Create Subversion repository

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 180 insertions, 0 deletions

diff --git a/lib/libpbm2.c b/lib/libpbm2.c
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+/* libpbm2.c - pbm utility library part 2
+**
+** Copyright (C) 1988 by Jef Poskanzer.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation.  This software is provided "as is" without express or
+** implied warranty.
+*/
+
+#include "pbm.h"
+#include "libpbm.h"
+#include "fileio.h"
+
+static bit 
+getbit (FILE * const file) {
+    char ch;
+
+    do {
+        ch = pm_getc( file );
+    } while ( ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r' );
+
+    if ( ch != '0' && ch != '1' )
+        pm_error( "junk in file where bits should be" );
+    
+    return ( ch == '1' ) ? 1 : 0;
+}
+
+
+
+void
+pbm_readpbminitrest( file, colsP, rowsP )
+    FILE* file;
+    int* colsP;
+    int* rowsP;
+    {
+    /* Read size. */
+    *colsP = (int)pm_getuint( file );
+    *rowsP = (int)pm_getuint( file );
+
+    /* *colsP and *rowsP really should be unsigned int, but they come
+       from the time before unsigned ints (or at least from a person
+       trained in that tradition), so they are int.  We could simply
+       consider negative numbers to mean values > INT_MAX/2 and much
+       code would just automatically work.  But some code would fail
+       miserably.  So we consider values that won't fit in an int to
+       be unprocessable.
+    */
+    if (*colsP < 0)
+        pm_error("Number of columns in header is too large.");
+    if (*rowsP < 0)
+        pm_error("Number of columns in header is too large.");
+    }
+
+void
+pbm_readpbminit( file, colsP, rowsP, formatP )
+    FILE* file;
+    int* colsP;
+    int* rowsP;
+    int* formatP;
+    {
+    /* Check magic number. */
+    *formatP = pm_readmagicnumber( file );
+    switch ( PBM_FORMAT_TYPE(*formatP) )
+    {
+        case PBM_TYPE:
+    pbm_readpbminitrest( file, colsP, rowsP );
+    break;
+
+    default:
+    pm_error( "bad magic number - not a pbm file" );
+    }
+    }
+
+void
+pbm_readpbmrow( file, bitrow, cols, format )
+    FILE* file;
+    bit* bitrow;
+    int cols, format;
+    {
+    register int col, bitshift;
+    register bit* bP;
+
+    switch ( format )
+    {
+    case PBM_FORMAT:
+    for ( col = 0, bP = bitrow; col < cols; ++col, ++bP )
+        *bP = getbit( file );
+    break;
+
+    case RPBM_FORMAT: {
+        register unsigned char item;
+        bitshift = -1;  item = 0;  /* item's value is meaningless here */
+        for ( col = 0, bP = bitrow; col < cols; ++col, ++bP )
+          {
+              if ( bitshift == -1 )
+                {
+                    item = pm_getrawbyte( file );
+                    bitshift = 7;
+                }
+              *bP = ( item >> bitshift ) & 1;
+              --bitshift;
+          }
+    }
+    break;
+
+    default:
+    pm_error( "can't happen" );
+    }
+    }
+
+
+
+void
+pbm_readpbmrow_packed(FILE *          const file, 
+                      unsigned char * const packed_bits,
+                      int             const cols, 
+                      int             const format) {
+
+    switch(format) {
+    case PBM_FORMAT: {
+        unsigned int col;
+        unsigned int byteIndex;
+
+        /* We first clear the return buffer, then set ones where needed */
+        for (byteIndex = 0; byteIndex < pbm_packed_bytes(cols); ++byteIndex)
+            packed_bits[byteIndex] = 0x00;
+
+        for (col = 0; col < cols; ++col) {
+            unsigned char mask;
+            mask = getbit(file) << (7 - col % 8);
+            packed_bits[col / 8] |= mask;
+        }
+    }
+    break;
+
+    case RPBM_FORMAT: {
+        int bytes_read;
+        bytes_read = fread(packed_bits, 1, pbm_packed_bytes(cols), file);
+             
+        if (bytes_read < pbm_packed_bytes(cols)) {
+            if (feof(file)) 
+                if (bytes_read == 0) 
+                    pm_error("Attempt to read a raw PBM image row, but "
+                             "no more rows left in file.");
+                else
+                    pm_error("EOF in the middle of a raw PBM row.");
+            else 
+                pm_error("I/O error reading raw PBM row");
+        }
+    }
+    break;
+    
+    default:
+        pm_error( "Internal error in pbm_readpbmrow_packed." );
+    }
+}
+
+
+
+bit**
+pbm_readpbm( file, colsP, rowsP )
+    FILE* file;
+    int* colsP;
+    int* rowsP;
+    {
+    register bit** bits;
+    int format, row;
+
+    pbm_readpbminit( file, colsP, rowsP, &format );
+
+    bits = pbm_allocarray( *colsP, *rowsP );
+
+    for ( row = 0; row < *rowsP; ++row )
+        pbm_readpbmrow( file, bits[row], *colsP, format );
+
+    return bits;
+    }