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https://github.com/nothings/stb
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stb_c_lexer.h: C99 hex float literals
* Add support for C99 hex float literals * + is acceptable in a floating-point exponent * log(n) implementation of pow for stb__clex_parse_float * Add hex int and float test cases
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stb_c_lexer.h
158
stb_c_lexer.h
@ -45,7 +45,8 @@
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#define STB_C_LEX_C_DECIMAL_INTS Y // "0|[1-9][0-9]*" CLEX_intlit
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#define STB_C_LEX_C_HEX_INTS Y // "0x[0-9a-fA-F]+" CLEX_intlit
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#define STB_C_LEX_C_OCTAL_INTS Y // "[0-7]+" CLEX_intlit
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#define STB_C_LEX_C_DECIMAL_FLOATS Y // "[0-9]*(.[0-9]*([eE]-?[0-9]+)?) CLEX_floatlit
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#define STB_C_LEX_C_DECIMAL_FLOATS Y // "[0-9]*(.[0-9]*([eE][-+]?[0-9]+)?) CLEX_floatlit
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#define STB_C_LEX_C99_HEX_FLOATS N // "0x{hex}+(.{hex}*)?[pP][-+]?{hex}+ CLEX_floatlit
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#define STB_C_LEX_C_IDENTIFIERS Y // "[_a-zA-Z][_a-zA-Z0-9]*" CLEX_id
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#define STB_C_LEX_C_DQ_STRINGS Y // double-quote-delimited strings with escapes CLEX_dqstring
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#define STB_C_LEX_C_SQ_STRINGS N // single-quote-delimited strings with escapes CLEX_ssstring
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@ -171,11 +172,6 @@ extern void stb_c_lexer_get_location(const stb_lexer *lexer, const char *where,
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#define Y(x) 1
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#define N(x) 0
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#if STB_C_LEX_USE_STDLIB(x)
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#define STB__CLEX_use_stdlib
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#include <stdlib.h>
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#endif
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#if STB_C_LEX_INTEGERS_AS_DOUBLES(x)
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typedef double stb__clex_int;
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#define intfield real_number
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@ -200,6 +196,10 @@ typedef long stb__clex_int;
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#define STB__clex_define_shifts
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#endif
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#if STB_C_LEX_C99_HEX_FLOATS(x)
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#define STB__clex_hex_floats
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#endif
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#if STB_C_LEX_C_HEX_INTS(x)
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#define STB__clex_hex_ints
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#endif
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@ -220,6 +220,11 @@ typedef long stb__clex_int;
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#define STB__clex_discard_preprocessor
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#endif
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#if STB_C_LEX_USE_STDLIB(x) && (!defined(STB__clex_hex_floats) || __STDC_VERSION__ >= 199901L)
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#define STB__CLEX_use_stdlib
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#include <stdlib.h>
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#endif
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// Now pick a definition of Y/N that's conducive to
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// defining the enum of token names.
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#if STB_C_LEX_DEFINE_ALL_TOKEN_NAMES(x) || defined(STB_C_LEXER_SELF_TEST)
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@ -364,34 +369,95 @@ static int stb__clex_parse_suffixes(stb_lexer *lexer, long tokenid, char *start,
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}
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#ifndef STB__CLEX_use_stdlib
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static double stb__clex_pow(double base, unsigned int exponent)
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{
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double value=1;
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for ( ; exponent; exponent >>= 1) {
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if (exponent & 1)
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value *= base;
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base *= base;
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}
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return value;
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}
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static double stb__clex_parse_float(char *p, char **q)
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{
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char *s = p;
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double value=0;
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while (*p >= '0' && *p <= '9')
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value = value*10 + (*p++ - '0');
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if (*p == '.') {
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double powten=1, addend = 0;
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++p;
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while (*p >= '0' && *p <= '9') {
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addend = addend*10 + (*p++ - '0');
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powten *= 10;
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int base=10;
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int exponent=0;
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#ifdef STB__clex_hex_floats
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if (*p == '0') {
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if (p[1] == 'x' || p[1] == 'X') {
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base=16;
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p += 2;
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}
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value += addend / powten;
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}
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if (*p == 'e' || *p == 'E') {
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#endif
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for (;;) {
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if (*p >= '0' && *p <= '9')
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value = value*base + (*p++ - '0');
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#ifdef STB__clex_hex_floats
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else if (base == 16 && *p >= 'a' && *p <= 'f')
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value = value*base + 10 + (*p++ - 'a');
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else if (base == 16 && *p >= 'A' && *p <= 'F')
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value = value*base + 10 + (*p++ - 'A');
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#endif
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else
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break;
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}
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if (*p == '.') {
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double pow, addend = 0;
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++p;
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for (pow=1; ; pow*=base) {
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if (*p >= '0' && *p <= '9')
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addend = addend*base + (*p++ - '0');
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#ifdef STB__clex_hex_floats
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else if (base == 16 && *p >= 'a' && *p <= 'f')
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addend = addend*base + 10 + (*p++ - 'a');
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else if (base == 16 && *p >= 'A' && *p <= 'F')
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addend = addend*base + 10 + (*p++ - 'A');
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#endif
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else
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break;
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}
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value += addend / pow;
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}
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#ifdef STB__clex_hex_floats
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if (base == 16) {
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// exponent required for hex float literal
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if (*p != 'p' && *p != 'P') {
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*q = s;
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return 0;
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}
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exponent = 1;
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} else
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#endif
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exponent = (*p == 'e' || *p == 'E');
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if (exponent) {
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int sign = p[1] == '-';
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int exponent=0;
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double pow10=1;
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p += 1+sign;
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unsigned int exponent=0;
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double power=1;
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++p;
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if (*p == '-' || *p == '+')
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++p;
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while (*p >= '0' && *p <= '9')
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exponent = exponent*10 + (*p++ - '0');
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// can't use pow() from stdlib, so do it slow way
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while (exponent-- > 0)
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pow10 *= 10;
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if (sign)
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value /= pow10;
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#ifdef STB__clex_hex_floats
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if (base == 16)
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power = stb__clex_pow(2, exponent);
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else
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value *= pow10;
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#endif
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power = stb__clex_pow(10, exponent);
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if (sign)
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value /= power;
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else
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value *= power;
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}
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*q = p;
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return value;
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@ -630,15 +696,37 @@ int stb_c_lexer_get_token(stb_lexer *lexer)
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goto single_char;
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case '0':
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#ifdef STB__clex_hex_ints
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#if defined(STB__clex_hex_ints) || defined(STB__clex_hex_floats)
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if (p+1 != lexer->eof) {
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if (p[1] == 'x' || p[1] == 'X') {
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char *q = p+2;
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char *q;
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#ifdef STB__clex_hex_floats
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for (q=p+2;
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q != lexer->eof && ((*q >= '0' && *q <= '9') || (*q >= 'a' && *q <= 'f') || (*q >= 'A' && *q <= 'F'));
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++q);
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if (q != lexer->eof) {
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if (*q == '.' STB_C_LEX_FLOAT_NO_DECIMAL(|| *q == 'p' || *q == 'P')) {
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#ifdef STB__CLEX_use_stdlib
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lexer->real_number = strtod((char *) p, (char**) &q);
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#else
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lexer->real_number = stb__clex_parse_float(p, &q);
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#endif
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if (p == q)
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return stb__clex_token(lexer, CLEX_parse_error, p,q);
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return stb__clex_parse_suffixes(lexer, CLEX_floatlit, p,q, STB_C_LEX_FLOAT_SUFFIXES);
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}
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}
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#endif // STB__CLEX_hex_floats
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#ifdef STB__clex_hex_ints
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#ifdef STB__CLEX_use_stdlib
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lexer->int_number = strtol((char *) p, (char **) &q, 16);
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#else
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stb__clex_int n=0;
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while (q != lexer->eof) {
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for (q=p+2; q != lexer->eof; ++q) {
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if (*q >= '0' && *q <= '9')
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n = n*16 + (*q - '0');
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else if (*q >= 'a' && *q <= 'f')
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@ -647,16 +735,16 @@ int stb_c_lexer_get_token(stb_lexer *lexer)
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n = n*16 + (*q - 'A') + 10;
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else
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break;
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++q;
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}
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lexer->int_number = n;
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#endif
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if (q == p+2)
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return stb__clex_token(lexer, CLEX_parse_error, p-2,p-1);
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return stb__clex_parse_suffixes(lexer, CLEX_intlit, p,q, STB_C_LEX_HEX_SUFFIXES);
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#endif
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}
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}
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#endif // STB__clex_hex_ints
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#endif // defined(STB__clex_hex_ints) || defined(STB__clex_hex_floats)
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// can't test for octal because we might parse '0.0' as float or as '0' '.' '0',
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// so have to do float first
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@ -788,6 +876,14 @@ multiline comments */
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void dummy(void)
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{
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double some_floats[] = {
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1.0501, -10.4e12, 5E+10,
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#ifdef STB__clex_hex_floats
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0x1.0p+24, 0xff.FP-8, 0x1p-23,
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#endif
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4.
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};
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printf("test %d",1); // https://github.com/nothings/stb/issues/13
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}
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@ -803,7 +899,7 @@ int main(int argc, char **argv)
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}
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fclose(f);
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stb_c_lexer_init(&lex, text, text+len, (char *) malloc(1<<16), 1<<16);
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stb_c_lexer_init(&lex, text, text+len, (char *) malloc(0x10000), 0x10000);
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while (stb_c_lexer_get_token(&lex)) {
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if (lex.token == CLEX_parse_error) {
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printf("\n<<<PARSE ERROR>>>\n");
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