ref: ba67a51cd3c7c56be7c809dbc6289cb41d67f619
parent: c1652ac96482c9a03970a0a59ccbcb04bc9596ea
author: rodri <rgl@antares-labs.eu>
date: Mon Mar 17 22:02:44 EDT 2025
improve the text parser
--- a/stl.c
+++ b/stl.c
@@ -5,7 +5,21 @@
#define min(a,b) ((a)<(b)?(a):(b))
+enum {+ TFACET, TNORMAL,
+ TOUTER, TLOOP,
+ TVERTEX,
+ TENDLOOP,
+ TENDFACET,
+ TENDSOLID,
+ TNUM,
+ TNL,
+};
+
typedef struct Line Line;
+typedef struct Token Token;
+typedef struct Tokenizer Tokenizer;
+
struct Line
{char *file;
@@ -12,6 +26,24 @@
ulong line;
};
+struct Token
+{+ int t;
+ char *s;
+ double v;
+};
+
+struct Tokenizer
+{+ Biobuf *in;
+ Token tok;
+ Line *ctx;
+ char *line;
+ char *f[10];
+ int nf;
+ int cur;
+};
+
static void
error(Line *l, char *fmt, ...)
{@@ -126,32 +158,100 @@
}
static char *
-getline(Line *l, Biobuf *b)
+getline(Biobuf *b)
{char *line;
- line = Brdstr(b, '\n', 1);
- if(line == nil){- werrstr("could not read a line");+ if((line = Brdstr(b, '\n', 1)) == nil)
return nil;
- }
- l->line++;
return line;
}
+static int
+idtoken(char *tok)
+{+ static char *tokens[] = {+ [TFACET] "facet",
+ [TNORMAL] "normal",
+ [TOUTER] "outer",
+ [TLOOP] "loop",
+ [TVERTEX] "vertex",
+ [TENDLOOP] "endloop",
+ [TENDFACET] "endfacet",
+ [TENDSOLID] "endsolid",
+ };
+ int i;
+
+ for(i = 0; i < nelem(tokens); i++)
+ if(strcmp(tok, tokens[i]) == 0)
+ return i;
+ return -1;
+}
+
+#define isnum(c) ((c)>='0'&&(c)<='9')
+#define couldbenum(c) ((c)=='+'||c=='-'||isnum(c))
+
+static int
+lex(Tokenizer *t)
+{+ char *ep;
+ int new;
+
+ new = t->line == nil;
+
+ if(t->cur < t->nf){+ t->tok.s = t->f[t->cur++];
+ if(couldbenum(t->tok.s[0])){+ t->tok.t = TNUM;
+ t->tok.v = strtod(t->tok.s, &ep);
+ if(*ep != 0){+ werrstr("misleading number-like '%s'", t->tok.s);+ return -1;
+ }
+ }else{+ t->tok.t = idtoken(t->tok.s);
+ if(t->tok.t < 0){+ werrstr("unknown token '%s'", t->tok.s);+ return -1;
+ }
+ }
+ }else{+ free(t->line);
+ if(!new){+ t->line = nil;
+ t->tok.t = TNL;
+ return TNL;
+ }
+ if((t->line = getline(t->in)) == nil){+ werrstr("could not read a line");+ return -1;
+ }
+ t->ctx->line++;
+ t->nf = tokenize(t->line, t->f, nelem(t->f));
+ t->cur = 0;
+ t->tok.t = lex(t);
+ }
+ return t->tok.t;
+}
+
static Stl *
parsetxt(Biobuf *bin)
{Line ctx;
+ Tokenizer tok;
Stltri *tri;
Stl *stl;
- char *line, *f[5];
- int nf, i;
+ char *line;
+ int i, j;
memset(&ctx, 0, sizeof(Line));
+ memset(&tok, 0, sizeof(Tokenizer));
+ tok.in = bin;
+ tok.ctx = &ctx;
+ ctx.line = 1;
/* header */
- if((line = getline(&ctx, bin)) == nil){+ if((line = getline(bin)) == nil){error(&ctx, "getline: %r");
return nil;
}
@@ -166,120 +266,82 @@
free(line);
for(;;){+ tri = nil;
+
/* facet normal i j k */
- if((line = getline(&ctx, bin)) == nil){-badline0:
- error(&ctx, "getline: %r");
+ if(lex(&tok) != TFACET || lex(&tok) != TNORMAL){+faceerr:
+ error(&ctx, "expected 'facet normal i j k'");
goto error;
}
- nf = tokenize(line, f, nelem(f));
-repeat:
- if(nf != 5){-notenough0:
- error(&ctx, "not enough fields %d", nf);
-cleanup0:
- free(line);
+ tri = mallocz(sizeof(Stltri), 1);
+ if(tri == nil){+ werrstr("mallocz: %r");goto error;
}
- if(strcmp(f[0], "facet") == 0 && strcmp(f[1], "normal") == 0){- tri = mallocz(sizeof(Stltri), 1);
- if(tri == nil){- werrstr("mallocz1: %r");- goto cleanup0;
+ for(i = 0; i < 3; i++){+ if(lex(&tok) != TNUM){+ error(&ctx, "expected number got '%s'", tok.tok.s);
+ goto error;
}
- tri->n[0] = strtod(f[2], nil);
- tri->n[1] = strtod(f[3], nil);
- tri->n[2] = strtod(f[4], nil);
- }else{- error(&ctx, "expected \"facet normal n₀ n₁ n₂\"");
- goto cleanup0;
+ tri->n[i] = tok.tok.v;
}
- free(line);
+ if(lex(&tok) != TNL)
+ goto faceerr;
/* outer loop */
- if((line = getline(&ctx, bin)) == nil){-badline1:
- free(tri);
- goto badline0;
+ if(lex(&tok) != TOUTER || lex(&tok) != TLOOP || lex(&tok) != TNL){+ error(&ctx, "expected 'outer loop'");
+ goto error;
}
- nf = tokenize(line, f, nelem(f));
- if(nf != 2){-notenough1:
- free(tri);
- goto notenough0;
- }
- if(strcmp(f[0], "outer") != 0 && strcmp(f[1], "loop") != 0){- error(&ctx, "expected \"outer loop\"");
-cleanup1:
- free(tri);
- goto cleanup0;
- }
- free(line);
/* [3]vertex x y z */
for(i = 0; i < 3; i++){- if((line = getline(&ctx, bin)) == nil)
- goto badline1;
- nf = tokenize(line, f, nelem(f));
- if(nf != 4)
- goto notenough1;
- if(strcmp(f[0], "vertex") == 0){- tri->v[i][0] = strtod(f[1], nil);
- tri->v[i][1] = strtod(f[2], nil);
- tri->v[i][2] = strtod(f[3], nil);
- }else{- error(&ctx, "expected \"vertex x y z\"");
- goto cleanup1;
+ if(lex(&tok) != TVERTEX){+verterr:
+ error(&ctx, "expected 'vertex x y z'");
+ goto error;
}
- free(line);
+ for(j = 0; j < 3; j++){+ if(lex(&tok) != TNUM){+ error(&ctx, "expected number got '%s'", tok.tok.s);
+ goto error;
+ }
+ tri->v[i][j] = tok.tok.v;
+ }
+ if(lex(&tok) != TNL)
+ goto verterr;
}
/* endloop */
- if((line = getline(&ctx, bin)) == nil)
- goto badline1;
- nf = tokenize(line, f, nelem(f));
- if(nf != 1)
- goto notenough1;
- if(strcmp(f[0], "endloop") != 0){- error(&ctx, "expected \"endloop\"");
- goto cleanup1;
+ if(lex(&tok) != TENDLOOP || lex(&tok) != TNL){+ error(&ctx, "expected 'endloop'");
+ goto error;
}
- free(line);
/* endfacet */
- if((line = getline(&ctx, bin)) == nil)
- goto badline1;
- nf = tokenize(line, f, nelem(f));
- if(nf != 1)
- goto notenough1;
- if(strcmp(f[0], "endfacet") == 0){- stl->tris = realloc(stl->tris, (stl->ntris+1)*sizeof(*stl->tris));
- if(stl->tris == nil){- error(&ctx, "realloc1: %r");
- goto cleanup1;
- }
- stl->tris[stl->ntris++] = tri;
- }else{- error(&ctx, "expected \"endfacet\"");
- goto cleanup1;
+ if(lex(&tok) != TENDFACET || lex(&tok) != TNL){+ error(&ctx, "expected 'endfacet'");
+ goto error;
}
- free(line);
+ stl->tris = realloc(stl->tris, (stl->ntris+1)*sizeof(*stl->tris));
+ if(stl->tris == nil){+ error(&ctx, "realloc1: %r");
+ goto error;
+ }
+ stl->tris[stl->ntris++] = tri;
/* endsolid? */
- if((line = getline(&ctx, bin)) == nil)
- goto badline0;
- nf = tokenize(line, f, nelem(f));
- if(nf < 2)
- goto notenough0;
- if(nf == 2 && strcmp(f[0], "endsolid") == 0){- free(line);
- break;
- }else
- goto repeat;
+ if(lex(&tok) != TENDSOLID){+ tok.cur--; /* unget */
+ continue;
+ }
+ break;
}
return stl;
error:
+ free(tri);
freestl(stl);
return nil;
}