
- break;
- if (((ch >= 'A') && (ch < 'A'-10+(int)base))
- || ((ch >= 'a') && (ch < 'a'-10+(int)base))
- )
- continue;
- else
- break;
- }
- }
- return ptr;
- }
- #define at_end_of_parse(ptr) \
- if (end_of_parse) \
- { *end_of_parse = (ptr); } \
- else \
- { if ((ptr) != string_limit) { throw read_number_junk_exception((ptr),string,string_limit); } }
- const cl_RA read_rational (const cl_read_flags& flags, const char * string, const char * string_limit, const char * * end_of_parse)
- {
- ASSERT((flags.syntax & ~(syntax_rational|syntax_maybe_bad)) == 0);
- // If no string_limit is given, it defaults to the end of the string.
- if (!string_limit)
- string_limit = string + ::strlen(string);
- if (flags.syntax & syntax_rational) {
- // Check for rational number syntax.
- var unsigned int rational_base = flags.rational_base;
- var const char * ptr = string;
- if (flags.lsyntax & lsyntax_commonlisp) {
- if (ptr == string_limit) goto not_rational_syntax;
- if (*ptr == '#') {
- // Check for #b, #o, #x, #nR syntax.
- ptr++;
- if (ptr == string_limit) goto not_rational_syntax;
- switch (*ptr) {
- case 'b': case 'B':
- rational_base = 2; break;
- case 'o': case 'O':
- rational_base = 8; break;
- case 'x': case 'X':
- rational_base = 16; break;
- default:
- var const char * base_end_ptr =
- skip_digits(ptr,string_limit,10);
- if (base_end_ptr == ptr) goto not_rational_syntax;
- if (base_end_ptr == string_limit) goto not_rational_syntax;
- if (!((*base_end_ptr == 'r') || (*base_end_ptr == 'R')))
- goto not_rational_syntax;
- var cl_I base = read_integer(10,0,ptr,0,base_end_ptr-ptr);
- if (!((base >= 2) && (base <= 36))) {
- std::ostringstream buf;
- fprint(buf, "Base must be an integer in the range from 2 to 36, not ");
- fprint(buf, base);
- throw runtime_exception(buf.str());
- }
- rational_base = FN_to_UV(base); ptr = base_end_ptr;
- break;
- }
- ptr++;
- }
- }
- var const char * ptr_after_prefix = ptr;
- var cl_signean sign = 0;
- if (ptr == string_limit) goto not_rational_syntax;
- switch (*ptr) {
- case '-': sign = ~sign;
- case '+': ptr++;
- default: break;
- }
- var const char * ptr_after_sign = ptr;
- if (flags.syntax & syntax_integer) {
- // Check for integer syntax: {'+'|'-'|} {digit}+ {'.'|}
- // Allow final dot only in Common Lisp syntax if there was no #<base> prefix.
- if ((flags.lsyntax & lsyntax_commonlisp) && (ptr_after_prefix == string)) {
- ptr = skip_digits(ptr_after_sign,string_limit,10);
- if (ptr != ptr_after_sign)
- if (ptr != string_limit)
- if (*ptr == '.') {
- ptr++;
- if ((ptr == string_limit) || !(((*ptr >= '0') && (*ptr <= '9')) || ((*ptr >= 'A') && (*ptr <= 'Z') && (*ptr != 'I')) || ((*ptr >= 'a') && (*ptr <= 'z') && (*ptr != 'i')) || (*ptr == '.') || (*ptr == '_') || (*ptr == '/'))) {
- at_end_of_parse(ptr);
- return read_integer(10,sign,ptr_after_sign,0,ptr-ptr_after_sign);
- }
- }
- }
- ptr = skip_digits(ptr_after_sign,string_limit,rational_base);
- if ((ptr == string_limit) || !(((*ptr >= '0') && (*ptr <= '9')) || ((*ptr >= 'A') && (*ptr <= 'Z') && (*ptr != 'I')) || ((*ptr >= 'a') && (*ptr <= 'z') && (*ptr != 'i')) || (*ptr == '.') || (*ptr == '_') || (*ptr == '/'))) {
- at_end_of_parse(ptr);
- return read_integer(rational_base,sign,ptr_after_sign,0,ptr-ptr_after_sign);
- }
- }
- if (flags.syntax & syntax_ratio) {
- // Check for ratio syntax: {'+'|'-'|} {digit}+ '/' {digit}+
- ptr = skip_digits(ptr_after_sign,string_limit,rational_base);
- if (ptr != ptr_after_sign)
- if (ptr != string_limit)
- if (*ptr == '/') {
- var const char * ptr_at_slash = ptr;
- ptr = skip_digits(ptr_at_slash+1,string_limit,rational_base);
- if (ptr != ptr_at_slash+1)
- if ((ptr == string_limit) || !(((*ptr >= '0') && (*ptr <= '9')) || ((*ptr >= 'A') && (*ptr <= 'Z') && (*ptr != 'I')) || ((*ptr >= 'a') && (*ptr <= 'z') && (*ptr != 'i')) || (*ptr == '.') || (*ptr == '_') || (*ptr == '/'))) {
- at_end_of_parse(ptr);
- return read_rational(rational_base,sign,ptr_after_sign,0,ptr_at_slash-ptr_after_sign,ptr-ptr_after_sign);
- }
- }
- }
- }
- not_rational_syntax:
- if (flags.syntax & syntax_maybe_bad) {
- ASSERT(end_of_parse);
- *end_of_parse = string;
- return 0; // dummy return
- }
- throw read_number_bad_syntax_exception(string,string_limit);
- }
- } // namespace cln