Compiler: Use in-memory buffers for reading files, and handle newlines better.

Imported from https://github.com/alliedmodders/sourcemod/pull/63.

compiler/libpc300/libpawnc.c

@@ -23,6 +23,7 @@
 
 #include <assert.h>
 #include <stdio.h>
+#include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include "sc.h"
@@ -119,6 +120,14 @@ static char *prefix[3]={ "error", "fatal error", "warning" };
   return 0;
 }
 
+typedef struct src_file_s {
+  FILE *fp;         // Set if writing.
+  char *buffer;     // IO buffer.
+  char *pos;        // IO position.
+  char *end;        // End of buffer.
+  size_t maxlength; // Maximum length of the writable buffer.
+} src_file_t;
+
 /* pc_opensrc()
  * Opens a source file (or include file) for reading. The "file" does not have
  * to be a physical file, one might compile from memory.
@@ -133,7 +142,45 @@ static char *prefix[3]={ "error", "fatal error", "warning" };
  */
 void *pc_opensrc(char *filename)
 {
-  return fopen(filename,"rt");
+  FILE *fp = NULL;
+  long length;
+  src_file_t *src = NULL;
+
+#if defined LINUX || defined __FreeBSD__ || defined __OpenBSD__ || defined DARWIN
+  struct stat fileInfo;
+  if (stat(filename, &fileInfo) != 0) {
+    return NULL;
+  }
+
+  if (S_ISDIR(fileInfo.st_mode)) {
+    return NULL;
+  }
+#endif
+
+  if ((fp = fopen(filename, "rb")) == NULL)
+    return NULL;
+  if (fseek(fp, 0, SEEK_END) == -1)
+    goto err;
+  if ((length = ftell(fp)) == -1)
+    goto err;
+  if (fseek(fp, 0, SEEK_SET) == -1)
+    goto err;
+
+  if ((src = (src_file_t *)calloc(1, sizeof(src_file_t))) == NULL)
+    goto err;
+  if ((src->buffer = (char *)calloc(length, sizeof(char))) == NULL)
+    goto err;
+  if (fread(src->buffer, length, 1, fp) != 1)
+    goto err;
+
+  src->pos = src->buffer;
+  src->end = src->buffer + length;
+  return src;
+
+err:
+  pc_closesrc(src);
+  fclose(fp);
+  return NULL;
 }
 
 /* pc_createsrc()
@@ -150,7 +197,23 @@ void *pc_opensrc(char *filename)
  */
 void *pc_createsrc(char *filename)
 {
-  return fopen(filename,"wt");
+  src_file_t *src = (src_file_t *)calloc(1, sizeof(src_file_t));
+  if (!src)
+    return NULL;
+  if ((src->fp = fopen(filename, "wt")) == NULL) {
+    pc_closesrc(src);
+    return NULL;
+  }
+
+  src->maxlength = 1024;
+  if ((src->buffer = (char *)calloc(1, src->maxlength)) == NULL) {
+    pc_closesrc(src);
+    return NULL;
+  }
+
+  src->pos = src->buffer;
+  src->end = src->buffer;
+  return src;
 }
 
 /* pc_closesrc()
@@ -159,8 +222,15 @@ void *pc_createsrc(char *filename)
  */
 void pc_closesrc(void *handle)
 {
-  assert(handle!=NULL);
+  src_file_t *src = (src_file_t *)handle;
-  fclose((FILE*)handle);
+  if (!src)
+    return;
+  if (src->fp) {
+    fwrite(src->buffer, src->pos - src->buffer, 1, src->fp);
+    fclose(src->fp);
+  }
+  free(src->buffer);
+  free(src);
 }
 
 /* pc_resetsrc()
@@ -169,8 +239,12 @@ void pc_closesrc(void *handle)
  */
 void pc_resetsrc(void *handle,void *position)
 {
-  assert(handle!=NULL);
+  src_file_t *src = (src_file_t *)handle;
-  fsetpos((FILE*)handle,(fpos_t *)position);
+  ptrdiff_t pos = (ptrdiff_t)position;
+
+  assert(!src->fp);
+  assert(pos >= 0 && src->buffer + pos <= src->end);
+  src->pos = src->buffer + pos;
 }
 
 /* pc_readsrc()
@@ -179,7 +253,35 @@ void pc_resetsrc(void *handle,void *position)
  */
 char *pc_readsrc(void *handle,unsigned char *target,int maxchars)
 {
-  return fgets((char*)target,maxchars,(FILE*)handle);
+  src_file_t *src = (src_file_t *)handle;
+  char *outptr = (char *)target;
+  char *outend = outptr + maxchars;
+
+  assert(!src->fp);
+
+  if (src->pos == src->end)
+    return NULL;
+
+  while (outptr < outend && src->pos < src->end) {
+    char c = *src->pos++;
+    *outptr++ = c;
+
+    if (c == '\n')
+      break;
+    if (c == '\r') {
+      // Handle CRLF.
+      if (src->pos < src->end && *src->pos == '\n') {
+        src->pos++;
+        if (outptr < outend)
+          *outptr++ = '\n';
+      }
+      break;
+    }
+  }
+
+  // Caller passes in a buffer of size >= maxchars+1.
+  *outptr = '\0';
+  return (char *)target;
 }
 
 /* pc_writesrc()
@@ -188,20 +290,51 @@ char *pc_readsrc(void *handle,unsigned char *target,int maxchars)
  */
 int pc_writesrc(void *handle,unsigned char *source)
 {
-  return fputs((char*)source,(FILE*)handle) >= 0;
+  char *str = (char *)source;
+  size_t len = strlen(str);
+  src_file_t *src = (src_file_t *)handle;
+
+  assert(src->fp && src->maxlength);
+
+  if (src->pos + len > src->end) {
+    char *newbuf;
+    size_t newmax = src->maxlength;
+    size_t newlen = (src->pos - src->buffer) + len;
+    while (newmax < newlen) {
+      // Grow by 1.5X
+      newmax += newmax + newmax / 2;
+      if (newmax < src->maxlength)
+        abort();
+    }
+
+    newbuf = (char *)realloc(src->buffer, newmax);
+    if (!newbuf)
+      abort();
+    src->pos = newbuf + (src->pos - src->buffer);
+    src->end = newbuf + newmax;
+    src->buffer = newbuf;
+    src->maxlength = newmax;
+  }
+
+  strcpy(src->pos, str);
+  src->pos += len;
+  return 0;
 }
 
 void *pc_getpossrc(void *handle)
 {
-  static fpos_t lastpos;  /* may need to have a LIFO stack of such positions */
+  src_file_t *src = (src_file_t *)handle;
 
-  fgetpos((FILE*)handle,&lastpos);
+  assert(!src->fp);
-  return &lastpos;
+  return (void *)(ptrdiff_t)(src->pos - src->buffer);
 }
 
 int pc_eofsrc(void *handle)
 {
-  return feof((FILE*)handle);
+  src_file_t *src = (src_file_t *)handle;
+
+  assert(!src->fp);
+  return src->pos == src->end;
 }
 
 /* should return a pointer, which is used as a "magic cookie" to all I/O

compiler/libpc300/sc1.c

@@ -508,7 +508,7 @@ int pc_compile(int argc, char *argv[])
   if (get_sourcefile(1)!=NULL) {
     /* there are at least two or more source files */
     char *tname,*sname;
-    FILE *ftmp,*fsrc;
+    void *ftmp,*fsrc;
     int fidx;
     #if defined __WIN32__ || defined _WIN32
       tname=_tempnam(NULL,"pawn");
@@ -524,10 +524,10 @@ int pc_compile(int argc, char *argv[])
       close(mkstemp(buffer));
       tname=buffer;
     #endif
-    ftmp=(FILE*)pc_createsrc(tname);
+    ftmp=(void*)pc_createsrc(tname);
     for (fidx=0; (sname=get_sourcefile(fidx))!=NULL; fidx++) {
       unsigned char tstring[128];
-      fsrc=(FILE*)pc_opensrc(sname);
+      fsrc=(void*)pc_opensrc(sname);
       if (fsrc==NULL)
         error(100,sname);
       pc_writesrc(ftmp,(unsigned char*)"#file ");
@@ -545,7 +545,7 @@ int pc_compile(int argc, char *argv[])
   } else {
     strcpy(inpfname,get_sourcefile(0));
   } /* if */
-  inpf_org=(FILE*)pc_opensrc(inpfname);
+  inpf_org=(void*)pc_opensrc(inpfname);
   if (inpf_org==NULL)
     error(100,inpfname);
   freading=TRUE;

compiler/libpc300/sc2.c

@@ -120,18 +120,18 @@ SC_FUNC void clearstk(void)
 SC_FUNC int plungequalifiedfile(char *name)
 {
 static char *extensions[] = { ".inc", ".p", ".pawn" };
-  FILE *fp;
+  void *fp;
   char *ext;
   int ext_idx;
 
   ext_idx=0;
   do {
-    fp=(FILE*)pc_opensrc(name);
+    fp=(void*)pc_opensrc(name);
     ext=strchr(name,'\0');      /* save position */
     if (fp==NULL) {
       /* try to append an extension */
       strcpy(ext,extensions[ext_idx]);
-      fp=(FILE*)pc_opensrc(name);
+      fp=(void*)pc_opensrc(name);
       if (fp==NULL)
         *ext='\0';              /* on failure, restore filename */
     } /* if */