读取Shape file文件（底层开发）

#include <stdio.h> #include <stdlib.h> #include "ShapeDesc.h" //输入文件 char* GetFileNameByInput(char buffer[]) { printf("Please input a shape file's name with directory\n"); while (gets(buffer)==NULL) { printf("Sorry, you input nothing,Please try again\n"); } return buffer; } //转换字节顺序 int Big2LittleEndian(int num) { int reverse; char bit0, bit1, bit2, bit3; bit0 = (num & 0x000000ff); bit1 = (num & 0x0000ff00) >> 8; bit2 = (num & 0x00ff0000) >> 16; bit3 = (num & 0xff000000) >> 24; reverse = (bit0 << 24) | (bit1 << 16) | (bit2 << 8) | (bit3); return reverse; } int main(int argc, char* argv[]) { char* sFileName; FILE *fp; char sBuffer[256]; if (argc < 2) { sFileName = GetFileNameByInput(sBuffer); } else sFileName = argv[1]; if((fp=fopen(sFileName,"rb"))==NULL) { perror("Can't open file, please check errors\n"); return 0; } unsigned int FileCode; unsigned int FileLength; int ShapeType; int temp; enum SHAPETYPE enumShpType; //读文件头 fread(&FileCode,sizeof(unsigned int),1,fp); int nCode = Big2LittleEndian(FileCode); if(9994 != nCode) { perror("This file is illegal shape file\n"); fclose(fp); return 0; } fread(&temp,sizeof(int),5,fp);//跳过5个integer fread(&FileLength,sizeof(unsigned int),1,fp); unsigned int nFLen = (unsigned int)Big2LittleEndian(FileLength); printf("This file has %u bytes",nFLen); fread(&temp,sizeof(int),1,fp);//跳过1个integer fread(&ShapeType,sizeof(int),1,fp); switch(ShapeType) { case 0 : enumShpType = NullShape; break; case 1 : enumShpType = Point; break; case 3 : enumShpType = Polyline; break; case 5 : enumShpType = Polygon; break; default:break; } printf("This Shape File's Type is %d\n",ShapeType); fseek(fp,100,SEEK_SET);//跳到文件头结束处 //读记录 RECORDHEADER rh; int i; while(!feof(fp)) { fread(&rh,sizeof(RECORDHEADER),1,fp);//记录头 printf("record number:%d, record length:%d\n",Big2LittleEndian(rh.RecordNumber) ,Big2LittleEndian(rh.RecordLength) ); if(enumShpType==Point) { POINT pt; fread(&temp,sizeof(int),1,fp); fread(&pt,sizeof(POINT),1,fp); printf("x:%f y:%f\n",pt.x ,pt.y ); } else if(enumShpType==Polyline) { POLYLINE pl; fread(&temp,sizeof(int),1,fp); fread(&pl.Box ,sizeof(double),4,fp); fread(&pl.NumParts ,sizeof(int),1,fp); fread(&pl.NumPoints ,sizeof(int),1,fp); pl.Parts =(int*) malloc(sizeof(int)*pl.NumParts ); pl.Points =(POINT*)malloc(sizeof(POINT)*pl.NumPoints ); fread(pl.Parts,sizeof(int),pl.NumParts ,fp); for(i=0;i<pl.NumParts ;i++) printf("the index of %dth part is %d\n",i,*(pl.Parts + i)); fread(pl.Points ,sizeof(POINT),pl.NumPoints ,fp); for(i=0;i<pl.NumPoints ;i++) printf("%dth point at x:%f y:%f\n",i,(pl.Points+i)->x ,(pl.Points+i)->y ); free(pl.Parts ); free(pl.Points ); } else if(enumShpType==Polygon) { POLYGON pg; fread(&pg.Box ,sizeof(double),4,fp); fread(&pg.NumParts ,sizeof(int),1,fp); fread(&pg.NumPoints ,sizeof(int),1,fp); pg.Parts =(int*) malloc(sizeof(int)*pg.NumParts ); pg.Points =(POINT*)malloc(sizeof(POINT)*pg.NumPoints ); fread(pg.Parts,sizeof(int),pg.NumParts ,fp); for(i=0;i<pg.NumParts ;i++) printf("the index of %dth part is %d\n",i,*(pg.Parts + i)); fread(pg.Points ,sizeof(POINT),pg.NumPoints ,fp); for(i=0;i<pg.NumPoints ;i++) printf("%dth point at x:%f y:%f\n",i,(pg.Points+i)->x ,(pg.Points+i)->y ); free(pg.Parts ); free(pg.Points ); } } fclose(fp); return 1; }