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stb_c_lexer.h: C99 hex float literals

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* 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
This commit is contained in:
Alan Hickman 2016-08-14 18:35:17 -07:00 committed by fahickman
parent c6b6239357
commit 49d3871d86
1 changed files with 127 additions and 31 deletions
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162
stb_c_lexer.h
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@ -45,7 +45,8 @@
#define STB_C_LEX_C_DECIMAL_INTS Y // "0|[1-9][0-9]*" CLEX_intlit
#define STB_C_LEX_C_HEX_INTS Y // "0x[0-9a-fA-F]+" CLEX_intlit
#define STB_C_LEX_C_OCTAL_INTS Y // "[0-7]+" CLEX_intlit
#define STB_C_LEX_C_DECIMAL_FLOATS Y // "[0-9]*(.[0-9]*([eE]-?[0-9]+)?) CLEX_floatlit
#define STB_C_LEX_C_DECIMAL_FLOATS Y // "[0-9]*(.[0-9]*([eE][-+]?[0-9]+)?) CLEX_floatlit
#define STB_C_LEX_C99_HEX_FLOATS N // "0x{hex}+(.{hex}*)?[pP][-+]?{hex}+ CLEX_floatlit
#define STB_C_LEX_C_IDENTIFIERS Y // "[_a-zA-Z][_a-zA-Z0-9]*" CLEX_id
#define STB_C_LEX_C_DQ_STRINGS Y // double-quote-delimited strings with escapes CLEX_dqstring
#define STB_C_LEX_C_SQ_STRINGS N // single-quote-delimited strings with escapes CLEX_ssstring
@ -171,11 +172,6 @@ extern void stb_c_lexer_get_location(const stb_lexer *lexer, const char *where,
#define Y(x) 1
#define N(x) 0
#if STB_C_LEX_USE_STDLIB(x)
#define STB__CLEX_use_stdlib
#include <stdlib.h>
#endif
#if STB_C_LEX_INTEGERS_AS_DOUBLES(x)
typedef double stb__clex_int;
#define intfield real_number
@ -200,6 +196,10 @@ typedef long stb__clex_int;
#define STB__clex_define_shifts
#endif
#if STB_C_LEX_C99_HEX_FLOATS(x)
#define STB__clex_hex_floats
#endif
#if STB_C_LEX_C_HEX_INTS(x)
#define STB__clex_hex_ints
#endif
@ -220,6 +220,11 @@ typedef long stb__clex_int;
#define STB__clex_discard_preprocessor
#endif
#if STB_C_LEX_USE_STDLIB(x) && (!defined(STB__clex_hex_floats) || __STDC_VERSION__ >= 199901L)
#define STB__CLEX_use_stdlib
#include <stdlib.h>
#endif
// Now pick a definition of Y/N that's conducive to
// defining the enum of token names.
#if STB_C_LEX_DEFINE_ALL_TOKEN_NAMES(x) || defined(STB_C_LEXER_SELF_TEST)
@ -364,34 +369,95 @@ static int stb__clex_parse_suffixes(stb_lexer *lexer, long tokenid, char *start,
}
#ifndef STB__CLEX_use_stdlib
static double stb__clex_pow(double base, unsigned int exponent)
{
double value=1;
for ( ; exponent; exponent >>= 1) {
if (exponent & 1)
value *= base;
base *= base;
}
return value;
}
static double stb__clex_parse_float(char *p, char **q)
{
char *s = p;
double value=0;
while (*p >= '0' && *p <= '9')
value = value*10 + (*p++ - '0');
if (*p == '.') {
double powten=1, addend = 0;
++p;
while (*p >= '0' && *p <= '9') {
addend = addend*10 + (*p++ - '0');
powten *= 10;
}
value += addend / powten;
}
if (*p == 'e' || *p == 'E') {
int sign = p[1] == '-';
int base=10;
int exponent=0;
double pow10=1;
p += 1+sign;
#ifdef STB__clex_hex_floats
if (*p == '0') {
if (p[1] == 'x' || p[1] == 'X') {
base=16;
p += 2;
}
}
#endif
for (;;) {
if (*p >= '0' && *p <= '9')
value = value*base + (*p++ - '0');
#ifdef STB__clex_hex_floats
else if (base == 16 && *p >= 'a' && *p <= 'f')
value = value*base + 10 + (*p++ - 'a');
else if (base == 16 && *p >= 'A' && *p <= 'F')
value = value*base + 10 + (*p++ - 'A');
#endif
else
break;
}
if (*p == '.') {
double pow, addend = 0;
++p;
for (pow=1; ; pow*=base) {
if (*p >= '0' && *p <= '9')
addend = addend*base + (*p++ - '0');
#ifdef STB__clex_hex_floats
else if (base == 16 && *p >= 'a' && *p <= 'f')
addend = addend*base + 10 + (*p++ - 'a');
else if (base == 16 && *p >= 'A' && *p <= 'F')
addend = addend*base + 10 + (*p++ - 'A');
#endif
else
break;
}
value += addend / pow;
}
#ifdef STB__clex_hex_floats
if (base == 16) {
// exponent required for hex float literal
if (*p != 'p' && *p != 'P') {
*q = s;
return 0;
}
exponent = 1;
} else
#endif
exponent = (*p == 'e' || *p == 'E');
if (exponent) {
int sign = p[1] == '-';
unsigned int exponent=0;
double power=1;
++p;
if (*p == '-' || *p == '+')
++p;
while (*p >= '0' && *p <= '9')
exponent = exponent*10 + (*p++ - '0');
// can't use pow() from stdlib, so do it slow way
while (exponent-- > 0)
pow10 *= 10;
if (sign)
value /= pow10;
#ifdef STB__clex_hex_floats
if (base == 16)
power = stb__clex_pow(2, exponent);
else
value *= pow10;
#endif
power = stb__clex_pow(10, exponent);
if (sign)
value /= power;
else
value *= power;
}
*q = p;
return value;
@ -630,15 +696,37 @@ int stb_c_lexer_get_token(stb_lexer *lexer)
goto single_char;
case '0':
#ifdef STB__clex_hex_ints
#if defined(STB__clex_hex_ints) || defined(STB__clex_hex_floats)
if (p+1 != lexer->eof) {
if (p[1] == 'x' || p[1] == 'X') {
char *q = p+2;
char *q;
#ifdef STB__clex_hex_floats
for (q=p+2;
q != lexer->eof && ((*q >= '0' && *q <= '9') || (*q >= 'a' && *q <= 'f') || (*q >= 'A' && *q <= 'F'));
++q);
if (q != lexer->eof) {
if (*q == '.' STB_C_LEX_FLOAT_NO_DECIMAL(|| *q == 'p' || *q == 'P')) {
#ifdef STB__CLEX_use_stdlib
lexer->real_number = strtod((char *) p, (char**) &q);
#else
lexer->real_number = stb__clex_parse_float(p, &q);
#endif
if (p == q)
return stb__clex_token(lexer, CLEX_parse_error, p,q);
return stb__clex_parse_suffixes(lexer, CLEX_floatlit, p,q, STB_C_LEX_FLOAT_SUFFIXES);
}
}
#endif // STB__CLEX_hex_floats
#ifdef STB__clex_hex_ints
#ifdef STB__CLEX_use_stdlib
lexer->int_number = strtol((char *) p, (char **) &q, 16);
#else
stb__clex_int n=0;
while (q != lexer->eof) {
for (q=p+2; q != lexer->eof; ++q) {
if (*q >= '0' && *q <= '9')
n = n*16 + (*q - '0');
else if (*q >= 'a' && *q <= 'f')
@ -647,16 +735,16 @@ int stb_c_lexer_get_token(stb_lexer *lexer)
n = n*16 + (*q - 'A') + 10;
else
break;
++q;
}
lexer->int_number = n;
#endif
if (q == p+2)
return stb__clex_token(lexer, CLEX_parse_error, p-2,p-1);
return stb__clex_parse_suffixes(lexer, CLEX_intlit, p,q, STB_C_LEX_HEX_SUFFIXES);
#endif
}
}
#endif // STB__clex_hex_ints
#endif // defined(STB__clex_hex_ints) || defined(STB__clex_hex_floats)
// can't test for octal because we might parse '0.0' as float or as '0' '.' '0',
// so have to do float first
@ -788,6 +876,14 @@ multiline comments */
void dummy(void)
{
double some_floats[] = {
1.0501, -10.4e12, 5E+10,
#ifdef STB__clex_hex_floats
0x1.0p+24, 0xff.FP-8, 0x1p-23,
#endif
4.
};
printf("test %d",1); // https://github.com/nothings/stb/issues/13
}
@ -803,7 +899,7 @@ int main(int argc, char **argv)
}
fclose(f);
stb_c_lexer_init(&lex, text, text+len, (char *) malloc(1<<16), 1<<16);
stb_c_lexer_init(&lex, text, text+len, (char *) malloc(0x10000), 0x10000);
while (stb_c_lexer_get_token(&lex)) {
if (lex.token == CLEX_parse_error) {
printf("\n<<<PARSE ERROR>>>\n");