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Diffstat (limited to '')
| -rw-r--r-- | gc/cord/cordxtra.c | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/gc/cord/cordxtra.c b/gc/cord/cordxtra.c new file mode 100644 index 0000000..a5be10d --- /dev/null +++ b/gc/cord/cordxtra.c @@ -0,0 +1,621 @@ +/* + * Copyright (c) 1993-1994 by Xerox Corporation. All rights reserved. + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program + * for any purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is granted, + * provided the above notices are retained, and a notice that the code was + * modified is included with the above copyright notice. + * + * Author: Hans-J. Boehm (boehm@parc.xerox.com) + */ +/* + * These are functions on cords that do not need to understand their + * implementation. They serve also serve as example client code for + * cord_basics. + */ +/* Boehm, December 8, 1995 1:53 pm PST */ +# include <stdio.h> +# include <string.h> +# include <stdlib.h> +# include <stdarg.h> +# include "cord.h" +# include "ec.h" +# define I_HIDE_POINTERS /* So we get access to allocation lock. */ + /* We use this for lazy file reading, */ + /* so that we remain independent */ + /* of the threads primitives. */ +# include "gc.h" + +/* For now we assume that pointer reads and writes are atomic, */ +/* i.e. another thread always sees the state before or after */ +/* a write. This might be false on a Motorola M68K with */ +/* pointers that are not 32-bit aligned. But there probably */ +/* aren't too many threads packages running on those. */ +# define ATOMIC_WRITE(x,y) (x) = (y) +# define ATOMIC_READ(x) (*(x)) + +/* The standard says these are in stdio.h, but they aren't always: */ +# ifndef SEEK_SET +# define SEEK_SET 0 +# endif +# ifndef SEEK_END +# define SEEK_END 2 +# endif + +# define BUFSZ 2048 /* Size of stack allocated buffers when */ + /* we want large buffers. */ + +typedef void (* oom_fn)(void); + +# define OUT_OF_MEMORY { if (CORD_oom_fn != (oom_fn) 0) (*CORD_oom_fn)(); \ + ABORT("Out of memory\n"); } +# define ABORT(msg) { fprintf(stderr, "%s\n", msg); abort(); } + +CORD CORD_cat_char(CORD x, char c) +{ + register char * string; + + if (c == '\0') return(CORD_cat(x, CORD_nul(1))); + string = GC_MALLOC_ATOMIC(2); + if (string == 0) OUT_OF_MEMORY; + string[0] = c; + string[1] = '\0'; + return(CORD_cat_char_star(x, string, 1)); +} + +CORD CORD_catn(int nargs, ...) +{ + register CORD result = CORD_EMPTY; + va_list args; + register int i; + + va_start(args, nargs); + for (i = 0; i < nargs; i++) { + register CORD next = va_arg(args, CORD); + result = CORD_cat(result, next); + } + va_end(args); + return(result); +} + +typedef struct { + size_t len; + size_t count; + char * buf; +} CORD_fill_data; + +int CORD_fill_proc(char c, void * client_data) +{ + register CORD_fill_data * d = (CORD_fill_data *)client_data; + register size_t count = d -> count; + + (d -> buf)[count] = c; + d -> count = ++count; + if (count >= d -> len) { + return(1); + } else { + return(0); + } +} + +int CORD_batched_fill_proc(const char * s, void * client_data) +{ + register CORD_fill_data * d = (CORD_fill_data *)client_data; + register size_t count = d -> count; + register size_t max = d -> len; + register char * buf = d -> buf; + register const char * t = s; + + while((buf[count] = *t++) != '\0') { + count++; + if (count >= max) { + d -> count = count; + return(1); + } + } + d -> count = count; + return(0); +} + +/* Fill buf with len characters starting at i. */ +/* Assumes len characters are available. */ +void CORD_fill_buf(CORD x, size_t i, size_t len, char * buf) +{ + CORD_fill_data fd; + + fd.len = len; + fd.buf = buf; + fd.count = 0; + (void)CORD_iter5(x, i, CORD_fill_proc, CORD_batched_fill_proc, &fd); +} + +int CORD_cmp(CORD x, CORD y) +{ + CORD_pos xpos; + CORD_pos ypos; + register size_t avail, yavail; + + if (y == CORD_EMPTY) return(x != CORD_EMPTY); + if (x == CORD_EMPTY) return(-1); + if (CORD_IS_STRING(y) && CORD_IS_STRING(x)) return(strcmp(x,y)); + CORD_set_pos(xpos, x, 0); + CORD_set_pos(ypos, y, 0); + for(;;) { + if (!CORD_pos_valid(xpos)) { + if (CORD_pos_valid(ypos)) { + return(-1); + } else { + return(0); + } + } + if (!CORD_pos_valid(ypos)) { + return(1); + } + if ((avail = CORD_pos_chars_left(xpos)) <= 0 + || (yavail = CORD_pos_chars_left(ypos)) <= 0) { + register char xcurrent = CORD_pos_fetch(xpos); + register char ycurrent = CORD_pos_fetch(ypos); + if (xcurrent != ycurrent) return(xcurrent - ycurrent); + CORD_next(xpos); + CORD_next(ypos); + } else { + /* process as many characters as we can */ + register int result; + + if (avail > yavail) avail = yavail; + result = strncmp(CORD_pos_cur_char_addr(xpos), + CORD_pos_cur_char_addr(ypos), avail); + if (result != 0) return(result); + CORD_pos_advance(xpos, avail); + CORD_pos_advance(ypos, avail); + } + } +} + +int CORD_ncmp(CORD x, size_t x_start, CORD y, size_t y_start, size_t len) +{ + CORD_pos xpos; + CORD_pos ypos; + register size_t count; + register long avail, yavail; + + CORD_set_pos(xpos, x, x_start); + CORD_set_pos(ypos, y, y_start); + for(count = 0; count < len;) { + if (!CORD_pos_valid(xpos)) { + if (CORD_pos_valid(ypos)) { + return(-1); + } else { + return(0); + } + } + if (!CORD_pos_valid(ypos)) { + return(1); + } + if ((avail = CORD_pos_chars_left(xpos)) <= 0 + || (yavail = CORD_pos_chars_left(ypos)) <= 0) { + register char xcurrent = CORD_pos_fetch(xpos); + register char ycurrent = CORD_pos_fetch(ypos); + if (xcurrent != ycurrent) return(xcurrent - ycurrent); + CORD_next(xpos); + CORD_next(ypos); + count++; + } else { + /* process as many characters as we can */ + register int result; + + if (avail > yavail) avail = yavail; + count += avail; + if (count > len) avail -= (count - len); + result = strncmp(CORD_pos_cur_char_addr(xpos), + CORD_pos_cur_char_addr(ypos), (size_t)avail); + if (result != 0) return(result); + CORD_pos_advance(xpos, (size_t)avail); + CORD_pos_advance(ypos, (size_t)avail); + } + } + return(0); +} + +char * CORD_to_char_star(CORD x) +{ + register size_t len = CORD_len(x); + char * result = GC_MALLOC_ATOMIC(len + 1); + + if (result == 0) OUT_OF_MEMORY; + CORD_fill_buf(x, 0, len, result); + result[len] = '\0'; + return(result); +} + +CORD CORD_from_char_star(const char *s) +{ + char * result; + size_t len = strlen(s); + + if (0 == len) return(CORD_EMPTY); + result = GC_MALLOC_ATOMIC(len + 1); + if (result == 0) OUT_OF_MEMORY; + memcpy(result, s, len+1); + return(result); +} + +const char * CORD_to_const_char_star(CORD x) +{ + if (x == 0) return(""); + if (CORD_IS_STRING(x)) return((const char *)x); + return(CORD_to_char_star(x)); +} + +char CORD_fetch(CORD x, size_t i) +{ + CORD_pos xpos; + + CORD_set_pos(xpos, x, i); + if (!CORD_pos_valid(xpos)) ABORT("bad index?"); + return(CORD_pos_fetch(xpos)); +} + + +int CORD_put_proc(char c, void * client_data) +{ + register FILE * f = (FILE *)client_data; + + return(putc(c, f) == EOF); +} + +int CORD_batched_put_proc(const char * s, void * client_data) +{ + register FILE * f = (FILE *)client_data; + + return(fputs(s, f) == EOF); +} + + +int CORD_put(CORD x, FILE * f) +{ + if (CORD_iter5(x, 0, CORD_put_proc, CORD_batched_put_proc, f)) { + return(EOF); + } else { + return(1); + } +} + +typedef struct { + size_t pos; /* Current position in the cord */ + char target; /* Character we're looking for */ +} chr_data; + +int CORD_chr_proc(char c, void * client_data) +{ + register chr_data * d = (chr_data *)client_data; + + if (c == d -> target) return(1); + (d -> pos) ++; + return(0); +} + +int CORD_rchr_proc(char c, void * client_data) +{ + register chr_data * d = (chr_data *)client_data; + + if (c == d -> target) return(1); + (d -> pos) --; + return(0); +} + +int CORD_batched_chr_proc(const char *s, void * client_data) +{ + register chr_data * d = (chr_data *)client_data; + register char * occ = strchr(s, d -> target); + + if (occ == 0) { + d -> pos += strlen(s); + return(0); + } else { + d -> pos += occ - s; + return(1); + } +} + +size_t CORD_chr(CORD x, size_t i, int c) +{ + chr_data d; + + d.pos = i; + d.target = c; + if (CORD_iter5(x, i, CORD_chr_proc, CORD_batched_chr_proc, &d)) { + return(d.pos); + } else { + return(CORD_NOT_FOUND); + } +} + +size_t CORD_rchr(CORD x, size_t i, int c) +{ + chr_data d; + + d.pos = i; + d.target = c; + if (CORD_riter4(x, i, CORD_rchr_proc, &d)) { + return(d.pos); + } else { + return(CORD_NOT_FOUND); + } +} + +/* Find the first occurrence of s in x at position start or later. */ +/* This uses an asymptotically poor algorithm, which should typically */ +/* perform acceptably. We compare the first few characters directly, */ +/* and call CORD_ncmp whenever there is a partial match. */ +/* This has the advantage that we allocate very little, or not at all. */ +/* It's very fast if there are few close misses. */ +size_t CORD_str(CORD x, size_t start, CORD s) +{ + CORD_pos xpos; + size_t xlen = CORD_len(x); + size_t slen; + register size_t start_len; + const char * s_start; + unsigned long s_buf = 0; /* The first few characters of s */ + unsigned long x_buf = 0; /* Start of candidate substring. */ + /* Initialized only to make compilers */ + /* happy. */ + unsigned long mask = 0; + register size_t i; + register size_t match_pos; + + if (s == CORD_EMPTY) return(start); + if (CORD_IS_STRING(s)) { + s_start = s; + slen = strlen(s); + } else { + s_start = CORD_to_char_star(CORD_substr(s, 0, sizeof(unsigned long))); + slen = CORD_len(s); + } + if (xlen < start || xlen - start < slen) return(CORD_NOT_FOUND); + start_len = slen; + if (start_len > sizeof(unsigned long)) start_len = sizeof(unsigned long); + CORD_set_pos(xpos, x, start); + for (i = 0; i < start_len; i++) { + mask <<= 8; + mask |= 0xff; + s_buf <<= 8; + s_buf |= s_start[i]; + x_buf <<= 8; + x_buf |= CORD_pos_fetch(xpos); + CORD_next(xpos); + } + for (match_pos = start; ; match_pos++) { + if ((x_buf & mask) == s_buf) { + if (slen == start_len || + CORD_ncmp(x, match_pos + start_len, + s, start_len, slen - start_len) == 0) { + return(match_pos); + } + } + if ( match_pos == xlen - slen ) { + return(CORD_NOT_FOUND); + } + x_buf <<= 8; + x_buf |= CORD_pos_fetch(xpos); + CORD_next(xpos); + } +} + +void CORD_ec_flush_buf(CORD_ec x) +{ + register size_t len = x[0].ec_bufptr - x[0].ec_buf; + char * s; + + if (len == 0) return; + s = GC_MALLOC_ATOMIC(len+1); + memcpy(s, x[0].ec_buf, len); + s[len] = '\0'; + x[0].ec_cord = CORD_cat_char_star(x[0].ec_cord, s, len); + x[0].ec_bufptr = x[0].ec_buf; +} + +void CORD_ec_append_cord(CORD_ec x, CORD s) +{ + CORD_ec_flush_buf(x); + x[0].ec_cord = CORD_cat(x[0].ec_cord, s); +} + +/*ARGSUSED*/ +char CORD_nul_func(size_t i, void * client_data) +{ + return((char)(unsigned long)client_data); +} + + +CORD CORD_chars(char c, size_t i) +{ + return(CORD_from_fn(CORD_nul_func, (void *)(unsigned long)c, i)); +} + +CORD CORD_from_file_eager(FILE * f) +{ + register int c; + CORD_ec ecord; + + CORD_ec_init(ecord); + for(;;) { + c = getc(f); + if (c == 0) { + /* Append the right number of NULs */ + /* Note that any string of NULs is rpresented in 4 words, */ + /* independent of its length. */ + register size_t count = 1; + + CORD_ec_flush_buf(ecord); + while ((c = getc(f)) == 0) count++; + ecord[0].ec_cord = CORD_cat(ecord[0].ec_cord, CORD_nul(count)); + } + if (c == EOF) break; + CORD_ec_append(ecord, c); + } + (void) fclose(f); + return(CORD_balance(CORD_ec_to_cord(ecord))); +} + +/* The state maintained for a lazily read file consists primarily */ +/* of a large direct-mapped cache of previously read values. */ +/* We could rely more on stdio buffering. That would have 2 */ +/* disadvantages: */ +/* 1) Empirically, not all fseek implementations preserve the */ +/* buffer whenever they could. */ +/* 2) It would fail if 2 different sections of a long cord */ +/* were being read alternately. */ +/* We do use the stdio buffer for read ahead. */ +/* To guarantee thread safety in the presence of atomic pointer */ +/* writes, cache lines are always replaced, and never modified in */ +/* place. */ + +# define LOG_CACHE_SZ 14 +# define CACHE_SZ (1 << LOG_CACHE_SZ) +# define LOG_LINE_SZ 9 +# define LINE_SZ (1 << LOG_LINE_SZ) + +typedef struct { + size_t tag; + char data[LINE_SZ]; + /* data[i%LINE_SZ] = ith char in file if tag = i/LINE_SZ */ +} cache_line; + +typedef struct { + FILE * lf_file; + size_t lf_current; /* Current file pointer value */ + cache_line * volatile lf_cache[CACHE_SZ/LINE_SZ]; +} lf_state; + +# define MOD_CACHE_SZ(n) ((n) & (CACHE_SZ - 1)) +# define DIV_CACHE_SZ(n) ((n) >> LOG_CACHE_SZ) +# define MOD_LINE_SZ(n) ((n) & (LINE_SZ - 1)) +# define DIV_LINE_SZ(n) ((n) >> LOG_LINE_SZ) +# define LINE_START(n) ((n) & ~(LINE_SZ - 1)) + +typedef struct { + lf_state * state; + size_t file_pos; /* Position of needed character. */ + cache_line * new_cache; +} refill_data; + +/* Executed with allocation lock. */ +static char refill_cache(client_data) +refill_data * client_data; +{ + register lf_state * state = client_data -> state; + register size_t file_pos = client_data -> file_pos; + FILE *f = state -> lf_file; + size_t line_start = LINE_START(file_pos); + size_t line_no = DIV_LINE_SZ(MOD_CACHE_SZ(file_pos)); + cache_line * new_cache = client_data -> new_cache; + + if (line_start != state -> lf_current + && fseek(f, line_start, SEEK_SET) != 0) { + ABORT("fseek failed"); + } + if (fread(new_cache -> data, sizeof(char), LINE_SZ, f) + <= file_pos - line_start) { + ABORT("fread failed"); + } + new_cache -> tag = DIV_LINE_SZ(file_pos); + /* Store barrier goes here. */ + ATOMIC_WRITE(state -> lf_cache[line_no], new_cache); + state -> lf_current = line_start + LINE_SZ; + return(new_cache->data[MOD_LINE_SZ(file_pos)]); +} + +char CORD_lf_func(size_t i, void * client_data) +{ + register lf_state * state = (lf_state *)client_data; + register cache_line * volatile * cl_addr = + &(state -> lf_cache[DIV_LINE_SZ(MOD_CACHE_SZ(i))]); + register cache_line * cl = (cache_line *)ATOMIC_READ(cl_addr); + + if (cl == 0 || cl -> tag != DIV_LINE_SZ(i)) { + /* Cache miss */ + refill_data rd; + + rd.state = state; + rd.file_pos = i; + rd.new_cache = GC_NEW_ATOMIC(cache_line); + if (rd.new_cache == 0) OUT_OF_MEMORY; + return((char)(GC_word) + GC_call_with_alloc_lock((GC_fn_type) refill_cache, &rd)); + } + return(cl -> data[MOD_LINE_SZ(i)]); +} + +/*ARGSUSED*/ +void CORD_lf_close_proc(void * obj, void * client_data) +{ + if (fclose(((lf_state *)obj) -> lf_file) != 0) { + ABORT("CORD_lf_close_proc: fclose failed"); + } +} + +CORD CORD_from_file_lazy_inner(FILE * f, size_t len) +{ + register lf_state * state = GC_NEW(lf_state); + register int i; + + if (state == 0) OUT_OF_MEMORY; + if (len != 0) { + /* Dummy read to force buffer allocation. */ + /* This greatly increases the probability */ + /* of avoiding deadlock if buffer allocation */ + /* is redirected to GC_malloc and the */ + /* world is multithreaded. */ + char buf[1]; + + (void) fread(buf, 1, 1, f); + rewind(f); + } + state -> lf_file = f; + for (i = 0; i < CACHE_SZ/LINE_SZ; i++) { + state -> lf_cache[i] = 0; + } + state -> lf_current = 0; + GC_REGISTER_FINALIZER(state, CORD_lf_close_proc, 0, 0, 0); + return(CORD_from_fn(CORD_lf_func, state, len)); +} + +CORD CORD_from_file_lazy(FILE * f) +{ + register long len; + + if (fseek(f, 0l, SEEK_END) != 0) { + ABORT("Bad fd argument - fseek failed"); + } + if ((len = ftell(f)) < 0) { + ABORT("Bad fd argument - ftell failed"); + } + rewind(f); + return(CORD_from_file_lazy_inner(f, (size_t)len)); +} + +# define LAZY_THRESHOLD (128*1024 + 1) + +CORD CORD_from_file(FILE * f) +{ + register long len; + + if (fseek(f, 0l, SEEK_END) != 0) { + ABORT("Bad fd argument - fseek failed"); + } + if ((len = ftell(f)) < 0) { + ABORT("Bad fd argument - ftell failed"); + } + rewind(f); + if (len < LAZY_THRESHOLD) { + return(CORD_from_file_eager(f)); + } else { + return(CORD_from_file_lazy_inner(f, (size_t)len)); + } +} |