bc: change bc_read_line() and zbc_vm_stdin() to avoid double buffers
function old new delta bc_read_line 129 124 -5 bc_vm_run 523 433 -90 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-95) Total: -95 bytes text data bss dec hex filename 980445 485 7296 988226 f1442 busybox_old 980350 485 7296 988131 f13e3 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
b7e61e3e4a
commit
82ea67fbfa
@ -1226,6 +1226,7 @@ static void bc_vec_string(BcVec *v, size_t len, const char *str)
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bc_vec_pushZeroByte(v);
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}
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#if ENABLE_FEATURE_BC_SIGNALS && ENABLE_FEATURE_EDITING
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static void bc_vec_concat(BcVec *v, const char *str)
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{
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size_t len, slen;
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@ -1240,6 +1241,7 @@ static void bc_vec_concat(BcVec *v, const char *str)
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v->len = len;
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}
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#endif
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static void *bc_vec_item(const BcVec *v, size_t idx)
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{
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@ -1326,29 +1328,21 @@ static size_t bc_map_index(const BcVec *v, const void *ptr)
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}
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#endif
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static int push_input_byte(BcVec *vec, char c)
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static int bad_input_byte(char c)
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{
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if ((c < ' ' && c != '\t' && c != '\r' && c != '\n') // also allow '\v' '\f'?
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|| c > 0x7e
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) {
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// Bad chars on this line, ignore entire line
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bc_error_fmt("illegal character 0x%02x", c);
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return 1;
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}
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bc_vec_pushByte(vec, (char)c);
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return 0;
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}
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// Note: it _appends_ data from the stdin to vec.
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static void bc_read_line(BcVec *vec)
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{
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bool bad_chars;
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do {
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int c;
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bad_chars = 0;
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bc_vec_pop_all(vec);
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again:
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fflush_and_check();
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#if ENABLE_FEATURE_BC_SIGNALS
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@ -1359,6 +1353,7 @@ static void bc_read_line(BcVec *vec)
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// GNU dc says "Interrupt!"
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fputs("\ninterrupted execution\n", stderr);
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}
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# if ENABLE_FEATURE_EDITING
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if (G_ttyin) {
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int n, i;
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@ -1371,15 +1366,20 @@ static void bc_read_line(BcVec *vec)
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}
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i = 0;
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for (;;) {
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c = line_buf[i++];
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char c = line_buf[i++];
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if (!c) break;
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bad_chars |= push_input_byte(vec, c);
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if (bad_input_byte(c)) goto again;
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}
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bc_vec_concat(vec, line_buf);
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# undef line_buf
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} else
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# endif
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#endif
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{
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int c;
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bool bad_chars = 0;
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size_t len = vec->len;
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IF_FEATURE_BC_SIGNALS(errno = 0;)
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do {
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c = fgetc(stdin);
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@ -1399,10 +1399,15 @@ static void bc_read_line(BcVec *vec)
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// printf 'print 123' | bc - fails (syntax error)
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break;
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}
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bad_chars |= push_input_byte(vec, c);
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bad_chars |= bad_input_byte(c);
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bc_vec_pushByte(vec, (char)c);
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} while (c != '\n');
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if (bad_chars) {
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// Bad chars on this line, ignore entire line
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vec->len = len;
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goto again;
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}
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}
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} while (bad_chars);
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bc_vec_pushZeroByte(vec);
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}
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@ -5374,12 +5379,12 @@ static BC_STATUS zbc_program_read(void)
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f = bc_program_func(BC_PROG_READ);
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bc_vec_pop_all(&f->code);
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bc_char_vec_init(&buf);
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sv_file = G.prog.file;
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G.prog.file = NULL;
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G.in_read = 1;
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bc_char_vec_init(&buf);
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bc_read_line(&buf);
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bc_parse_create(&parse, BC_PROG_READ);
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@ -7039,7 +7044,7 @@ err:
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static BC_STATUS zbc_vm_stdin(void)
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{
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BcStatus s;
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BcVec buf, buffer;
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BcVec buffer;
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size_t str;
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bool comment;
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@ -7047,8 +7052,6 @@ static BC_STATUS zbc_vm_stdin(void)
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bc_lex_file(&G.prs.l);
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bc_char_vec_init(&buffer);
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bc_char_vec_init(&buf);
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bc_vec_pushZeroByte(&buffer);
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// This loop is complex because the vm tries not to send any lines that end
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// with a backslash to the parser. The reason for that is because the parser
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@ -7058,16 +7061,18 @@ static BC_STATUS zbc_vm_stdin(void)
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comment = false;
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str = 0;
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for (;;) {
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size_t prevlen = buffer.len;
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char *string;
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bc_read_line(&buf);
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if (buf.len <= 1) // "" buf means EOF
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bc_read_line(&buffer);
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// No more input means EOF
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if (buffer.len <= prevlen + 1) // (we expect +1 for NUL byte)
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break;
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string = buf.v;
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string = buffer.v + prevlen;
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while (*string) {
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char c = *string;
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if (string == buf.v || string[-1] != '\\') {
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if (string == buffer.v || string[-1] != '\\') {
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// checking applet type is cheaper than accessing sbgn/send
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if (IS_BC) // bc: sbgn = send = '"'
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str ^= (c == '"');
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@ -7089,17 +7094,20 @@ static BC_STATUS zbc_vm_stdin(void)
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string++;
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}
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}
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bc_vec_concat(&buffer, buf.v);
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if (str || comment)
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if (str || comment) {
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buffer.len--; // backstep over the trailing NUL byte
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continue;
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}
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// Check for backslash+newline.
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// we do not check that last char is '\n' -
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// if it is not, then it's EOF, and looping back
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// to bc_read_line() will detect it:
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string -= 2;
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if (string >= buf.v && *string == '\\')
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if (string >= buffer.v && *string == '\\') {
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buffer.len--;
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continue;
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}
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s = zbc_vm_process(buffer.v);
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if (s) {
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@ -7121,7 +7129,6 @@ static BC_STATUS zbc_vm_stdin(void)
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s = bc_error("comment end could not be found");
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}
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bc_vec_free(&buf);
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bc_vec_free(&buffer);
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RETURN_STATUS(s);
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}
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