create a new fskip_ahead() to unify all the forward seeking that is done

diff --git a/src/flac/encode.c b/src/flac/encode.c
index 52fc9e2..4a34e3a 100644 (file)
--- a/src/flac/encode.c
+++ b/src/flac/encode.c
@@ -155,6 +155,7 @@ static FLAC__bool read_little_endian_uint32(FILE *f, FLAC__uint32 *val, FLAC__bo
 static FLAC__bool read_big_endian_uint16(FILE *f, FLAC__uint16 *val, FLAC__bool eof_ok, const char *fn);
 static FLAC__bool read_big_endian_uint32(FILE *f, FLAC__uint32 *val, FLAC__bool eof_ok, const char *fn);
 static FLAC__bool read_sane_extended(FILE *f, FLAC__uint32 *val, FLAC__bool eof_ok, const char *fn);
+static FLAC__bool fskip_ahead(FILE *f, FLAC__uint64 offset);
 
 /*
  * public routines
@@ -264,14 +265,9 @@ flac__encode_aif(FILE *infile, long infilesize, const char *infilename, const ch
                        sample_rate= xx;
 
                        /* skip any extra data in the COMM chunk */
-                       FLAC__ASSERT(skip<=LONG_MAX);
-                       while(skip>0U && fseek(infile, skip, SEEK_CUR)<0) {
-                               unsigned int need= min(skip, sizeof ucbuffer_);
-                               if(fread(ucbuffer_, 1U, need, infile)<need) {
-                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping extra COMM data\n", encoder_session.inbasefilename);
-                                       return EncoderSession_finish_error(&encoder_session);
-                               }
-                               skip-= need;
+                       if(!fskip_ahead(infile, skip)) {
+                               flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping extra COMM data\n", encoder_session.inbasefilename);
+                               return EncoderSession_finish_error(&encoder_session);
                        }
 
                        /*
@@ -318,7 +314,9 @@ flac__encode_aif(FILE *infile, long infilesize, const char *infilename, const ch
                        }
                        block_size= xx;
 
-                       if(fseek(infile, offset, SEEK_CUR)) {
+                       /* skip any SSND offset bytes */
+                       FLAC__ASSERT(offset<=LONG_MAX);
+                       if(!fskip_ahead(infile, offset)) {
                                flac__utils_printf(stderr, 1, "%s: ERROR: skipping offset in SSND chunk\n", encoder_session.inbasefilename);
                                return EncoderSession_finish_error(&encoder_session);
                        }
@@ -341,25 +339,9 @@ flac__encode_aif(FILE *infile, long infilesize, const char *infilename, const ch
                        FLAC__ASSERT(!options.common.sector_align || encoder_session.until == 0);
 
                        if(encoder_session.skip>0U) {
-                               FLAC__uint64 remaining= encoder_session.skip*bytes_per_frame;
-
-                               /* do 1<<30 bytes at a time, since 1<<30 is a nice round number, and */
-                               /* is guaranteed to be less than LONG_MAX */
-                               while(remaining>0U)
-                               {
-                                       unsigned long skip= (unsigned long)(remaining % (1U<<30));
-
-                                       FLAC__ASSERT(skip<=LONG_MAX);
-                                       while(skip>0 && fseek(infile, skip, SEEK_CUR)<0) {
-                                               unsigned int need= min(skip, sizeof ucbuffer_);
-                                               if(fread(ucbuffer_, 1U, need, infile)<need) {
-                                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
-                                                       return EncoderSession_finish_error(&encoder_session);
-                                               }
-                                               skip-= need;
-                                       }
-
-                                       remaining-= skip;
+                               if(!fskip_ahead(infile, encoder_session.skip*bytes_per_frame)) {
+                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
 
@@ -439,27 +421,10 @@ flac__encode_aif(FILE *infile, long infilesize, const char *infilename, const ch
                        }
 
                        if(trim>0) {
-                               FLAC__uint64 remaining= (unsigned int)trim*bytes_per_frame;
-
                                FLAC__ASSERT(!options.common.sector_align);
-
-                               /* do 1<<30 bytes at a time, since 1<<30 is a nice round number, and */
-                               /* is guaranteed to be less than LONG_MAX */
-                               while(remaining>0U)
-                               {
-                                       unsigned long skip= (unsigned long)(remaining % (1U<<30));
-
-                                       FLAC__ASSERT(skip<=LONG_MAX);
-                                       while(skip>0 && fseek(infile, skip, SEEK_CUR)<0) {
-                                               unsigned int need= min(skip, sizeof ucbuffer_);
-                                               if(fread(ucbuffer_, 1U, need, infile)<need) {
-                                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
-                                                       return EncoderSession_finish_error(&encoder_session);
-                                               }
-                                               skip-= need;
-                                       }
-
-                                       remaining-= skip;
+                               if(!fskip_ahead(infile, trim*bytes_per_frame)) {
+                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
 
@@ -530,13 +495,9 @@ flac__encode_aif(FILE *infile, long infilesize, const char *infilename, const ch
                                unsigned long skip= xx+(xx & 1U);
 
                                FLAC__ASSERT(skip<=LONG_MAX);
-                               while(skip>0U && fseek(infile, skip, SEEK_CUR)<0) {
-                                       unsigned int need= min(skip, sizeof ucbuffer_);
-                                       if(fread(ucbuffer_, 1U, need, infile)<need) {
-                                               fprintf(stderr, "%s: ERROR during read while skipping unknown chunk\n", encoder_session.inbasefilename);
-                                               return EncoderSession_finish_error(&encoder_session);
-                                       }
-                                       skip-= need;
+                               if(!fskip_ahead(infile, skip)) {
+                                       fprintf(stderr, "%s: ERROR during read while skipping unknown chunk\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
                }
@@ -711,17 +672,9 @@ int flac__encode_wav(FILE *infile, long infilesize, const char *infilename, cons
                        FLAC__ASSERT(!options.common.sector_align || encoder_session.until == 0);
 
                        if(encoder_session.skip > 0) {
-                               if(fseek(infile, bytes_per_wide_sample * (unsigned)encoder_session.skip, SEEK_CUR) < 0) {
-                                       /* can't seek input, read ahead manually... */
-                                       unsigned left, need;
-                                       for(left = (unsigned)encoder_session.skip; left > 0; ) { /*@@@ WATCHOUT: 4GB limit */
-                                               need = min(left, CHUNK_OF_SAMPLES);
-                                               if(fread(ucbuffer_, bytes_per_wide_sample, need, infile) < need) {
-                                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
-                                                       return EncoderSession_finish_error(&encoder_session);
-                                               }
-                                               left -= need;
-                                       }
+                               if(!fskip_ahead(infile, encoder_session.skip * bytes_per_wide_sample)) {
+                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
 
@@ -805,17 +758,10 @@ int flac__encode_wav(FILE *infile, long infilesize, const char *infilename, cons
                        }
 
                        if(trim > 0) {
-                               if(fseek(infile, bytes_per_wide_sample * (unsigned)trim, SEEK_CUR) < 0) {
-                                       /* can't seek input, read ahead manually... */
-                                       unsigned left, need;
-                                       for(left = (unsigned)trim; left > 0; ) { /*@@@ WATCHOUT: 4GB limit */
-                                               need = min(left, CHUNK_OF_SAMPLES);
-                                               if(fread(ucbuffer_, bytes_per_wide_sample, need, infile) < need) {
-                                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
-                                                       return EncoderSession_finish_error(&encoder_session);
-                                               }
-                                               left -= need;
-                                       }
+                               FLAC__ASSERT(!options.common.sector_align);
+                               if(!fskip_ahead(infile, trim * bytes_per_wide_sample)) {
+                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
 
@@ -896,18 +842,9 @@ int flac__encode_wav(FILE *infile, long infilesize, const char *infilename, cons
                                unsigned long skip = xx+(xx & 1U);
 
                                FLAC__ASSERT(skip<=LONG_MAX);
-                               if(fseek(infile, skip, SEEK_CUR) < 0) {
-                                       /* can't seek input, read ahead manually... */
-                                       unsigned left, need;
-                                       const unsigned chunk = sizeof(ucbuffer_);
-                                       for(left = skip; left > 0; ) {
-                                               need = min(left, chunk);
-                                               if(fread(ucbuffer_, 1, need, infile) < need) {
-                                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping unsupported sub-chunk\n", encoder_session.inbasefilename);
-                                                       return EncoderSession_finish_error(&encoder_session);
-                                               }
-                                               left -= need;
-                                       }
+                               if(!fskip_ahead(infile, skip)) {
+                                       flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping unsupported sub-chunk\n", encoder_session.inbasefilename);
+                                       return EncoderSession_finish_error(&encoder_session);
                                }
                        }
                }
@@ -999,18 +936,9 @@ int flac__encode_raw(FILE *infile, long infilesize, const char *infilename, cons
                if(skip_bytes > lookahead_length) {
                        skip_bytes -= lookahead_length;
                        lookahead_length = 0;
-                       if(fseek(infile, (long)skip_bytes, SEEK_CUR) < 0) {
-                               /* can't seek input, read ahead manually... */
-                               unsigned left, need;
-                               const unsigned chunk = sizeof(ucbuffer_);
-                               for(left = skip_bytes; left > 0; ) {
-                                       need = min(left, chunk);
-                                       if(fread(ucbuffer_, 1, need, infile) < need) {
-                                               flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
-                                               return EncoderSession_finish_error(&encoder_session);
-                                       }
-                                       left -= need;
-                               }
+                       if(!fskip_ahead(infile, skip_bytes)) {
+                               flac__utils_printf(stderr, 1, "%s: ERROR during read while skipping samples\n", encoder_session.inbasefilename);
+                               return EncoderSession_finish_error(&encoder_session);
                        }
                }
                else {
@@ -2183,3 +2111,19 @@ FLAC__bool read_sane_extended(FILE *f, FLAC__uint32 *val, FLAC__bool eof_ok, con
 
        return true;
 }
+
+FLAC__bool fskip_ahead(FILE *f, FLAC__uint64 offset)
+{
+       static unsigned char dump[8192];
+
+       while(offset > 0) {
+               long need = (long)min(offset, LONG_MAX);
+               if(fseek(f, need, SEEK_CUR) < 0) {
+                       need = min(offset, sizeof(dump));
+                       if(fread(dump, need, 1, f) < 1)
+                               return false;
+               }
+               offset -= need;
+       }
+       return true;
+}