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bc: simplify input pointer manipulation while lexing

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function                                             old     new   delta
bc_lex_name                                           70      68      -2
zbc_lex_number                                       177     174      -3
bc_vm_init                                           679     676      -3
bc_lex_whitespace                                     42      39      -3
zbc_parse_text_init                                   55      51      -4
bc_lex_lineComment                                    37      29      -8
bc_lex_assign                                         34      26      -8
zbc_lex_next                                        2039    1965     -74
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/8 up/down: 0/-105)           Total: -105 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2018-12-25 23:15:59 +01:00
parent ecb62edd47
commit c192b0442b
1 changed files with 55 additions and 60 deletions
Download Patch File Download Diff File Expand all files Collapse all files

115
miscutils/bc.c
View File

@@ -714,10 +714,9 @@ typedef struct BcParse {
smallint lex; // was BcLexType // first member is most used
smallint lex_last; // was BcLexType
bool lex_newline;
size_t lex_i;
size_t lex_line;
size_t lex_len;
const char *lex_inbuf;
const char *lex_end;
const char *lex_next_at; // last lex_next() was called at this string
const char *lex_filename;
FILE *lex_input_fp;
@@ -2748,12 +2747,9 @@ static void bc_lex_lineComment(void)
{
BcParse *p = &G.prs;
// Try: echo -n '#foo' | bc
size_t i;
p->lex = XC_LEX_WHITESPACE;
i = p->lex_i;
while (i < p->lex_len && p->lex_inbuf[i] != '\n')
i++;
p->lex_i = i;
while (p->lex_inbuf < p->lex_end && *p->lex_inbuf != '\n')
p->lex_inbuf++;
}
static void bc_lex_whitespace(void)
@@ -2761,19 +2757,19 @@ static void bc_lex_whitespace(void)
BcParse *p = &G.prs;
p->lex = XC_LEX_WHITESPACE;
for (;;) {
char c = p->lex_inbuf[p->lex_i];
char c = *p->lex_inbuf;
if (c == '\n') // this is XC_LEX_NLINE, not XC_LEX_WHITESPACE
break;
if (!isspace(c))
break;
p->lex_i++;
p->lex_inbuf++;
}
}
static BC_STATUS zbc_lex_number(char start)
{
BcParse *p = &G.prs;
const char *buf = p->lex_inbuf + p->lex_i;
const char *buf = p->lex_inbuf;
size_t len, i, ccnt;
bool pt;
@@ -2803,7 +2799,7 @@ static BC_STATUS zbc_lex_number(char start)
//ccnt is the number of chars in the number string, excluding possible
//trailing "[\<newline>].[\<newline>]" (with any number of \<NL> repetitions).
//i is buf[i] index of the first not-yet-parsed char after that.
p->lex_i += i;
p->lex_inbuf += i;
// This might overestimate the size, if there are "\<NL>"'s
// in the number. Subtracting number_of_backslashes*2 correctly
@@ -2850,7 +2846,7 @@ static void bc_lex_name(void)
p->lex = XC_LEX_NAME;
i = 0;
buf = p->lex_inbuf + p->lex_i - 1;
buf = p->lex_inbuf - 1;
for (;;) {
char c = buf[i];
if ((c < 'a' || c > 'z') && !isdigit(c) && c != '_') break;
@@ -2867,7 +2863,7 @@ static void bc_lex_name(void)
bc_vec_string(&p->lex_strnumbuf, i, buf);
// Increment the index. We minus 1 because it has already been incremented.
p->lex_i += i - 1;
p->lex_inbuf += i - 1;
//return BC_STATUS_SUCCESS;
}
@@ -2954,11 +2950,10 @@ static bool bc_lex_more_input(void)
}
p->lex_inbuf = G.input_buffer.v;
p->lex_i = 0;
// bb_error_msg("G.input_buffer.len:%d '%s'", G.input_buffer.len, G.input_buffer.v);
p->lex_len = G.input_buffer.len - 1; // do not include NUL
p->lex_end = p->lex_inbuf + G.input_buffer.len - 1; // do not include NUL
return p->lex_len != 0;
return G.input_buffer.len > 1;
}
IF_BC(static BC_STATUS zbc_lex_token(void);)
@@ -2983,7 +2978,7 @@ static BC_STATUS zbc_lex_next(void)
// Comments are also XC_LEX_WHITESPACE tokens and eaten here.
s = BC_STATUS_SUCCESS;
do {
if (p->lex_i == p->lex_len) {
if (p->lex_inbuf == p->lex_end) {
p->lex = XC_LEX_EOF;
if (!G.prs.lex_input_fp)
RETURN_STATUS(BC_STATUS_SUCCESS);
@@ -2991,9 +2986,9 @@ static BC_STATUS zbc_lex_next(void)
G.prs.lex_input_fp = NULL;
RETURN_STATUS(BC_STATUS_SUCCESS);
}
// here it's guaranteed that p->lex_i is below p->lex_len
// here it's guaranteed that p->lex_ibuf is below p->lex_end
}
p->lex_next_at = p->lex_inbuf + p->lex_i;
p->lex_next_at = p->lex_inbuf;
dbg_lex("next string to parse:'%.*s'",
(int)(strchrnul(p->lex_next_at, '\n') - p->lex_next_at),
p->lex_next_at
@@ -3034,8 +3029,7 @@ static BC_STATUS zbc_lex_next_and_skip_NLINE(void)
static BC_STATUS zbc_lex_text_init(const char *text)
{
G.prs.lex_inbuf = text;
G.prs.lex_i = 0;
G.prs.lex_len = strlen(text);
G.prs.lex_end = text + strlen(text);
G.prs.lex = G.prs.lex_last = XC_LEX_INVALID;
RETURN_STATUS(zbc_lex_next());
}
@@ -3047,7 +3041,7 @@ static BC_STATUS zbc_lex_identifier(void)
BcParse *p = &G.prs;
BcStatus s;
unsigned i;
const char *buf = p->lex_inbuf + p->lex_i - 1;
const char *buf = p->lex_inbuf - 1;
for (i = 0; i < ARRAY_SIZE(bc_lex_kws); ++i) {
const char *keyword8 = bc_lex_kws[i].name8;
@@ -3069,7 +3063,7 @@ static BC_STATUS zbc_lex_identifier(void)
}
// We minus 1 because the index has already been incremented.
p->lex_i += j - 1;
p->lex_inbuf += j - 1;
RETURN_STATUS(BC_STATUS_SUCCESS);
}
@@ -3097,11 +3091,11 @@ static BC_STATUS zbc_lex_string(void)
p->lex = XC_LEX_STR;
nls = 0;
i = p->lex_i;
i = 0;
for (;;) {
char c = p->lex_inbuf[i];
if (c == '\0') {
p->lex_i = i;
p->lex_inbuf += i;
RETURN_STATUS(bc_error("unterminated string"));
}
if (c == '"')
@@ -3110,15 +3104,15 @@ static BC_STATUS zbc_lex_string(void)
i++;
}
len = i - p->lex_i;
len = i;
// This check makes sense only if size_t is (much) larger than BC_MAX_STRING.
if (SIZE_MAX > (BC_MAX_STRING | 0xff)) {
if (len > BC_MAX_STRING)
RETURN_STATUS(bc_error("string too long: must be [1,"BC_MAX_STRING_STR"]"));
}
bc_vec_string(&p->lex_strnumbuf, len, p->lex_inbuf + p->lex_i);
bc_vec_string(&p->lex_strnumbuf, len, p->lex_inbuf);
p->lex_i = i + 1;
p->lex_inbuf += i + 1;
p->lex_line += nls;
G.err_line = p->lex_line;
@@ -3129,8 +3123,8 @@ static BC_STATUS zbc_lex_string(void)
static void bc_lex_assign(unsigned with_and_without)
{
BcParse *p = &G.prs;
if (p->lex_inbuf[p->lex_i] == '=') {
p->lex_i++;
if (*p->lex_inbuf == '=') {
p->lex_inbuf++;
with_and_without >>= 8; // store "with" value
} // else store "without" value
p->lex = (with_and_without & 0xff);
@@ -3145,7 +3139,7 @@ static BC_STATUS zbc_lex_comment(void)
const char *buf = p->lex_inbuf;
p->lex = XC_LEX_WHITESPACE;
i = p->lex_i; /* here buf[p->lex_i] is the '*' of opening comment delimiter */
i = 0; /* here lex_inbuf[0] is the '*' of opening comment delimiter */
for (;;) {
char c = buf[++i];
check_star:
@@ -3156,13 +3150,13 @@ static BC_STATUS zbc_lex_comment(void)
goto check_star;
}
if (c == '\0') {
p->lex_i = i;
p->lex_inbuf += i;
RETURN_STATUS(bc_error("unterminated comment"));
}
nls += (c == '\n');
}
p->lex_i = i + 1;
p->lex_inbuf += i + 1;
p->lex_line += nls;
G.err_line = p->lex_line;
@@ -3175,12 +3169,13 @@ static BC_STATUS zbc_lex_token(void)
{
BcParse *p = &G.prs;
BcStatus s = BC_STATUS_SUCCESS;
char c = p->lex_inbuf[p->lex_i++], c2;
char c = *p->lex_inbuf++;
char c2;
// This is the workhorse of the lexer.
switch (c) {
// case '\0': // probably never reached
// p->lex_i--;
// p->lex_inbuf--;
// p->lex = XC_LEX_EOF;
// p->lex_newline = true;
// break;
@@ -3214,11 +3209,11 @@ static BC_STATUS zbc_lex_token(void)
bc_lex_assign(BC_LEX_OP_ASSIGN_MODULUS, XC_LEX_OP_MODULUS);
break;
case '&':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '&') {
s = zbc_POSIX_does_not_allow_bool_ops_this_is_bad("&&");
if (s) RETURN_STATUS(s);
p->lex_i++;
p->lex_inbuf++;
p->lex = BC_LEX_OP_BOOL_AND;
} else {
p->lex = XC_LEX_INVALID;
@@ -3233,9 +3228,9 @@ static BC_STATUS zbc_lex_token(void)
bc_lex_assign(BC_LEX_OP_ASSIGN_MULTIPLY, XC_LEX_OP_MULTIPLY);
break;
case '+':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '+') {
p->lex_i++;
p->lex_inbuf++;
p->lex = BC_LEX_OP_INC;
} else
bc_lex_assign(BC_LEX_OP_ASSIGN_PLUS, XC_LEX_OP_PLUS);
@@ -3244,15 +3239,15 @@ static BC_STATUS zbc_lex_token(void)
p->lex = BC_LEX_COMMA;
break;
case '-':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '-') {
p->lex_i++;
p->lex_inbuf++;
p->lex = BC_LEX_OP_DEC;
} else
bc_lex_assign(BC_LEX_OP_ASSIGN_MINUS, XC_LEX_OP_MINUS);
break;
case '.':
if (isdigit(p->lex_inbuf[p->lex_i]))
if (isdigit(*p->lex_inbuf))
s = zbc_lex_number(c);
else {
p->lex = BC_LEX_KEY_LAST;
@@ -3260,7 +3255,7 @@ static BC_STATUS zbc_lex_token(void)
}
break;
case '/':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '*')
s = zbc_lex_comment();
else
@@ -3301,9 +3296,9 @@ static BC_STATUS zbc_lex_token(void)
p->lex = (BcLexType)(c - '[' + BC_LEX_LBRACKET);
break;
case '\\':
if (p->lex_inbuf[p->lex_i] == '\n') {
if (*p->lex_inbuf == '\n') {
p->lex = XC_LEX_WHITESPACE;
p->lex_i++;
p->lex_inbuf++;
} else
s = bc_error_bad_character(c);
break;
@@ -3343,11 +3338,11 @@ static BC_STATUS zbc_lex_token(void)
p->lex = (BcLexType)(c - '{' + BC_LEX_LBRACE);
break;
case '|':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '|') {
s = zbc_POSIX_does_not_allow_bool_ops_this_is_bad("||");
if (s) RETURN_STATUS(s);
p->lex_i++;
p->lex_inbuf++;
p->lex = BC_LEX_OP_BOOL_OR;
} else {
p->lex = XC_LEX_INVALID;
@@ -3369,13 +3364,13 @@ static BC_STATUS zbc_lex_token(void)
static BC_STATUS zdc_lex_register(void)
{
BcParse *p = &G.prs;
if (G_exreg && isspace(p->lex_inbuf[p->lex_i])) {
if (G_exreg && isspace(*p->lex_inbuf)) {
bc_lex_whitespace(); // eats whitespace (but not newline)
p->lex_i++; // bc_lex_name() expects this
p->lex_inbuf++; // bc_lex_name() expects this
bc_lex_name();
} else {
bc_vec_pop_all(&p->lex_strnumbuf);
bc_vec_push(&p->lex_strnumbuf, &p->lex_inbuf[p->lex_i++]);
bc_vec_push(&p->lex_strnumbuf, p->lex_inbuf++);
bc_vec_pushZeroByte(&p->lex_strnumbuf);
p->lex = XC_LEX_NAME;
}
@@ -3394,15 +3389,15 @@ static BC_STATUS zdc_lex_string(void)
nls = 0;
depth = 1;
i = p->lex_i;
i = 0;
for (;;) {
char c = p->lex_inbuf[i];
if (c == '\0') {
p->lex_i = i;
p->lex_inbuf += i;
RETURN_STATUS(bc_error("string end could not be found"));
}
nls += (c == '\n');
if (i == p->lex_i || p->lex_inbuf[i - 1] != '\\') {
if (i == 0 || p->lex_inbuf[i - 1] != '\\') {
if (c == '[') depth++;
if (c == ']')
if (--depth == 0)
@@ -3416,11 +3411,11 @@ static BC_STATUS zdc_lex_string(void)
bc_vec_pushZeroByte(&p->lex_strnumbuf);
// This check makes sense only if size_t is (much) larger than BC_MAX_STRING.
if (SIZE_MAX > (BC_MAX_STRING | 0xff)) {
if (i - p->lex_i > BC_MAX_STRING)
if (i > BC_MAX_STRING)
RETURN_STATUS(bc_error("string too long: must be [1,"BC_MAX_STRING_STR"]"));
}
p->lex_i = i;
p->lex_inbuf += i;
p->lex_line += nls;
G.err_line = p->lex_line;
@@ -3451,7 +3446,7 @@ static BC_STATUS zdc_lex_token(void)
}
s = BC_STATUS_SUCCESS;
c = p->lex_inbuf[p->lex_i++];
c = *p->lex_inbuf++;
if (c >= '%' && c <= '~'
&& (p->lex = dc_char_to_LEX[c - '%']) != XC_LEX_INVALID
) {
@@ -3484,7 +3479,7 @@ static BC_STATUS zdc_lex_token(void)
bc_lex_whitespace();
break;
case '!':
c2 = p->lex_inbuf[p->lex_i];
c2 = *p->lex_inbuf;
if (c2 == '=')
p->lex = XC_LEX_OP_REL_NE;
else if (c2 == '<')
@@ -3493,13 +3488,13 @@ static BC_STATUS zdc_lex_token(void)
p->lex = XC_LEX_OP_REL_GE;
else
RETURN_STATUS(bc_error_bad_character(c));
p->lex_i++;
p->lex_inbuf++;
break;
case '#':
bc_lex_lineComment();
break;
case '.':
if (isdigit(p->lex_inbuf[p->lex_i]))
if (isdigit(*p->lex_inbuf))
s = zbc_lex_number(c);
else
s = bc_error_bad_character(c);
@@ -3651,7 +3646,7 @@ static void bc_parse_reset(void)
p->func = bc_program_func_BC_PROG_MAIN();
}
p->lex_i = p->lex_len;
p->lex_inbuf = p->lex_end;
p->lex = XC_LEX_EOF;
IF_BC(bc_vec_pop_all(&p->exits);)