82ea67fbf
Denys Vlasenko
2018-12-13
Subject
bc: change bc_read_line() and zbc_vm_stdin() to avoid double buffers
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Architecture & Compiler Flags
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Build Log
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Commit Diff GitHub →
miscutils/bc.c+34 -27
| @@ -1226,6 +1226,7 @@ static void bc_vec_string(BcVec *v, size_t len, const char *str) | |
| bc_vec_pushZeroByte(v); | |
| } | |
| + | #if ENABLE_FEATURE_BC_SIGNALS && ENABLE_FEATURE_EDITING |
| static void bc_vec_concat(BcVec *v, const char *str) | |
| { | |
| size_t len, slen; | |
| @@ -1240,6 +1241,7 @@ static void bc_vec_concat(BcVec *v, const char *str) | |
| v->len = len; | |
| } | |
| + | #endif |
| static void *bc_vec_item(const BcVec *v, size_t idx) | |
| { | |
| @@ -1326,29 +1328,21 @@ static size_t bc_map_index(const BcVec *v, const void *ptr) | |
| } | |
| #endif | |
| - | static int push_input_byte(BcVec *vec, char c) |
| + | static int bad_input_byte(char c) |
| { | |
| if ((c < ' ' && c != '\t' && c != '\r' && c != '\n') // also allow '\v' '\f'? | |
| || c > 0x7e | |
| ) { | |
| - | // Bad chars on this line, ignore entire line |
| bc_error_fmt("illegal character 0x%02x", c); | |
| return 1; | |
| } | |
| - | bc_vec_pushByte(vec, (char)c); |
| return 0; | |
| } | |
| + | // Note: it _appends_ data from the stdin to vec. |
| static void bc_read_line(BcVec *vec) | |
| { | |
| - | bool bad_chars; |
| - | |
| - | do { |
| - | int c; |
| - | |
| - | bad_chars = 0; |
| - | bc_vec_pop_all(vec); |
| - | |
| + | again: |
| fflush_and_check(); | |
| #if ENABLE_FEATURE_BC_SIGNALS | |
| @@ -1359,6 +1353,7 @@ static void bc_read_line(BcVec *vec) | |
| // GNU dc says "Interrupt!" | |
| fputs("\ninterrupted execution\n", stderr); | |
| } | |
| + | |
| # if ENABLE_FEATURE_EDITING | |
| if (G_ttyin) { | |
| int n, i; | |
| @@ -1371,15 +1366,20 @@ static void bc_read_line(BcVec *vec) | |
| } | |
| i = 0; | |
| for (;;) { | |
| - | c = line_buf[i++]; |
| + | char c = line_buf[i++]; |
| if (!c) break; | |
| - | bad_chars |= push_input_byte(vec, c); |
| + | if (bad_input_byte(c)) goto again; |
| } | |
| + | bc_vec_concat(vec, line_buf); |
| # undef line_buf | |
| } else | |
| # endif | |
| #endif | |
| { | |
| + | int c; |
| + | bool bad_chars = 0; |
| + | size_t len = vec->len; |
| + | |
| IF_FEATURE_BC_SIGNALS(errno = 0;) | |
| do { | |
| c = fgetc(stdin); | |
| @@ -1399,10 +1399,15 @@ static void bc_read_line(BcVec *vec) | |
| // printf 'print 123' | bc - fails (syntax error) | |
| break; | |
| } | |
| - | bad_chars |= push_input_byte(vec, c); |
| + | bad_chars |= bad_input_byte(c); |
| + | bc_vec_pushByte(vec, (char)c); |
| } while (c != '\n'); | |
| + | if (bad_chars) { |
| + | // Bad chars on this line, ignore entire line |
| + | vec->len = len; |
| + | goto again; |
| + | } |
| } | |
| - | } while (bad_chars); |
| bc_vec_pushZeroByte(vec); | |
| } | |
| @@ -5374,12 +5379,12 @@ static BC_STATUS zbc_program_read(void) | |
| f = bc_program_func(BC_PROG_READ); | |
| bc_vec_pop_all(&f->code); | |
| - | bc_char_vec_init(&buf); |
| sv_file = G.prog.file; | |
| G.prog.file = NULL; | |
| G.in_read = 1; | |
| + | bc_char_vec_init(&buf); |
| bc_read_line(&buf); | |
| bc_parse_create(&parse, BC_PROG_READ); | |
| @@ -7039,7 +7044,7 @@ err: | |
| static BC_STATUS zbc_vm_stdin(void) | |
| { | |
| BcStatus s; | |
| - | BcVec buf, buffer; |
| + | BcVec buffer; |
| size_t str; | |
| bool comment; | |
| @@ -7047,8 +7052,6 @@ static BC_STATUS zbc_vm_stdin(void) | |
| bc_lex_file(&G.prs.l); | |
| bc_char_vec_init(&buffer); | |
| - | bc_char_vec_init(&buf); |
| - | bc_vec_pushZeroByte(&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 | |
| @@ -7058,16 +7061,18 @@ static BC_STATUS zbc_vm_stdin(void) | |
| comment = false; | |
| str = 0; | |
| for (;;) { | |
| + | size_t prevlen = buffer.len; |
| char *string; | |
| - | bc_read_line(&buf); |
| - | if (buf.len <= 1) // "" buf means EOF |
| + | bc_read_line(&buffer); |
| + | // No more input means EOF |
| + | if (buffer.len <= prevlen + 1) // (we expect +1 for NUL byte) |
| break; | |
| - | string = buf.v; |
| + | string = buffer.v + prevlen; |
| while (*string) { | |
| char c = *string; | |
| - | if (string == buf.v || string[-1] != '\\') { |
| + | if (string == buffer.v || string[-1] != '\\') { |
| // checking applet type is cheaper than accessing sbgn/send | |
| if (IS_BC) // bc: sbgn = send = '"' | |
| str ^= (c == '"'); | |
| @@ -7089,17 +7094,20 @@ static BC_STATUS zbc_vm_stdin(void) | |
| string++; | |
| } | |
| } | |
| - | bc_vec_concat(&buffer, buf.v); |
| - | if (str || comment) |
| + | if (str || comment) { |
| + | 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 >= buf.v && *string == '\\') |
| + | if (string >= buffer.v && *string == '\\') { |
| + | buffer.len--; |
| continue; | |
| + | } |
| s = zbc_vm_process(buffer.v); | |
| if (s) { | |
| @@ -7121,7 +7129,6 @@ static BC_STATUS zbc_vm_stdin(void) | |
| s = bc_error("comment end could not be found"); | |
| } | |
| - | bc_vec_free(&buf); |
| bc_vec_free(&buffer); | |
| RETURN_STATUS(s); | |
| } | |