bc: remove all logic for multi-line buffering

function                                             old     new   delta
zbc_vm_process                                       865     874      +9
zbc_parse_text_init                                   51      38     -13
bc_read_line                                         394     345     -49
peek_inbuf                                           292      69    -223
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 9/-285)           Total: -276 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-12-26 18:46:03 +01:00
parent 7d32e25bf3
commit b1b7996a2a

View File

@ -715,7 +715,6 @@ typedef struct BcParse {
smallint lex_last; // was BcLexType
size_t lex_line;
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;
@ -2473,21 +2472,6 @@ static FAST_FUNC void bc_result_free(void *result)
}
}
#if ENABLE_FEATURE_BC_SIGNALS && ENABLE_FEATURE_EDITING
static void bc_vec_concat(BcVec *v, const char *str)
{
size_t len, slen;
slen = strlen(str);
len = v->len + slen + 1;
if (v->cap < len) bc_vec_grow(v, slen);
strcpy(v->v + v->len, str);
v->len = len;
}
#endif
static int bad_input_byte(char c)
{
if ((c < ' ' && c != '\t' && c != '\r' && c != '\n') // also allow '\v' '\f'?
@ -2499,10 +2483,10 @@ static int bad_input_byte(char c)
return 0;
}
// Note: it _appends_ data from fp to vec.
static void bc_read_line(BcVec *vec, FILE *fp)
{
again:
bc_vec_pop_all(vec);
fflush_and_check();
#if ENABLE_FEATURE_BC_SIGNALS
@ -2542,7 +2526,7 @@ static void bc_read_line(BcVec *vec, FILE *fp)
if (!c) break;
if (bad_input_byte(c)) goto again;
}
bc_vec_concat(vec, line_buf);
bc_vec_string(vec, n, line_buf);
# undef line_buf
} else
# endif
@ -2550,13 +2534,12 @@ static void bc_read_line(BcVec *vec, FILE *fp)
{
int c;
bool bad_chars = 0;
size_t len = vec->len;
do {
#if ENABLE_FEATURE_BC_SIGNALS
if (G_interrupt) {
// ^C was pressed: ignore entire line, get another one
vec->len = len;
bc_vec_pop_all(vec);
goto intr;
}
#endif
@ -2575,7 +2558,6 @@ static void bc_read_line(BcVec *vec, FILE *fp)
// Bad chars on this line
if (!G.prs.lex_filename) { // stdin
// ignore entire line, get another one
vec->len = len;
goto again;
}
bb_perror_msg_and_die("file '%s' is not text", G.prs.lex_filename);
@ -2743,113 +2725,13 @@ static BC_STATUS zbc_num_parse(BcNum *n, const char *val, unsigned base_t)
static bool bc_lex_more_input(void)
{
BcParse *p = &G.prs;
unsigned str; // bool for bc, string nest count for dc
bool comment;
bc_vec_pop_all(&G.input_buffer);
// This loop is complex because the vm tries not to send any lines that end
// with a backslash to the parser. The reason for that is because the parser
// treats a backslash+newline combo as whitespace, per the bc spec. In that
// case, and for strings and comments, the parser will expect more stuff.
//
// bc cases to test interactively:
// 1 #comment\ - prints "1<newline>" at once (comment is not continued)
// 1 #comment/* - prints "1<newline>" at once
// 1 #comment" - prints "1<newline>" at once
// 1\#comment - error at once (\ is not a line continuation)
// 1 + /*"*/2 - prints "3<newline>" at once
// 1 + /*#*/2 - prints "3<newline>" at once
// "str\" - prints "str\" at once
// "str#" - prints "str#" at once
// "str/*" - prints "str/*" at once
// "str#\ - waits for second line
// end" - ...prints "str#\<newline>end"
//This is way too complex, we duplicate comment/string logic of lexer
//TODO: switch to char-by-char input like hush does it
str = 0;
comment = false; // stays always false for dc
for (;;) {
size_t prevlen = G.input_buffer.len;
char *string;
bc_read_line(&G.input_buffer, G.prs.lex_input_fp);
// No more input means EOF
if (G.input_buffer.len <= prevlen + 1) // (we expect +1 for NUL byte)
break;
string = G.input_buffer.v + prevlen;
while (*string) {
char c = *string++;
#if ENABLE_BC
if (comment) {
// We are in /**/ comment, exit only on "*/"
if (c == '*' && *string == '/') {
comment = false;
string++;
}
continue;
}
#endif
// We are not in /**/ comment
if (str) {
// We are in "string" (bc) or [string] (dc)
if (IS_BC) {
// bc strings have no escapes: \\ is not special,
// \n is not, \" is not, \<newline> is not.
str = (c != '"'); // clear flag when " is seen
} else {
// dc strings have no escapes as well, can nest
if (c == ']')
str--;
if (c == '[')
str++;
}
continue;
}
// We are not in a string or /**/ comment
// Is it a #comment? Return the string (can't have continuation)
if (c == '#')
goto return_string;
#if ENABLE_BC
if (IS_BC) {
// bc: is it a start of /**/ comment or string?
if (c == '/' && *string == '*') {
comment = true;
string++;
continue;
}
str = (c == '"'); // set flag if " is seen
continue;
}
#endif
// dc: is it a start of string?
str = (c == '[');
} // end of "check all chars in string" loop
if (str != 0 || comment) {
G.input_buffer.len--; // backstep over the trailing NUL byte
continue;
}
// Check for backslash+newline.
// We do not check that last char is '\n' -
// if it is not, then it's EOF, and looping back
// to bc_read_line() will detect it:
string -= 2;
if (string >= G.input_buffer.v && *string == '\\') {
G.input_buffer.len--;
continue;
}
break;
}
return_string:
p->lex_inbuf = G.input_buffer.v;
// bb_error_msg("G.input_buffer.len:%d '%s'", G.input_buffer.len, G.input_buffer.v);
p->lex_end = p->lex_inbuf + G.input_buffer.len - 1; // do not include NUL
return G.input_buffer.len > 1;
}
@ -2872,9 +2754,22 @@ static bool bc_lex_more_input(void)
// In many cases, you can use fast *p->lex_inbuf instead of peek_inbuf():
// unless prev char might have been '\n', *p->lex_inbuf is '\0' ONLY
// on real EOF, not end-of-buffer.
//
// bc cases to test interactively:
// 1 #comment\ - prints "1<newline>" at once (comment is not continued)
// 1 #comment/* - prints "1<newline>" at once
// 1 #comment" - prints "1<newline>" at once
// 1\#comment - error at once (\ is not a line continuation)
// 1 + /*"*/2 - prints "3<newline>" at once
// 1 + /*#*/2 - prints "3<newline>" at once
// "str\" - prints "str\" at once
// "str#" - prints "str#" at once
// "str/*" - prints "str/*" at once
// "str#\ - waits for second line
// end" - ...prints "str#\<newline>end"
static char peek_inbuf(void)
{
if (G.prs.lex_inbuf == G.prs.lex_end) {
if (*G.prs.lex_inbuf == '\0') {
if (G.prs.lex_input_fp)
if (!bc_lex_more_input())
G.prs.lex_input_fp = NULL;
@ -3060,7 +2955,6 @@ 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_end = text + strlen(text);
G.prs.lex = G.prs.lex_last = XC_LEX_INVALID;
RETURN_STATUS(zbc_lex_next());
}
@ -3652,7 +3546,7 @@ static void bc_parse_reset(void)
p->func = bc_program_func_BC_PROG_MAIN();
}
p->lex_inbuf = p->lex_end;
p->lex_inbuf += strlen(p->lex_inbuf);
p->lex = XC_LEX_EOF;
IF_BC(bc_vec_pop_all(&p->exits);)